ASAS-SN Discovery of A Probable Supernova in CGCG 448-007

ATel #8162; J. Brimacombe (Coral Towers Observatory), W. Wiethoff (University of Minnesota, Duluth), R. A. Koff (Antelope Hills Observatory), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, D. Godoy-Rivera (Ohio State), B. J. Shappee (Hubble Fellow, Carnegie Observatories), J. L. Prieto (Diego Portales; MAS), D. Bersier (LJMU), Subo Dong, Ping Chen (KIAA-PKU), S. Kiyota (Variable Star Observers League in Japan), G. Krannich (Roof Observatory Kaufering), G. Masi (Virtual Telescope Project, Ceccano, Italy), B. Nicholls (Mt. Vernon Obs., New Zealand), J. Nicolas (Groupe SNAUDE, France)
on 14 Oct 2015; 03:13 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

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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 CGCG 448-007.

ASASSN-15re was discovered in images obtained on UT 2015-10-13.30 at V~16.8 mag. We also detect the object in images obtained on UT 2015-10-10.29 (V~17.0). We do not detect (V>17.7) the object in images taken on UT 2015-10-09.33 and before. Images obtained by J. Brimacombe, W. Wiethoff, and R. A. Koff confirm the discovery of the transient. This figure shows the archival SDSS g-band image of the host (left) and the W. Wiethoff confirmation image (right). The red circle has a radius of 3" and is centered on the position of the transient in the W. Wiethoff image.

The position of ASASSN-15re is approximately 1.7" North and 1.3" East from the center of the galaxy CGCG 448-007 (z=0.030314, d=123 Mpc, via NED), giving an absolute V-band magnitude of approximately -18.9 (m-M=35.45, A_V=0.206). 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-15re  20:48:07.78    +16:23:01.33      2015-10-13.30      16.8          -18.9               2.14 

 
Obs. UT Date         V mag 
2015-10-09.33        >17.7 
2015-10-10.29         17.0 
2015-10-13.30         16.8 

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 Science Fund. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.