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MASTER: bright dwarf nova outburst and 2 OT

ATel #8293; O. Gress , P. Balanutsa, V. Lipunov, E. Gorbovskoy (Lomonosov MSU), N. Samus(INASAN, SAI MSU),N. Tiurina, V. Kornilov, A. Kuznetsov, I. Gorbunov, D. Vlasenko, E. Popova, V. Vladimirov (M. V. Lomonosov MSU, SAI), N. Budnev, K. Ivanov (Irkutsk State University, Applied Physics Institute), R. Rebolo, M. Serra-Ricart, N. Lodieu, G. Israelian (The Instituto de Astrofisica de Canarias), D. Buckley, S. Potter, M. Kotze (South African Astronomical Observatory)
on 17 Nov 2015; 17:54 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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

MASTER OT J224405.86+434532.2 discovery - possible dwarf nova outburst, ampl>3m

MASTER-Tunka auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 349171 )discovered OT source at (RA, Dec) = 22h 44m 05.86s +43d 45m 32.2s on 2015-11-16.51056 UT.
The OT unfiltered magnitude is 15.9m (the limit is 18.8m).
The OT is seen in 3 images at this night. We have reference images without OT, for ex. on 2011-07-12.72193 UT with unfiltered magnitude limit 18.9m.

MASTER-Net archive photometry is the following:
Date, UT m_OT (unfiltered, W=0.2B+0.8R USNOB1)
2015-09-09 14:08:24 16.0
2015-07-23 21:46:06 16.4
2014-10-04 19:59:54 16.5
2014-09-04 20:21:00 15.9
2010-11-08 17:17:28 18.3

The upper limits (unfiltered, W=0.2B+0.8R USNOB1) are the following:
2015-04-26 22:52:11 17.1
2014-07-12 21:39:18 18.5
2013-09-05 17:22:55 18.5
2012 - Mar, Apr, June, Sept, Oct, Nov, Dec
2011-07-12 17:19:35 18.9
2010-09-11 14:05:46 17.4
There is V0374 Lac variable star ( also known as USNO star with known B=(18.6-19.8), R=18.6 , the difference between observation time for B2 and R2 mags is 2 years.)
The coordinates in GCVS for this star are the coordinates for its western neigbour (7" diff.)

So we suggest the dwarf nova outburst with Amplitude more then 3m.

Spectral observations are required.

The discovery and reference images are available at http://master.sai.msu.ru/static/OT/MASTEROTJ224405.86+434532.2.jpg

MASTER OT J031911.88+163152.7 detection - possible UVCet-type flare

MASTER-IAC auto-detection system discovered OT source at (RA, Dec) = 03h 19m 11.88s +16d 31m 52.7s. The OT is seen in 3 images with the following unfiltered magnitudes:
2015-11-17.071 m_OT=17.6
2015-11-17.078 m_OT=19.3
2015-11-17.086 m_OT~20.0
We have reference image without OT on 2015-11-15.07128 UT with unfiltered magnitude limit 20.1m.

There is only WISE source, so we suggest the red dwarf flare

The discovery and reference images are available at http://master.sai.msu.ru/static/OT/031911.88163152.7.png

MASTER OT J071020.81-592606.6 detection - possible UVCet type flare

MASTER-SAAO auto-detection system discovered OT source at (RA, Dec) = 07h 10m 20.81s -59d 26m 06.6s. The OT is seen at 4 images with the following unfiltered magnitudes:
2015-11-07 21:58:36 m_lim=19.9
2015-11-07 22:09:55 m_OT=19.4
2015-11-07 22:13:24 m_OT=19.4
2015-11-07 22:16:52 m_OT=18.9
2015-11-07 22:25:12 m_OT~20.2
We have reference image without OT on 2014-12-21.90351 UT with unfiltered magnitude limit 20.7m.
The discovery and reference images are available at http://master.sai.msu.ru/static/OT/071020.81-592606.6.png

List of Optical Transients discovered by MASTER

MASTER Global Robotic Net