ASAS-SN Discovery of A Probable Supernova near GALEXASC J001127.51-062549.8
ATel #8226; Subo Dong (KIAA-PKU), K. Z. Stanek, J. S. Brown, 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), Ping Chen (KIAA-PKU), J. Brimacombe (Coral Towers Observatory), R. A. Koff (Antelope Hills Observatory)
on 30 Oct 2015; 10:58 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Subo Dong (dongsubo@pku.edu.cn)
Subjects: Optical, Supernovae, Transient
Referred to by ATel #: 8230
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 GALEXASC J001127.51-062549.8.
ASASSN-15sf was discovered in images obtained on UT 2015-10-30.08 at V~16.5 mag. We also detect the object in images obtained on UT 2015-10-28.22 (V~17.0) and UT 2015-10-29.23 (V~16.7). We do not detect (V>16.8) the object in images taken on UT 2015-10-27.34 and before. A V-band image obtained on 2015-10-30.14 with the LCOGT 1-m robotic telescope at Cerro Tololo confirms the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the LCOGT V-band confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the LCOGT image.
The position of ASASSN-15sf is approximately 12" away from the center of the galaxy GALEXASC J001127.51-062549.8 (no redshift information available from NED). Properties of the new source are summarized below:
Object RA (J2000) DEC (J2000) Disc. UT Date Disc. V mag Approx. Abs. Mag Offset from Host (")
ASASSN-15sf 00:11:27.6 -06:25:38.4 2015-10-30.08 16.5 N/A 12
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 Mt. Cuba Astronomical Foundation, the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, 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.
