Additional SPIRITS Discoveries of Infrared Transients and Variables without Counterparts in Reference Imaging

ATel #10172; J. E. Jencson, M. M. Kasliwal, S. Adams, D. Cook, S. Tinyanont, S. Kwan, T. Prince (Caltech), R. M. Lau (Caltech/JPL), D. Perley (DARK), F. Masci, G. Helou, L. Armus, J. Surace, S. D. Van Dyk (Caltech/IPAC), A. Cody (NASA Ames), M. L. Boyer (NASA Goddard), H. E. Bond, A. Monson (PSU), J. Bally (UC Boulder), Y. Cao, R. Khan, E. Levesque (U. Washington), 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 15 Mar 2017; 21:36 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Mansi Manoj Kasliwal (mansi@astro.caltech.edu)

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We report the discoveries of mid-infrared transients/eruptive variables found by the Spitzer InfraRed Intensive Transients Survey (SPIRITS) using Spitzer Early Release Data (ATel #6644, #7929, #8688, #8940, #9434). 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, arXiv:1701.01151) 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) and no detected counterpart at optical wavelengths. Of the events reported here, SPIRITS 16abq has a lower peak luminosity consistent with a classical nova. Here, we list events with no counterpart in the Spitzer reference images (2004-2007).

 
Name         | RA (J2000)  | Dec (J2000) | Host Galaxy (DM; Ref.) | UT-discovery | Peak [3.6] (abs) | Peak [4.5] (abs) | Max. [3.6]-[4.5] | iPTF Optical Limits 
SPIRITS 17as  | 12:40:06.02 | -11:38:14.1 | M 104 (30.3, a)        | 2016-10-13 | 17.2 (-13.1) | 17.0 (-13.3) | 0.2   | ...                  |  
SPIRITS 17ar  | 13:05:36.89 | -49:23:38.2 | NGC 4945 (27.9, a)     | 2016-10-12 | ...  (...)   | 15.7 (-12.2) | > 0.0 | ...                  |  
SPIRITS 17g   | 03:47:29.89 | +68:03:13.1 | IC 342 (27.7, a)       | 2016-12-21 | ...  (...)   | 16.6 (-11.1) | > 0.6 | R > 19.9; 2017-03-02 |  
SPIRITS 16abq | 00:40:20.95 | +41:39:35.6 | M 110 (24.5, a)        | 2016-11-09 | 16.8 (-7.7)  | 16.8 (-7.7)  | 0.1   | R > 21.4; 2016-11-09 | 

a) Tully et al. 2013, AJ, 146, 86

We encourage continued follow-up to discern the nature of these events. Please contact us if additional information is needed. We caution that in most cases we do not have spectroscopic confirmation of redshift and there is some chance that a few of them may be unrelated foreground or background events.