ASAS-SN Discovery of Two Possible Supernovae in Hosts with Unknown Redshifts
ATel #7450; T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, A. B. Danilet, G. Simonian, U. Basu, N. Goss, J. F. Beacom, T. A. Thompson (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong (KIAA-PKU), P. R. Wozniak (LANL), E. Falco (CfA), J. Brimacombe (Coral Towers Observatory), D. Szczygiel, G. Pojmanski (Warsaw University Observatory)
on 27 Apr 2015; 04:31 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (firstname.lastname@example.org)
Subjects: Optical, Supernovae, Transient
Referred to by ATel #: 7458
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 a two new transient sources, possibly supernovae, both near potential hosts with unknown redshifts.
ASASSN-15hy was discovered in images obtained on UT 2015-04-25.210 at V~16.4 mag. We also detect the object in images obtained on UT 2015-04-26.210 (V~16.2). We do not detect (V>16.8) the object in images taken on UT 2015-04-21.34 and before. An image obtained on UT 2015-04-27.09 with the LCOGT 1-m robotic telescope in Sutherland, South Africa confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the LCOGT g-band confirmation image (right). The red circle has a radius of 4" and is centered on the position of the transient in the LCOGT image.
The position of ASASSN-15hy is approximately 6.4" North and 11.2" West from what appears to be a galaxy in archival DSS images, but the potential host is not listed in NED.
ASASSN-15hz was discovered in images obtained on UT 2015-04-26.38 at V~17.2 mag. We do not detect (V>17.5) the object in images taken on UT 2015-04-19.310 and before. An image obtained on UT 2015-04-27.13 with the LCOGT 1-m robotic telescope in Sutherland, South Africa confirms the discovery of the transient. This figure shows the archival DSS image of the host (left) and the LCOGT g-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-15hz is approximately 3.3" South and 1.4" East from the center of the galaxy APMUKS(BJ) B222606.49-654315.6, which has no available redshift in NED. (See here.)
Properties of the new sources 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-15hy 20:10:02.35 -00:44:21.31 2015-04-25.21 16.4 N/A 12.9
ASASSN-15hz 22:29:38.08 -65:27:56.24 2015-04-26.38 17.2 N/A 3.58
Obs. UT Date V mag
Obs. UT Date V mag
Follow-up observations, particularly spectroscopy, 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.