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ASAS-SN Discovery of A Probable Supernova in UGC 01332

ATel #7863; K. Z. Stanek, T. W.-S. Holoien, 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)
on 1 Aug 2015; 18:37 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Krzysztof Stanek (stanek.32@osu.edu)

Subjects: Optical, Supernovae

Referred to by ATel #: 7871

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 an elliptical galaxy UGC 01332.

ASASSN-15nn was discovered in images obtained on UT 2015-07-24.59 at V~16.7. It was also detected on images obtained on UT 2015-07-28.51 (V~16.2), UT 2015-07-30.61 (V~16.6) and UT 2015-08-01.6 (V~16.4). It was not detected in images obtained on 2015-07-19.56 (V>17.4). Images obtained on UT 2015-08-01 with the 1-m LCOGT robotic telescope at McDonald Observatory confirm the discovery of the transient. This figure shows the archival DSS image of the host (left) and the confirmation images (center and right). The red circle has a radius of 1.5" and is centered on the position of the transient in the LCOGT images.

The position of ASASSN-15nn is approximately 1.5" from the center of the galaxy UGC 01332 (z=0.022619, d=91 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.7 at discovery (m-M=34.8, A_V=0.56). Properties of the new source are summarized in the table below:

Object       RA (J2000)     DEC (J2000)    Disc. UT Date   Disc. V mag  Approx. Abs. Mag   Offset from Host (") 
ASASSN-15nn  01:52:18.17    +48:05:17.3     2015-07-24.5     16.7         -18.7                     1.5    

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.