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Bright CV and possible Supernova detected by MASTER

ATel #5122; V. Yecheistov, N. Tiurina, V. Lipunov, D. Denisenko, E. Gorbovskoy, P. Balanutsa, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov (Moscow State University, SAI), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress, A. Frolova (Irkutsk State University), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal 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, A. Gabovich (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 11 Jun 2013; 15:18 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, Cataclysmic Variable, Supernovae, Transient

Referred to by ATel #: 5127

MASTER OT J210334.55+234128.9 - bright CV

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 21h 03m 34.55s +23d 41m 28.9s on 2013-06-09.73351 UT. The OT unfiltered magnitude is 14.8m (limit 18.7m). The OT is seen in 7 images. There is no minor planet at this place. We have unfiltered reference image with OT at 18.4m on 2011-09-17.59690 UT (limiting magnitude 19.5).

The object at minimum is identical to the star USNO-A2.0 1125-17740099 (21 03 34.58 +23 41 29.0 R=18.1 B=18.3) and USNO-B1.0 1136-0515396 (21 03 34.572 +23 41 28.71 B1=19.10 R1=18.25 B2=20.17 R2=18.77 I=17.94). It is present in SDSS as SDSS J210334.57+234128.4 with the magnitudes u=19.94 g=19.83 r=19.11 i=18.54 z=18.13. There is also an UV counterpart GALEX J210334.6+234128 (FUV=21.19+/-0.33 NUV=20.35+/-0.12) and near-IR object 2MASS 21033457+2341283 (J=15.70+/-0.07 H=15.50+/-0.12 K=15.09+/-0.13).

There is nothing at this position in 1RXS, GCVS and AAVSO VSX. This area of sky in Vulpecula is not covered by Catalina Sky Survey.

The object was observed by MASTER in a high state before, having reached 14.0m on 2012 Nov. 24, but was not detected as a transient. Outburst dates (mid-exposures) and magnitudes are listed in the table below together with the recent non-detection from Kislovodsk 18 days before the outburst.

----------------------------------------- 
Obs. date, UT    Mag  Band  Observatory 
----------------------------------------- 
2012-01-09.414  15.12  R    MASTER-Amur 
2012-11-24.525  14.02  W    MASTER-Tunka 
2012-11-24.563  13.96  W    MASTER-Tunka 
2012-11-24.596  14.00  W    MASTER-Tunka 
2012-11-28.503  14.77  W    MASTER-Amur 
2012-11-28.535  14.87  W    MASTER-Amur 
2013-05-22.923  <17.8  W    MASTER-Kislovodsk 
2013-06-09.701  14.85  W    MASTER-Tunka 
2013-06-09.734  14.81  W    MASTER-Tunka 
-----------------------------------------

Based on the outburst amplitude and UV detection we conclude that MASTER OT J210334.55+234128.9 is a new cataclysmic variable. SDSS colors suggest the large contribution from the secondary component (likely of K spectral class) and long orbital period. The system is most likely a dwarf nova of UGSS subtype.

Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/210334.55234128.9.png

MASTER OT J164601.94+062759.3 - PSN in UGC 10535

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 16h 46m 01.94s +06d 27m 59.3s on 2013-06-10.70100 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 2011-05-14.73556 UT with unfiltered magnitude limit 18.6m.

The OT is located 6" east and 14" north of the center of UGC 10535 galaxy. We suggest that MASTER OT J164601.94+062759.3 is a possible supernova. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/164601.94062759.3.png

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net