Two bright OTs and one PSN discovered by MASTER

ATel #4084; P. Balanutsa, V. Lipunov, D. Denisenko, V. Shumkov, E. Gorbovskoy, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, D. Zimnukhov (Moscow State University, SAI), V. Krushinsky, I. Zalozhnih, A. Popov (Ural Federal University) K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress (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), S. Shurpakov, P. Podvorotniy (MASTER team members), Hugo Levato and Carlos Saffe (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio; ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest (Observatorio Astronomico Felix Aguilar; OAFA)
on 2 May 2012; 13:09 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

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MASTER OT J182201.93+324906.7 - bright outburst of the new cataclysmic variable in Lyra

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 18h 22m 01.93s +32d 49m 06.7s on 2012-04-29.79112 UT. The OT unfiltered magnitude is 15.4m (limit 17.7m). The OT is seen in 2 images. There is no minor planet at this place.

We have reference image without OT on 2011-06-02.93377 UT with unfiltered magnitude limit 18.8m. There is a faint (B~21.5m) blue star at the position of MASTER OT J182201.93+324906.7 on the digitized Palomar plates, but not in USNO-B or GSC catalogues. We have measured its coordinates from the sum of POSS-II plates as 18 22 01.94 +32 49 08.4. Color-combined chart (5'x5' field of view) composed from B, R and IR Palomar images is available at http://observ.pereplet.ru/images/J1822+3249-BRIR5x5.jpg

We have found one previous outburst of this object in the publicly available Palomar/NEAT data. 15 images from 5 nights in 1997-1998 are available. The object was below the detection limit on 4 of them, but has brightened to ~17m on three 1998 Aug. 18 images.

The object is present in GALEX catalogue with the following ultraviolet magnitudes: GALEX J182201.9+324908 FUV=21.19+/-0.46 NUV=21.54+/-0.30

The object is not present in AAVSO VSX, 2MASS and 1RXS catalogs. Its position is not covered by SDSS and CRTS.

Based on the blue color, amplitude of variability and detection of the previous outburst we conclude that MASTER OT J182201.93+324906.7 is a new cataclysmic variable (dwarf nova) in bright outburst, most likely a superoutburst. Photometric time series and spectroscopic follow up are encouraged.

The discovery and reference images are available at: http://observ.pereplet.ru/images/182201.93324906.7.png

OT MASTER123132.13+003935.1 - PSN

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 12h 31m 32.13s +00d 39m 35.1s on 2012-04-24.77963 UT. The OT unfiltered magnitude is 19.1m (limit 19.9m).

The OT is seen in 2 images. There is no minor planet at this place. There are three SDSS galaxies J123132.19+003933.8, J123132.19+003933.7, J123132.19+003933.7 with offsets 1.6, 1.6 and 1.7 correspondingly. We have reference image without OT on 2011-03-28.97990 UT with unfiltered magnitude limit 22.0m.

Follow up observations are required.

The discovery and reference images are available at: http://observ.pereplet.ru/images/MASTER123132.13+003935.1.jpg

OT MASTER184809.40+395440.5 - bright OT (CV?)

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 18h 48m 09.40s +39d 54m 40.5s on 2012-04-30.95288 UT. The OT unfiltered magnitude is 16.0m (limit 19.7m).

The OT is seen in 4 images. There is no minor planet at this place. There are two SDSS DR8 stars within 3-4 arcsec offset with rmag>20. We have reference image without OT on 2011-08-31.71822 UT with unfiltered magnitude limit 19.9m.

Spectral observations are required. The discovery and reference images are available at: http://observ.pereplet.ru/images/184809.40395440.5.png

We thank K. Sokolovsky for useful discussions.

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