ASAS-SN Discovery of A Probable Supernova in an Uncataloged Host Galaxy

ATel #8066; B. Nicholls (Mt. Vernon Obs., New Zealand), J. S. Brown, K. Z. Stanek, T. W.-S. Holoien, C. S. Kochanek, 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), E. Conseil (Association Francaise des Observateurs d'Etoiles Variables), J. M. Fernandez (Observatory Inmaculada del Molino), S. Kiyota (Variable Star Observers League in Japan), P. Marples (Leyburn Observatory, Australia), G. Masi (Virtual Telescope Project, Ceccano, Italy)
on 18 Sep 2015; 14:13 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (brown@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 "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in an uncataloged host galaxy.

ASASSN-15ps was discovered in images obtained on UT 2015-09-17.37 at V~17.5 mag. We do not detect (V>17.4) the object in images taken on UT 2015-09-13.310 and before. An image obtained on 2015-09-18 by B. Nicholls confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the B. Nicholls confirmation image (right). The red circle has a radius of 3" and is centered on the position of the transient in the B. Nicholls image.

The position of ASASSN-15ps is approximately 3.26" North and 3.41" East from the center of the uncataloged host galaxy (no redshift information available). 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-15ps  06:14:46.195    -66:13:00.99      2015-09-17.37      17.5          N/A               4.72 

 
Obs. UT Date         V mag 
2015-09-13.310        >17.4 
2015-09-17.37         17.5 

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.