ASAS-SN Discovery of A Probable Supernova in 2MASX J05401415-3848285

ATel #7259; J. Brimacombe (Coral Towers Observatory), S. Kiyota (Variable Star Observers League in Japan), R. A. Koff (Antelope Hills Observatory), G. Krannich (Roof Observatory Kaufering), 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 I84), J. M. Fernandez (Observatory Inmaculada del Molino), W. Wiethoff (University of Minnesota, Duluth)
on 20 Mar 2015; 17:28 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

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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 2MASX J05401415-3848285:

 
Object       RA (J2000)     DEC (J2000)      Disc. UT Date   Disc. V mag 
ASASSN-15fk  05:40:12.18   -38:48:42.51      2015-03-19.12    17.0 

ASASSN-15fk was discovered in images obtained on UT 2015-03-19.12 at V~17.0 mag. We also detect the object on UT 2015-03-20.15 (V~17.3) and UT 2015-03-16.13 (V~17.0). We do not detect (V>17.4) the object in images taken on UT 2015-03-14.07 and before. Images obtained by J. Brimacombe on UT 2015-03-20.40 with the RCOS 41-cm telescope near Siding Spring Observatory and by S. Kiyota on UT 2015-03-20.43 using a 0.5m CDK + FLI PL-9000 at the ITelescope.NET site at Siding Springs 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 circle has a radius of 5" and is centered on the position of the transient in the S. Kiyota image.

The position of ASASSN-15fk is approximately 13.8" South and 23.4" West from the center of the galaxy 2MASX J05401415-3848285 (z=0.035972, d=153 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.0 (m-M=35.92, A_V=0.076). 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.