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ASASSN-16np: Discovery of A Probable Supernova in IC 0493

ATel #9796; J. Brimacombe (Coral Towers Observatory), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, J. Shields (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong, S. Bose, Ping Chen (KIAA-PKU), S. Kiyota (Variable Star Observers League in Japan), P. Marples (Leyburn Observatory, Australia), B. Nicholls (Mt. Vernon Obs., New Zealand), R. S. Post (Post Astronomy), G. Stone (Sierra Remote Observatories)`
on 26 Nov 2016; 21:16 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

Subjects: Optical, Supernova Remnant, Transient

Referred to by ATel #: 9797, 9805

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 IC 0493. If confirmed, this will be the 400th supernova discovered by ASAS-SN.

ASASSN-16np (AT 2016inu) was discovered in images obtained on UT 2016-11-26.59 at V~16.8 mag. We also detect the object in images obtained on UT 2016-11-24.65 (V~17.0). We do not detect (V>16.8) the object in images taken on UT 2016-11-15.48 and before. An image obtained on UT 2016-11-26 by J. Brimacombe confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the J. Brimacombe confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the J. Brimacombe image.

The position of ASASSN-16np is approximately 15.0" South and 3.2" West from the center of the galaxy IC 0493 (z=0.020708, d=89.4 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.1 (m-M=34.76, A_V=0.106). 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-16np  08:07:27.35   +25:07:47.54     2016-11-26.59      16.8          -18.1               15.34 
Obs. UT Date         V mag 
2016-11-15.48        >16.8 
2016-11-24.65         17.0 
2016-11-26.59         16.8 

Follow-up observations are encouraged.

While we are participating in the TNS system to minimize potential confusion, ASAS-SN will continue using ASASSN-16xx transient names as our primary nomenclature (including supernovae, but also other classes of transients), and we encourage others to do the same. We prefer merging the names as ASASSN-16xx (AT2016xyz) to preserve, rather than anonymize, the origin of the transient.

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, and the 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.