[vsnet-alert 15238] OT J122221.6-311525 = bright CRTS transient

[Taichi Kato]

OT J122221.6-311525 = bright CRTS transient

SSS130101:122222-311525 http://nesssi.cacr.caltech.edu/SSS/20130101/1301010310804113661.html 12 22 21.63 -31 15 24.9 12.36 No SDSS object CV

   No outburst was recorded in ASAS-3.

ROSAT source:
122221.4 -311544 (2000.0) 1RXS-F_J122221.5-311545 0.050 0.75 0.05

===

ATEL #4699							     ATEL #4699

Title:	Detection of a Bright Optical Transient by CRTS
Author:	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).
Queries:	ajd at cacr.caltech.edu
Posted:	4 Jan 2013; 00:24 UT
Subjects:Optical, Cataclysmic Variable, Transient, Variables

Further to ATel#4678, here we report the CRTS discovery of 
<a href=http://nesssi.cacr.caltech.edu/SSS/20130101/1301010310804113661.html>SSS130101:122222-311525</a>.

This source was detected at V = 12.3+/-0.1 in four images taken by the
<a href=http://www.mso.anu.edu.au/~rmn/>Siding Spring Survey</a>  
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  
<a href="http://crts.caltech.edu/ATEL/SSS/1301010310804113661.atel.html">here</a>.