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Possible Supernova and two CVs detected by MASTER

ATel #5098; V. Shumkov, V. Yecheistov, D. Denisenko, V. Lipunov, E. Gorbovskoy, P. Balanutsa, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov (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, A. Gabovich (Blagoveshchensk Educational University), P. Podvorotny, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (OAFA)
on 3 Jun 2013; 12:24 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, Cataclysmic Variable, Supernovae, Transient, Variables

MASTER OT J153605.15+135706.9 - PSN in PGC 1445026

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 15h 36m 05.15s +13d 57m 06.9s on 2013-05-27.89161 UT. The OT unfiltered magnitude is 17.5m (limit 18.5m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-04-23.954 UT with unfiltered magnitude limit 19.9m.

The object is located 9.3" east and 3.6" north of the center of PGC 1445026 galaxy. We suggest that MASTER OT J153605.15+135706.9 is a possible supernova. Spectral confirmation is required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/153605.15135706.9.jpg

MASTER OT J200116.78+044142.6 - CV (not a SR variable)

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 20h 01m 16.78s +04d 41m 42.6s on 2013-05-31.70625 UT. The OT unfiltered magnitude is 14.6m (limit 16.5m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-04-15.79271 UT with unfiltered magnitude limit 17.2m.

The object is identical to the variable star USNO-A2.0 0900-17428262 discovered by T. Kryachko, A. Samokhvalov and B. Satovskiy (PZP, Vol. 12, No. 21, 2012). Kryachko et al. report SR: type, possible period of 39.8d and magnitude range 16.78-19.27 (unfiltered with the red zero point). However, the object is blue on the digitized Palomar plates (both POSS-I and POSS-II) and in USNO-A2.0 catalog: USNO-A2.0 0900-17428262 (20 01 16.80 +04 41 44.1 R=17.2 B=17.4). USNO-B1.0 gives for the star USNO-B1.0 0946-0506020 (20 01 16.742 +04 41 43.34) a proper motion of (-14, -14) mas/year, not expected for a semi-regular (usually red giant) variable. OT also has an UV counterpart GALEX J200116.7+044143 (FUV=21.71+/-0.35, NUV=20.63+/-0.16). This area of sky is not covered by SDSS and CRTS. Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J200116+044142-BRIR5x5.jpg (200% zoom).

Based on the blue color, amplitude of variability and proper motion we suggest that MASTER OT J200116.78+044142.6 is a new cataclysmic variable, likely a dwarf nova. Spectroscopic and photometric observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/200116.78044142.6.png

MASTER OT J221926.10+395436.3 - new large-amplitude CV

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 22h 19m 26.10s +39d 54m 36.3s on 2013-06-02.77100 UT. The OT unfiltered magnitude is 16.1m (limit 18.0m). The OT is seen in 3 images. There is no minor planet at this place. We have reference image without OT on 2012-11-18.49744 UT with unfiltered magnitude limit 19.1m.

Object is not present in any catalogs. There is nothing at this position on the digitized Palomar plates and or their combination to the limiting magnitude ~22, as well as on SDSS images (m_lim~23). No previous outbursts were detected by Catalina Sky Survey. This area of sky in Lacerta was not covered by NEAT.

Based on the outburst amplitude (~7m or more) we suggest that MASTER OT J221926.10+395436.3 is a new cataclysmic variable, likely a dwarf nova of UGWZ (WZ Sge) subtype. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/221926.10395436.3.png

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net