Three Optical Transients detected by MASTER

ATel #4938; P. Balanutsa, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Yecheistov, 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), P. Podvorotny, V. Shumkov, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (OAFA)
on 2 Apr 2013; 23:10 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

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MASTER OT J164114.46+192840.9 - new CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 16h 41m 14.46s +19d 28m 40.9s on 2013-03-31.01380 UT. The OT unfiltered magnitude is 16.3m (limit 18.3m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-05-28.842 UT with unfiltered magnitude limit 19.7m.

The object at quiescence is identical to the star SDSS J164114.49+192840.5 (u=22.11, g=22.14, r=21.70, i=21.44, z=20.91). It is present in GSC 2.3.2 with coordinates 16 41 14.512 +19 28 40.71 and jmag=21.66. No previous outbursts were detected on 12 Palomar plates and by CRTS. There is nothing at this position in 1RXS, GALEX, 2MASS, USNO, GCVS and AAVSO VSX.

Based on the amplitude of variability (about 5m) and blue color we conclude that MASTER OT J164114.46+192840.9 is a new cataclysmic variable in outburst. Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/164114.46192840.9.png

MASTER OT J201403.13+535152.5 - CV or PSN

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 20h 14m 03.13s +53d 51m 52.5s on 2013-04-01.03234 UT. The OT unfiltered magnitude is 16.9m (limit 19.0m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2010-11-10.68868 UT with magnitude limit in 'BLANK' filter 20.3m.

There is nothing at this position in any catalogue. This area of sky in Cygnus is not covered by CSS and SDSS. Nothing is visible on the combination of digitized Palomar plates to limiting magnitude ~21.5m. Most likely the object is a new cataclysmic variable in outburst. However, we note that the OT is located 31.6" west and 38.1" south of the center of PGC 2453368 galaxy. Color-combined (BRIR) DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J201403+535152.5.jpg

Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/201403.13535152.5.png

MASTER OT J175753.35+344227.5 - new CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 17h 57m 53.35s +34d 42m 27.5s on 2013-04-02.05797 UT. The OT unfiltered magnitude is 17.1m (limit 19.1m). The OT is seen in 4 images. There is no minor planet at this place. We have reference image without OT on 2010-11-16.67409 UT with magnitude limit in 'BLANK' filter 19.6m.

There is nothing at this position in any catalogue. No previous outbursts were detected by CRTS. This area of sky in Hercules is not covered by SDSS. The faint blue star is marginally visible on digitized Palomar plates. Color-combined (BRIR) DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J175753+344227-BRIR5x5.jpg

We suggest that MASTER OT J175753.35+344227.5 is a new cataclysmic variable in outburst. Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/175753.35344227.5.png

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