ASAS-SN Discovery of A Probable Supernova in 2MASX J22340166-3223490
ATel #8386; B. Nicholls (Mt. Vernon Obs., New Zealand), G. Bock (Runaway Bay Observatory, Australia), J. Brimacombe (Coral Towers Observatory), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, D. Godoy-Rivera, U. Basu (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong, Ping Chen (KIAA-PKU), I. Cruz (Cruz Observatory), S. Kiyota (Variable Star Observers League in Japan), G. Krannich (Roof Observatory Kaufering), G. Masi (Virtual Telescope Project, Ceccano, Italy), W. Wiethoff (University of Minnesota, Duluth)
on 8 Dec 2015; 18:07 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)
Subjects: Optical, Supernovae, Transient
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 2MASX J22340166-3223490.
ASASSN-15tu was discovered in images obtained on UT 2015-12-08.09 at V~16.3 mag. We also detect the object in images obtained on UT 2015-12-04.11 (V~16.3). We do not detect (V>17.1) the object in images taken on UT 2015-11-28.02 and before. Images obtained by multiple observers on UT 2015-12-08 confirm the detecttion of the transient. This figure shows the archival DSS image of the host (left) and the J. Brimacombe confirmation image (right). The red circle has a radius of 5" and is centered on the position of the transient in the J. Brimacombe. image.
The position of ASASSN-15tu is approximately 4.4" South and 11.7" East from the center of the galaxy 2MASX J22340166-3223490 (z=0.01260, d=48.3 Mpc, via NED), giving an absolute V-band magnitude of approximately -17.2 (m-M=33.42, A_V=0.038). Properties of the new source 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-15tu 22:34:02.58 -32:23:53.58 2015-12-08.09 16.3 -17.2 12.5
Obs. UT Date V mag
2015-11-28.02 >17.1
2015-12-04.11 16.3
2015-12-08.09 16.3
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.
