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ASAS-SN Discovery of A Probable Supernova in SDSS J080519.59+225751.1

ATel #8098; J. Nicolas (Groupe SNAUDE, France), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, D. Godoy Rivera, G. Simonian, U. Basu, 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, Ping Chen (KIAA-PKU), J. Brimacombe (Coral Towers Observatory), E. Falco (CfA), P. R. Wozniak (LANL), G. Pojmanski (Warsaw University Observatory), G. Bock (Runaway Bay Observatory, Australia), J. G. Carballo (Observatorio Cerro del Viento MPC 184), I. Cruz (Cruz Observatory), S. Kiyota (Variable Star Observers League in Japan), P. Marples (Leyburn Observatory, Australia), G. Masi (Virtual Telescope Project, Ceccano, Italy)
on 26 Sep 2015; 05:42 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 #: 8105

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 J080519.59+225751.1.

ASASSN-15py was discovered in images obtained on UT 2015-09-25.61 at V~17.1 mag. We do not detect (V>17.2) the object in images taken on UT 2015-09-23.51 and before. An image obtained by J. Nicolas on UT 2015-09-26.11 using a 0.28-m telescope at Observatoire Les Mauruches, France confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the J. Nicolas confirmation image (right). The red circle has a radius of 3" and is centered on the position of the transient in the J. Nicolas image.

The position of ASASSN-15py is approximately 1.5" South and 1.3" West from the center of the galaxy SDSS J080519.59+225751.1 (z=0.044743, d=193 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.5 (m-M=36.43, A_V=0.183). 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-15py  08:05:19.50    +22:57:49.59      2015-09-25.61      17.1          -19.5               1.98 
Obs. UT Date         V mag 
2015-09-23.51        >17.2 
2015-09-25.61         17.1 

Follow-up observations are encouraged.

We thank LCOGT and its staff for their continued support of ASAS-SN. ASAS-SN is supported by NSF grant AST-1515927, the Mt. Cuba Astronomical Foundation, and the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.