SPIRITS Discoveries of Recent Infrared Transients with Spitzer Early Release Data

ATel #7929; J. E. Jencson (Caltech), M. M. Kasliwal (Carnegie/Princeton, Caltech), S. Tinyanont (HMC, Caltech), Y. Cao, T. Prince (Caltech), D. Perley (DARK), F. Masci, G. Helou, L. Armus, J. Surace, S. van Dyk (IPAC), A. Cody (NASA Ames), M. Boyer, R. Khan (NASA Goddard), H. Bond, A. Monson (PSU), J. Bally, E. Levesque (UC Boulder), R. Williams (STSCI), P. A. Whitelock (SAAO, UCT), S. Mohamed (SAAO), R. 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), O. Fox (UC Berkeley), M. Phillips, E. Hsiao, N. Morrell, C. Gonzalez, C. Contreras (LCO)
on 19 Aug 2015; 22:42 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Mansi Manoj Kasliwal (mansi@astro.caltech.edu)

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The Spitzer InfraRed Intensive Transients Survey (SPIRITS; ATel #6644) is a systematic search of 194 nearby galaxies for infrared transients with the IRAC camera on the warm Spitzer telescope to a depth of 20th mag (Vega) with varying cadences between a week to a year. Since mid-2015, the SPIRITS team has made extensive use of Spitzer Early Release Data. Under this system, high-level calibrated data products are released 1-3 days after the observations, prior to their release in the Spitzer Heritage Archive. The SPIRITS team is now routinely downloading, processing, and scanning our program's Early Release Data for infrared transients and variables within a day of when it is made available. Here we report several recently discovered infrared transients/strong variables of particular interest, selected due to their high luminosity, extreme color, or lack of a conspicuous pre-outburst counterpart:

 
SPIRITS Name | RA (J2000)  | Dec (J2000) | Host Galaxy (DM) | UT-discovery | [3.6] (abs)  | [4.5] (abs)  | [3.6]-[4.5] | Notes 
 
15qv         | 03:18:09.34 | -66:29:59.4 | NGC 1313 (28.2)  | 2015-08-13   | 17.4 (-10.8) | 18.7 (-9.5)  | -1.3        | a 
15qo         | 03:18:15.26 | -66:30:03.4 | NGC 1313 (28.2)  | 2015-08-13   | 16.3 (-11.9) | 15.7 (-12.5) | 0.6         | a 
15qh         | 22:02:42.07 | -51:17:22.3 | IC 5152 (26.6)   | 2015-08-06   | 18.9 (-7.7)  | 16.2 (-10.4) | 2.7         | b 
15pz         | 10:44:02.36 | +11:42:15.1 | M95 (29.7)       | 2015-08-03   | 17.2 (-12.5) | 17.6 (-12.1) | -0.4        | a 
15nz         | 13:37:08.37 | -29:50:19.7 | M83 (28.4)       | 2015-07-02   | 18.9 (-9.5)  | 16.7 (-11.7) | 2.2         | a 
15mr         | 12:39:54.87 | +61:36:46.3 | NGC 4605 (28.8)  | 2015-07-01   | 15.7 (-13.1) | 15.5 (-13.3) | 0.2         | a 
15mo         | 14:03:10.76 | +54:22:49.1 | M101 (29.3)      | 2015-07-01   | 17.7 (-11.6) | 16.8 (-12.5) | 0.9         | a 
15mn         | 14:03:49.44 | +54:20:50.7 | M101 (29.3)      | 2015-07-01   | 18.7 (-10.6) | 17.0 (-12.3) | 1.7         | a 
15mk         | 10:03:18.90 | +68:43:52.1 | NGC 3077 (27.8)  | 2015-07-01   | 16.5 (-11.3) | 15.7 (-12.1) | 0.8         | a 
 

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

b) No counterpart in reference (2010).

We note that many of these sources lie in the intermediate luminosity gap between classical novae and supernovae, and we encourage follow-up to discern their nature as eruptive or explosive phenomena. Please contact us if additional information (such as finding charts) is needed. We caution that we do not have spectroscopic confirmation that these transients belong to the reported host galaxies, and there is some chance they are unrelated foreground or background events.