Two bright OTs detected by MASTER

ATel #4790; V. Yecheistov, S. Shurpakov, D. Denisenko, V. Lipunov, E. Gorbovskoy, P. Balanutsa, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, D. Zimnukhov (Moscow State University, SAI), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov, A. Punanova (Ural Federal 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 the Pulkovo observatory RAS), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov (Blagoveshchensk Educational University), V. Shumkov, P. Podvorotny (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (Observatorio Astronomico Felix Aguilar; OAFA)
on 6 Feb 2013; 08:46 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

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MASTER OT J070740.72+702630.0 - new bright CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 07h 07m 40.72s +70d 26m 30.0s on 2013-02-05.44692 UT. The OT unfiltered magnitude is 14.5m (limit 18.4m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-08-20.69378 UT with unfiltered magnitude limit 19.2m.

There is a faint blue star at the position of the OT on Palomar images which is present in GSC 2.3.2 with the following coordinates and magnitudes: RA=07 07 40.633, Dec=+70 26 30.25, Fmag=19.90, jmag=20.72. The color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J070740+702630-BRIR5x5.jpg

The object has also an UV counterpart GALEX J070740.7+702629 (FUV=N/A, NUV=20.87+/-0.22). There is nothing at this position in 2MASS and 1RXS catalogs, as well as in GCVS and AAVSO VSX. This area of sky is not covered by CRTS, SDSS and NEAT.

Based on the outburst amplitude (about 6m) we conclude that MASTER OT J070740.72+702630.0 is most likely a dwarf nova of UGSU (SU UMa) subtype. Spectral and photometric observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/070740.72702630.0.png

MASTER OT J123526.99+163030.9 - new bright CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 12h 35m 26.99s +16d 30m 30.9s on 2013-02-05.72786 UT. The OT unfiltered magnitude is 14.5m (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 2010-04-06.68109 UT with magnitude limit 18.3m.

The object is identical to the star SDSS J123526.92+163031.2 with quiescent magnitudes u=21.99(15), g=22.00(7), r=21.79(7), i=22.24(16), z=21.87(43). No previous outbursts were detected on 9 DSS plates taken from 1956 to 1999, on 57 Palomar/NEAT images obtained on 18 different nights from 1998 Apr. 23 to 2003 Apr. 03 and by Catalina Sky Survey. There is nothing at this position in USNO-B1.0, GSC, 2MASS, 1RXS, GCVS catalogs and in AAVSO VSX.

Based on the outburst amplitude (more than 7m) and blue color at quiescence we conclude that MASTER OT J123526.99+163030.9 is a new cataclysmic variable, most likely of UGWZ (WZ Sge) type. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/123526.99163030.9.png

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