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ASASSN-16am: Discovery of A Probable Supernova in CGCG 328-018

ATel #8556; G. Masi (Virtual Telescope Project, Ceccano, Italy), 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), S. Kiyota (Variable Star Observers League in Japan)
on 17 Jan 2016; 02:14 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (brown@astronomy.ohio-state.edu)

Subjects: Optical, Supernovae, Transient

Referred to by ATel #: 8560

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 328-018.

ASASSN-16am (AT 2016N) was discovered in images obtained on UT 2016-01-15.36 at V~17.4 mag. We also detect the object in images obtained on UT 2016-01-10.28 (V~17.4) and UT 2016-01-12.47 (V~17.8). We do not detect (V>17.9) the object in images taken on UT 2016-01-07.39 and before. An image obtained on 2016-01-16 by G. Masi confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the G. Masi confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the G. Masi image.

The position of ASASSN-16am is approximately 13.5" North and 4.8" East from the center of the galaxy CGCG 328-018 (z=0.015024, d=61.7 Mpc, via NED), giving an absolute V-band magnitude of approximately -17.0 (m-M=33.92, A_V=0.470). 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-16am  04:45:21.278  +73:23:41.09      2016-01-15.36      17.4          -17.0               14.33 
Obs. UT Date         V mag 
2016-01-07.39        >17.9 
2016-01-10.28         17.4 
2016-01-12.47         17.8 
2016-01-15.36         17.4 

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.