ASAS-SN Discovery of A Probable Supernova in 2MASX J15322270+4150586
ATel #7780; G. Masi (Virtual Telescope Project, Ceccano, Italy), J. Nicolas (Groupe SNAUDE, France), 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), J. Brimacombe (Coral Towers Observatory), E. Falco (CfA), P. R. Wozniak (LANL), D. Szczygiel, G. Pojmanski (Warsaw University Observatory)
on 9 Jul 2015; 23:16 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Krzysztof Stanek (email@example.com)
Subjects: Optical, Supernovae, Transient
Referred to by ATel #: 7787
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 2MASX J15322270+4150586.
ASASSN-15mg was discovered in images obtained on UT 2015-07-09.37 at V~17.1 mag. We do not detect (V>17.3) the object in images taken on UT 2015-07-06.38 and before. An image obtained on 2015-07-09 by G. Masi confirms the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the G. Masi confirmation image (right). The red circle has a radius of 3" and is centered on the position of the transient in the G. Masi image.
The position of ASASSN-15mg is approximately 1.29" North and 0.54" West from the center of the galaxy 2MASX J15322270+4150586 (z=0.043, d=183 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.3 (m-M=36.31, A_V=0.089). 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-15mg 15:32:22.80 +41:50:59.6 2015-07-09.37 17.1 -19.3 1.4
Obs. UT Date V mag
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.