tag:blogger.com,1999:blog-66249954270456993792024-03-05T14:57:33.164-08:00Ultraviolet Supernovauvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.comBlogger30125tag:blogger.com,1999:blog-6624995427045699379.post-85313198810095255942019-08-26T13:05:00.000-07:002019-08-26T13:05:56.686-07:00Exciting Discovery or Data Problem?<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEju5kdBm-pKICJdVGWkn5ivXWt9h_kL_g69VkAtARPRs80LyhFPOFe9HnvMSeajj31k7Mezz_qzIcCVM9UklzYLNZUdpk4r4_mjxA8JojiEqGQMNpH94THVwKVQMJoS3DhHwn3ItWp9iTU5/s1600/SN2012G_lightcurve.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="612" data-original-width="792" height="247" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEju5kdBm-pKICJdVGWkn5ivXWt9h_kL_g69VkAtARPRs80LyhFPOFe9HnvMSeajj31k7Mezz_qzIcCVM9UklzYLNZUdpk4r4_mjxA8JojiEqGQMNpH94THVwKVQMJoS3DhHwn3ItWp9iTU5/s320/SN2012G_lightcurve.jpg" width="320" /></a></div>
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So my preliminary photometry of SN2012G had a first data point which was intriguingly high. One (or maybe two) high point in each filter for iPTF14atg was claimed to be the long-sought signature of a type Ia supernova impacting its companion in a paper published in Nature (Cao et al. 2015). So an early high point in SN2012G could be another example. Or it could be a problem with the data.<br />
<br />
We recently (and finally!) obtained the host galaxy template for SN2012G in an effort to do the final photometry for SOUSA to complete our Ia sample. So I redid the analysis and looked more closely at the images. Indeed the first image has a readout streak from a bright star which goes right through the supernova location. So no Nature paper for SN2012G. But the corrected photometry will be posted soon to SOUSA.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhslmmnb75d5L-XpQ0xqUvz8NgEDGG_Etl4Nm_3mvWJhGLkpnr0aS2uBIsLFkYkfFPY2PbhHN1G8cfGQecpSYD76aosJxzDX9fw94l_2hwdjgp5QoSBQ0Vr4rzK12wKZs12XX-GQeVx5rim/s1600/SN2012G_firstw1frame.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="646" data-original-width="680" height="304" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhslmmnb75d5L-XpQ0xqUvz8NgEDGG_Etl4Nm_3mvWJhGLkpnr0aS2uBIsLFkYkfFPY2PbhHN1G8cfGQecpSYD76aosJxzDX9fw94l_2hwdjgp5QoSBQ0Vr4rzK12wKZs12XX-GQeVx5rim/s320/SN2012G_firstw1frame.jpg" width="320" /></a></div>
<br />uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com1tag:blogger.com,1999:blog-6624995427045699379.post-42578742959349049792018-09-21T13:07:00.000-07:002018-09-21T13:17:06.701-07:00Swift UVOT Grism Tools<br />
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While I have focused mainly on Swift UVOT photometry, UVOT also has a UV and an optical grism with which to obtain spectroscopy.<br />
<br />
For supernovae, the spectra extraction is more complicated than long slit spectrum extraction because the dispersed spectra often go across the host galaxy and their can be other sources or spectra which overlap.<br />
For most of the mission, the UVOT grisms were only calibrated for a certain part of the detector, so we usually did what was called a "slew in place". This involves targeting the object and then immediately retargeting the object with the grism so that the target was in the right place. This can only be done in the planned timeline so there was usually a couple of days delay to schedule it. Paul Kuin's new grism calibration is valid over a larger area, so grism observations no longer require a slew-in-place in a planned schedule. So they can be done as a rapid ToO upload. Since we did the slew-in-place procedure for so many years (and still do it for grism observations put into the plan) you should probably make it clear when you submit the ToO request that you want the grism observations as soon as possible and don't need a slew-in-place. But for observations scheduled into the plan, a slew in place is probably best.<br />
<br />
Here is some of the grism documentation:<br />
There is an IDL program called simgrism by Wayne Landsman which allows you to see how a given roll angle will affect the location of the spectrum and how it might overlap. It shows you what a particular roll angle will look like as far as contamination goes, but you have to know which roll angles are observable anyway. There is a range of about 20 degrees available on any given date.<br />
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<br />
As far as contamination goes, my grad student Mike Smitka has developed a method to do something similar to galaxy subtraction with the grism images. It isn't a direct subtraction, but uses the template image for the background so it can estimate the non-linear corrections. He describes the method in this paper:<br />
<a href="http://adsabs.harvard.edu/abs/2016PASP..128c4501S">http://adsabs.harvard.edu/abs/2016PASP..128c4501S</a><br />
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Paul Kuin implemented it into the grism reduction software as reading the background from the template image rather than an actual subtraction. But it requires template images taken an integer number of years after the original observation (so that the roll angle is available again). Mike obtained template images for a sample of Ia grism spectra.<br />
Yen-Chen Pan and Ryan Foley have also modified the background subtraction to do better than the default extraction. <a href="http://adsabs.harvard.edu/abs/2018MNRAS.479..517P">http://adsabs.harvard.edu/abs/2018MNRAS.479..517P</a><br />
<br />
<br />
<a href="http://adsabs.harvard.edu/abs/2015MNRAS.449.2514K">http://adsabs.harvard.edu/abs/2015MNRAS.449.2514K</a><br />
<a href="http://adsabs.harvard.edu/abs/2014ascl.soft10004K">http://adsabs.harvard.edu/abs/2014ascl.soft10004K</a><br />
<a href="http://www.mssl.ucl.ac.uk/~npmk/Grism/uvotpy_doc/index.html">http://www.mssl.ucl.ac.uk/~npmk/Grism/uvotpy_doc/index.html</a><br />
<br />
<a href="http://idlastro.gsfc.nasa.gov/ftp/landsman/simgrism/">http://idlastro.gsfc.nasa.gov/ftp/landsman/simgrism/</a><br />
<br />
There is now an online tool for finding out what roll angles are available for a given ra, dec, and observation date. You can use this with the idl program simgrism.pro to pick roll angles which avoid bright stars in the dispersed spectrum.<br />
<a href="https://www.swift.psu.edu/roll.php">https://www.swift.psu.edu/roll.php</a><br />
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Other documentation:<br />
<a href="https://swift.gsfc.nasa.gov/analysis/uvot_ugrism.html">https://swift.gsfc.nasa.gov/analysis/uvot_ugrism.html</a><br />
<a href="https://swift.gsfc.nasa.gov/analysis/uvot_vgrism.html">https://swift.gsfc.nasa.gov/analysis/uvot_vgrism.html</a>uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-28813312293699474562018-06-14T09:57:00.004-07:002018-06-14T09:57:59.840-07:00Hundreds of Swift Supernovae<div class="separator" style="clear: both; text-align: center;">
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For a conference in Stockholm I made this excessive plot to show off the amount of Swift data we have. The legend gives a complete (I think) list of the over 600 supernovae we've observed with Swift. Plotted are the uvm2 absolute magnitudes and uvm2-v colors of all the supernova data I had on my laptop, accounting for about half of all the supernovae. That means there is still some more data reduction to be done, but also a huge sample of supernova data to be doing science with.<br />
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<br />uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-7105976808683298522016-08-08T13:01:00.000-07:002016-12-08T06:03:51.871-08:00Interpreting Flux from Broadband PhotometryMany of the techniques used on optical data to convert broadband photometry to flux, including creating spectral energy distributions and integrating the pseudobolometric flux, don't work very well in the ultraviolet. After struggling with these issues for years, I wrote the following paper to demonstrate the difficulties and quantify the effects. It is now on <a href="http://arxiv.org/abs/1608.02599">astro-ph</a> and published in the <a href="http://adsabs.harvard.edu/abs/2016AJ....152..102B">Astronomical Journal</a>.<br />
<br />
The figures in the paper were designed to compare effects with a consistent wavelength range within the confines of a two column article. So many of the figures are tall and hard to read if you are reading or projecting the paper onto a typical wide screen (like for many astro-ph/astrocoffee style discussions). I have created a pdf with most of the figures reproduced as single panels. <a href="https://drive.google.com/open?id=0B96KvPmYalj6UVpDX0dnQlFpelE">That version is here. </a><br />
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Comments are welcome.uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com13tag:blogger.com,1999:blog-6624995427045699379.post-22783010626586426132016-05-25T06:13:00.000-07:002016-05-25T07:09:04.072-07:00Swift Target of Opportunity Priorities (urgency)The stated meanings of the Swift Target of Opportunity (ToO) priorities are listed below. For new supernovae I recommend a "High Urgency" ToO. During the day it will sometimes be executed within a few hours as an uploaded target directly to the spacecraft. At the latest it will be discussed the next morning--if you submit it after hours it is visible to the Swift team but does not actively page them until the next morning. If the SN is older, a medium or low urgency request would be more appropriate. This includes requests for continued campaigns on Swift SNe which can be planned and rerequested several days before the already requested exposures are completed so that the campaign goes on continuously but without requiring immediate action by the Swift team or bumping out previously planned targets. The normal planning schedule is also copied from the Swift ToO page below.<br />
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<br />
A "Highest Urgency" ToO might be appropriate for a very nearby, very young supernova. SN2011fe, with a very recent upper limit, would certainly qualify. If a SN is discovered one night and confirmed the next night, it is probably is fine to do it as a high urgency.<br />
<br />
<br />
<br />
From the Swift Target of Opportunity request page:<br />
<br />
<br />
#################### (previous version used yellow highlighting which was awful to read)<br />
<br />
<br />
<br />
Response Priorities:<br />
<br />
A "Highest Urgency" ToO will immediately page the Swift PI and Science Operations team, even in the middle of the night.<br />
"High Urgency" ToO requests will page the PI and Science Operations team immediately during working hours.<br />
"Medium Urgency" requests will be handled during daylight hours.<br />
"Low Urgency" requests will be handled at the daily planning meeting which is 9-10am Eastern Time (USA) M-F.<br />
<br />
Please avoid using the Highest Urgency unless absolutely essential, for example<br />
<br />
Galactic or local-group supernova<br />
High-probability gravitational wave event<br />
High-probability neutrino event<br />
Highly exceptional GRB or SGR<br />
<br />
Normal Planning Timeline: Below is the typical schedule for producing and submitting the observing schedules. Please give a few extra days for submitting ToOs around the holidays.<br />
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<table cellpadding="0" cellspacing="0" style="border-collapse: collapse; margin-left: auto; margin-right: auto; padding: 0;"><tbody>
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<td style="border: solid 1px #ccc; padding: 5px;">Day of the Week</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Submit the Schedule for*</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Create the Schedule for</td><td><br /></td></tr>
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<td style="border: solid 1px #ccc; padding: 5px;">Monday</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Tuesday</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Wednesday</td><td><br /></td></tr>
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<td style="border: solid 1px #ccc; padding: 5px;">Tuesday</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Wednesday</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Thursday</td><td><br /></td></tr>
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<td style="border: solid 1px #ccc; padding: 5px;">Wednesday</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Thursday</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Friday & Saturday</td><td><br /></td></tr>
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<td style="border: solid 1px #ccc; padding: 5px;">Thursday</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Friday & Saturday</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Sunday & Monday</td><td><br /></td></tr>
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<td style="border: solid 1px #ccc; padding: 5px;">Friday</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Sunday & Monday</td><td><br /></td><td style="border: solid 1px #ccc; padding: 5px;">Tuesday</td><td><br /></td></tr>
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<td colspan="3" style="padding: 5px;"><div>
All times are in Eastern Time (USA).<br />
*Schedules are submitted in the mornings.
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</span>uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com1tag:blogger.com,1999:blog-6624995427045699379.post-10615736535725321772016-02-22T10:52:00.000-08:002017-12-21T13:31:15.667-08:00uvot analysis error messagesThis is just a listing I'm starting of error messages I see while doing UVOT analysis of supernovae , what the real problem was, and how to fix it. Most (possibly all) are not issues with the software but problems with how one is trying to use the software.<br />
<br />
uvotmaghist getting hung up -- activity monitor listing uvotinteg as taking 99% of the CPU time but not getting anywhere. <br />
<br />
problem -- region files contained two lines, one with the correct source position and one with some other position not in the field of view<br />
<br />
fix -- fix the region files, rerun uvotmaghist<br />
<br />
<br />
uvotmaghist reporting divide by zero error --<br />
<br />
problem -- background region was not covered by the image (though it may have fallen within the zero count square made to encompass the full height and width of the image). Especially a problem when combining full field and smaller hardware/software windows.<br />
<br />
fix -- fix the region so it stays within the image for all the images being processed with uvotmaghist<br />
<br />
frankenstein images where parts of a summed image seem to be wrapped around rather than just mosaiced<br />
<br />
problem -- I think the problem was having multiple instances of uvotimsum running at the same time so the parameter file contained values from the other terminal<br />
<br />
fix -- do them one at a time rather than multi-tasking the same command in different windows<br />
<br />
<br />
if the galaxy count rates come out as negative, it could be that the supernova comes from a clean region and the background region happens to have a higher average count rate. But the source region file could be bogus -- two entries for example -- confusing the standard 5" aperture that is computed for coincidence loss.<br />
<br />
<br />
processing vv data for PSNJ09100885+5003396<br /># Beware of galaxy count rates > ~ 6 <br />vv count rate is 1.65534055233002<br />ftcalc(4838,0x7fff7375f000) malloc: *** error for object 0x7fca3af001d0: incorrect checksum for freed object - object was probably modified after being freed.<br />*** set a breakpoint in malloc_error_break to debug<br />^CAbort<br />Dumping CFITSIO error stack:<br />--------------------------------------------------<br />ffopen could not interpret primary array header of file: <br />PSNJ09100885+5003396_vv_phot.fits<br />--------------------------------------------------<br />CFITSIO error stack dump complete.<br />CFITSIO ERROR END_OF_FILE: tried to move past end of file<br />Task fthedit 2.00 terminating with status 107<br />fparkey4.3 : unable to open the FITS file PSNJ09100885+5003396_vv_phot.fits<br />fparkey4.3 : Error Status Returned : 107<br />fparkey4.3 : tried to move past end of file<br /><br />fparkey4.3 : ***** FITSIO Error Stack Dump *****<br />ffopen could not interpret primary array header of file:<br />PSNJ09100885+5003396_vv_phot.fits<br />Dumping CFITSIO error stack:<br />--------------------------------------------------<br />ffopen could not interpret primary array header of file: <br />PSNJ09100885+5003396_vv_phot.fits<br />--------------------------------------------------<br />CFITSIO error stack dump complete.<br />CFITSIO ERROR END_OF_FILE: tried to move past end of file<br />Task fthedit 2.00 terminating with status 107<br />Dumping CFITSIO error stack:<br />--------------------------------------------------<br />ffopen could not interpret primary array header of file: <br />PSNJ09100885+5003396_vv_phot.fits<br />--------------------------------------------------<br />CFITSIO error stack dump complete.<br />CFITSIO ERROR END_OF_FILE: tried to move past end of file<br />Task fthedit 2.00 terminating with status 107<br />Dumping CFITSIO error stack:<br />--------------------------------------------------<br />
<br />
fix -- this may have been caused by the '+' in the name. Changing the name to PSN it ran fine. uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com1tag:blogger.com,1999:blog-6624995427045699379.post-82228615252531690742016-01-28T08:32:00.000-08:002019-02-07T09:38:07.468-08:00Swift Supernova Analysis WorkflowI'm writing this mostly for some undergraduates who will help with some data reduction, but others might find the links and steps useful.<br />
<br />
Swift supernova spreadsheet<br />
<br />
<a href="https://docs.google.com/spreadsheets/d/1h1RB28-5BK1D-KmThlyTyvfvWO9oVJJ8-zfa22ZHXR4/">https://docs.google.com/spreadsheets/d/1h1RB28-5BK1D-KmThlyTyvfvWO9oVJJ8-zfa22ZHXR4/</a><br />
<br />
The first few columns of that spreadsheet are used to create the Swift supernova website with links added for images, data, and light curves which exist in the folder<br />
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<a href="http://people.physics.tamu.edu/pbrown/SwiftSN/swift_sn.html">http://people.physics.tamu.edu/pbrown/SwiftSN/swift_sn.html</a><br />
<br />
The official target of opportunity list is at:<br />
<a href="https://www.swift.psu.edu/secure/toop/summary.php">https://www.swift.psu.edu/secure/toop/summary.php</a><br />
<br />
Current supernova are listed at<br />
<a href="https://www.swift.psu.edu/secure/toop/supernovae.php">https://www.swift.psu.edu/secure/toop/supernovae.php</a><br />
<br />
Those pages can be used to find which supernovae have been proposed and which are still being observed. With a name or target id (the name of the supernova or host is preferred when searching as sometimes multiple target ids are used for the same target).<br />
<br />
######## Downloading data<br />
<br />
For recent (less than one week) data on current supernovae, you can download the data from the quicklook site. For these quick reductions I just download the *_sk.img images into a folder /currentSwiftSNe/SNname/<br />
<br />
>cd Desktop /SN/currentSwiftSNe/ <br />
<br />
<a href="http://swift.gsfc.nasa.gov/cgi-bin/sdc/ql?">http://swift.gsfc.nasa.gov/cgi-bin/sdc/ql?</a><br />
<br />
For archived data, I download all image files from the Swift Archive checking the Swift auxiliary data and Swift uvot data boxes. These I download into a /SwiftSNarchive/SNname/ folder<br />
<br />
>cd Desktop /SN/SwiftSNarchive/ <br />
<br />
<a href="http://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/swift.pl">http://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/swift.pl</a><br />
<br />
########## Processing data<br />
<br />
My scripts look for all the gzipped data (so you can exclude data by unzipping it) so first zip it. And at some point you might need to go into the tcsh shell<br />
<br />
>mkdir SNname<br />
> cd SNname<br />
<br />
>touch SNname_downloadcommands.txt &<br />
>edit SNname_downloadcommands.txt<br />
<br />
Paste the downloaded data from the archive into the text editor and then source it<br />
<br />
>source SNname_downloadcommands.txt<br />
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create a ds9 region file with a radius of 3 arcseconds centered on the supernova and called SNname_3.reg. Also make a background region file named SNname_bkg.reg which has a similar background and a SNname_bkgclear.reg region clear of background stars and galaxy flux.<br />
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> gzip -f */uvot/image/*sk.img<br />
> tcsh<br />
> source $SNSCRIPTS/makecommands14.1.txt <SNname> <optional template obs id><br />
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This generates commands to sum together the data by observation id and then append them together into one multi-extension fits file per filter plus the template images<br />
<br />
> source SNname_allcommands.txt<br />
> source $SNSCRIPTS/SNgalsub15.1.maghist.txt SNname<br />
<br />
and a bunch of figures might pop up and a SNname_uvotB15.1.dat file will be created (among others). Then I exit tcsh and make a plot with xmgrace.<br />
<br />
<br />
> exit<br />
> xmgrace &<br />
<br />
I save it as a pnm file and then convert it to jpg<br />
> convert SNname_lightcurve.pnm SNname_lightcurve.jpg<br />
<br />
I also make a three color image<br />
<br />
ds9 -scale log -rgb -red SNname_vv_sum.img.gz -green SNname_uu_sum.img.gz -blue SNname_m2_sum.img.gz<br />
<br />
adjust the colors contrast and brightness.<br />
Then save image > png > save as SNname_uvot.png<br />
<br />
<br />
<br />
<br />
<br />uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com1tag:blogger.com,1999:blog-6624995427045699379.post-69001489724890266652015-11-18T11:52:00.000-08:002015-11-18T11:52:04.835-08:00Making Swift out of Science (instead of just science from Swift)<span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317">A few
weeks ago for our Swift Satellite meeting I made some "value-added"
Swift models by printing or photoshopping science papers onto the pdf
model that was made by the education/public outreach group from Swift.<br class="yiv5797747891" clear="none" id="yiv5797747891yui_3_16_0_1_1445787670214_6322" /><a class="yiv5797747891" href="http://science.nasa.gov/media/medialibrary/2010/03/31/swmodguide5.pdf" id="yiv5797747891yui_3_16_0_1_1445787670214_6318" rel="nofollow" shape="rect" target="_blank">http://science.nasa.gov/media/medialibrary/2010/03/31/swmodguide5.pdf</a></span><br />
<br />
<span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317">These models were meant to represent the different science coming out of Swift. </span><br />
<span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317"><br /></span>
<span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317"><br /></span>
<span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317"><br /></span>
<span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317">Paper models aren't easy to take safely on an airplane, so I kept them flat and began assembling them at my sister-in-law's house Saturday night before driving up to the meeting Monday morning.</span><br />
<span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317"><br /></span>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhuGx4W1bB2CEh13PPUMSr9iJwdIh5BRH0bebzXHnNW9VFrXHF2M8i9ib8h-CKcxI_e1kNRWKrw3FPvcM9UudmBeexbuzMMnzxboBRQ0_rSvViRUM9pd6zvbGlG1a33oJ2tf1j5tV60JFy6/s1600/201510Oct27+168.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhuGx4W1bB2CEh13PPUMSr9iJwdIh5BRH0bebzXHnNW9VFrXHF2M8i9ib8h-CKcxI_e1kNRWKrw3FPvcM9UudmBeexbuzMMnzxboBRQ0_rSvViRUM9pd6zvbGlG1a33oJ2tf1j5tV60JFy6/s320/201510Oct27+168.JPG" width="320" /></a></div>
<span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317">Originally
I had planned on printing the models on top of the science paper. </span><span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317"><span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317">I used a recent paper from Peter Milne
showing some exciting results enabled by Swift -- the discovery of
multiple classes of type Ia supernova based on their ultraviolet colors
and the apparent change in the fractions of those classes with
redshift. </span>The
first one went into the printer upside down, so I used the original
model to tell me where to cut and fold, but only the science paper is
visible from the outside. The hotel next to mine had a really cool looking purple light shining on its wall so I went over there to take a few pictures.</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTZFmtudVk9I7KBz79bbPH03hxf2NorHY5-XqMe1zMHc5cdw9B2dJ90RywZ4HT6mVzj00ik0s9bRfWgqwtdlfBFbzQtHqcpvLyzF7TH1SLgQWJU3VYq5cTXjNpAPS95hbOYjLebDrw0IpZ/s1600/photo.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTZFmtudVk9I7KBz79bbPH03hxf2NorHY5-XqMe1zMHc5cdw9B2dJ90RywZ4HT6mVzj00ik0s9bRfWgqwtdlfBFbzQtHqcpvLyzF7TH1SLgQWJU3VYq5cTXjNpAPS95hbOYjLebDrw0IpZ/s320/photo.JPG" width="221" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkTAelKAv9osv0Qed1Ch-FacxW4r_GuXj7ISqTCU71wO8X0W1KfbC_V3hUfCYER54v7uLOWcFYnKArNEeQIzQwnGZrKeIyGNYj_AJuUID0Cyctjn7ARmyhB5h2AApmxYQ1sJe8IeNlf_kE/s1600/201510Oct27+202.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkTAelKAv9osv0Qed1Ch-FacxW4r_GuXj7ISqTCU71wO8X0W1KfbC_V3hUfCYER54v7uLOWcFYnKArNEeQIzQwnGZrKeIyGNYj_AJuUID0Cyctjn7ARmyhB5h2AApmxYQ1sJe8IeNlf_kE/s320/201510Oct27+202.JPG" width="320" /></a></div>
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The second one I wanted to look more like Swift, so I took the pdf model and photoshopped (gimp-ed?) titles, author lists, figures, and tables from several key Swift papers onto the parts of the model. When possible I tried to make it match -- there is a picture of someone assembling the BAT printed on the side of the BAT, the UVOT features pretty pictures, the XRT includes an image of the mirrors and an awesome X-ray echo from a bursting star. The solar panels feature the four main instrument papers, Gehrels et al. 2004, Roming et al. 2005, Burrows et al. 2005, and Barthelmy et al. 2005. I finished assembling this one during the conference dinner and gave it to the Swift Principle Investigator Neil Gehrels.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFw1Vb_rAS74Cv5sLKRZGpCaCOnkv-ZWXkelS1mTPp-EqUDC9eIW_4rekqfN-i4rDpaa6qsggSf-YSToTUWSLasPNZx4VPalHLS6jyxhSRIWP0RjI6Jv_KaLDngOLkHqyVVc4zbVRZhC67/s1600/201510Oct27+212.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFw1Vb_rAS74Cv5sLKRZGpCaCOnkv-ZWXkelS1mTPp-EqUDC9eIW_4rekqfN-i4rDpaa6qsggSf-YSToTUWSLasPNZx4VPalHLS6jyxhSRIWP0RjI6Jv_KaLDngOLkHqyVVc4zbVRZhC67/s320/201510Oct27+212.JPG" width="320" /></a></div>
I brought along the printouts for a third model but didn't know if I'd actually make it. This one featured a paper by the conference organizer's grad student printed on top of the model. Both were printed in black and white, which is why the picture below looks like it was taken in b&w. Dieter Hartmann expressed enough interest in the other models I made, that I figured I should make the model I had planned to give to him anyway (being a local he wouldn't have to worry about transporting it).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBI9og7aKAOY-zk3YSoNLBd1qId6YDjpKutYDO7111ir_CxivwrBaHbYQsA5pit7DezAusvBT6U-vQGN78pMRI306CtPAboY4RKzMuJMgiwfbOp6eBD_2x8fTLc5HtX83DHv2L8xfsn988/s1600/201510Oct27+217.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBI9og7aKAOY-zk3YSoNLBd1qId6YDjpKutYDO7111ir_CxivwrBaHbYQsA5pit7DezAusvBT6U-vQGN78pMRI306CtPAboY4RKzMuJMgiwfbOp6eBD_2x8fTLc5HtX83DHv2L8xfsn988/s320/201510Oct27+217.JPG" width="320" /></a></div>
<span class="yiv5797747891" id="yiv5797747891yui_3_16_0_1_1445787670214_6317"><br /></span>uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com1tag:blogger.com,1999:blog-6624995427045699379.post-3563969875651296972015-03-04T10:29:00.002-08:002015-03-04T10:52:17.065-08:00SOUSA data useSo the Swift data is all public. Different people request observations of different supernovae. Sometimes multiple people request data on the same supernova. Other people could have requested data on a particular supernova but it was already being observed. Some of us people spend a lot of time monitoring the observations and modifying the observing plans accordingly. Some of us were involved in getting template observations. Others might have just pulled the public data from the archive and published it. Sometimes there are multiple versions of the photometry independently done and published. With my SOUSA archive, the same data might be tabulated and used by different people. So proper credit is a tricky thing, so here are some of my thoughts.<br />
<br />
I recommend citing any papers which originally presented
Swift data on that object and where the data actually comes from (making
clear whether you are using their photometry or your own reduction for
example). For the data available on my website, you should cite the
Swift Optical/Ultraviolet Supernova Archive (SOUSA) paper as the source
< <a href="http://adsabs.harvard.edu/abs/2014Ap%26SS.354...89B" id="yiv1832500716yui_3_16_0_1_1423749822410_3081" rel="nofollow" shape="rect" target="_blank">http://adsabs.harvard.edu/abs/2014Ap%26SS.354...89B</a>
>, and the data files usually indicate if there was a previous
publication. If you make extensive use of the UVOT data and/or want advice on
the analysis, it might be appropriate to involve me and add me as a
coauthor. If you are using your own reduction of the data, make sure to indicate the calibration you used (which should be the updated version of Breeveld et al. 2011) and whether they are Vega or AB magnitudes.<br />
<br />
If using the SOUSA data, I suggest adding something like this to the observations section:<br />
<br />
This supernova was also observed in the UV with the Ultra-Violet/Optical Telescope (UVOT; \citealp{Roming_etal_2005} on the Swift spacecraft \citep{Gehrels_etal_2004}. The UV photometry was obtained from the Swift Optical/Ultraviolet Supernova Archive\footnote{<a class="url_link" href="http://swift.gsfc.nasa.gov/docs/swift/sne/swift_sn.html" target="_blank">http://swift.gsfc.nasa.gov/docs/swift/sne/swift\_sn.html</a>} (SOUSA; \citealp{Brown_etal_2014}). The reduction is based on that of \citet{Brown_etal_2009}, including subtraction of the host galaxy count rates and uses the
revised UV zeropoints and time-dependent sensitivity from \citet{Breeveld_etal_2011}. <br />
<br />
<br />
and in the acknowledgements:<br />
<br />
The work made use of Swift/UVOT data reduced by P. J. Brown and released in the Swift Optical/Ultraviolet Supernova Archive (SOUSA). SOUSA is supported by NASA's Astrophysics Data Analysis Program through grant NNX13AF35G.<br />
<br />uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-11347551278600811592014-11-20T15:25:00.000-08:002015-04-08T14:45:20.161-07:00Happy Birthday Swift !! Ten years ago the Swift satellite was launched into space. In honor of that anniversary I made this montage of one hundred of the supernovae Swift has observed. Here's to ten more years !!<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZWdqRPxO3ocIa2dORI7y1KlzKbzfYfIrJLO8YEesYlXmcIdMxojZkEd_WDiATt-IriqMwHBNfzL_IiS-tisb55oQGEJubEmfEuHNmKjUrVmBbBfn3En1i4muk03jeNX8Jl63ekQaksQCe/s1600/SN100_Swift.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZWdqRPxO3ocIa2dORI7y1KlzKbzfYfIrJLO8YEesYlXmcIdMxojZkEd_WDiATt-IriqMwHBNfzL_IiS-tisb55oQGEJubEmfEuHNmKjUrVmBbBfn3En1i4muk03jeNX8Jl63ekQaksQCe/s1600/SN100_Swift.png" height="358" width="640" /></a></div>
<br />
<br />
The picture is a mosaic of 100 supernovae and their galaxies observed by Swift. The rendering of Swift is by <span style="font-size: x-small;">NASA E/PO, Sonoma State University, <a href="mailto:aurore@universe.sonoma.edu">Aurore
Simonnet</a></span>uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-62483798141852350602014-10-07T12:23:00.002-07:002014-12-19T09:13:52.838-08:00SOUSA SCRIPTSWARNING: these instructions are a work in progress but posted here so I can get feedback from some people. If you try them, please let me know if they work for you, where you need more instruction, etc.<br />
<br />
As a part of the Swift Optical/Ultraviolet Supernova Archive (SOUSA) I am reducing and making public as many supernova light curves as I can. In order to be open about my reduction methods and enable others to reduce Swift data on their own, I am posting the scripts that I use to produce light curves of SNe. These scripts could be used to produce light curves of any other single object as well. If you use these scripts in a publication, please cite the SOUSA paper which describes the basic method and put something in the acknowledgements. I haven't extensively tested these scripts on other computers--I use a Macbook Pro 10.6.8 and a newer Macbook Pro. If you have problems or questions, e-mail me or post it in the comments below.<br />
<br />
<br />
<a name='more'></a><br />
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<br />
You will need the <a href="http://heasarc.gsfc.nasa.gov/lheasoft/">HEASOFT</a> package and the Swift <a href="http://heasarc.gsfc.nasa.gov/docs/heasarc/caldb/caldb_intro.html">CALDB</a> (calibration database).<br />
Here are my reduction scripts. The reside in a folder with the alias $SNSCRIPTS. The recipe using them is underneath, where I begin commenting out the comments to show which are the actual commands. You should probably first understand how uvotimsum is used to combine images and uvotsource is used to do the photometry on an image. These scripts use those and other commands to streamline the steps for doing the photometry on a whole bunch of images.<br />
<br />
<a href="https://drive.google.com/file/d/0B96KvPmYalj6ZXI2dl82UU1aZVk/edit?usp=sharing">makecommands14.1.txt</a><br />
<br />
<a href="https://drive.google.com/file/d/0B96KvPmYalj6QUR3NU1wcFpVZGc/edit?usp=sharing">SNgalsub14.1.maghist.txt</a><br />
<br />
# I have a SN data folder in which I have folders for each individual SN.<br />
<br />
mkdir SN2006gy<br />
cd SN2006gy<br />
<br />
#Recent data (less than a week old) can be downloaded from the Quicklook site.<br />
#If you can't find the target by name you can look up the Target ID on the Swift ToO page.<br />
#For my scripts you will need to gzip the files before running the scripts.<br />
<br />
#Older data can be downloaded from the Swift Archive.<br />
#Search using the SN name, host galaxy name, or the position<br />
#(with a search radius of 5 arcmin) to make sure you get all of the data<br />
#for that source position. Sometimes a SN is observed using multiple Target IDs<br />
#or there are pre-SN images useful as galaxy templates.<br />
#Clicking on the down arrow under "start time" will sort the observations.<br />
#If there is a pre-explosion or late time observations that can be used as a template,<br />
#write it down. You can click on the boxes to select all the Target IDs.<br />
#Scroll down to "Data Products" and choose to download the UVOT folder.<br />
#For SN2006gy there was one SN observation.<br />
#There are four later observations targeting the host galaxy of SN2008L. <br />
#Click on the "Create Download Script" button. You will get the following wget commands:<br />
<br />
<nobr><b>wget -q -nH --cut-dirs=5 -r -l0 -c -N -np -R 'index*'
-erobots=off --retr-symlinks
http://heasarc.gsfc.nasa.gov/FTP/swift/data/obs/2013_07//00049990002/uvot/</b></nobr><br />
<nobr><b>wget -q -nH --cut-dirs=5 -r -l0 -c -N -np -R 'index*'
-erobots=off --retr-symlinks
http://heasarc.gsfc.nasa.gov/FTP/swift/data/obs/2013_07//00049990001/uvot/</b></nobr><br />
<nobr><b>wget -q -nH --cut-dirs=5 -r -l0 -c -N -np -R 'index*'
-erobots=off --retr-symlinks
http://heasarc.gsfc.nasa.gov/FTP/swift/data/obs/2013_09//00049990004/uvot/</b></nobr><br />
<nobr><b>wget -q -nH --cut-dirs=5 -r -l0 -c -N -np -R 'index*'
-erobots=off --retr-symlinks
http://heasarc.gsfc.nasa.gov/FTP/swift/data/obs/2013_07//00049990003/uvot/</b></nobr><br />
<nobr><b>wget -q -nH --cut-dirs=5 -r -l0 -c -N -np -R 'index*'
-erobots=off --retr-symlinks
http://heasarc.gsfc.nasa.gov/FTP/swift/data/obs/2007_02//00030817002/uvot/</b></nobr><br />
<br />
# I would create a text file to keep these in for the possible redownload of the data<br />
<br />
touch SN2006gy_downloadcommands.txt<br />
edit SN2006gy_downloadcommands.txt<br />
<br />
#paste the files here, save and close.<br />
# if it has a pre-explosion galaxy image (name is a galaxy or something # and occurs before the SN year) or an observation a year or so <br />
# after the SN observations stopped<br />
# 000*45812*010 000*targetid*obsnumber<br />
# write down the target id or obsid, unique number 0004581201<br />
#<br />
source SN2006gy_downloadcommands.txt <br />
# <br />
# switch shells<br />
<br />
tcsh<br />
<br />
# this command creates a script of commands to run<br />
# you supply the SN name and the template target number<br />
# or some unique number that the templates have that the SN images don't<br />
# if there isn't such a number, for example, if the template images continued<br />
# with the same target id as the SN observations, then put the full observation id<br />
# of the first template observation and then you can manually<br />
# edit the *_appendcommands.txt or *_allcommands.txt files to change<br />
# where the later observations are being appended to.<br />
<br />
source $SNSCRIPTS/makecommands14.1.txt SN2006gy 49990<br />
<br />
#This creates a text file of commands which will sum up the individual epochs<br />
#and then append them all to a single file.<br />
#A separate file is made for each filter for the SN observations and the template.<br />
#You can then execute this file.<br />
#This file of commands is made instead of just executing the commands<br />
#so that you can edit it as needed.<br />
#For example, maybe certain exposure show star streaks from the spacecraft drifting.<br />
#Frames where the coordinate system is off can be fixed or excluded.<br />
#Those extensions can be excluded from the sums and then the<br />
# appendcommands.txt files reexecuted. That is why it is separate from the sumcommands.txt.<br />
#To run them all you can just do:<br />
<br />
source SN2006gy_allcommands.txt <br />
<br />
exit<br />
# you have to exit the tcsh shell to use ds9 and xmgrace on my machine<br />
<br />
ds9 SN2006gy_vv_sum.img &<br />
<br />
# you are now trying to identify the supernova<br />
# and create a region file with a 3 arcsecond radius circle at its position <br />
# click on analysis --> image server --> sao dss --> retrieve<br />
# <br />
# frame --> match --> frame --> wcs<br />
# frame --> blink<br />
# <br />
# if you see the SN click on it to make a circle<br />
# <br />
# if you don't see an obvious new source, get coordinates from<br />
# http://www.cbat.eps.harvard.edu/lists/Supernovae.html<br />
# <br />
# double click on circle<br />
# <br />
# degree --> arcsec<br />
# set to 3 --> apply<br />
# region --> save filename SN2006gy_3.reg<br />
# should be in ds9 format, fk5 coordinate system<br />
# make two new regions<br />
# <br />
# one should be a little bigger with similar galaxy light <br />
# save as SN2006gy_bkg.reg<br />
# <br />
# the other is in a blank sky near the galaxy, can be large<br />
# save as SN2006gy_bkgclear.reg<br />
#<br />
<br />
tcsh<br />
<br />
#Now to run the SN photometry you execute the following script<br />
#which is a wrapper for the uvotsource/uvotmaghist photometry codes.<br />
#The fits file of photometry outputs is manipulated to subtract the galaxy count rates.<br />
<br />
source $SNSCRIPTS/SNgalsub14.1.maghist.txt SN2006gy<br />
exit<br />
<br />
# This should give you a SNZZZZ_uvotB14.1.dat file which contains all the photometry. uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-56940709513040178982014-09-19T14:56:00.002-07:002014-12-08T14:10:41.335-08:00Predicting UV brightness<div class="separator" style="clear: both; text-align: left;">
Here are some plots that may help predict the ultraviolet brightness of a supernova. They are based on the sample and figures from the Swift Optical/Ultraviolet Supernova Archive (SOUSA) paper but focusing on the mid-ultraviolet uvm2 filter. The top plot shows the absolute magnitudes as a function of epoch for a prototype of most SN classes as observed with Swift/UVOT. The right axis shows the redshift limit corresponding to a magnitude of uvm2=20 (<a href="http://ultravioletsupernova.blogspot.com/2014/07/sousa-swift-optical-ultraviolet.html">a reasonable limit</a>). This could be useful for estimating the redshift range for particular supernova classes for Swift proposals or evaluating the observability of new supernovae now or at later epochs. The bottom plot shows the uvm2-v colors to allow one to estimate the uvm2 magnitude based on a current or predicted optical magnitude, the type and phase. If you use these plots, please cite the <a href="http://adsabs.harvard.edu/doi/10.1007/s10509-014-2059-8">SOUSA paper</a> they are based on.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiL25Aj8r9tMD8ohLe6ceEaLjnnuSw4LTx4jgr2ABeO7TB38xWNKxKYyag4X3cwezvVIkzISIUGcZHffSHjfcT_0WfNovKq4szlvzThlXCMSk4oTQkXxIGv7AD0ch21uxv5lv4SLC5cQJm9/s1600/m2plots.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiL25Aj8r9tMD8ohLe6ceEaLjnnuSw4LTx4jgr2ABeO7TB38xWNKxKYyag4X3cwezvVIkzISIUGcZHffSHjfcT_0WfNovKq4szlvzThlXCMSk4oTQkXxIGv7AD0ch21uxv5lv4SLC5cQJm9/s1600/m2plots.png" height="640" width="472" /></a></div>
<br />uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-81112788252420125242014-08-28T14:10:00.002-07:002014-09-19T14:42:53.449-07:00High quality images<div class="separator" style="clear: both; text-align: center;">
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Isn't that image beautiful? </div>
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When Swift was selected by <a href="http://www.popsci.com/military-aviation-space/article/2005-11/swift" target="_blank">Popular Science</a> </div>
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as one of the best new things in 2005, </div>
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my picture even made it into a national magazine.</div>
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<a href="http://swift.gsfc.nasa.gov/results/releases/images/SN2005cs/sn05cs-color_big.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://swift.gsfc.nasa.gov/results/releases/images/SN2005cs/sn05cs-color_big.jpg" height="320" width="259" /></a></div>
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<br />
<br />
<a name='more'></a>Yes, I cringe every time I see that image. You know what? That was the very first color image I made as a graduate student. We had just started observing SN2005cs in M51 with Swift and I was told (on short notice probably) that I needed to give a report at the daily science planning meeting. I had made a pretty decent image but had not had to share it yet, so I just made a quick screen shot on my computer, posted it to our online wiki where the others could see it, and didn't think much more of it. Apparently some time later they wanted a cool picture from Swift ( and gamma ray and x-ray telescopes don't make that pretty of images) so someone took this picutre and forwarded it on. Eventually it made it into a press release and Popular Science before I even knew about it.<br />
<br />
I like to think my images look better now. I actually make the images the same why I did that one -- loading them into the red,green,blue color channels of ds9. The difference is printing them as higher resolution postscript images after filling the screen to get the maximum number of pixels. Here is my latest version of M51. Bonus points to whoever discovers the anacronism.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQXPxxA2YW6bdvcZxxqI4DkEiPdi9AGE-AESZVdgAAWyoSB5seNBT9Umlz1WQvojsNIYlRGrBAUYH3oFGFNAu7R_bnHJn4dB6x4Ofiqu2ZCZhB8cpD9zfegPyg8uNYA8uJN5XcZVD__di5/s1600/M51_4x6name.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQXPxxA2YW6bdvcZxxqI4DkEiPdi9AGE-AESZVdgAAWyoSB5seNBT9Umlz1WQvojsNIYlRGrBAUYH3oFGFNAu7R_bnHJn4dB6x4Ofiqu2ZCZhB8cpD9zfegPyg8uNYA8uJN5XcZVD__di5/s1600/M51_4x6name.jpg" height="640" width="426" /></a></div>
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<br />uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com3tag:blogger.com,1999:blog-6624995427045699379.post-46482169895675271612014-07-16T10:00:00.000-07:002014-07-16T12:17:31.630-07:00SOUSA: the Swift Optical Ultraviolet Supernova Archive<h2>
</h2>
<h2>
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHnIZohnUhKRhp6TK8eCQ3q-QmTynsYDQma4nf0vl_QLFFkBX46YENQpS1xzgWRcDrnR2uS-kz5caI8OFtZAJIURNmEK8W9fBApYqX-JW_KR6F5h4rKOtSbYfrhY8AK2gdvS0LHZiTuXX6/s1600/sousa_galaxy.png" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHnIZohnUhKRhp6TK8eCQ3q-QmTynsYDQma4nf0vl_QLFFkBX46YENQpS1xzgWRcDrnR2uS-kz5caI8OFtZAJIURNmEK8W9fBApYqX-JW_KR6F5h4rKOtSbYfrhY8AK2gdvS0LHZiTuXX6/s1600/sousa_galaxy.png" height="320" width="185" /></a><span style="font-size: x-large;">Swift</span></h2>
<h2>
<span style="font-size: x-large;">
Optical</span></h2>
<h2>
<span style="font-size: x-large;">
Ultraviolet</span></h2>
<h2>
<span style="font-size: x-large;">
Supernova</span></h2>
<h2>
<span style="font-size: x-large;">
Archive</span></h2>
<br />
<br />
<br />
<br />
<br />
SOUSA is an archive-in-the-making of
all of the Swift supernova data. In its final form, it will contain the
images and intermediate photometry products as well as the final
photometry. To begin with, we are providing the revised photometry of
SNe we've already published onto the <a href="http://ultravioletsupernova.blogspot.com/2014/04/swiftuvot-calibration.html">updated photometric calibration</a>.
More SNe will be updated as we go. The paper describing the
photometric reduction will be published in Astrophysics and Space
Science and is available on <a href="http://arxiv.org/abs/1407.3808">astro-ph</a>.<br />
<br />
One
use of the data we already have is improving what we do with Swift/UVOT
during the rest of its lifetime. Some of the plots in the paper should
be useful for proposing new SNe for observation with Swift or preparing
Guest Investigator proposals. For example, the plot below gives a
rough idea of the brightness of SNe in the mid-ultraviolet. This allows
one to estimate the distance to which one could detect a SN down to a
given limiting magnitude. The right axis of the plot gives the distance
modulus for a limiting magnitude of uvm2=20.<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpiiFjeCg8qGwdNVPxcwpqQJTlBhw7qB1WATKTe4MpIrNZGTTqO9a90C3SGWU_wxcAkI-njWtLKYDd2DzOX8V_9OhI9ahiGdmMMLv0E7sTs0litEhB9102BCezNH0Wi12r2N48f-B5xQi9/s1600/plotallsne_m2abs.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpiiFjeCg8qGwdNVPxcwpqQJTlBhw7qB1WATKTe4MpIrNZGTTqO9a90C3SGWU_wxcAkI-njWtLKYDd2DzOX8V_9OhI9ahiGdmMMLv0E7sTs0litEhB9102BCezNH0Wi12r2N48f-B5xQi9/s1600/plotallsne_m2abs.png" height="290" width="640" /></a></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiT2Z-LiD8rB-hp4HJRjxJespITdS3wI01JHs2sPkO5U8BlVmSu5fw60wrxkKGTpY2maSU91DQa2zhRH5ELXMP_NvAfEm72j3G5R2ICJXJkYzR9vPIUIlFBIusHzi1Nph2sqdBoagtpJ0J1/s1600/m2upperlimits.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiT2Z-LiD8rB-hp4HJRjxJespITdS3wI01JHs2sPkO5U8BlVmSu5fw60wrxkKGTpY2maSU91DQa2zhRH5ELXMP_NvAfEm72j3G5R2ICJXJkYzR9vPIUIlFBIusHzi1Nph2sqdBoagtpJ0J1/s1600/m2upperlimits.png" height="281" width="400" /></a></div>
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<div class="separator" style="clear: both; text-align: center;">
</div>
<br />
The limiting magnitude UVOT reaches is a function of the
exposure time and the brightness of the underlying galaxy (due to our
conservative method of subtracting the galaxy flux and propagating its
uncertainty into the final photometry and limits). For low
contamination, 1000 seconds will reach a limiting magnitude of 20.
Based on the exposure time ratios for the preferred UVOT mode 0x223f,
3000 seconds of exposure are needed for the full 6 filters.<br />
<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibUGTv3O-4m4SV0dxjbrn4YW211ytY9uD0qnHW4dgoGA8GFTiDx8QxuHPzZ0kmT0zPAY6UbbwLQ2TBUxH7humW4MQDLpGI_Du7pdcfSSK2pfUiKSdkQYzrgv5YLOSBaH-7e9_ky-mvi9yI/s1600/fourplot.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibUGTv3O-4m4SV0dxjbrn4YW211ytY9uD0qnHW4dgoGA8GFTiDx8QxuHPzZ0kmT0zPAY6UbbwLQ2TBUxH7humW4MQDLpGI_Du7pdcfSSK2pfUiKSdkQYzrgv5YLOSBaH-7e9_ky-mvi9yI/s1600/fourplot.png" height="640" width="640" /> </a></div>
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
This
plot shows the color and absolute magnitude evolution for a well
observed supernova of most subclasses. This could be used to estimate
the class and/or epoch of a SN with UV/optical photometry. The plots
could also be helpful in planning what epochs could be reached to a
given limiting magnitude. </div>
uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com1tag:blogger.com,1999:blog-6624995427045699379.post-9694243614644202322014-04-15T10:51:00.000-07:002014-07-14T14:06:22.369-07:00Swift Supernova photometry version B14.1.dat formatI've made a new version of my UVOT supernova photometry code, I think fixing the upper limit issues with version <a href="http://ultravioletsupernova.blogspot.com/2013/10/swiftuvot-photometry-version-132.html">13.2</a> and fixing some overestimated errors when doing aperture corrections. Before going through all the supernovae (yet again!) I would like to finalize the final output format that will be used by others. Fits tables can be shared which provide all the nitty gritty details of source counts, coincidence loss correction factors, and such, but I would like these data text files to contain 90% of what anyone else would want. Below is a sample for SN2005cf. Suggests are welcome, especially if other columns would be useful outputs.<br />
<br />
################<br />
# SN2005cf magnitudes from Swift UVOT <br />
# generated Mon Mar 31 22:35:16 CDT 2014 using version 2014.1 <br />
# of Peter Brown's photometry pipeline <br />
# and version Swift_Rel4.2(Bld31)_25Nov2013 of HEASOFT <br />
# <br />
# Data comes from the Swift Data Center <br />
# A 5 arcsec aperture is used to measure the counts for the coincidence loss correction, <br />
# a 3 or 5 arcsec source aperture (based on the error) was used for the aperture photometry <br />
# subtracting off the galaxy count rate in a template image (if available), <br />
# and applying an aperture correction as appropriate (based on average psf in Swift CALDB)<br />
# and zeropoints from Breeveld et al. (2011) which update Poole et al. (2008) <br />
# including a time-dependent sensitivity loss <br />
# to put the magnitudes on the UVOT photometric system described in that paper. <br />
#<br />
# Brown, P. J., Holland, S. T., Immler, S., et al. 2009, ApJ, 137, 4517<br />
# Brown, P. J., et al. 2014, Ap\&SS<br />
# Breeveld, A. A., Landsman, W., Holland, S. T., et al. 2011, in AIP Conf. Proc. 1358, <br />
# Gamma-Ray Bursts 2010, ed. J. E. McEnergy, J. L. Racusin, & N. Gehrels <br />
# (Melville, NY: AIP), 373; arXiv:1102.4717 <br />
# Poole, T. S., Breeveld, A. A., Page, M. J., et al. 2008, MNRAS, 383, 627<br />
# <br />
# <br />
# Original reference for Swift observations: <br />
# Wang, X., et al. 2009, ApJ, 697, 380 <br />
# The data have been reanalyzed with the revised zeropoints <br />
# and sensitivity corrections of Breeveld et al. 2011. <br />
# Use of this final version should also reference Brown et al. 2014, Ap\%SS, submitted <br />
# <br />
# The underlying galaxy had the following count rates <br />
# in a 5 arcsec aperture at the source position <br />
# (missing filters list 0 but used a background region similar to the SN ): <br />
# Galaxy count rates in 5" aperture<br />
# V 0.202 0.127865<br />
# B 0.101 0.194355<br />
# U 0.205 0.0936644<br />
# UVW1 0.052 0.0255154<br />
# UVM2 0.029 0.00996702<br />
# UVW2 0.005 0.0109126<br />
# <br />
# There are no known issues with this photometry. <br />
# b and v data consistent with BV data from <br />
# Pastorello et al. 2007, MNRAS, 376, 1301 S corrected mags<br />
# S corrected mags from Wang et al. 2009, ApJ, 697, 380<br />
<br />
# MJD Mag MagErr 3SigMagLimit 0.98SatLimit Rate RateErr ApSize Exposure DateObs Tstart Tstop <br />
# <br />
# uvw2 <br />
53525.0428 17.794 0.114 20.315 11.085 0.683 0.072 3.000 283.226 2005-06-04T00:59:12 139539551.990120 139539839.754778<br />
<br />
# <br />
# uvm2 <br />
53525.0466 NULL NULL 19.679 10.555 0.044 0.021 3.000 212.361 2005-06-04T01:05:21 139539920.975120 139540136.738778<br />
<br />
<br />
################<br />
<br />
<br />
<br />
The final format is now:<br />
<br />
# Filter MJD[days] Mag MagErr 3SigMagLim 0.98SatLim[mag] Rate[c/s] RateErr[c/s] Ap[arcsec] Frametime[s] Exp[s] Telapse[s]<br /># <br />UVW2 53525.0428 17.794 0.114 20.315 11.085 0.683 0.1 3.000 0.0110322 283.23 287.76<br />uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com2tag:blogger.com,1999:blog-6624995427045699379.post-52280673810065922562014-04-15T08:37:00.001-07:002017-07-08T19:44:25.601-07:00Swift Supernova Presentation PlotsHere are a few general purpose plots highlighting Swift's SN
observations. Specific science results can be pulled from the papers,
but this is just to show a few of the global characteristics that are
science-y enough for the specific science in the currently published
suite of papers. Some plots like this might appear in my archive
paper(s) though.<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhdnQm-cCUHpUWpiD5kTs8M0wNQ_J7XGk_oVpsJzZ-n1kpR7GCoN6sTVdx3f5yXbvkjMcOQahz-vjYbAi_FIt4yWXogCepHPG1srpJp9F_Nkw3j1oYy7aI79nr8IiGHVwa9S9ju5hNrczMw/s1600/SN100_Swift.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="899" data-original-width="1600" height="358" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhdnQm-cCUHpUWpiD5kTs8M0wNQ_J7XGk_oVpsJzZ-n1kpR7GCoN6sTVdx3f5yXbvkjMcOQahz-vjYbAi_FIt4yWXogCepHPG1srpJp9F_Nkw3j1oYy7aI79nr8IiGHVwa9S9ju5hNrczMw/s640/SN100_Swift.png" width="640" /></a></div>
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<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglB2O4VYxNXINwAPjvQvcDV4xnx2Ue1E39wVBUE8SyKP6Bndq8qPcsPa0mU7RQ7X41NIyLBPktN6NutU-oNRVzMAsuVungZKfvpg1WXd-YFblHO3dmdKPThaohl5gT8Zj-MbiJ_4J-nAYZ/s1600/m2plots.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1600" data-original-width="1183" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglB2O4VYxNXINwAPjvQvcDV4xnx2Ue1E39wVBUE8SyKP6Bndq8qPcsPa0mU7RQ7X41NIyLBPktN6NutU-oNRVzMAsuVungZKfvpg1WXd-YFblHO3dmdKPThaohl5gT8Zj-MbiJ_4J-nAYZ/s640/m2plots.png" width="472" /></a></div>
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<br /></div>
<div class="separator" style="clear: both; text-align: center;">
The above plot includes a well observed supernova from all of the major classes and most of the subclasses. The redshift limit on the upper right refers to the distance at which we could detect a particular supernova phase with Swift UVOT for a limiting magnitude of uvm2~20. </div>
<div class="separator" style="clear: both; text-align: center;">
The Swift UVOT data could similar predict the detectability of supernovae </div>
<div class="separator" style="clear: both; text-align: center;">
by future ultraviolet missions.</div>
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<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitH_wJ3zT2G-4jRoJhcqbBWj7fa4VGF7lZXPdP1y9VDc7N19Vv1jst5NpBo2enfKeX_-rUD4kTtWHB4QT-xBlIBmcvtbBepBUKWQDs29kZC_IwXwE4nJv3lJ2ullFCfxizzw75nDS9TE9Y/s1600/UVexplosionSNe_hiresblackwithsatspb.png" style="margin-left: auto; margin-right: auto;"><img border="0" height="456" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitH_wJ3zT2G-4jRoJhcqbBWj7fa4VGF7lZXPdP1y9VDc7N19Vv1jst5NpBo2enfKeX_-rUD4kTtWHB4QT-xBlIBmcvtbBepBUKWQDs29kZC_IwXwE4nJv3lJ2ullFCfxizzw75nDS9TE9Y/s1600/UVexplosionSNe_hiresblackwithsatspb.png" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Many
satellites have contributed ultraviolet observations of supernovae over
the years, but Swift has revolutionized the field. Large samples allow
the differences within subclasses to be studied in detail.
http://people.physics.tamu.edu/pbrown/SwiftSN/UVexplosionSwiftSNe.png</td></tr>
</tbody></table>
<br />
<a name='more'></a><br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUIxjS3IjCtxrU77BC1fjIYyfRPhpWpKnBK3yCYwH6oUcDMPc1UjjHzNcw032WaP34hfzV7xhLJfCkhNNMNWbGt_Ru5IKDNyF7IUBJ-ondGOqAO_D_17lb8mHQtDKYtx-9B62yRlKSu9qB/s1600/plotallsne_w1.png" style="margin-left: auto; margin-right: auto;"><img border="0" height="289" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUIxjS3IjCtxrU77BC1fjIYyfRPhpWpKnBK3yCYwH6oUcDMPc1UjjHzNcw032WaP34hfzV7xhLJfCkhNNMNWbGt_Ru5IKDNyF7IUBJ-ondGOqAO_D_17lb8mHQtDKYtx-9B62yRlKSu9qB/s1600/plotallsne_w1.png" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Swift
Supernova light curves over the years in the near-UV uvw1 filter.
http://people.physics.tamu.edu/pbrown/SwiftSN/plotallsne_w1.png</td></tr>
</tbody></table>
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTwCjyGAA_sn-sJW2htgb6MgvjCRifZwXrXVuyBT9dFalkf5mEPFttX7ESy8-qXwlazeQhZSD_7wUKnOKgxzw-crUb7-C-Ip-DFNr0BgXjGzSmHQlR7zYfUTnpkFxQkm3HaQQKWytZAESS/s1600/redshift_allSNe.png" style="margin-left: auto; margin-right: auto;"><img border="0" height="218" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTwCjyGAA_sn-sJW2htgb6MgvjCRifZwXrXVuyBT9dFalkf5mEPFttX7ESy8-qXwlazeQhZSD_7wUKnOKgxzw-crUb7-C-Ip-DFNr0BgXjGzSmHQlR7zYfUTnpkFxQkm3HaQQKWytZAESS/s1600/redshift_allSNe.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Redshift
distribution of all the supernovae observed by Swift. 95% of the
supernovae are at redshifts less than 0.05, but Superluminous SNe are
detectable to much higher distances.
http://people.physics.tamu.edu/pbrown/SwiftSN/redshift_allSNe.png</td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiofwmEisYA89t2OmEJtpG7R4U5TMr4I8ek__yHwwu9fltPGUU1Nso_MpJF_GbYSW0YXqWIq48_MDBTtvL8PAicV1SSnWPrAsaIDXl0KvkZZqvVWVnuiy7CMC2HIk_6YldVhTikfoLkwW01/s1600/redshift_allSNep05.png" style="margin-left: auto; margin-right: auto;"><img border="0" height="218" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiofwmEisYA89t2OmEJtpG7R4U5TMr4I8ek__yHwwu9fltPGUU1Nso_MpJF_GbYSW0YXqWIq48_MDBTtvL8PAicV1SSnWPrAsaIDXl0KvkZZqvVWVnuiy7CMC2HIk_6YldVhTikfoLkwW01/s1600/redshift_allSNep05.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Redshift distribution for the SNe with z < 0.05. http://people.physics.tamu.edu/pbrown/SwiftSN/redshift_allSNep05.png</td></tr>
</tbody></table>
<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZCgLggEFjTJ7HZ-rFzjhPvJAcEBDlus0A8AlS9-5QBrweeyqmaZ0M0CrRd4UyVv8SKlXgUgtD8d8EgosCS58I5lMm9-2PfgQzva1M9CPuUf4E7aRDQ5kAA_8kdtPLQDegCEbLcVNkH6kY/s1600/SwiftSNpietypes.png" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZCgLggEFjTJ7HZ-rFzjhPvJAcEBDlus0A8AlS9-5QBrweeyqmaZ0M0CrRd4UyVv8SKlXgUgtD8d8EgosCS58I5lMm9-2PfgQzva1M9CPuUf4E7aRDQ5kAA_8kdtPLQDegCEbLcVNkH6kY/s1600/SwiftSNpietypes.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Fraction of Swift supernova observations of different type of
supernovae. All subclasses relating to the broader phenomological class
are grouped together. ? includes possible supernova imposters, LBV
eruptions, or explosions of unknown origin.
http://people.physics.tamu.edu/pbrown/SwiftSN/SwiftSNpietypes.png</td></tr>
</tbody></table>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7SvqWg4Va9rQUnXz0sPMUsm_mZQT6-DNmvBGeo_CsgMRdYUgmI7puBidMxAcWPv62QLNQDBTR0_7gSpqg9C1qkMDxHVt1ytXPsRkqYGIZsZp29O2SNeHzA6TwKsmLzsjaBhVsrC4_Wn06/s1600/UVexplosionSNe.png" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="285" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7SvqWg4Va9rQUnXz0sPMUsm_mZQT6-DNmvBGeo_CsgMRdYUgmI7puBidMxAcWPv62QLNQDBTR0_7gSpqg9C1qkMDxHVt1ytXPsRkqYGIZsZp29O2SNeHzA6TwKsmLzsjaBhVsrC4_Wn06/s1600/UVexplosionSNe.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Number of
Supernovae observed in the Ultraviolet each year from a variety of
spacecraft. Caveats: a few Supernovae are double counted if observed by
multiple spacecraft (e.g. SNe 1987A and 1992A). Also, they are plotted
with respect to the year of the supernova rather than the date of the
observation.
http://people.physics.tamu.edu/pbrown/SwiftSN/UVexplosionSNeSwiftontop.png</td></tr>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZOUbBgmT8tF7oHiL97ZbqkNlSLcQLw3JyBgijDc7-o9A0UuCfmmJB1O7mcYBoLh3V8lHz7AF9TN0Uyv8T_aHsRyzHEykHFYqqNqYScMzFA_4K9jUOOM8KuMqzlHhDn5b66b2B-F6BXA3s/s1600/UVexplosionSNeNoSwift.png" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZOUbBgmT8tF7oHiL97ZbqkNlSLcQLw3JyBgijDc7-o9A0UuCfmmJB1O7mcYBoLh3V8lHz7AF9TN0Uyv8T_aHsRyzHEykHFYqqNqYScMzFA_4K9jUOOM8KuMqzlHhDn5b66b2B-F6BXA3s/s1600/UVexplosionSNeNoSwift.png" width="174" /></a></div>
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9jb45D2O_q9-G10QycK-H1-BDTk8AW_a03-buWlu-0ztMzmX-YDCgaF2yGiH5j8AlX7ofORSJ1takhMiFYnO5D2qlnD7ynUbwIWa-trI2JJGxPWtMsu5tOBuiGpP-S1mXJ_na4o5_Q0uO/s1600/UVexplosionSNeSwiftofftop.png" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9jb45D2O_q9-G10QycK-H1-BDTk8AW_a03-buWlu-0ztMzmX-YDCgaF2yGiH5j8AlX7ofORSJ1takhMiFYnO5D2qlnD7ynUbwIWa-trI2JJGxPWtMsu5tOBuiGpP-S1mXJ_na4o5_Q0uO/s1600/UVexplosionSNeSwiftofftop.png" width="174" /></a><br />
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Plots
showing the non-Swift UV Supernovae and the addition of the Swift
Supernovae on the same scale to show how far "off the charts" the Swift
explosion is. <br />
http://people.physics.tamu.edu/pbrown/SwiftSN/UVexplosionSNeNoSwift.png<br />
http://people.physics.tamu.edu/pbrown
/SwiftSN/UVexplosionSNeSwiftofftop.png uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-3456135964706584932014-04-14T08:40:00.000-07:002014-07-14T14:06:59.449-07:00Swift/UVOT calibrationThe calibration has been improved over the years, with the zeropoints of
Poole et al. 2008 being updated in Breeveld et al. 2011. As of
2010-11-30 these new zeropoints have been included in the Swift CALDB
used with the HEASARC software (ie uvotsource and uvotmaghist). A
sensitivity loss of about 1% per year has also been discovered and is
incorporated into the HEASARC software as of 2010-6-30. Many papers reference only the Poole et al. 2008 calibration, but we hope the new zeropoints and sensitivity correction are being implemented.<br />
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<pre>Filter Zero Point Error
V 17.89 0.01
B 19.11 0.02
U 18.34 0.02
UVW1 17.44 0.03
UVM2 16.85 0.03
UVW2 17.38 0.03
White 20.29 0.04
</pre>
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The site <a href="http://swift.gsfc.nasa.gov/analysis/uvot_digest/zeropts.html" target="_blank">here</a> also gives the AB zeropoints, but I don't list them here to avoid confusion.<br />
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The official filter curves are given in the <a href="http://heasarc.gsfc.nasa.gov/docs/heasarc/caldb/data/swift/uvota/index.html" target="_blank">CALDB</a> but in a fits format designed for certain x-ray analysis tools. I have placed ascii version of the curves on this <a href="http://people.physics.tamu.edu/pbrown/pjbrown_uvot.html" target="_blank">page</a>. The curves are the effective area of the filters in units of cm^2, ie multiplying the area of the telescope mirror with the transmission functions of the filters, reflectivity of the mirrors, and corrections to match the inflight observations. uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com1tag:blogger.com,1999:blog-6624995427045699379.post-50600133419059513392014-04-03T09:16:00.003-07:002014-04-03T09:16:55.498-07:00Ultra Super Super Explosions<div class="separator" style="clear: both; text-align: center;">
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjA2ACeBUnbadiiadkMD0VmtA_F0_-HBCUOP48MwApsiOa74RuKGiJVcO9xEAMvRozHqfQDqrHZ9SL3zkwaeCJADyLVngajVPYbm2vVuBqiL6OxlWnnmLTNQGOzvDSruTCgFw8Oxa6pTbP-/s1600/Supers3_uvot_labeledshort.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjA2ACeBUnbadiiadkMD0VmtA_F0_-HBCUOP48MwApsiOa74RuKGiJVcO9xEAMvRozHqfQDqrHZ9SL3zkwaeCJADyLVngajVPYbm2vVuBqiL6OxlWnnmLTNQGOzvDSruTCgFw8Oxa6pTbP-/s1600/Supers3_uvot_labeledshort.png" height="188" width="640" /></a></div>
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I tried to add another superlative to the title: Ultraviolet Observations of Super-Chandrasekhar Mass Type Ia Supernova Candidates with Swift UVOT. It would have been fair, since these objects are extreme, but seemed cheesy. Nevertheless, Ultra-Super-Super Explosions seems an adequate short title.<br />
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<a name='more'></a><br /><br />
<br />Of the three objects studied, only one is a clear Super-Chandrasekhar mass SN Ia (2009dc). SN2012dn was spectroscopically identified as similar to those events. SN2011aa is very broad, and similarly UV bright, but not directly connected to the other Supers based on the data available to me, but Kamiya had a poster at the Munich supernova meeting showing the photometric light curves to match Super-Chandrasekhar mass SN models.<br />
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<a href="http://people.physics.tamu.edu/pbrown/SwiftSN/SCcandidateUVOTphotometry.tar" target="_blank">Here is the photometry. </a> uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-50250758437937923492014-03-18T09:46:00.000-07:002014-03-18T09:46:17.946-07:00Bright Stars<div class="separator" style="clear: both; text-align: center;">
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Swift/UVOT has brightness limits to protect the detector. The limit is approximately V~ 5 but depends on the spectral type and which filter(s) you want to use. A 20' radius is checked to allow for different position angles and uncertainty in the spacecraft pointing. Based on the color and optical brightness, the count rate in each filter is predicted. If the predicted count rate is higher than the limit for a requested filter, that filter is skipped in the observing sequence and only the requested filters that are deemed safe are observed. There is a bright star checker at the following link, but it only tells you which bright stars are in the field--it doesn't actually tell you which filters can and can't be observed. Rough limits for bright stars, as well as the allowed angles from the sun, earth, moon, and planets, are posted at http://swift.gsfc.nasa.gov/analysis/uvot_digest/numbers.html<br />
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Because the white filter and the grisms let in photons from the widest wavelength range, they have the strictest limits. The UV filters, on the other hand, are the least likely to be prohibited. Note, these are the brightness limits of stars which can be safely observed. The bright limits at which you can do photometry are much fainter (though different analysis using the halos or the readout streaks can push brighter than normal aperture photometry, see http://adsabs.harvard.edu/abs/2013MNRAS.436.1684P ).<br />
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In addition to the strict safety limits, bright stars can also interfere with the data analysis. Stars of moderate brightness (I should quantify this better, but the star below is about 9th mag in V) will have a filled in halo with a 20 arcsec diameter. A fainter halo is visible around it, with a radius of 140 arcsec, which gets brighter for brighter stars and will mess up the photometry of faint sources. Bright sources in the halo may still be recoverable by choosing a background region of similar brightness. <br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3y7TrpRZXgJ8opx6Y3eeges_0-eaRd852bI8J2YDfj1vKaKACSb-GnFPt16vpUCqxvROsMX19l0SL8lpC_5pHmRp-HCRBguGHQrYxMHsvZu43nUi8kjktoUDZM5j_ssZFfpEpDyU34sNW/s1600/BrightStars-1.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3y7TrpRZXgJ8opx6Y3eeges_0-eaRd852bI8J2YDfj1vKaKACSb-GnFPt16vpUCqxvROsMX19l0SL8lpC_5pHmRp-HCRBguGHQrYxMHsvZu43nUi8kjktoUDZM5j_ssZFfpEpDyU34sNW/s1600/BrightStars-1.gif" height="188" width="320" /> </a></div>
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[ details of the above image which I first sent out in reference to SN2007C ]</div>
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So you know the issues involved, I've attached an<br />image from the field of GRB060729. (it is a UVW1<br />image so that we can see the effect in the UV of<br />bright stars--the effect is worse in the optical for<br />us, but the usefullness of the UV data is our main<br />concern.) It shows the 20" radius bright core around<br />a 9th mag star and the 2' radius halo around an 8th mag star<br />(the halo is faintly visible around the fainter star<br />but not a dominant problem). So being within 20" of a<br />star brighter than 10th or so would be nearly<br />impossible. The larger halo would be hard to subtract<br />correctly but not a show stopper if the SN is<br />interesting and bright enough. And if there are stars<br />brighter than 7th or so within 20' of the target<br />pointing we can't observe at all. (That's something<br />the Swift people will check since it depends on the<br />spectral type, number of sources, and such, but just<br />so people are aware.) </div>
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<br />uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-11020882749563382392014-01-24T17:36:00.001-08:002014-01-24T17:36:08.534-08:00Supernova SN2014J in M82<br />
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<a href="http://people.physics.tamu.edu/pbrown/SNinM82/SNinM82_uvot_before_after.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="http://people.physics.tamu.edu/pbrown/SNinM82/SNinM82_uvot_before_after.png" height="388" width="640" /></a></div>
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Here are my before and after images of the new Supernova in M82. The picture with the supernova looks grainier because it has much less exposure time. <br />
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NASA just had a press release : http://www.nasa.gov/content/goddard/nasa-spacecraft-take-aim-at-nearby-supernova/#.UuMU6PbnZjMuvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-10556702491167073192013-10-24T08:49:00.001-07:002013-10-24T09:15:36.504-07:00Swift/UVOT photometry version 13.2<br />
Swift has observed hundreds of supernovae over the last nine years, including dozens of very well sampled light curves published in many different papers (<a href="http://ultravioletsupernova.blogspot.com/2013/10/swift-supernova-publications.html" target="_blank">see post to Swift SN publication list here</a>). The calibration has been improved over the years, with the zeropoints of Poole et al. 2008 being updated in Breeveld et al. 2011. As of 2010-11-30 these new zeropoints have been included in the Swift CALDB used with the HEASARC software (ie uvotsource and uvotmaghist). A sensitivity loss of about 1% per year has also been discovered and is incorporated into the HEASARC software as of 2010-6-30. Combining these effects could lead to a 0.1 magnitude error when comparing new and old photometry. <br />
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To allow an accurate comparison between new SNe and those published earlier in the mission, I have redone the photometry for using the latest calibration. The photometry for the SNe Ia published in <a href="http://adsabs.harvard.edu/abs/2009AJ....137.4517B" target="_blank">Brown et al. 2009</a> and <a href="http://adsabs.harvard.edu/abs/2012ApJ...749...18B" target="_blank">2012</a> have been redone and posted <a href="http://people.physics.tamu.edu/pbrown/SwiftSN/SN_Ia_UVOT_B09B12_13.2.tar" target="_blank">here</a>. The original references are given in the files, and I will be redoing other SNe as time allows. I have also posted the reduction code <a href="http://people.physics.tamu.edu/pbrown/SwiftSN/SNgalsub13.2.txt" target="_blank">here</a>. Please report any bugs, suspicious data, or deviations from ground photometry (for B and V, the Swift u band is quite different from ground-based u' or U) in the comments below or to uv dot supernova at gmail dot com. <br />
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A set of CC SN photometry from <a href="http://adsabs.harvard.edu/abs/2013arXiv1303.1190P" target="_blank">Pritchard et al. 2013</a> on the same system (but slightly different analysis) is posted <a href="http://people.physics.tamu.edu/pbrown/SwiftSN/SN_CC_UVOT_Pritchard.tar" target="_blank">here</a>. <br />
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Notes:<br />
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The coincidence-loss saturation limit is currently set at 0.98 counts per frame. This should be more rigorously tested.<br />
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There is something wrong with the three sigma upper limits, as the SN2006mr photometry lists magnitudes that are only 1-2 sigma detections. I think the photometry is right, but there is an inconsistency in how the photometric errors are calculated and how the upper limits are calculated. It might be the inclusion of the galaxy subtraction errors in the limit, as SN2006mr had the largest underlying galaxy count rate.<br />
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<br />uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-69254251092078922332013-10-10T00:21:00.003-07:002014-04-22T10:55:32.429-07:00Swift Supernovae in the Future (2014-2018) Brainstorm ListSwift Supernovae in the Future (2014-2018) Brainstorm List<br />
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This post is intended as a brainstorming list to dump new ideas about what Swift should be doing in regards to supernovae over the next four years. We don't need a list of all the wonderful science you could do, but how different target selection or observations can add to the science we are doing. Adding something here doesn't necessarily mean you think we should do it, but that it could be done. Adding something does not obligate you to do anything about it now, but we may ask for more details or ideas on implementation. Suggestions do not need to be strongly justified on this page, but sometimes a brief clarification is useful. Obviously we cannot do everything, but by airing these ideas we can probably find more synergistic observations which can benefit multiple projects. Please add your ideas in the comments.<br />
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SNe in the Hubble Flow -- a large fraction of the Swift SNe are at very low redshifts (z<0.02) where the peculiar velocity contribution to the absolute magnitude error is greater than 0.1 mag (in the absence of other distance measurements). More SNe Ia could be targeted in the range 0.02 < z < 0.03 or so, and UV bright SNe II even farther out. [ Peter B]<br />
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Early grism observations -- the updated grism software includes calibration for positions across much of the field. A slew in place, while desirable in the planned schedules, is no longer necessary, so grism observations can be uploaded to Swift as immediate targets for earlier spectra. [Peter B]<br />
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[ April 22, 2014 Update -- I only listed a few ideas so that others could contribute without having most ideas already listed. Since there hasn't been much response, I'll go ahead and list the other ideas I have. ]<br />
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V grism observations of SNe Ia -- We've focused mostly on the UV grism since the V grism only extends a little past what can be done from the ground (to about 2900 Angstroms). But there are interesting features there that might explain the difference between NUV-red and NUV-blue SNe, and using the V grism would allow for SNe to be targeted at higher redshifts than the UV grism.<br />
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Reddened SNe -- Now that we've got a large sample of low reddened SNe to compare with we should also target mildly reddened SNe (E(B-V) <~ 0.5) to understand the wavelength dependence of the extinction law(s?) applicable to SNe <br />
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V grism observations of reddened SNe? We can't get much mid-UV flux anyway, but V grism observations could probe the extinction law down to 2900 Angstroms<br />
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UV light curves of SNe Ib/c -- we still don't have many good light curves of SNe Ib/c, especially in the mid-UV (uvm2 band). There aren't many close enough to detect in short observations (2 ks) but we could take longer exposures to get light curves of SNe Ib/c a little farther away.<br />
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Distance-limited sample of SNe IIP -- IIn<br />
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Target all SLSN candidates brighter than g/B/V ~ 20 -- some might not be UV bright but we could get a feel for what fraction are and what the brightness distribution is in the UVuvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-40020455960671573022013-10-07T00:57:00.000-07:002015-09-24T10:46:22.362-07:00Swift Supernova PublicationsI am trying to create a master list of all publications presenting or making significant use of Swift Supernova data. Right now I am sticking to refereed (or arXiv papers in the refereeing process) papers but may add ATELs and IAU Circulars at some point -- there are quite a few. Please alert me to any I am missing. To minimize clutter I will delete comments after adding the reference.<br />
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https://docs.google.com/document/d/1V1WVF9--sWfTfV_4vjoXQ-KtzFNl13WVpUbDZEf4JS0/edit?usp=sharing<br />
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As of September 2015 I count 107 publications from 63 different authors. uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-79090428332577543502013-08-21T11:47:00.000-07:002013-08-21T11:47:40.525-07:00Swift SN Timeline<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9UU1q4jAtPyVucWqeFY8zFH0OFmmFT04kcOZ05034TpDazYTBDIPQ6q57FbvHyUW7ulZEcZSUbIZiw-D38hXAxg2CkcqQamKWJVuvos2fFWPBhGxo5Ewap2DFmAfboYD4h8frxojzct3-/s1600/plotallsne_w1_landscape.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="216" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9UU1q4jAtPyVucWqeFY8zFH0OFmmFT04kcOZ05034TpDazYTBDIPQ6q57FbvHyUW7ulZEcZSUbIZiw-D38hXAxg2CkcqQamKWJVuvos2fFWPBhGxo5Ewap2DFmAfboYD4h8frxojzct3-/s640/plotallsne_w1_landscape.png" width="640" /></a></div>
Here is a timeline of Swift SN observations through mid-2012. It demonstrates the continuity of our program, with the light curves of individual SNe being well sampled in time and multiple SNe being followed up at any given time. The dynamic range for our observations in uvw1 is about 11 (the saturation point) down to a limiting magnitude of 21 for reasonable exposure times and typical galaxy contamination.uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com0tag:blogger.com,1999:blog-6624995427045699379.post-82619884665706511582013-08-21T09:20:00.000-07:002013-08-27T06:29:35.878-07:00Swift Supernovae -- What are bad targets?Which supernovae make good candidates for Swift observations is a
very science-dependent question and has different answers to different
people. So I will start with things that make SNe poor targets for
Swift as they are independent of the science.<br />
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Too faint: if we can't detect it, are the upper limits obtained still useful? This depends on the SN type/intrinsic luminosity/distance/extinction. This has roughly been translated into a distance limit of z<0.03 for SNe Ia, but UV bright, luminous SNe II can be observed to farther distances (even z~0.2) <br />
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High extinction: A_V >~ 0.5 This is just a rough guide, as it also depends on source brightness/distance/exposure time.<br />
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UV
wavelengths are a sensitive probe of extinction. There is a certain
range of reddening which is significant enough for the UV to constrain
the amount and wavelength dependence of the reddening. But too much and
we don't detect it at all and the expected brightness may be so much
fainter than our upper limits that they don't constrain anything. This
applies to both MW and host galaxy reddening. The MW reddening can be
known ahead of time via <a href="http://ned.ipac.caltech.edu/" target="_blank">NED</a>.
The host galaxy reddening isn't usually known in advance, but if it is
described as heavily reddened based on the optical data, than it is
probably already too much for the UV. This is of course distance and
SED dependent. A very nearby type II SN can be more heavily reddened
than a distant Ic and still be detected. <br />
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Contamination: while galaxy light can be subtracted off, if the underlying galaxy is too bright it contributes to the<a href="http://ultravioletsupernova.blogspot.com/2013/08/coincidence-loss-issues.html" target="_blank"> coincidence loss</a>
in a way that may not be correctable. The cutoff value I use is 5
counts/second within a 5" aperture. That value may not mean anything to
you if you don't do UVOT photometry, but that threshold is frequently
crossed for very nearby SNe (z~0.005) within their host galaxy. Because
of the lower throughput of the UV filters it rarely affects the UV
light. So severe galaxy contamination can be a very bad thing, but we should also be careful of moderate galaxy contamination because we never know how long Swift will be around and if we can get template images to subtract the galaxy. For good targets we shouldn't not observe them because of that fear, but if we are choosing between two possible targets or creating selection criteria for a sample for which we can be choosy, then low galaxy contamination is preferred.<br />
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Nearby Star Contamination: similar to galaxy
light, a nearby star can contribute to coincidence loss in a way that is
hard or impossible to correct for. This was the case for SN2005am.
Avoid m<15 stars or galaxy nuclei within 8" or so. Most stars are
fainter in the UV so this becomes less of an issue. If the UV data
still looks useful, we will usually continue taking data in the optical
filters as well (sometimes with different modes to ameliorate some of
the problems) in case they can be fixed in the future. Some data will turn out to be useless, but for transient objects there is no way to go back and take data you skipped the first time around. uvhttp://www.blogger.com/profile/11141300249210548366noreply@blogger.com2