ASASSN-16lx: Discovery of A Supernova in IC 0607
ATel #9666; J. S. Brown, K. Z. Stanek, Stephan Frank (Ohio State), J. L. Prieto (Diego Portales; MAS), T. W.-S. Holoien, C. S. Kochanek, J. Shields (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), D. Bersier (LJMU), Subo Dong, S. Bose, Ping Chen (KIAA-PKU), J. Brimacombe (Coral Towers Observatory)
on 25 Oct 2016; 00:23 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 IC 0607.
ASASSN-16lx (AT 2016hht) was discovered in images obtained on UT 2016-10-19.62 at V~15.5 mag. We also detect the object in images obtained on UT 2016-10-16.63 (V~15.6). We do not detect (V>15.6) the object in images taken on UT 2016-10-15.63 and before. This figure shows the archival SDSS image of the host (left), the ASAS-SN V-band reference image (middle), and the ASAS-SN subtraction image (right). The red circle has a radius of 10" and is centered on the position of the transient in the subtraction image.
The position of ASASSN-16lx is approximately 3.1" South and 46.8" West from the center of the galaxy IC 0607 (z=0.018596, d=82.2 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.1 (m-M=34.53, A_V=0.115). Spectra of ASASSN-16lx obtained on 2016-10-21 with OSMOS on the MDM 2.4-m Hiltner telescope show the transient to be a Type Ia supernova near peak. The expansion velocity of the ejecta, as estimated from the Si II 635.5 nm line, is about 9700 km/s. 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-16lx 10:24:05.32 +16:44:27.67 2016-10-19.62 15.5 -19.1 46.9
Obs. UT Date V mag
2016-10-15.63 >15.6
2016-10-16.63 15.6
2016-10-19.62 15.5
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.
