ASASSN-16kw: Discovery of A Probable Supernova in 2MASX J05080487-4141151
ATel #9555; T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, 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), J. Brimacombe (Coral Towers Observatory)
on 27 Sep 2016; 15:43 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@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 "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX J05080487-4141151.
ASASSN-16kw (AT 2016gqc) was discovered in images obtained on UT 2016-09-27.34 at V~17.1 mag. We also detect the object in images obtained on UT 2016-09-25.32 (V~16.8) and UT 2016-09-20.27 (V~17.2). We do not detect (V>17.1) the object in images taken on UT 2016-09-18.27 and before. This figure shows the archival DSS image of the host (left), the ASAS-SN V-band reference image of the host (center), and the ASAS-SN V-band subtraction image from the discovery epoch (right). The red circle has a radius of 5" and is centered on the position of the transient in the ASAS-SN image.
The position of ASASSN-16kw is approximately 1.4" North and 3.7" East from the center of the galaxy 2MASX J05080487-4141151 (z=0.044534, d=190 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.4 (m-M=36.39, A_V=0.061). 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-16kw 05:08:05.22 -41:41:13.66 2016-09-27.34 17.1 -19.4 3.96
Obs. UT Date V mag
2016-09-18.27 >17.1
2016-09-20.27 17.2
2016-09-25.32 16.8
2016-09-27.34 17.1
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.
