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ASAS-SN Discovery of a Likely Supernova in 2MASX_J12470274-2414435

ATel #6252; T. W.-S. Holoien (Ohio State), J. Brimacombe (Coral Towers Observatory), K. Z. Stanek, B. J. Shappee, A. B. Davis, C. S. Kochanek, J. Jencson, U. Basu, J. F. Beacom (Ohio State), J. L. Prieto (Princeton/Diego Portales), D. Bersier (LJMU), D. Szczygiel, G. Pojmanski (Warsaw University Observatory)
on 20 Jun 2014; 20:40 UT
Credential Certification: Thomas Holoien (tholoien@astronomy.ohio-state.edu)

Subjects: Optical, Supernovae, Transient

Referred to by ATel #: 6293

During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the recently commissioned double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy 2MASX_J12470274-2414435

Object       RA (J2000)     DEC (J2000)      Disc. UT Date   Disc. V mag 
ASASSN-14cu  12:47:02.68    -24:14:41.3     2014-06-18.04     17.2    

ASASSN-14cu was discovered in images obtained 2014 UT June 18.04 at V~17.2 mag. We also detect the object in images obtained on June 20.05 (V~16.2) and possibly detect the object on June 02.07 (V~17.1), but we do not detect (V>17.1) the object in images taken on 2014 UT June 01.07 and before. Images obtained on UT June 18.55 with the RCOS 16" telescope near Siding Spring Observatory and on UT June 19.90 with the LCOGT 1-m robotic telescope in Sutherland, South Africa, confirm the detection of the transient. This figure shows the ASAS-SN reference image (top left), ASAS-SN June 20.05 subtraction image (top right), archival DSS image (bottom left), and the LCOGT confirmation image (bottom right). The red circle has a radius of 3.0" at the position of the SN.

The ASAS-SN position of ASASSN-14cu is approximately 2.7" North and 5.0" East of the core of 2MASX_J12470274-2414435 (z=0.024797, d=108 Mpc, via NED), which would give it an absolute V mag of approx. -19.2 in the latest epoch (m-M=35.18, A_V=0.260, Schlafly & Finkbeiner 2011).

As the object appears to be getting brighter, follow-up observations are strongly encouraged.

We thank LCOGT and its staff for their continued support of ASAS-SN. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.