MASTER-OAFA: new OT outburst

ATel #11537; D. Savinov, V. Shumkov (Ozersk), V. Lipunov (Lomonosov MSU), R. Podesta (OAFA), H. Levato (ICATE), V. Kornilov, E. Gorbovskoy, N. Tiurina, I. Gorbunov, P. Balanutsa, A. Kuznetsov, Yu. Ishmuhametova, V. Chazov, D. Vlasenko, V. Vladimirov, O. Gress, T. Pogrosheva, D. Zimnukhov (Lomonosov Moscow State University, SAI), C. Lopez, F. Podesta (Observatorio Astronomico Felix Aguilar San Juan University), C. Saffe (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio), V. Senik (KSS), A. Gabovich(BSPU), D. Kuvshinov
on 16 Apr 2018; 13:35 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

Subjects: Optical, Request for Observations, Cataclysmic Variable, Transient, Variables

MASTER OT J090900.56+044904.1 discovery - new OT, preliminary dwarf nova outburst, ampl>5.5m
MASTER-OAFA auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L )
discovered OT source at (RA, Dec) = 09h 09m 00.56s +04d 49m 04.1s on 2018-04-16.11132 UT. The OT unfiltered magnitude is 17.2m (mlim=19.3m).
The OT is seen in 8 images (2018-04-16 02:32:37/04:38:26UT).

We have reference images without OT on 2017-02-20.20391 UT with 19.7 unfiltered magnitude limit.
There is no known sources in VIZIER, it means 22m POSS limit in history and more then 4.8mag of current outburst amplitude.
There is marginally seen source in Sloan images, but it is not presented in SDSS catalogues, it means 23m red limits (for ex., more brighter RADec=137.25029,+04.81057, r=22.81)
Spectral observations are required.

The discovery and reference images are
http://master.sai.msu.ru/static/OT/090900.56044904.1.png

List of Optical Transients discovered by MASTER

MASTER Global Robotic Net