ASAS-SN Discovery of a Probable Supernova in PGC 060077

ATel #5183; K. Z. Stanek, B. J. Shappee, C. S. Kochanek, J. Jencson, U. Basu, J. F. Beacom (Ohio State), J. L. Prieto (Princeton), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), M. Dubberley, M. Elphick, S. Foale, E. Hawkins, D. Mullens, W. Rosing, R. Ross, Z. Walker (Las Cumbres Observatory)
on 1 Jul 2013; 16:40 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Krzysztof Stanek (stanek.32@osu.edu)

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During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"; ATel #5110, #5138, #5168, #5177, #5181), using data from the double 14-cm "Brutus" telescope in Haleakala, Hawaii, we discovered a new transient source, likely a supernova:

 
Object       RA (J2000)    DEC (J2000)     Disc. UT Date   Approx. Disc. V mag 
 
ASASSN-13aw  17:19:30.195 +47:42:06.50    2013 July 1.4    16.1 

No source is detected on 6/25 or in earlier images (V>17 mag), with detection in four images on 7/01 and possible detection on 6/28. See the ASAS-SN discovery images at this location, top left panel shows the reference image, top right shows the DSS image on the same angular scale, lower left is the non-detection on 06/25 and lower right is the detection image on 07/01 (both bottom images show image subtraction residuals). Circle with the 15" radius has the same position in all images.

The new source is approximately 2.5" South and 9" West of the z=0.016835 spiral galaxy PGC 060077, giving it an absolute magnitude of approximately -18.4 (m-M=34.4, A_V=0.07, Schlafly & Finkbeiner 2011) and an offset from the galaxy of approximately 3.5 kpc for a distance of 75 Mpc. Follow-up observations are planned and encouraged.

For more information about the ASAS-SN project, see this link and also ASAS-SN Transients page.