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Possible SN and two CVs detected by MASTER

ATel #4857; V. Yecheistov, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, P. Balanutsa, 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, 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 5 Mar 2013; 00:37 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, Cataclysmic Variable, Supernovae, Transient

MASTER OT J180312.78+114154.7 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 18h 03m 12.78s +11d 41m 54.7s on 2013-03-01.86645 UT. The OT unfiltered magnitude is 17.2m (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 2012-05-29.71810 UT with unfiltered magnitude limit 18.6m.

The OT is identical to the star SDSS J180312.64+114154.7 (u=20.62 g=20.62 r=20.31 i=20.24 z=20.00). It also has an UV counterpart GALEX J180312.5+114154 (FUV=N/A, NUV=21.93+/-0.38). The object is not present in 1RXS, 2MASS, GCVS and AAVSO VSX. It is not covered by Catalina Sky Survey.

The variability is evident on 1st and 2nd epoch Palomar plates and in USNO-B1 catalogue: USNO-B1.0 1016-0316884 18 03 12.666 +11 41 54.86 pmRA=12 pmDE=-14 B1=18.41 R1=17.76 B2=19.88 R2=19.27.

Palomar/NEAT has observed this area of sky in Ophiuchus on 17 different nights from 1997 July 05 to 2005 Aug. 31. A total of 47 images were taken, 33 of them are usable. The star was bright on two July 1997 images, but faint on 11 nights between Aug. 1997 and Aug. 2003.

Based on SDSS colors, UV detection and amplitude of variability we conclude that MASTER OT J180312.78+114154.7 is a new cataclysmic variable. Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/180312.78114154.7.png

MASTER OT J063332.19+265600.2 - new CV?

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 06h 33m 32.19s +26d 56m 00.2s on 2013-03-02.66922 UT. The OT unfiltered magnitude is 15.8m (limit 17.7m). The OT is seen in 5 images. There is no minor planet at this place. We have reference image without OT on 2012-10-20.80389 UT with unfiltered magnitude limit 18.8m.

The OT is identical to the star SDSS J063332.32+265559.0 (u=21.57 g=21.37 r=20.49 i=19.99 z=19.60). This area of sky in Gemini is not covered by CRTS and GALEX. No previous outbursts were detected on 24 NEAT images taken during 7 nights from 2001 Oct. 03 to 2002 Feb. 14. There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX.

Based on the amplitude of variability we suggest that MASTER OT J063332.19+265600.2 is likely a new CV (dwarf nova in outburst). Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/063332.19265600.2.png

MASTER OT J081031.62+111450.2 - PSN

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 08h 10m 31.62s +11d 14m 50.2s on 2013-03-03.49920 UT. The OT unfiltered magnitude is 16.4m (limit 18.0m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-10-22.83454 UT with unfiltered magnitude limit 18.4m.

There is an object SDSS J081031.68+111451.4 with type GALAXY and magnitudes u=23.28 g=20.92 r=20.35 i=20.00 z=19.81. OT offset from the galaxy is 1"W and 1"S.

No previous outbursts were detected at this position neither in 112 NEAT images obtained during 40 nights from 1997 Nov. 26 to 2006 Dec. 22 nor in CRTS DR2 (CSS and MLS data) during 2005-2012. This area of sky is not covered by GALEX.

Spectral confirmation is required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/081031.62111450.2.png

List of optical transients discovered by MASTER

Global MASTER Robotic Net