ASASSN-16ai: Discovery of A Probable Supernova in UGC 09450
ATel #8537; 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)
on 13 Jan 2016; 01:52 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jonathan Brown (firstname.lastname@example.org)
Subjects: Optical, Supernovae, Transient
Referred to by ATel #: 8540
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 UGC 09450.
ASASSN-16ai was discovered in images obtained on UT 2016-01-12.58 at V~17.0 mag. We also detect the object in images obtained on UT 2016-01-10.57 (V~17.0), UT 2016-01-07.61 (V~17.2), UT 2016-01-03.59 (V~17.1), and UT 2015-12-29.64 (V~17.2). We do not detect (V>16.6) the object in images taken on UT 2015-12-24.62 and before. This figure shows the ASAS-SN V-band reference image (left), the ASAS-SN subtraction image (middle), and the archival SDSS image of the host (right). The red circle has a radius of 5" and is centered on the position of the transient in the subtraction image.
The position of ASASSN-16ai is approximately 4.4" South and 8.6" West from the center of the galaxy UGC 09450 (z=0.014900, d=64.6 Mpc, via NED), giving an absolute V-band magnitude of approximately -17.1 (m-M=34.05, A_V=0.088). 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-16ai 14:39:44.73 +23:23:43.27 2016-01-12.58 17.0 -17.1 9.66
Obs. UT Date V mag
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.