MASTER Detection of Two Cataclysmic Variables in One Image

ATel #6967; P. Balanutsa, V. Lipunov, E. Gorbovskoy, N. Tiurina, D. Denisenko, A. Kuznetsov, M. Pruzhinskaya, A. Rufanov, V. Vladimirov, V. G. Kornilov (Lomonosov Moscow State University, SAI), O. Gres, K. Ivanov, S. Yazev, N. Budnev, V. Poleshchuk, E. Konstantinov (Irkutsk State University) A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk Solar Station of Pulkovo Observatory RAS), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov, A. Gabovich (Blagoveshchensk Educational University), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), D. Buckley, S. Potter, A. Kniazev, M. Kotze (South African Astronomical Observatory), V. Shumkov, S. Shurpakov (MASTER team members)
on 20 Jan 2015; 18:19 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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The following two objects were found on the same images by MASTER-Tunka robotic telescope (2x2 deg field of view) and are separated by 55'.

MASTER OT J015746.16+511023.2 - independent discovery of ASASSN-15aw

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 01h 57m 46.16s +51d 10m 23.2s on 2015-01-18.65101 UT. The unfiltered OT magnitude is 15.9m (limit 19.5m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2012-01-02.53252 UT with unfiltered magnitude limit 19.1m. There was a past outburst in MASTER-Amur unfiltered images on 2012-11-05.720 UT (15.0m) and 2012-11-05.751 UT (15.1m).

The object is identical to ASASSN-15aw discovered on 2015-01-15.26 (V=15.8) and 2015-01-16.32 UT (V=15.7) by ASAS-SN (Shappee et al., 2014). The OT at quiescence is identical to the blue star USNO-B1.0 1411-0052176 (B1=19.56 B2=20.39 R2=19.68). Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J015746+511023-BRIR5x5.jpg (2x zoom). The object has an UV counterpart GALEX J015745.9+511024 (FUV=21.28+/-0.42 NUV=21.23+/-0.30). Nothing is present at this position in 1RXS, 2MASS and GCVS. This area of sky in Perseus is not covered by SDSS, NEAT and Catalina Sky Survey.

Based on the blue color and previous outburst, MASTER OT J015746.16+511023.2 is a new cataclysmic variable (dwarf nova). Follow up observations are encouraged. MASTER-Tunka discovery and reference images are available at: http://master.sai.msu.ru/static/OT/015746.16511023.2.png

MASTER OT J020337.92+510805.7 - new CV

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 02h 03m 37.92s +51d 08m 05.7s on 2015-01-18.65101 UT. The OT magnitude in clear filter is 17.8m (limit 19.5m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2011-12-17.46388 UT with unfiltered magnitude limit 19.1m.

The OT at quiescence is identical to the blue star USNO-A2.0 1350-01927678 (B=17.8 R=18.3) = USNO-B1.0 1411-0054546 (B1=18.10 R1=18.50 B2=20.68 R2=N/A I=18.41). The star was in outburst on 1953-10-13 blue and red POSS-I plates. Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J020337+510805-BRIR5x5.jpg (2x zoom). The object has an UV counterpart GALEX J020337.8+510806 (FUV=20.15+/-0.19 NUV=20.14+/-0.13). Nothing is present at this position in 1RXS, 2MASS, GCVS and AAVSO VSX.

Based on the blue color and amplitude of variability, MASTER OT J020337.92+510805.7 is a new cataclysmic variable (likely a dwarf nova in outburst). Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/020337.92510805.7.png

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