Two Optical Transients detected by MASTER

ATel #5994; 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), 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 21 Mar 2014; 13:46 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J192809.82+551616.5 - possible CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 19h 28m 09.82s +55d 16m 16.5s on 2014-03-20.74883 UT. The OT unfiltered magnitude is 16.7m (limit 18.0m). The OT is seen in 9 images. There is no minor planet at this place. We have reference image without OT on 2011-06-12.69185 UT with unfiltered magnitude limit 19.2m. The object was first detected on 2014-03-16.77837 UT at unfiltered magnitude 15.9 (limit 17.1m).

There is nothing at this position on the digitized Palomar plates and on their combination to the limiting magnitude ~22.5. Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J192809+551616-BRIR5x5.jpg (2x zoom). Object is not present in any catalogs. This area of sky in Cygnus is not covered by SDSS, NEAT and CRTS.

Based on the outburst amplitude (more than 6m), MASTER OT J192809.82+551616.5 is most likely a dwarf nova or classical Nova. Spectral confirmation is required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/192809.82551616.5.png

MASTER OT J210622.20+252120.4 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 21h 06m 22.20s +25d 21m 20.4s on 2014-03-20.81343 UT. The OT unfiltered magnitude is 15.7m (limit 17.2m). The OT is seen in 6 images. There is no minor planet at this place. We have reference image without OT on 2012-08-22.71307 UT with unfiltered magnitude limit 18.6m.

The OT at quiescence is identical to the blue star USNO-B1.0 1153-0521040 (21 06 22.222 +25 21 20.81 pmRA=2 pmDE=-16 B1=19.96 R1=18.90 B2=20.32 R2=19.92 I=18.38). Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J210622+252120-BRIR5x5.jpg (2x zoom). There is an UV counterpart with two entries in GALEX DR6: GALEX J210622.2+252120 (FUV=20.48+/-0.28 NUV=20.87+/-0.16) and GALEX J210622.1+252121 (FUV=21.34+/-0.36 NUV=20.73+/-0.25). There is nothing at this position in 1RXS, 2MASS, GCVS and AAVSO VSX. This area of sky in Vulpecula is not covered by SDSS, NEAT and CRTS.

Based on the blue color, proper motion and outburst amplitude (~4m), MASTER OT J210622.20+252120.4 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/210622.20252120.4.png

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