Assassin Picture of the Week

2013 July 17

How ASAS-SN Discovers Supernovae: Case of Supernova ASASSN-13bb

This APOW illustrates how we look for and (now and then) discoverer new supernovae and other transient objects (several per night). The top left panel shows part of a ASAS-SN "reference image," created from co-adding many images of the same field from previous visits with our telescope. Because we have large pixels (7.5 arcsec/pixel), we also use higher angular resolution archival images to see what our field looks like: top right shows the DSS image (digitized photographic plates) on the same angular scale. On lower left is one of the 90-sec V-band images on 07/04 used to detect a supernova candidate we called ASASSN-13bb. In order to better identify new sources we use a method called "image subtraction" to create a difference image (lower right), which clearly shows a new source. Circle with the 15" radius has the same position. This was clear enough detection that based on ASAS-SN data alone we announced via ATel a discovery of a probable supernova in UGC 01395, which was then confirmed as a Type Ia supernova through spectroscopy.
See the previous APOW.
This homepage is maintained by Ben Shappee and Kris Stanek. Updated Wed Jul 17 12:33:30 EDT 2013

eXTReMe Tracker