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Possible Supernova and two Bright CVs detected by MASTER

ATel #5688; P. Balanutsa, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, V. Kornilov, N. Shatskiy, V. Chazov, A. Kuznetsov, A. Rufanov, V. Vladimirov, V. Yecheistov (Moscow State University, SAI), A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk Solar Station of Pulkovo Observatory), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress (Irkutsk State University), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov, A. Gabovich (Blagoveshchensk Educational University), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), P. Podvorotny, V. Shumkov, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez, F. Podest (OAFA)
on 24 Dec 2013; 14:04 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

Subjects: Optical, Cataclysmic Variable, Supernovae, Transient

Referred to by ATel #: 8277

MASTER OT J030559.89+043238.2 - possible Supernova

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 03h 05m 59.89s +04d 32m 38.2s on 2013-12-21.79815 UT. The OT unfiltered magnitude is 17.2m (limit 19.0m). The OT is seen in 4 images. We have reference image without OT on 2010-11-04.96552 UT with unfiltered m_lim=20.1.

The OT is located 4" east and 8" south of galaxy SDSS J030559.63+043246.0 (g=18.88 r=18.35 i=18.08). The object has been reported to CBAT TOCP as PSN J03055989+0432382. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/030559.89043238.2.png

MASTER OT J051054.52+181042.9 - new CV

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 05h 10m 54.52s +18d 10m 42.9s on 2013-12-23.63068 UT. The OT unfiltered magnitude is 15.9m (limit 17.8m). The OT is seen in 8 images. We have reference image without OT on 2011-12-24.65278 UT with unfiltered m_lim=19.3.

The OT at quiescence is identical to the star USNO-B1.0 1081-0087945 (05 10 54.539 +18 10 43.23 B2=20.02 R2=19.67). Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J051054+181042-BRIR5x5.jpg (200% zoom). There is a faint X-ray source 1WGA J0510.9+1810 (0.00324 cnts/s) with 13" error radius 4" away and 1SWXRT J051054.6+181042 (0.00371 cnts/s, error radius 6") in 2.5". There is nothing at this position in 2MASS, GCVS and AAVSO VSX. This area of sky in Taurus is not covered by SDSS.

Object was observed by Mount Lemmon Survey with 100 detections from Nov. 2005 to Jan. 2013. Two outbursts were detected: to 16.6m on 2008 Dec. 31 and to 16.0m on 2010 Feb. 20. Object varies between 19.5 to 20.2 at quiescence.

Based on the blue color, amplitude of variability (~4m) and previous outbursts we conclude that MASTER OT J051054.52+181042.9 is a new cataclysmic variable (dwarf nova). Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/051054.52181042.9.png

MASTER OT J041923.57+653004.3 - bright CV

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 04h 19m 23.57s +65d 30m 04.3s on 2013-12-23.91087 UT. The OT unfiltered magnitude is 13.9m (limit 18.7m). The OT is seen in 9 images. We have unfiltered reference image with OT at 16.5m on 2011-01-12.75616 UT (limit 19.4m). The object was observed by MASTER-Amur in outburst to 13.95m on 2013-01-27.684 UT fading to 14.9m by 2013-02-06.417 UT, but was not detected as a transient.

The OT at quiescence is identical to the star USNO-A2.0 1500-03665468 (04 19 23.58 +65 30 04.1 R=16.7 B=18.5) = USNO-B1.0 1555-0091928 (04 19 23.576 +65 30 04.28 B1=18.76 R1=16.39 B2=16.61 R2=16.84 I=14.35). It was likely in outburst on 1993 Oct. 08 IR plate. Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J0419+6530-comps.jpg (10'x9' FOV).

The OT is located 8" from X-ray source 1RXS J041924.8+653006 (error 10", flux 0.050+/-0.012 cnts/s, HR1=0.90+/-0.20, HR2=0.75+/-0.16). Variability was identified by D. Denisenko in 2006.

The object has an IR counterpart 2MASS 04192359+6530042 (J=14.48 H=13.98 K=13.71). There is nothing at this position in GCVS and AAVSO VSX. This area of sky in Camelopardalis is not covered by SDSS and CRTS.

ROSAT hardness ratios are typical for dwarf novae. Based on the outburst amplitude and rather red colors MASTER OT J041923.57+653004.3 is likely a cataclysmic variable of UGSS (SS Cyg) type. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/041923.57653004.3.png

List of Optical Transients discovered by MASTER

Global MASTER Robotic Net