ASASSN-16bb: Discovery of A Probable Supernova in SDSS J140557.36+435257.2

ATel #8621; S. Kiyota (Variable Star Observers League in Japan), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, 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), R. A. Koff (Antelope Hills Observatory), G. Masi (Virtual Telescope Project, Ceccano, Italy)
on 1 Feb 2016; 05:21 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

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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 J140557.36+435257.2.

ASASSN-16bb (AT 2016zc) was discovered in images obtained on UT 2016-01-31.60 at V~16.6 mag. We also detect the object in images obtained on 2016-01-28.56 (V~16.5). We do not detect (V>16.7) the object in images taken on UT 2016-01-26.55 and before. An image obtained by S. Kiyota on UT 2016-02-01.18 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-16bb is approximately 5.0" North and 2.9" West from the center of the galaxy SDSS J140557.36+435257.2 (z=0.033749, d=145 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.2 (m-M=35.80, A_V=0.02). 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-16bb  14:05:57.10    +43:53:02.20      2016-01-31.60      16.6          -19.2               5.78 

 
Obs. UT Date         V mag 
2016-01-26.55        >16.7 
2016-01-28.56         16.5 
2016-01-31.60         16.6 

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.