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ASAS-SN Discovery of A Probable Supernova in CGCG 064-017

ATel #7000; E. Conseil (Association Francaise des Observateurs d'Etoiles Variables), J. M. Fernandez (Observatory Inmaculada del Molino), R. A. Koff (Antelope Hills Observatory), J. Brimacombe (Coral Towers Observatory), C. Gonzalez, C. Contreras (Las Campanas Observatory), Eric Y. Hsaio (Aarhus University) T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, A. B. Danilet, G. Simonian, U. Basu, N. Goss, J. F. Beacom (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), S. Kiyota (Variable Star Observers League in Japan), B. Nicholls (Mt. Vernon Obs., New Zealand)
on 27 Jan 2015; 20:03 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 CGCG 064-017:

Object       RA (J2000)     DEC (J2000)      Disc. UT Date   Disc. V mag 
ASASSN-15cd  09:59:14.99   +12:59:18.27      2015-01-26.46    17.0 

ASASSN-15cd was discovered in images obtained on UT 2015-01-26.46 at V~17.0 mag. We also detect the object in images obtained on UT 2015-01-23.46 (V~17.1), UT 2015-01-21.46 (V~17.4), and UT 2015-01-19.49 (V~17.2). We do not detect (V>17.7) the object in images taken on UT 2015-01-16.48 and before. Images obtained on UT 2015-01-27.33 with the Swope 1-m telescope at Las Campanas Observatory and at earlier times on 2015-01-26 and 2015-01-27 by multiple other observers and telescopes confirm the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the Swope i-band confirmation image (right). The red circle has a radius of 2.0" and is centered on the position of the transient in the Swope image.

The position of ASASSN-15cd is approximately 1.8" North and 3.4" East from the center of the starburst galaxy CGCG 064-017 (z=0.034352, d=150 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.0 (m-M=35.88, A_V=0.083). 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.