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One very bright and one bright OT detected by MASTER

ATel #4441; D. Denisenko, P. Podvorotny, P. Balanutsa, S. Shurpakov, N. Tiurina, E. Gorbovskoy, V. Lipunov, 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), V. Shumkov, (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (Observatorio Astronomico Felix Aguilar; OAFA)
on 1 Oct 2012; 15:16 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, X-ray, Cataclysmic Variable, Transient

Referred to by ATel #: 5788

MASTER OT J042609.34+354144.8 - outburst of white dwarf in wide binary system with the common PM

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 04h 26m 09.34s +35d 41m 44.8s on 2012-09-30.66381 UT. The OT unfiltered magnitude is 12.9m (limit 17.9m). The OT is seen in 2 images. There is no minor planet at this place.

We have reference image without flare on 2012-02-07.64459 UT with magnitude limit in 'R' filter 17.3m.

The object is identical to the 16th mag. star USNO-B1.0 1256-0072787 (R.A.=04 26 09.297 Dec.=+35 41 45.37 pmRA=16 pmDE=-42 B1=16.71 R1=16.16 B2=16.05 R2=15.73 I=15.39) and to the infrared object 2MASS 04260931+3541451 (J=15.30+/-0.04 H=14.80+/-0.05 K=14.45+/-0.06). There is also an ultraviolet object at the same position GALEX J042609.3+354145 (FUV=17.70+/-0.05 NUV=17.52+/-0.03). Finally, there is a bright X-ray source 1RXS J042608.9+354151 (flux 0.111+/-0.018 cnts/sec, hardness ratios HR1=1.00+/-0.05 HR2=0.38+/-0.14) with 9" error circle formally at 7" from the OT. HR1=1.00 in ROSAT is typical for dwarf novae (for example, 1RXS J231935.0+364705).

The OT is a south-western component of a binary system with 16.6" separation and common proper motion. The second component is a red dwarf 2MASS 04261052+3541528 with IR magnitudes J=13.65+/-0.02 H=12.92+/-0.02 K=12.65+/-0.02. This binary is listed in WDS catalog as CRB 64. The object is not present in GCVS and AAVSO VSX.

No previous outbursts were detected on 6 Palomar plates and 3 NEAT images. However, there was an outburst to 13.4m on JD=2454771 in CRTS data and likely two fainter ones to 14.4m and 14.7m.

Color-combined (BRIR) DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J0426093+354145-BRIR.jpg (10'x10' FOV). Follow up photometric and spectroscopic observations are required.

The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/042609.34354144.8.png

MASTER OT J000820.50+773119.1 - CV?

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 00h 08m 20.50s +77d 31m 19.1s on 2012-09-27.88833 UT. The OT unfiltered magnitude is 16.6m (limit 18.8m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2010-09-26.90697 UT with unfiltered magnitude limit 19.1m.

There is a faint blue star (magnitude ~21) at the position of the OT on POSS-II plates. It is present in GSC 2.3.2 catalog with coordinates 00 08 20.387 +77 31 19.02 and jmag=21.05. There is nothing at this position in USNO-B1.0, 2MASS, GALEX, 1RXS and GCVS catalogs. This area is not covered by SDSS, CSS and NEAT.

The galactic latitude is 15 deg. Based on blue color and amplitude of variability we suggest that MASTER OT J000820.50+773119.1 is likely a cataclysmic variable (dwarf nova) in outburst.

Follow up observations are requested.

The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/000820.50773119.1.png

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