ASAS-SN Discovery of A Probable Supernova in CGCG 063-098

ATel #7413; J. Brimacombe (Coral Towers Observatory), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, A. B. Danilet, G. Simonian, U. Basu, N. Goss, 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), P. R. Wozniak (LANL), E. Falco (CfA), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), J. G. Carballo (Observatorio Cerro del Viento MPC 184), S. Kiyota (Variable Star Observers League in Japan), R. A. Koff (Antelope Hills Observatory), G. Krannich (Roof Observatory Kaufering), L. A.G. Monard (Klein Karoo Observatory), B. Nicholls (Mt. Vernon Obs., New Zealand), J. Nicolas (Groupe SNAUDE, France), W. Wiethoff (University of Minnesota, Duluth)
on 19 Apr 2015; 20:42 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@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 "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy CGCG 063-098.

ASASSN-15hg was discovered in images obtained on UT 2015-04-19.33 at V~16.9 mag. We do not detect (V>17.9) the object in images taken on UT 2015-04-13.34 and before. An image obtained by J. Brimacombe on UT 2015-04-19.63 with the RCOS 41-cm telescope near Siding Spring Observatory confirms 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 5" and is centered on the position of the transient in the J. Brimacombe image.

The position of ASASSN-15hg is approximately 0.2" North and 9.1" West from the center of the galaxy CGCG 063-098 (z=0.029771, d=130 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.8 (m-M=35.57, A_V=0.134). 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-15hg  09:53:48.62   +09:11:37.78      2015-04-19.33      16.9          -18.8               9.1 

 
Obs. UT Date         V mag 
2015-04-13.34        >17.9 
2015-04-19.33         16.9 

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.