[vsnet-alert 17698] ASASSN-14gs

[Taichi Kato]

ASASSN-14gs

   Possible high amplitude dwarf nova.

The Astronomer's Telegram                   http://www.astronomerstelegram.org

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ATEL #6450							     ATEL #6450

Title:	ASAS-SN Discovery of A Bright Transient near PGC 058582
Author:	S. Kiyota (Variable Star Observers League in Japan), B. Nicholls
		(Mt. Vernon Obs., New Zealand), J. Brimacombe (Coral Towers Observatory),
		T. W.-S. Holoien, K. Z. Stanek, B. J. Shappee, A. B. Davis, C. S.
		Kochanek, U. Basu, J. F. Beacom (Ohio State), J. L. Prieto (Diego
		Portales; MAS), D. Bersier (LJMU), D. Szczygiel, G. Pojmanski (Warsaw
		University Observatory), E. Conseil (Association Francaise des Observateurs
		d'Etoiles Variables), I. Cruz (Cruz Observatory), L. A.G. Monard
		(Klein Karoo Observatory), J. Nicolas (Groupe SNAUDE, France)
Queries:	tholoien at astronomy.ohio-state.edu
Posted:	6 Sep 2014; 15:34 UT
Subjects:Optical, Supernovae, Transient

During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or
"Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro
Tololo, Chile, we discovered a new transient source, possibly a supernova,
near the galaxy PGC 058582: 

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

ASASSN-14gs  16:36:11.17    -26:12:02.78     2014-09-06.01     14.5 

ASASSN-14gs was discovered in images obtained on UT 2014-09-06.01 at V~14.5
mag. We do not detect (V>16.8) the object in images taken on UT 2014-08-29.05
and before. Images obtained by S. Kiyota on UT 2014-09-06.36 using a 0.5m
CDK + FLI PL-9000 at the ITelescope.NET site at Siding Springs Observatory,
by B. Nicholls on UT 2014-09-06.41 using the 30cm telescope at Mt. Vernon
Observatory, and by J. Brimacombe on UT 2014-09-06.42 with the RCOS 41-cm
telescope near Siding Spring Observatory confirm the discovery of the transient.
This <a href=http://www.astronomy.ohio-state.edu/~assassin/followup/asassn-14gs.png>figure</a>
shows the S. Kiyota confirmation image (left) and the archival DSS image
of the same location (right). The red circle has a radius of 5" and is
centered on the position of the transient in the S. Kiyota image. 

The position of ASASSN-14gs is approximately 8.2" North and 54.8" East
from the center of the galaxy PGC 058582 (z=0.013709, d=56.1 Mpc, via NED).
If this is indeed a supernova associated with this galaxy, this would give
it an absolute V-band magnitude of approximately -20.7 (m-M=33.74, A_V=1.46).
However, given the magnitude and location of the source, a large amplitude
cataclysmic variable outburst is also a possible explanation. Follow-up
observations, especially spectroscopy, are encouraged. 

We thank LCOGT and its staff for their continued support of ASAS-SN. For
more information about the ASAS-SN project, see the <a href=http://www.astronomy.ohio-state.edu/~assassin/index.shtml>ASAS-SN
Homepage</a> and the list of all <a href=http://www.astronomy.ohio-state.edu/~assassin/transients.html>ASAS-SN
transients</a>.