MASTER OTs: PSN and dwarf nova outburst with Ampl>5.5m

ATel #8252; P. Balanutsa, V. Vladimirov, V. Lipunov, E. Gorbovskoy (Lomonosov MSU), D. Buckley (SAAO), V. Kornilov, N. Tiurina, A. Kuznetsov, D. Vlasenko, I. Gorbunov, V. Chazov, E. Popova (M. V.Lomonosov Moscow State University, SAI), S. Potter, A. Knyazev, M. Kotze (South African Astronomical Observatory), R. Rebolo Lopez, M. Serra-Ricart, G. Israelian, N. Lodieu, L. Suarez-Andres ( Instituto de Astrofisica de Canarias), O. Gress, N. Budnev, K. Ivanov (Irkutsk State University, Applied Physics Institute), A. Tlatov, V. Senik, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Krushinskiy (Ural Federal University), Yu. Sergienko, A. Gabovich, V. Yurkov (Blagoveschensk Educational State University)
on 6 Nov 2015; 22:35 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J115328.30-752242.8 discovery - possible SN in unknown galaxy or new dwarf nova outburst with ampl>4.8m

MASTER-SAAO auto-detection system ( Lipunov et al., Advances in Astronomy, MASTER Global Robotic Net, 2010 ) discovered OT source at (RA, Dec) = 11h 53m 28.30s -75d 22m 42.8s on 2015-11-03.02269 UT.
The OT unfiltered magnitude is 17.5m (the limit is 18.8m). The OT is seen in 4 images. We have reference image without OT on 2015-03-12.98314 UT with unfiltered magnitude limit 19.4m.
There is no known source in VIZIER database inside 5". There is a galaxy-like GSC2.2 source in 8.4" with Bmag=19.3m.
So we can suggest an SN in this galaxy or dwarf nova outburst with ampl>4.8m (POSS limit is about 22m).
Spectral observations are required.
The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/115328.30-752242.8.png

MASTER OT J174238.72-654023.3 discovery - new dwarf nova outburst with ampl>5.5m

MASTER-SAAO auto-detection system discovered OT source at (RA, Dec) = 17h 42m 38.72s -65d 40m 23.3s on 2015-11-03.76037 UT with unfiltered magnitude 17.2m (limit 19.9m)
This OT was seen in 12 images. We have reference image without OT on 2015-06-20.78638 UT with unfiltered magnitude limit 19.5m. We reobserved it on 2015-11-06 20:36:28.801 , ufiltered m_OT=16.5 (3 images).
There is no known source in VIZIER database, it means, that up to POSS limit(22m) there was no registered outburst befor (in CRTS database too). So we suggest the dwarf nova outburst with amplitude more then 5.5m
Spectral observations are required.
The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/174238.72-654023.3.png

MASTER Global Robotic Net