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ASAS-SN Discovery of a Bright Transient in SDSS J171000.70+270619.6

ATel #6133; T. W.-S. Holoien, K. Z. Stanek, C. S. Kochanek, B. J. Shappee, J. Jencson, U. Basu, A. B. Davis, J. F. Beacom (Ohio State), J. L. Prieto (Princeton), J. Brimacombe (Coral Towers Observatory), D. Szczygiel, G. Pojmanski (Warsaw University Observatory), D. Bersier (LJMU)
on 12 May 2014; 21:43 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Krzysztof Stanek (stanek.32@osu.edu)

Subjects: Optical, Supernovae, Transient

Referred to by ATel #: 6143, 6144

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 in the center of SDSS J171000.70+270619.6:

Object       RA (J2000)       DEC (J2000)        Disc. UT Date    Disc. V mag 
ASASSN-14ax    17:10:00.7    +27:06:19.61        2014-05-04.47       16.5 
ASASSN-14ax was discovered in images obtained 2014 UT May 04.47 at V~16.5 mag. We also detect the transient at roughly the same magnitude in images obtained on 2014 UT May 07.47, UT May 08.47, UT May 10.46, and UT May 11.46, and do not detect (V>17.0) this object in images taken on 2014 UT Apr. 23.61 and before. This figure shows the ASAS-SN discovery subtraction image (top left), the latest ASAS-SN discovery image from May 11 (top right), the ASAS-SN reference image (bottom left), and the archival DSS image (bottom right). The red circle has a radius of 5" centered on the galaxy position from SDSS.

The transient's position in the ASAS-SN data is consistent with the position of the galaxy SDSS J171000.70+270619.6 (PhotZ = 0.058 +/- 0.026, from SDSS). There is no strong variability in CRTS at the transient position and the potential host galaxy is not a known AGN. The ASAS-SN coordinates of the source are consistent with the center of the galaxy, implying this could be a supernova, activity of a previously unknown AGN, or potentially something more exotic, such as a tidal disruption event. If we take the SDSS PhotZ redshift at face value, the luminosity distance of the source would be d~260 Mpc, giving an absolute V mag of approx. -20.7 (m-M=37.07, A_V=0.134, Schlafly & Finkbeiner 2011). Follow-up observations, especially spectroscopy, are 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.