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ASASSN-16ci: Discovery of A Type Ia Supernova in NGC 1272

ATel #8765; Ryan Chornock, Reza Katebi (Ohio University), J. S. Brown, T. W.-S. Holoien, K. Z. Stanek, 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)
on 3 Mar 2016; 13:46 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 "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, most likely a supernova, in the galaxy NGC 1272.

ASASSN-16ci (AT 2016arc) was discovered in images obtained on UT 2016-02-26.24 at V~16.5 mag. We also detect the object in images obtained on UT 2016-03-02.23 (V~16.3), and UT 2016-03-01.23 (V~16.2). We do not detect (V>16.9) the object in images taken on UT 2016-02-22.24 and before. An image obtained on 2016-03-03 by R. Chornock with the MDM 2.4-m Hiltner telescope confirms the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the MDM 2.4-m confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the MDM 2.4-m image. We also obtained a spectrum of ASASSN-16ci on UT 2016-03-03 with OSMOS on the MDM 2.4-m Hiltner telescope, which suggests ASASSN-16ci to be a Type Ia supernova around maximum light.

The position of ASASSN-16ci is approximately 1.0" South and 0.3" East from the center of the galaxy NGC 1272 (z=0.012725, d=50.5 Mpc, via NED), giving an absolute V-band magnitude of approximately -17.5 (m-M=33.52, A_V=0.441). 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-16ci  03:19:21.321    +41:29:25.61      2016-02-26.24      16.5          -17.5               1.04 
Obs. UT Date         V mag 
2016-02-22.24        >16.9 
2016-02-26.24         16.5 
2016-03-01.23         16.2 
2016-03-02.23         16.3 

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, 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.