MASTER-SAAO: 2 dwarf nova outbursts

ATel #8010; P. Balanutsa, V. Lipunov, E. Gorbovskoy (Lomonosov MSU), D. Buckley (SAAO), V. Kornilov, N. Tiurina, A. Kuznetsov, I. Gorbunov, V. Chazov, D. Vlasenko (Lomonosov Moscow State University, Sternberg Astronomical Institute), S. Potter, M. Kotze (South African Astronomical Observatory), R. Rebolo, M. Serra-Ricart, N. Lodieu, G. Israelian (The Instituto de Astrofisica de Canarias), O. Gress, N. M. Budnev, K. Ivanov (Applied Physics Institute, Irkutsk State University), A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk Solar Station of the Pulkovo Observatory), V. Krushinski, I. Zalozhnykh (Ural Federal University), Yu. Sergienko, A. Gabovich, V. Yurkov (Blagoveschensk Educational State University)
on 7 Sep 2015; 10:45 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J222712.34-495710.9 discovery -new dwarf nova outburst Ampl>3.6m (no VIZIER source)

MASTER-SAAO auto-detection system( Lipunov et al., Advances in Astronomy, MASTER Global Robotic Net, 2010 ) discovered OT source at (RA, Dec) = 22h 27m 12.34s -49d 57m 10.9s on 2015-09-05.83653 UT.

The OT unfiltered magnitude is 18.6m (limit 20.4m).

There are 5 images with this OT (2015-09-05.83653/05.8578 UT). There is no minor planet at this place. We have reference image without OT on 2014-12-25.79104 UT with unfiltered magnitude limit 19.9m. There is no any source inside 10" in VIZIER database(up to 21-22m). So we can suggest the dwarf nova outburst with amplitude more then 3.4m.

Spectral observations are required.

The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/222712.34-495710.9.png

MASTER OT J142507.82-351056.7 discovery - dwarf nova in outburst, Ampl>3m (GALEX UV)

MASTER-SAAO auto-detection system discovered OT source at (RA, Dec) = 14h 25m 07.82s -35d 10m 56.7s on 2015-09-05.78049 UT.

There are 6 images with OT m_OT=17.6 this night(the limit is 19.1m). There are about 50 images on 2015-05-24(19.3), 2015-05-10(19.5), 2015-03-30 (m_lim=19.3), 2015-03-05(m_lim=18.5), 2015-01-19(m_lim=19.4), 2015-01-08, 2015-01-04(m_lim=18.9), 2015-01-03 (m_lim=19.0) without OT in MASTER-SAAO database.
There are images with previous outburst on 2015-01-01.074/01.086UT with unfiltered m_OT=18.6 in MASTER-SAAO db.
There is a GSC2.3 star with only Blue 20.72m, and GALEX source with FUV=19.757 and NUV=18.867 (white dwarf).
So we can suggest the dwarf nova outburst with Ampl>3m.

Spectral observations are required.

The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/142507.82-351056.7.png

MASTER Global Robotic Net