Possible Supernova and new CV discovered by MASTER

ATel #6130; V. Shumkov, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, P. Balanutsa, 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), 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. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov (Ural Federal University), P. Podvorotny, S. Shurpakov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez, F. Podest (OAFA)
on 9 May 2014; 11:04 UT
Credential Certification: Nataly Tyurina (tiurina@sai.msu.ru)

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MASTER OT J172145.92+694914.1 - possible Supernova

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 17h 21m 45.92s +69d 49m 14.1s on 2014-05-08.58949 UT. The OT unfiltered magnitude is 17.3m (limit 18.4m). The OT is seen in 6 images. There is no minor planet at this place. We have reference image without OT on 2012-10-22.45747 UT with unfiltered magnitude limit 19.1m. Sum of six 60-sec unfiltered exposures by MASTER-Amur on 2014 May 08.588-08.619 UT is uploaded to http://master.sai.msu.ru/static/OT/J172145+694914-MASTER-Amur.jpg

The new object is located 10" east and 7" north of the center of galaxy Kazarian 654 = PGC 2732472 = SDSS J172144.04+694907.3 (g=16.89 r=16.19 i=15.82) = GALEX J172144.6+694907 (FUV=19.51 NUV=18.99) = 2MASX J17214397+6949069 (J=14.22 H=14.03 K=13.30). Spectral confirmation is required. Discovery and reference images are available at: http://master.sai.msu.ru/static/OT/172145.92694914.1.png

MASTER OT J232100.42+494614.0 - new CV

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 23h 21m 00.42s +49d 46m 14.0s on 2014-05-08.71441 UT. The OT unfiltered magnitude is 15.5m (limit 17.6m). The OT is seen in 23 images. There is no minor planet at this place. We have reference image without OT on 2011-08-24.68904 UT with magnitude limit in R filter 18.6m. The object had been also observed in the high state by MASTER-Amur on 2012-10-12.556 UT (15.2m) and on 2014-01-11.375 UT (15.4m), but was not discovered as a transient then.

The OT at quiescence is identical to the blue star USNO-B1.0 1397-0491066 (23 21 00.416 +49 46 14.65 pmRA=4 pmDE=8 B1=16.65 R1=15.66 B2=16.58 R2=18.33 I=18.35). Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J232100+494614-BRIR.jpg (10'x10' FOV). The star is showing large variability on the digitized Palomar plates. Comparison of 1990-09-23 and 1992-08-07 POSS-II red plates is uploaded to http://master.sai.msu.ru/static/OT/J232100+494614-POSS-R.jpg (5'x5' FOV).

The object has an UV counterpart GALEX J232100.4+494615 (FUV=20.14+/-0.28 NUV=20.21+/-0.15). There is nothing at this position in 1RXS, GCVS and AAVSO VSX. This area of sky in Andromeda is not covered by SDSS and CRTS.

Based on the blue color, amplitude of variability (~3m) and previous detections, MASTER OT J232100.42+494614.0 is a new cataclysmic variable (dwarf nova in outburst). Follow up observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/232100.42494614.0.png

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