[vsnet-alert 16016] ASASSN-13bq (ATEL)

Taichi Kato tkato at kusastro.kyoto-u.ac.jp
Thu Jul 18 09:43:10 JST 2013

   This object may be a CV in outburst.

ATEL #5209							     ATEL #5209

Title:	ASAS-SN Discovery of a Bright Optical Transient Near PGC 065535
Author:	K. Z. Stanek, B. J. Shappee, C. S. Kochanek, J. Jencson, U.
		 Basu, T. Haloien, J. F. Beacom (Ohio State), J. L. Prieto (Princeton),
		D. Szczygiel, G. Pojmanski (Warsaw University Observatory), M. Dubberley,
		M. Elphick, S. Foale, E. Hawkins, D. Mullens, W. Rosing, R. Ross,
		Z. Walker (Las Cumbres Observatory), J. Brimacombe (Coral Towers Observatory)
Queries:	stanek.32 at osu.edu
Posted:	16 Jul 2013; 16:53 UT
Subjects:Optical, Cataclysmic Variable, Supernovae, Transient

During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or

"Assassin"; ATel #5138, #5168, #5177, #5183, #5186, #5193), using data
the double 14-cm "Brutus" telescope in Haleakala, Hawaii, we 
discovered a new transient source, possibly a bright supernova or a CV

in outburst:

Object       RA (J2000)    DEC (J2000)     Disc. UT Date   Approx. Disc.
V mag 

ASASSN-13bq  20 51 13.447 -18 38 52.63     2013 7 16.45     15.0 

No source is detected on 7/14 or in earlier images (V>17 mag), with 
initial strong detection in two ASAS-SN images on 7/16, followed by 
confirmation detection still the same night (3.7 hours later) on 
another four images, giving consistent magnitude estimate.  See the 

image</a>, top left panel shows the reference image, top right shows 
the DSS image on the same angular scale, lower left is one of the 
90-sec V-band images on 07/14 and lower right is the first detection 
image on 07/16. Circle with the 15" radius has the same position. 

The new source is approximately 71.2" South and 73.1" East of the 
center of z=0.020257 (86 Mpc) galaxy PGC 065535, giving it an 
absolute magnitude of approximately M_V=-19.8 (m-M=34.7, A_V=0.16, 
Schlafly & Finkbeiner 2011) and a projected distance from the galaxy 
center of approximately 41 kpc.

However, close to our position, about 8" away, there is a faint 
USNO-B1.0 source with B=21.4, but fairly red colors. A faint source is

also present 7" away in the CRTS catalog, but it shows no significant 
previous variability. These two datum argue somewhat against 
ASASSN-13bq being a CV in an outburst. Follow-up spectroscopy to 
determine the nature of this source is strongly encouraged.

For more information about the ASAS-SN project, see <a 
href=http://www.astronomy.ohio-state.edu/~assassin/>this link</a> and 
also <a 

Transients</a> page.

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