ASAS-SN Discovery of Two Probable Supernovae in NGC 0745 and LCRS B021111.4-453206
ATel #7915; Subo Dong (KIAA-PKU), K. Z. Stanek, C. S. Kochanek, J. S. Brown, A. B. Danilet, T. W.-S. Holoien, G. Simonian, U. Basu, J. F. Beacom, T. A. Thompson (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), J. Brimacombe (Coral Towers Observatory), E. Falco (CfA), P. R. Wozniak E. Falco (CfA), P. R. Wozniak (LANL), D. Szczygiel, G. Pojmanski (Warsaw University Observatory)
on 16 Aug 2015; 08:34 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Subo Dong (dongsubo@pku.edu.cn)
Subjects: Optical, Supernovae
During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered two new transient sources, most likely supernovae, in the galaxies NGC 0745 and LCRS B021111.4-453206.
ASASSN-15ol was discovered in images obtained on UT 2015-08-15.20 at V ~ 16.4. We also detect the object in images obtained on UT 2015-08-14.24 (V~17.1). We do not detect (V>16.3) the object in images taken on UT 2015-08-01.32 and before. A V-band image obtained by 1.0m LCOGT telescope at Siding Spring on UT 2015-08-15.66 confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the LCOGT 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-15ol is approximately 15" from the center of the galaxy NGC 0745 (z=0.019777, via NED), giving an absolute V-band magnitude of approximately -18.2 (m-M=34.51, A_V=0.084).
ASASSN-15om was discovered in images obtained on UT 2015-08-15.42 at V ~ 17.1. We do not detect (V>17.4) the object in images taken on UT 2015-08-13.24 and before. A V-band image obtained by 1.0m LCOGT telescope at Siding Spring on UT 2015-08-15.65 confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the LCOGT 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-15om is approximately 7" from the center of the galaxy LCRS B021111.4-453206 (z=0.041719, via NED), giving an absolute V-band magnitude of approximately -19.1 (m-M=36.14, A_V=0.056).
Properties of the new sources and photometry are summarized in the tables below:
Object RA (J2000) DEC (J2000) Disc. UT Date Disc. V mag
ASASSN-15ol 01:54:06.04 -56:41:42.50 2015-08-15.20 16.43
ASASSN-15om 02:13:07.47 -45:18:08.04 2015-08-15.42 17.13
Follow-up observations of both sources are encouraged.
We thank LCOGT and its staff for their continued support of ASAS-SN. ASAS-SN is supported in part by 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.
