MASTER-Net: PSN and dwarf novae

ATel #7566; O. Gress (ISU), V. Vladimirov, V. Lipunov (Lomonosov MSU), D. Buckley (SAAO), E. Gorbovskoy, V. Kornilov, N. Tiurina(Lomonosov MSU), N. Samus (INASAN), S. Antipin, P. Balanutsa, A. Kuznetsov, V. Chazov, E. Popova (Lomonosov Moscow State University, Sternberg Astronomical Institute), S. Potter, A. Kniazev, M. Kotze (The South African Astronomical Observatory), N. Budnev, K. Ivanov, S. Yazev, V. Poleshchuk (Irkutsk State University), A. Tlatov, D. Dormidontov, V. Senik, A. Parkhomenko, (Kislovodsk solar station of the Pulkovo observatory RAS), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), Yu. Sergienko, V. Yurkov, A. Gabovich (Blagoveschensk State Educational University), V. Shumkov, S. Shurpakov (MASTER-Team)
on 26 May 2015; 19:29 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J225624.49-333456.0 discovery - new Dwarf Nova outburst (Ampl>3.8m) or possible SN in 6dFJ2256308-333429 galaxy

MASTER-SAAO auto-detection system ( Lipunov et al., Advances in Astronomy, MASTER Global Robotic Net, 2010 ) discovered OT source at (RA, Dec) = 22h 56m 24.49s -33d 34m 56.0s on 2015-05-26.03661 UT.
The OT unfiltered magnitude is 18.2m (the limit is 20.2m).

There are 5 images with OT from 2015-05-26.03661 to 2015-05-26.064.

We have reference image without OT on 2015-04-09.13021 UT with 19.8 unfiltered magnitude limit. There is no known source in VIZIER database inside 5", CRTS observed this area, but has never seen a source. So we can suggest the Dwarf Nova outburst with amplitude more then 3.8m.
There is bright galaxy in 83", and there is a possibility to be a PSN in it.

Spectral observations are required.

The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/225624.49-333456.0.png

MASTER OT J211809.20+265714.0 discovery - Dwarf Nova outburst with Ampl>4m

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 21h 18m 09.20s +26d 57m 14.0s on 2015-05-25.90788 UT.
The OT unfiltered magnitude is 17.8m (the limit is 19.0m).

The OT is seen in 3 images. There is no minor planet at this place.
We have reference image without OT on 2011-08-31.84289 UT with 20.0 unfiltered magnitude limit.

There is GSC2.3 star with jmag=21.85. So we can suggest that MASTER OT is the Dwarf Nova outburst with Ampl>4m.

Spectral observations are required.

The discovery and reference images are available at:http://master.sai.msu.ru/static/OT/211809.20265714.0.png

MASTER OT J210819.26+315453.4 discovery - new Dwarf Nova outburst with Ampl>4.3

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 21h 08m 19.26s +31d 54m 53.4s on 2015-05-25.90998 UT.
The OT unfiltered magnitude is 17.7m (the limit is 18.8m).

The OT is seen in 7 images. There is no minor planet at this place.

We have a lot of images without OT in MASTER-Kislovodsk database, for ex.,on 2013-11-09.64701 UT with 18.5 unfiltered magnitude limit.

Spectral observations are required.

The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/210819.26315453.4.png

MASTER Global Robotic Net