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New CV and Possible Nova in M31 discovered by MASTER

ATel #5355; V. Yecheistov, D. Denisenko, V. Lipunov, E. Gorbovskoy, P. Balanutsa, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Vladimirov (Moscow State University, SAI), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov, A. Gabovich (Blagoveshchensk Educational University), 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), P. Podvorotny, V. Shumkov, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (OAFA)
on 2 Sep 2013; 20:37 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, Cataclysmic Variable, Nova, Transient

MASTER OT J002423.75+454728.7 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 00h 24m 23.75s +45d 47m 28.7s on 2013-08-26.69771 UT. The OT unfiltered magnitude is 16.9m (limit 19.3m). The OT is seen in 6 images. There is no minor planet at this place. We have reference image without OT on 2012-10-10.64701 UT with unfiltered magnitude limit 20.3m.

The object at quiescence is identical to the faint blue star present in USNO-B catalogue as USNO-B1.0 1357-0011498 (00 24 23.602 +45 47 29.46, B2=20.77) and in GSC 2.3.2 (00 24 23.672 +45 47 28.85, jmag=20.65). Color-combined (BRIR) DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J002423+454728-BRIR5x5.jpg (200% zoom). There is also an UV counterpart with two entries in GALEX DR6: GALEX J002423.7+454729 (FUV=17.12+/-0.03, NUV=17.57+/-0.02) in outburst on 2010-06-03 and GALEX J002423.6+454728 (FUV=N/A, NUV=21.63+/-0.28) at quiescence on 2012-05-16.

Nothing is present at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. No previous outbursts were detected by Catalina Sky Survey and NEAT. This area of sky in Andromeda is not covered by SDSS.

Based on the blue color, UV detection and amplitude of variability (about 5m) we conclude that MASTER OT J002423.75+454728.7 is a new 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/002423.75454728.7.png

MASTER OT J003712.10+403904.0 - possible Nova in M31

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 00h 37m 12.10s +40d 39m 04.0s on 2013-08-26.71814 UT. The OT unfiltered magnitude is 17.8m (limit 18.8m). The OT is seen in 6 images. There is no minor planet at this place. We have reference image without OT on 2013-08-13.71722 UT with unfiltered magnitude limit 19.0m.

The object has brightened to 16.7m on MASTER-Amur unfiltered image on Aug. 28.727 UT (limit 18.8m). It was also observed by MASTER-Kislovodsk with the following Red magnitudes: Aug. 27.958, 18.1; Aug. 29.939, 17.4.

The OT is located 3781" west and 2224" south of the nucleus of NGC 224 (M31), at the outskirts of Andromeda galaxy. There is nothing at this position in any catalogs and on Palomar plates. The nearest object in Sloan Digital Sky Survey is 3.8" away (SDSS J003711.79+403902.4, r=23.05). Since the outburst amplitude is more than 6m, MASTER OT J003712.10+403904.0 is likely a classical nova in M31. However, dwarf nova outburst in our Galaxy can not be completely excluded.

Spectral observations are required. The discovery, confirmation and reference images are available at: http://master.sai.msu.ru/static/OT/003712.10403904.0.png

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net