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Bright outburst of CSS 015052+332622 and one new CV detected by MASTER

ATel #4475; D. Denisenko, P. Balanutsa, E. Gorbovskoy, V. Lipunov, 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 (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 (Observatorio Astronomico Felix Aguilar; OAFA)
on 10 Oct 2012; 15:45 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, Cataclysmic Variable, Transient

MASTER OT J194012.33+382320.8 - new CV?

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 19h 40m 12.33s +38d 23m 20.8s on 2012-10-08.50941 UT. The OT magnitude in 'V' filter is 18.0m (limit 18.7m). The OT is seen in 5 images. There is no minor planet at this place. We have reference image without OT on 2011-08-04.61921 UT with unfiltered magnitude limit 19.8m.

There is a faint blue star (magnitude ~21.5) within 1" from the position of the OT visible on POSS-II plates. Color-combined (BRIR) DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J194012+382320-BRIR5x5.jpg (5'x5' FOV).

There is nothing at this position in USNO-B1.0, GSC 2.3.2, 2MASS, 1RXS and GCVS catalogs and in AAVSO VSX. This area is not covered by SDSS, GALEX, NEAT and CSS.

The galactic latitude is 8 deg. Based on the blue color we suggest that MASTER OT J194012.33+382320.8 is likely a faint cataclysmic variable (dwarf nova) in outburst. Follow up observations are encouraged.

The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/194012.33382320.8.png

MASTER OT J015051.58+332621.6 - bright outburst of CSS 111006:015052+332622 = 1RXS J015051.8+332622

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 01h 50m 51.58s +33d 26m 21.6s on 2012-10-10.50419 UT. The OT unfiltered magnitude is 14.6m (limit 18.6m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-09-24.74727 UT with unfiltered magnitude limit 19.4m.

This object is listed in AAVSO VSX as CSS 111006:015052+332622 with the variability range in white light 15.32-18.1. We note that the object is identical to ROSAT X-ray source 1RXS J015051.8+332622 (error radius 12") formally 3" away. The flux 0.040+/-0.013 cnts/s and hardness ratios HR1=1.00+/-0.22 HR2=0.73+/-0.18 are typical for dwarf novae of UGSU type.

The star is an UV source GALEX J015051.4+332621 (FUV=19.51+/-0.15, NUV=19.43+/-0.11). It is also present in SDSS DR8 as SDSS J015051.52+332621.8 with the following magnitudes: u=17.87 g=18.19 r=18.10 i=18.01 z=17.77. Small (g-r) and (r-i) color indices indicate a little contribution from the secondary component which means low-mass companion and likely a short orbital period.

MASTER-Amur telescope has observed this area 3 times in the previous 5 nights. We have the following photometry (unfiltered with the Red zero point):

2012-10-06.527 UT 18.6
2012-10-07.481 UT 17.9
2012-10-08.472 UT 17.9
2012-10-10.473 UT 14.5
2012-10-10.504 UT 14.6

The fast rise and unfiltered magnitude higher than the previously reported maximum suggest this outburst is a superoutburst. Photometric time series are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/015051.58332621.6_1.png

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