Three Optical Transients discovered by MASTER

ATel #5585; V. Vladimirov, P. Balanutsa, D. Denisenko, E. Gorbovskoy, V. Lipunov, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Yecheistov (Moscow State University, SAI), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov, A. Gabovich (Blagoveshchensk Educational University), 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. 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 16 Nov 2013; 20:01 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

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MASTER OT J083148.05+643427.3 - new CV or PSN

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 08h 31m 48.05s +64d 34m 27.3s on 2013-11-07.72190 UT. The OT unfiltered magnitude is 17.7m (limit 18.5m). The OT is seen in 4 images. There is no minor planet at this place. We have reference image without OT on 2011-02-08.59435 UT with unfiltered magnitude limit 19.4m. The OT was confirmed on MASTER-Tunka unfiltered images on 2013 Nov. 14.710-14.713 UT at 17.8m.

Nothing is present at this position on digitized Palomar plates and in 1RXS, USNO, 2MASS catalogues, as well as in GCVS and AAVSO VSX. The OT is located within 1" of the UV source GALEX J083148.1+643428 (NUV=22.27+/-0.65). The object is likely a dwarf nova in outburst. However, we note there is a galaxy 3.5" away SDSS J083148.59+643427.7 (u=22.89 g=23.18 r=21.39 i=21.30 z=21.29). It is possible that MASTER OT J083148.05+643427.3 is a supernova.

Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/083148.05643427.3.jpg

MASTER OT J075450.18+091020.2 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 07h 54m 50.18s +09d 10m 20.2s on 2013-11-09.79977 UT. The OT magnitude in V filter is 16.0m (limit 17.0m). The OT is seen in 5 images. There is no minor planet at this place. We have reference image without OT on 2012-10-19.79699 UT with unfiltered magnitude limit 18.1m.

Object is not present in 1RXS, USNO, 2MASS, GCVS and AAVSO VSX. The OT is identical to the star SDSS J075450.16+091019.6 (u=21.06 g=21.19 r=21.13 i=21.19 z=21.01). There is also an UV counterpart GALEX J075450.1+091018 (FUV=21.77+/-0.29, NUV=21.11+/-0.19).

Object was observed in high state by Catalina Sky Survey on two nights: 2007 Dec. 19 (17.3m) and 2012 Apr. 17 (16.8m). 101 NEAT images were obtained on 34 different nights from 1997 Dec. 29 to 2005 Apr. 19. No outbursts were detected.

Based on the blue color, amplitude of variability (~5m) and detection of previous outbursts by CRTS we suggest that MASTER OT J075450.18+091020.2 is most likely a dwarf nova of UGSU (SU UMa) type. Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/075450.18091020.2.jpg

MASTER OT J031424.73+461049.0 - Possible Supernova in PGC 166460

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 03h 14m 24.73s +46d 10m 49.0s on 2013-11-11.75690 UT. The OT unfiltered magnitude is 16.2m (limit 18.7m). The OT is seen in 6 images. There is no minor planet at this place. We have reference image without OT on 2011-10-27.98777 UT with unfiltered magnitude limit 19.5m.

The OT is located 11.7" east and 0.1" south of the center of the galaxy PGC 166640. We have reported it to CBAT TOCP as PSN J03142473+4610490. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/031424.73461049.0.png

Note on MASTER OT J080659.02+460811.6

We note that PSN J08065902+4608116 = MASTER OT J080659.02+460811.6 reported in ATel #5536 is located in the low surface brightness galaxy PGC 22774 = MCG+08-15-039. Only a few supernovae were observed in LSB galaxies. Spectral confirmation is still needed.

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