MASTER: optical transients

ATel #10465; O. Gress, T. Pogrosheva, V. Lipunov (Lomonosov MSU), R. Podesta (OAFA), H. Levato (ICATE), D. Buckley (SAAO), E. Gorbovskoy, N. Tiurina, V. Shumkov, P. Balanutsa, A. Kuznetsov, V. Kornilov, V. Chazov, D. Vlasenko, V. Vladimirov, I. Gorbunov, A. Krylov (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), A. Gabovich (BSPU)
on 6 Jun 2017; 10:31 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J195357.46-630110.3 discovery - possibly dwarf nova, ampl>4.5m

MASTER-OAFA auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 19h 53m 57.46s -63d 01m 10.3s on 2017-06-04.06779 UT.
The OT unfiltered magnitude is 17.5m (mlim=18.1m).
The OT is seen in 3 images. There is no minor planet at this place. We have reference image without OT on 2017-04-03.24109 UT with 19.1 unfiltered magnitude limit
We reobserved it on 2017-06-05 22:49:01.893 with m_OT=18.5.
There is GSC2.3 star in 0.8" with blue jmag=22.11 on 1979.707, so the ampl of current outburst was more then 4.5m
The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/195357.46-630110.3.png

MASTER OT J141350.21-304032.8 detection - dwarf nova outburst, ampl>3.5m

MASTER-OAFA auto-detection system discovered OT source at (RA, Dec) = 14h 13m 50.21s -30d 40m 32.8s on 2017-05-29.04012 UT.
The OT unfiltered magnitude is 16.5m (mlim=19.3m). The OT is seen in 11 images.
We have reference image without OT on 2017-04-03.21322 UT with 20.1m unfiltered magnitude limit.
Previous outburst was on 2016-07-24 02:07:27.769UT with m_OT=15.5
.It means more then 3.5m of current outburst and >4.5m in last 2016y's outburst.
There is a GALEX source in 0.8", i.e. accretion process.
Spectral observations are required.
The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/141350.21-304032.8.png

MASTER OT J203042.96-195842.8 detection

MASTER-OAFA auto-detection system detected OT source at (RA, Dec) = 20h 30m 42.96s -19d 58m 42.8s on 2017-05-25.30853 UT.
The OT unfiltered magnitude is 18.9m (mlim=19.7m).
The OT is seen in 3 image. There is no minor planet at this place.
We have reference image without OT on 2017-03-11 03:20:26UT (MASTER-SAAO) with mlim=19.0, on 2016-11-19.04358 UT with 19.5m unfiltered magnitude limit .
The nearest known source is Gaia's with Gmag=18.3, and WISE source in 2.8" with J-K=0.7m.
22m POSS limit in history gives current ampl>2.7m.
Spectral observations are required.
The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/203042.96-195842.8.png

MASTER Global Robotic Net