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ASAS-SN Discovery of A Probable Bright Supernova in Mrk 0576

ATel #7691; S. Kiyota (Variable Star Observers League in Japan), J. Brimacombe (Coral Towers Observatory), 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), E. Falco (CfA), P. R. Wozniak (LANL), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), E. Conseil (Association Francaise des Observateurs d'Etoiles Variables), J. M. Fernandez (Observatory Inmaculada del Molino), R. A. Koff (Antelope Hills Observatory), G. Masi (Virtual Telescope Project, Ceccano, Italy), J. Nicolas (Groupe SNAUDE, France)
on 23 Jun 2015; 04:21 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

Subjects: Optical, Supernovae, Transient

Referred to by ATel #: 7692, 7956

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 bright supernova, in the galaxy Mrk 0576.

ASASSN-15lp was discovered in images obtained on UT 2015-06-20.61 at V~15.1 mag. We also detect the object in images obtained on UT 2015-06-21.61 (V~15.2). We do not detect (V>16.8) the object in images taken on UT 2015-02-08.21 and before. (Due to the field being behind the Sun, we do not have more recent observations of the host.) Multiple confirmation images, including an image obtained on UT 2015-06-20.98 with the LCOGT 1-m robotic telescope in Cerro Tololo, Chile, confirm the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the LCOGT V-band confirmation image (right). The red circle has a radius of 2" and is centered on the position of the transient in the LCOGT image.

The position of ASASSN-15lp is approximately 1.1" South and 1.0" East from the center of the galaxy Mrk 0576 (z=0.017686, d=69.6 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.3 (m-M=34.21, A_V=0.181). 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-15lp  01:49:10.32   +05:38:23.32      2015-06-20.61      15.1          -19.3               1.49 
Obs. UT Date         V mag 
2015-02-08.21        >16.8 
2015-06-20.61         15.1 
2015-06-21.61         15.2 

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.