Spitzer detections and pre-discovery limits for nova candidate PNV J09552547+6903458 in M81
ATel #12679; J. E. Jencson, M. M. Kasliwal, S. Adams, S. Tinyanont (Caltech), R. Williams (STScI), and R. D. Gehrz (U. Minnesota) on behalf of the SPIRITS collaboration
on 23 Apr 2019; 03:26 UT
Credential Certification: Jacob Jencson (jj@astro.caltech.edu)
Subjects: Infra-Red, Optical, Nova, Transient
We report detections of an infrared counterpart to the nova candidate PNV J09552547+6903458 in Spitzer/IRAC 3.6 and 4.5 micron images ([3.6] and [4.5]) of M81 taken as part of the Spitzer InfraRed Intensive Transient Survey (SPIRITS; Kasliwal et al. 2017). The transient, recovered by our automated transient detection pipeline and designated SPIRITS 19bj, was first reported as a possible nova on 2019-02-21 by Hornoch et al. (ATel #12525). Here, we list our photometry (Vega mag) of the source, and pre-outburst limits from non-detections:
UT Date | MJD | [3.6] (error) | [4.5] (error)
2019-02-10.22 | 58524.22 | >15.5 | >14.9
2019-04-01.43 | 58574.43 | 16.4 (0.3) | 15.7 (0.4)
Assuming a distance modulus for M81 of 27.8 mag (Jang et al. 2012), the absolute magnitude at [4.5] is -12.0 mag. This is similar to the absolute L-band magnitude of nova V1500 Cygni 1975 at M_L=-11.9. The bright IR detections reported here (cf. the optical peak at R = 17.9 mag on 2019-02-18.21; ATel #12525) indicate the object is likely a strong dust-forming nova that commonly form dust in the interval 1-3 months after outburst.
