ASAS-SN Discovery of A Probable Supernova in Unknown Redshift Galaxy 2MASX J0058421-1404122

ATel #7808; J. Brimacombe (Coral Towers Observatory), R. A. Koff (Antelope Hills Observatory), J. S. Brown, K. Z. Stanek, T. W.-S. Holoien, C. S. Kochanek, A. B. Danilet, 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 (KIAA-PKU), E. Falco (CfA), P. R. Wozniak (LANL), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), J. M. Fernandez (Observatory Inmaculada del Molino), G. Masi (Virtual Telescope Project, Ceccano, Italy), L. A.G. Monard (Klein Karoo Observatory), B. Nicholls (Mt. Vernon Obs., New Zealand), J. Nicolas (Groupe SNAUDE, France)
on 18 Jul 2015; 14:56 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (brown@astronomy.ohio-state.edu)

Tweet

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 J0058421-1404122.

ASASSN-15mp was discovered in images obtained on UT 2015-07-17.27 at V~16.7 mag. We also detect the object in images obtained on UT 2015-07-14.55 (V~16.9), UT 2015-07-15.28 (V~16.9), and UT 2015-07-18.27 (V~16.6). We do not detect (V>16.5) the object in images taken on UT 2015-07-03.33 and before. Follow-up images obtained with several telescopes confirm the discovery of the transient. This figure shows the archival DSS image of the host (left) and the J. Brimacombe confirmation image (right). The red circle has a radius of 3" and is centered on the position of the transient in the J. Brimacombe image.

The position of ASASSN-15mp is approximately 0.4" North and 0.8" East from the center of the galaxy 2MASX J0058421-1404122 (no redshift information available from NED). 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-15mp  00:58:45.265    -14:04:11.82      2015-07-17.27      16.7          N/A               0.89 

 
Obs. UT Date         V mag 
2015-07-03.33        >16.5 
2015-07-14.55         16.9 
2015-07-15.28         16.9 
2015-07-17.27         16.7 
2015-07-18.27         16.6 

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.