SPIRITS discovery of 4 Infrared Transients and Variables with Spitzer/IRAC

ATel #12089; J. E. Jencson, M. M. Kasliwal, S. Adams, D. Cook, S. Tinyanont, S. Kwan, T. Prince (Caltech), R. M. Lau (Caltech/JPL), D. Perley (LJMU), F. Masci, G. Helou, L. Armus, J. Surace, S. D. Van Dyk (Caltech/IPAC), A. Cody (NASA Ames), H. E. Bond, A. Monson (PSU), J. Bally (UC Boulder), R. Khan, E. Levesque (U. Washington), M. L. Boyer, O. Fox, R. Williams (STScI), P. A. Whitelock (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), M. Cantiello (UCSB), N. Langer (U. Bonn), E. Ofek (WIS), 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 8 Oct 2018; 22:20 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Jacob Jencson (jj@astro.caltech.edu)

Tweet

We report the discoveries of infrared transients/strong 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). 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, ApJ, 839, 88) defined by peak luminosities between those of novae and supernovae in the range -11 > [4.5] > -14 or 6.3 < log(L/Lsun) < 7.5, [3.6]-[4.5] colors between 0.3 and 1.6 mag, and no detected counterpart at optical wavelengths. In the table below, we list peak observed magnitudes at [3.6] and [4.5], and maximum observed [3.6]-[4.5] colors.

 
Name         | RA (J2000)  | Dec (J2000) | Host Galaxy (DM; Ref.)    | UT-discovery | Peak [3.6] (abs)  | Peak [4.5] (abs) | Max. [3.6]-[4.5] | Notes 
SPIRITS 18eo | 09:32:06.36 | 21:30:14.2  | NGC2903 (29.8, e)         | 2018-09-07   | 16.7 (-13.1)      | 16.1 (-13.7)     | 0.6              | a 
SPIRITS 18ec | 13:30:03.07 | 47:10:12.7  | MESSIER051a (29.3, f)     | 2018-08-13   | 17.0 (-12.3)      | 16.3 (-13.0)     | 1.3              | a,c 
SPIRITS 18dz | 09:32:04.41 | 21:32:50.5  | NGC2903 (29.8, e)         | 2018-08-01   | 16.8 (-13.1)      | 16.1 (-13.8)     | 0.7              | b,d 
SPIRITS 18ae | 14:03:17.81 | 54:18:52.9  | MESSIER101 (29.2, f)      | 2018-04-24   | 17.4 (-11.8)      | 16.5 (-12.6)     | >1.2             | a,c 

a) Fainter counterpart in reference (2004 - 2008).

b) No counterpart in reference (2007).

c) Previous history of variability.

d) Transient has disappeared in follow-up observations taken with Spitzer/IRAC in both channels on 2018-09-07.

e) Sorce et al. 2014, MNRAS, 444, 527

f) Tully et al. 2013, ApJ, 146, 86

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.