ASAS-SN Discovery of A Probable Supernova in SDSS J085940.13+151113.6

ATel #7228; J. Brimacombe (Coral Towers Observatory), S. Kiyota (Variable Star Observers League in Japan), 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 15 Mar 2015; 20:28 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 quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy SDSS J085940.13+151113.6:

 
Object       RA (J2000)     DEC (J2000)      Disc. UT Date   Disc. V mag 
ASASSN-15ez  08:59:40.20    +15:11:12.5      2015-03-15.210    16.9 

ASASSN-15ez was discovered in images obtained on UT 2015-03-15.210 at V~16.9 mag. We do not detect (V>17.2) the object in images taken on UT 2015-02-27.30 and before. Images obtained by J. Brimacombe on UT 2015-03-15.60 with the RCOS 41-cm telescope near Siding Springs Observatory and by S. Kiyota on UT 2015-03-15.61 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 SDSS g-band image of the host (left) and the J. Brimacombe confirmation image (right). The red circle has a radius of 4.0" and is centered on the position of the transient in the J. Brimacombe image.

The position of ASASSN-15ez is approximately 1.1" South and 0.4" East from the center of the galaxy SDSS J085940.13+151113.6 (z=0.028724, d=125 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.7 (m-M=35.48, A_V=0.101). 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.