Three Optical Transients discovered by MASTER

ATel #6172; P. Balanutsa, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, V. Kornilov, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Vladimirov, V. Yecheistov (Moscow State University, SAI), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress (Irkutsk State University), A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk Solar Station of Pulkovo Observatory), 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 26 May 2014; 12:01 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J145426.01+615015.9 - new CV or PSN

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 14h 54m 26.01s +61d 50m 15.9s on 2014-05-24.67833 UT. The OT unfiltered magnitude is 19.0m (limit 20.0m). The OT is seen in 3 images. There is no minor planet at this place. We have reference image without OT on 2012-04-09.74780 UT with unfiltered magnitude limit 19.6m.

The OT is within 1" of the faint blue object SDSS J145425.96+615015.8 (g=22.58 r=22.81 i=22.86) with Type: GALAXY and a flag (Too Few Good Detections). The object looks stellar on the sum of digitized Palomar plates (3xBRIR). There is nothing at this position in 1RXS, GALEX, USNO-B1, 2MASS, GCVS and AAVSO VSX. This area of sky in Draco is not covered by CRTS.

Based on the blue color and amplitude of variability (~4m), MASTER OT J145426.01+615015.9 is likely a new cataclysmic variable (dwarf nova in outburst) or a supernova. Spectral confirmation is required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/145426.01615015.9.png

MASTER OT J170623.60+012018.0 - fast transient of unknown nature

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 17h 06m 23.60s +01d 20m 18.0s on 2014-05-24.69940 UT. The OT unfiltered magnitude is 17.0m (limit 19.1m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2011-05-08.80655 UT with unfiltered magnitude limit 19.7m. The object was detected at 16:45:22 UT and 16:47:08 UT. It was not present on the image obtained 1.8 minutes before, on 16:43:45 UT (limit 19.1m) and has faded below 19.2m on the second triplet of images 1hr later, at 17:47:48 UT.

There is nothing at this position in any catalogs and on digitized Palomar plates. The nearest star is 4.5" to south-west. Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J170623+012018-BRIR5x5.jpg (2x zoom). This area of sky in Ophiuchus is not covered by SDSS. There were no gamma-ray bursts detected at the flare time. MASTER OT J170623.60+012018.0 is likely a new variable of UV Ceti type (flaring red dwarf). Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/170623.60012018.0.png

MASTER OT J165219.43+574523.9 - flaring red dwarf

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 16h 52m 19.43s +57d 45m 23.9s on 2014-05-24.72037 UT. The OT unfiltered magnitude is 18.7m (limit 19.7m). The OT is seen in 3 images from 17:15:35 to 17:19:05 UT. There is no minor planet at this place. We have reference image without OT on 2014-03-27.79235 UT with unfiltered magnitude limit 20.2m. The object has faded below 19.7m on the second triplet of images 1hr later, at 18:20:31 UT.

The OT is within 3.2" of the infrared object 2MASS J16521966+5745213 (J=16.50+/-0.15 H=15.77+/-0.17 K=15.39+/-0.21) and within 1.5" of WISE J165219.53+574522.6 (W1=15.3+/-0.03 W2=15.16+/-0.05) - obviously the same star with proper motion between 2MASS and WISE. There is nothing at this position in 1RXS, USNO-B, GCVS and AAVSO VSX. This area of sky in Draco is not covered by SDSS. MASTER OT J165219.43+574523.9 is a new variable of UV Ceti type (flaring red dwarf). Follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/165219.43574523.9.png

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