Detection of a Bright Optical Transient by CRTS

ATel #4699; A. J. Drake, S. G. Djorgovski, A. A. Mahabal, M. J. Graham, R. Williams (Caltech); R. McNaught (ANU); J. Prieto (Princeton); M. Catelan (PUC Chile); E. Christensen, S. M. Larson (LPL/UA).
on 4 Jan 2013; 00:24 UT
Credential Certification: Andrew J. Drake (ajd@cacr.caltech.edu)

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Further to ATel#4678, here we report the CRTS discovery of SSS130101:122222-311525. This source was detected at V = 12.3+/-0.1 in four images taken by the Siding Spring Survey on 2013-01-01 UT and is located at RA=12:22:21.63 Dec=-31:15:24.9

Based on 230 measurements (from 90 nights of observation between Aug. 2005 and Aug. 2012), the object has an average magnitude of V ~19. The source exhibits variability at the level of ~1 magnitude in this archival data, yet shows no prior outbursts. The source is well detected by GALEX (with NUV =18.9+/-0.1 and FUV 19.6+/-0.2) and may match ROSAT X-ray source 1RXS J122221.5-311545. The object is also a very good positional match to radio source NVSS J122222-311529. However, it is no clear source is seen in radio observations from the SUMSS and VLSS surveys.

This large, bright outburst, along with the UV detection and correspondence with an X-ray source, are most consistent with a cataclysmic variable. However, association with a radio source is generally unexpected for CVs and may be coincidental or spurious. Further observations are required to determine the nature of this event. A finding chart is available here.