ASAS-SN Discovery of A Probable Supernova near ESO 047-G004

ATel #7719; J. Brimacombe (Coral Towers Observatory), T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, J. S. Brown, A. B. Danilet, G. Simonian, U. Basu, 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), G. Masi (Virtual Telescope Project, Ceccano, Italy)
on 26 Jun 2015; 20:33 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 double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, near the galaxy ESO 047-G004.

ASASSN-15lx was discovered in images obtained on UT 2015-06-26.36 at V~17.3 mag. We do not detect (V>17.3) the object in images taken on UT 2015-06-25.14 and before. An image obtained by J. Brimacombe on UT 2015-06-26.69 with the CDK 43-cm telescope at Savannah Skies Observatory confirms the discovery 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 3" and is centered on the position of the transient in the J. Brimacombe image.

The position of ASASSN-15lx is approximately 14.28" Northeast from the center of the galaxy ESO 047-G004 (z=0.012625, d=51.8 Mpc, via NED), giving an absolute V-band magnitude of approximately -16.4 (m-M=33.57, A_V=0.156) if this is the host galaxy. We note that there is another uncatalogued source visible in the DSS image near the position of the transient that could be the actual host galaxy. 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-15lx  20:36:05.24    -73:06:32.41      2015-06-26.36      17.3          -16.4               14.28 

 
Obs. UT Date         V mag 
2015-06-25.14        >17.3 
2015-06-26.36         17.3 

Follow-up observations 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.