ASAS-SN Discovery of Two Probable Supernovae in CGCG 107-031 and SDSS J112849.43+295454.2
ATel #7094; J. Brimacombe (Coral Towers Observatory), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, A. B. Danilet, G. Simonian, U. Basu, N. Goss, J. F. Beacom (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), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), R. A. Koff (Antelope Hills Observatory), S. Kiyota (Variable Star Observers League in Japan), B. Nicholls (Mt. Vernon Obs., New Zealand)
on 17 Feb 2015; 19:29 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (firstname.lastname@example.org)
Subjects: Optical, Supernovae, Transient
Referred to by ATel #: 7103
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 two new transient sources, most likely supernovae, in the galaxies CGCG 107-031 and SDSS J112849.43+295454.2:
Object RA (J2000) DEC (J2000) Disc. UT Date Disc. V mag
ASASSN-15dd 15:43:59.07 +19:12:40.74 2015-02-15.58 17.1
ASASSN-15de 11:28:49.65 +29:54:52.51 2015-02-17.40 17.0
ASASSN-15dd was discovered in images obtained on UT 2015-02-15.58 at V~17.1 mag. We also detect the object in images obtained on UT 2015-02-17.58 (V~16.6), UT 2015-02-17.56 (V~16.6), and UT 2015-02-15.52 (V~16.7). We do not detect (V>16.7) the object in images taken on UT 2015-02-08.55 and before. An image obtained by J. Brimacombe on UT 2015-02-17.68 with the CDK 43-cm telescope at Savannah Skies Observatory confirms the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the J. Brimacombe confirmation image (right). The red circle has a radius of 3.0" and is centered on the position of the transient in the J. Brimacombe image.
The position of ASASSN-15dd is approximately 0.7" South and 2.5" East from the center of the galaxy CGCG 107-031 (z=0.024374, d=104 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.1 (m-M=35.08, A_V=0.15).
ASASSN-15de was discovered in images obtained on UT 2015-02-17.40 at V~17.0 mag. We do not detect (V>17.3) the object in images taken on UT 2015-02-17.46 and before. An image obtained by J. Brimacombe on UT 2015-02-17.65 with the CDK 43-cm telescope at Savannah Skies Observatory confirms the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the J. Brimacombe confirmation image (right). The red circle has a radius of 4.0" and is centered on the position of the transient in the J. Brimacombe image.
The position of ASASSN-15de is approximately 1.8" South and 2.8" East from the center of the galaxy SDSS J112849.43+295454.2 (z=0.051720, d=225 Mpc, via NED), giving an absolute V-band magnitude of approximately -19.8 (m-M=36.76, A_V=0.06).
Follow-up observations of both transients 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.