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ASAS-SN Discovery of A Probable Supernova in 2MASX J15254441+5921091

ATel #7568; J. Nicolas (Groupe SNAUDE, France), J. M. Fernandez (Observatory Inmaculada del Molino), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, 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), S. Kiyota (Variable Star Observers League in Japan), L. A.G. Monard (Klein Karoo Observatory), B. Nicholls (Mt. Vernon Obs., New Zealand), W. Wiethoff (University of Minnesota, Duluth)
on 27 May 2015; 02:37 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

Subjects: Optical, Supernovae, Transient

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 J15254441+5921091.

ASASSN-15ke was discovered in images obtained on UT 2015-05-26.35 at V~17.0 mag. We also detect the object in images obtained on UT 2015-05-24.38 (V~17.2). We do not detect (V>17.1) the object in images taken on UT 2015-05-21.24 and before. Images obtained by J. Nicolas on UT 2015-05-26.88 using a 0.41-m telescope at Observatoire Chante-Perdrix-Dauban, France, and by J. M. Fernandez on UT 2015-05-26.97 with a 20-cm Celestron C8 telescope at Observatory Inmaculada del Molina in Osuna, Spain, confirm 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-15ke is approximately 0.7" North and 3.2" East from the center of the galaxy 2MASX J15254441+5921091 (z=0.045359, d=194 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.5 (m-M=36.43, A_V=0.03). 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-15ke  15:25:44.81   +59:21:10.09      2015-05-26.35      17.0          -19.5               3.28 
Obs. UT Date         V mag 
2015-05-21.24        >17.1 
2015-05-24.38         17.2 
2015-05-26.35         17.0 

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.