ASAS-SN Discovery of A Probable Supernova in An Unknown Redshift Galaxy 2MASX J17210913+2534558
ATel #7536; J. Brimacombe (Coral Towers Observatory), K. Z. Stanek, T. W.-S. Holoien, C. S. Kochanek, J. S. Brown, 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), E. Falco (CfA), P. R. Wozniak (LANL), D. Szczygiel, G. Pojmanski (Warsaw University Observatory)
on 19 May 2015; 18:31 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Krzysztof Stanek (stanek.32@osu.edu)
Subjects: Optical, Supernovae, Transient
Referred to by ATel #: 7550
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 a new transient source, most likely a
supernova, in the galaxy 2MASX J17210913+2534558.
ASASSN-15jm was discovered in images obtained on UT 2015-05-19.41 at
V=17.1, and it was also marginally detected on UT 2015-05-13.46 at
V=17.6. It was not detected in images obtained on UT 2015-05-11.37
(V>17.1). An image obtained by J. Brimacombe on UT 2015-05-19T17:20
using a 33-cm telescope at Savannah Skies Observatory, Australia,
confirms the discovery of the transient. This
figure shows the archival DSS image of the host (left) and the
confirmation image (right). The red circle has a radius of 2" and is
centered on the position of the transient in the J. Brimacombe
image.
The position of ASASSN-15jm is approximately 1.3" from the center of
the galaxy
2MASX J17210913+2534558, clearly a spiral galaxy in SDSS images,
but with an unknown redshift. Properties of the new source are
summarized in the table below:
Object RA (J2000) DEC (J2000) Disc. UT Date Disc. V mag Approx. Abs. Mag Offset from Host (")
ASASSN-15jm 17:21:09.189 25:34:55.50 2015-05-19.41 17.1 --- 1.3
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.