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ASAS-SN Discovery of A Probable Supernova in NGC 3774

ATel #6860; T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, A. B. Davis, G. Simonian, U. Basu, N. Goss, J. F. Beacom (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong (KIAA-PKU), P. R. Wozniak (LANL), J. Brimacombe (Coral Towers Observatory), D. Szczygiel, G. Pojmanski (Warsaw University Observatory)
on 31 Dec 2014; 01:46 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Krzysztof Stanek (stanek.32@osu.edu)

Subjects: Supernovae, Transient

Referred to by ATel #: 6876, 6882

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, most likely a supernova, in the galaxy NGC 3774:

Object       RA (J2000)     DEC (J2000)      Disc. UT Date   Disc. V mag 
ASASSN-14my  11:38:29.98   -08:58:35.79      2014-12-30.29    16.5 

ASASSN-14my was discovered in images obtained on UT 2014-12-30.29 at V~16.5 mag. We also detect the object in images obtained on UT 2014-12-30.55 (V~16.5) and UT 2014-12-28.29 (V~17.0). We do not detect (V>17.5) the object in images taken on UT 2014-12-26.29 and before. An image obtained on UT 2014-12-30.443 with the LCOGT 1-m robotic telescope at McDonald Observatory confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the LCOGT g-band confirmation image (right). The red lines are centered on the position of the transient in the LCOGT image.

The position of ASASSN-14my is approximately 1.7" South and 4.1" West from the center of the galaxy NGC 3774 (z=0.020514, d=90.8 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.4 (m-M=34.79, A_V=0.104). Follow-up observations 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 ASAS-SN Homepage and the list of all ASAS-SN transients.