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ASAS-SN Discovery of A Probable Supernova in LCRS B102206.7-024353

ATel #7398; S. Kiyota (Variable Star Observers League in Japan), J. Brimacombe (Coral Towers Observatory), B. Nicholls (Mt. Vernon Obs., New Zealand), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, A. B. Danilet, G. Simonian, U. Basu, N. Goss, J. F. Beacom, T. A. Thompson (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), E. Falco (CfA), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), J. G. Carballo (Observatorio Cerro del Viento MPC 184), R. A. Koff (Antelope Hills Observatory), G. Krannich (Roof Observatory Kaufering), L. A.G. Monard (Klein Karoo Observatory), J. Nicolas (Groupe SNAUDE, France), W. Wiethoff (University of Minnesota, Duluth)
on 15 Apr 2015; 15:32 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

Subjects: Optical, Supernovae, Transient

Referred to by ATel #: 7405, 7411

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 LCRS B102206.7-024353.

ASASSN-15hc was discovered in images obtained on UT 2015-04-15.20 at V~17.0 mag. We also detect the object in images obtained on UT 2015-04-12.20 (V~16.6). We do not detect (V>17.3) the object in images taken on UT 2015-04-06.23 and before. Images obtained by S. Kiyota on UT 2015-04-15.42 using a 0.5m CDK + FLI PL-9000 at the ITelescope.NET site at Siding Springs Observatory, by J. Brimacombe on UT 2015-04-15.44 with the RCOS 41-cm telescope near Siding Spring Observatory, and by B. Nicholls on UT 2015-04-15.45 using the 30-cm telescope at Mt. Vernon Observatory confirm the discovery of the transient. This figure shows the archival DSS image of the host (left) and the S. Kiyota confirmation image (right). The red lines indicate the position of the transient in the S. Kiyota image.

The position of ASASSN-15hc is approximately 0.3" South and 5.1" West from the center of the galaxy LCRS B102206.7-024353 (z=0.030978, d=136 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.8 (m-M=35.66, A_V=0.117). Properties of the new source and photometry are summarized in the tables below:

Object       RA (J2000)     DEC (J2000)      Disc. UT Date   Disc. V mag  Approx. Abs. Mag   Offset from Host (") 
ASASSN-15hc  10:24:38.82   -02:59:07.82      2015-04-15.20      17.0          -18.8               5.11 
Obs. UT Date         V mag 
2015-04-06.23        >17.3 
2015-04-12.20         16.6 
2015-04-15.20         17.0 

Follow-up observations are encouraged.

We thank LCOGT and its staff for their continued support of ASAS-SN. ASAS-SN is supported in part by Mt. Cuba Astronomical Foundation. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.