Spitzer pre-discovery limits on PS17cke (=AT2017des)
ATel #10299; J. E. Jencson (Caltech), R. M. Lau (JPL/Caltech), M. M. Kasliwal (Caltech), H. E. Bond (PSU), S. Adams (Caltech), A. Cody (NASA Ames), F. Masci (Caltech/IPAC) on behalf of the SPIRITS collaboration
on 21 Apr 2017; 17:33 UT
Credential Certification: Jacob Jencson (jj@astro.caltech.edu)
Subjects: Infra-Red, Optical, Nova, Supernovae, Transient
We report limits from mid-infrared pre-discovery imaging of supernova candidate PS17cke (=AT2017des) discovered by the Pan-STARRS Survey for Transients (ATel #10283). Spitzer/IRAC images at 3.6 and 4.5 micron ([3.6] and [4.5]) of the putative host, NGC 4532 (mu = 30.65 mag, D = 13.5 Mpc from NED), were taken on UT 2017-04-07.73 (MJD 57850.73) as part of the ongoing Spitzer InfraRed Intensive Transients Survey (SPIRITS; Kasliwal et al. 2017). Image subtraction was performed using Spitzer/IRAC [3.6] and [4.5] images from UT 2007-02-17.54 as references. No transient source is detected at the reported position of AT2017des to Vega system 5-sigma limiting magnitudes of [3.6] > 18.49 mag (> -12.16 mag absolute) and [4.5] > 17.46 mag (> -13.19 mag absolute). If AT2017des is a supernova, these limits likely constrain the explosion date to 9 days before the reported first detection on 2017-04-16. A future epoch of Spitzer/IRAC imaging is scheduled for 2017-05-06 as part of the regular SPIRITS observing program.
