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ASASSN-16np: Discovery of A Probable Supernova in SDSS J123643.42+260647.1

ATel #9798; J. Brimacombe (Coral Towers Observatory), G. Stone (Sierra Remote Observatories), J. S. Brown, K. Z. Stanek, T. W.-S. Holoien, C. S. Kochanek, 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)
on 27 Nov 2016; 20:20 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 SDSS J123643.42+260647.1.

ASASSN-16np (AT 2016inu) was discovered in images obtained on UT 2016-11-14.65 at V~15.9 mag. We also detect the object in images obtained on UT 2016-11-26.65 (V~16.8). We do not detect (V>18.0) the object in images taken on UT 2016-07-09.25 and before. An image obtained on 2016-11-16 by J. Brimacombe confirms the discovery of the transient. This figure shows the archival SDSS g-band 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 1.5" North and 2.9" West from the center of the galaxy SDSS J123643.42+260647.1 (z=0.020835, d=91.1 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.9 (m-M=34.75, A_V=0.044). 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  12:36:43.21    +26:06:48.67     2016-11-14.65      15.9          -18.9               3.26 
Obs. UT Date         V mag 
2016-07-09.25        >18.0 
2016-11-14.65         15.9 
2016-11-26.65         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.