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ASASSN-16al: Discovery of A Probable Supernova in UGCA 397

ATel #8549; S. Kiyota (Variable Star Observers League in Japan), J. S. Brown, K. Z. Stanek, T. W.-S. Holoien, C. S. Kochanek, D. Godoy-Rivera, U. Basu (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong, Ping Chen (KIAA-PKU), J. Brimacombe (Coral Towers Observatory), G. Bock (Runaway Bay Observatory, Australia), R. A. Koff (Antelope Hills Observatory)
on 15 Jan 2016; 13:44 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (brown@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 "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy UGCA 397.

ASASSN-16al (AT 2016L) was discovered in images obtained on UT 2016-01-15.36 at V~17.0 mag. We do not detect (V>15.6) the object in images taken on UT 2016-01-14.38 and before. An image obtained on 2016-01-15 by S. Kiyota confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the S. Kiyota confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the S. Kiyota image.

The position of ASASSN-16al is approximately 2.1" South and 49.9" East from the center of the galaxy UGCA 397 (z=0.009297, d=41.3 Mpc, via NED), giving an absolute V-band magnitude of approximately -16.3 (m-M=33.06, A_V=0.276). 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-16al  15:00:27.468  -13:33:09.00      2016-01-15.36      17.0          -16.3               49.94 
Obs. UT Date         V mag 
2016-01-14.38        >15.6 
2016-01-15.36         17.0 

Follow-up observations are encouraged.

We thank LCOGT and its staff for their continued support of ASAS-SN. ASAS-SN is supported by NSF grant AST-1515927, the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, the Mt. Cuba Astronomical Foundation, George Skestos, and the Robert Martin Ayers Sciences Fund. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.