SPIRITS discoveries of 8 Infrared Transients and Eruptive Variables with Spitzer/IRAC
ATel #12675; J. E. Jencson, M. M. Kasliwal, S. Adams, D. Cook, S. Tinyanont (Caltech), R. M. Lau (JAXA), D. Perley (LJMU), F. Masci, G. Helou, L. Armus, J. Surace, S. D. Van Dyk (Caltech/IPAC), A. Cody (NASA Ames), H. E. Bond (PSU), J. Bally (UC Boulder), M. L. Boyer, O. Fox, R. Williams (STScI), P. A. Whitelock, E. Getachew (SAAO, UCT), S. Mohamed (SAAO), R. D. Gehrz, S. Amodeo, D. Shenoy, R. Carlon, A. Cass, D. Corgan, D. Dykhoff, J. Faella, T. Gburek (U. Minnesota), N. Smith (U. Arizona), J. Johansson (OKC/WIS), M. Parthasarathy (IIA), E. Hsiao (FSU), M. Phillips, N. Morrell, C. Gonzalez, C. Contreras (LCO), on behalf of the SPIRITS collaboration
on 20 Apr 2019; 02:19 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Jacob Jencson (jj@astro.caltech.edu)
Subjects: Infra-Red, Optical, Nova, Supernovae, Transient, Variables
We report the discoveries of infrared transients and eruptive variables found in the course of the Spitzer InfraRed Intensive Transients Survey (SPIRITS) using Spitzer Early Release Data (ATel #6644, #7929, #8688, #8940, #9434, #10171, #10172, #10488, #10903, #11575, #12089). Some of these events may belong to an emerging class of infrared (IR) transients known as eSPecially Red Intermediate Luminosity Transient Events (SPRITEs; Kasliwal et al. 2017) having by peak luminosities between those of novae and supernovae in the range -11 > M_[4.5] > -14 (4.0 < log(nu L_nu) [Lsun] < 5.2) and no detected counterparts at optical wavelengths. In the table below, we list peak observed magnitudes at [3.6] and [4.5], and [3.6] - [4.5] colors at the time of the [4.5] peak.
Name | RA (J2000) | Host Galaxy (DM; d) | Peak [3.6] (abs)| [3.6]-[4.5]
| Dec (J2000) | UT-discovery | Peak [4.5] (abs)| Notes
-------------|-------------------|---------------------|-----------------|-------------
SPIRITS 18hb | 20:35:07.68 | NGC 6946 (28.3) | 15.8 (-12.5) | 0.8
| +60:11:16.2 | 2018-11-27 | 15.0 (-13.3) | a,c
SPIRITS 18nu | 03:46:45.62 | IC 342 (27.7) | 15.4 (-12.3) | 0.2
| +68:03:26.8 | 2018-12-17 | 15.2 (-12.5) | b
SPIRITS 18ny | 03:46:32.35 | IC 342 (27.7) | 16.6 (-11.1) | 0.5
| +68:05:17.0 | 2018-12-17 | 16.1 (-11.6) | b
SPIRITS 19q | 07:37:18.21 | NGC 2403 (27.5) | 13.2 (-14.3) | 0.7
| +65:33:49.0 | 2019-01-24 | 12.5 (-15.0) | a
SPIRITS 19bf | 12:03:13.3 | NGC 4051 (30.2) | 17.7 (-12.5) | 1.2
| +44:31:07.8 | 2019-03-23 | 16.7 (-13.5) | a,c
SPIRITS 19bh | 03:33:49.12 | NGC 1365 (31.3) | 16.1 (-15.2) | ...
| -36:04:26.7 | 2019-04-01 | 17.2 (-14.1) | a
SPIRITS 19bl | 09:56:02.78 | M81 (27.8) | 17.4 (-10.4) | 1.0
| +69:05:18.9 | 2019-04-01 | 16.4 (-11.4) | b
SPIRITS 19br | 12:41:41.21 | NGC 4631 (29.4) | 17.1 (-12.2) | ...
| +32:31:48.4 | 2019-04-07 | 16.3 (-13.1) | a,c
a) Fainter counterpart in reference (2004 - 2008).
b) No counterpart in reference (2003 - 2008).
c) Previous history of variability.
d) Reference for distances: NGC 6946 (Pejcha & Prieto 2015), IC 342 (Wu et al. 2014), NGC 2403 (Radburn-Smith et al. 2011), NGC 4051 (Tully et al. 2013), NGC 1365 (Jang et al. 2018), M81 (Jang et al. 2012), NGC 4631 (Monachesi et al. 2016).
We encourage continued follow-up to discern the nature of these events. Please contact us if additional information (such as finding charts) is needed. We caution that in most cases we do not have spectroscopic confirmation that these transients belong to the reported host galaxies, and there is some chance that they may be unrelated foreground or background events.
