MASTER-SAAO discovery: possible ultraluminous SN in GALEX galaxy or CV (ampl>5.1m)
ATel #9595; P. Balanutsa, V. Lipunov (Lomonosov MSU), D. Buckley (SAAO), R. Podesta (OAFA), H. Levato (ICATE), E. Gorbovkoy, N. Tiurina, A. Kuznetsov, V. Kornilov, V. Shumkov, O. Gress, K. Ivanov, V. Vladimirov (Lomonosov MSU), S. Potter (SAAO), C. Lopez, F. Podesta (Observatorio Astronomico Felix Aguilar), C. Saffe (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio), T. Pogrosheva
on 5 Oct 2016; 08:54 UT
Credential Certification: Nataly Tyurina (firstname.lastname@example.org)
Subjects: Optical, Cataclysmic Variable, Supernovae, Transient
Referred to by ATel #: 10872
MASTER OT J235631.58-505643.2 discovery - ultraluminous PSN in AGN GALEXASC J235631.46-505642.1 galaxy (in cluster) or CV with ampl>5.1m
MASTER-SAAO auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 23h 56m 31.58s -50d 56m 43.2s on 2016-10-04 21:27:26.34UT with unfiltered m_OT=17.4 (mlim=20.6).
The OT is seen in 2 images in MASTER-SAAO (discovery) and in 2 images in MASTER-OAFA (2016-10-05 04:31:01UT).
We have reference image without OT on 2016-08-07 07:36:06UT in MASTER-OAFA with unfiltered m_lim=20.8 .
There is a galaxy cluster in this area, so this OT can be the ultraluminous SN.
There is a GALEX host galaxy in 0.025 arcmin with possible AGN (unknown redshift, etc).
The second scenario is dwarf nova outburst with amplitude more then 5.1m (there is blue GSC2.3.2star in 0.6" with known only jmag=22.5, MASTER W is calibrated by USNO-B1 stars as 0.2B+0.8R)
The discovery and reference images are http://master.sai.msu.ru/static/OT/MASTEROTJ235631.58-505643.2.jpg
Spectral observations are required List of Optical Transients discovered by MASTER
MASTER Global Robotic Net