SPIRITS Discoveries of Infrared Transients with Spitzer

ATel #6644; M. M. Kasliwal (Carnegie/Princeton), S. Tinyanont (HMC), J. Jencson, Y. Cao, D. Perley, D. O'Sullivan, T. Prince (Caltech), F. Masci, G. Helou, L. Armus, J. Surace, A. Cody, S. van Dyk (IPAC), H. Bond (PSU), J. Bally, E. Levesque (UC Boulder), R. Williams (STSCI), P. A. Whitelock (SAAO, UCT), S. Mohamed (SAAO), R. Gehrz, D. Shenoy, R. Carlon, D. Corgan, D. Dykhoff (U. Minnesota), N. Smith (U. Arizona), M. Cantiello (UCSB), N. Langer (U. Bonn), E. Ofek (WIS), M. Parthasarathy (IIA & IUCAA), M. Phillips, E. Hsiao, N. Morrell, C. Gonzalez, C. Contreras (LCO)
on 29 Oct 2014; 22:18 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 (SPRIITS) is the first large-scale systematic search for infrared transients in the nearby universe. We are seaching 190 nearby galaxies with the IRAC camera aboard the warm Spitzer telescope, to a depth of 20th mag (Vega) at 3.6 and 19th mag at 4.5 microns, at a cadence of one and six months.

Here, we report the recent discovery of unusual infrared transients/strong variables:

 
Name         |RA (J2000)  |DEC (J2000) |Host Galaxy (DM) |UT-discovery |[3.6] (abs)  |[4.5] (abs)      |[3.6]-[4.5] | Comments    
-------------+------------+------------+-----------------+-------------+-------------+-----------------+------------+----------------------------------- 
SPIRITS14bsb |01:35:06.72 |-41:26:13.4 |NGC0625   (28.1) |2014-10-3    |13.8 (-14.3) |13.2 mag (-14.9) |0.6 mag     | Near HII region - LBV?  
SPIRITS14bmc |00:54:49.68 |-37:39:51.2 |NGC0300   (26.4) |2014-9-5     |15.8 (-10.6) |15.1 mag (-11.3) |0.7 mag     | No Archival History of Variability 
SPIRITS14beq |22:02:41.52 |-51:17:34.5 |IC5152    (26.6) |2014-8-26    |17.0 (-9.5)  |16.7 mag (-9.9)  |0.3 mag     | Rising Light Curve   
SPIRITS14bay |12:56:43.25 |+21:42:25.7 |MESSIER064(28.3) |2014-8-20    |17.4 (-10.9) |16.2 mag (-12.1) |1.2 mag     | No Archival History of Variability 

We encourage follow-up to discern the nature of these sources. We note that no optical counterpart was detected prior to infrared discovery for SPIRITS14bay in iPTF imaging (near-daily coverage 2014-02-09 to 2014-05-28), for SPIRITS14beq in Swope imaging (2014-08-02) and for SPIRITS14bmc in Swope imaging (2014-06-20) to about 20 mag. We caution that we do not have spectroscopic confirmation that these transients belong to the putative host galaxies and there is some chance they are unrelated foreground or background events.

Additional details about the SPIRITS survey and a longer list of older transients, some with extensive follow-up, will be presented in a forthcoming publication. New transient discoveries will continue to be reported via ATel.