Three Optical Transients discovered by MASTER

ATel #5486; V. Yecheistov, P. Balanutsa, D. Denisenko, E. Gorbovskoy, V. Lipunov, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Vladimirov, D. Cheryasov, M. Kornilov, B. Safonov, D. Gareyeva (Moscow State University, SAI), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov, A. Gabovich (Blagoveshchensk Educational University), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress, A. Frolova (Irkutsk State University), A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk Solar Station of Pulkovo Observatory), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), P. Podvorotny, V. Shumkov, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez, F. Podest (OAFA), M. I. Panasyuk, S. I. Svertilov, A. F. Iyudin, L. A. Kuzmichev (SINP MSU)
on 18 Oct 2013; 20:36 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

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MASTER OT J212901.84+385831.3 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 21h 29m 01.84s +38d 58m 31.3s on 2013-10-16.45439 UT. The OT unfiltered magnitude is 16.2m (limit 17.6m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2011-11-22.37397 UT with magnitude limit in 'R' filter 18.1m.

There is a blue star within 1" from the OT in several catalogues: USNO-A2.0 1275-15792989 (21 29 01.764 +38 58 31.98 B=19.2 R=19.2) and USNO-B1.0 1289-0464929 (B1=19.40 R1=19.14 B2=19.80 R2=18.67 I=18.36). The star appears double on the digitized Palomar plates. Color-combined finder chart is uploaded to http://master.sai.msu.ru/static/OT/J212901+385831-BRIR5x5.jpg (200% zoom).

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. There is a faint UV object nearby GALEX J212902.0+385833 (NUV=20.97+/-0.38). This area of sky in Cygnus is not covered by SDSS, NEAT and CRTS.

Based on the blue color and outburst amplitude (~4m), MASTER OT J212901.84+385831.3 is a cataclysmic variable (dwarf nova in outburst). Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/212901.84385831.3.jpg

MASTER OT J132729.58+745832.8 - new CV candidate

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 13h 27m 29.58s +74d 58m 32.8s on 2013-10-17.58052 UT. The OT unfiltered magnitude is 17.1m (limit 17.9m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2013-07-16.65765 UT with unfiltered magnitude limit 19.2m.

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. This area of sky in Ursa Minor is not covered by CRTS and NEAT. There is a faint blue star 1.8" from the OT listed in catalogs as USNO-A2.0 1575-03348040 (13 27 29.883 +74 58 34.1 B=18.8 R=19.3) and USNO-B1.0 1649-0071545 (13 27 29.835 +74 58 34.27 B1=19.82 R1=19.66 B2=20.07 R2=19.69 I=19.38). It has an UV counterpart GALEX J132729.7+745834 (FUV=19.89+/-0.12, NUV=19.99+/-0.07). Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J132729+745832-BRIR.jpg (10'x10' FOV).

Based on the blue color and UV detection, MASTER OT J132729.58+745832.8 is likely a cataclysmic variable. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/132729.58745832.8.jpg

MASTER OT J074940.48+071557.1 - new CV candidate

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 07h 49m 40.48s +07d 15m 57.1s on 2013-10-17.76016 UT. The OT unfiltered magnitude is 15.3m (limit 16.8m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-03-27.53987 UT with unfiltered magnitude limit 17.9m.

There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. No previous outbursts were detected by CRTS and NEAT. This area of sky in Leo Minor is not covered by GALEX. There is a faint star SDSS J074940.52+071558.8 (u=25.75, g=24.94, r=23.45, i=21.53, z=20.84) 1.9" from the OT. It is not clear if it is related to the transient.

Based on the outburst amplitude (at least ~6m), MASTER OT J074940.48+071557.1 is likely a dwarf nova of UGSU or UGWZ type in superoutburst. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/074940.48071557.1.jpg

This work was supported by the Ministry of Education and Science of the Russian Federation under the Agreement No. 8415 (27.08.2012).

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