Possible Supernova and two OTs detected by MASTER

ATel #5044; S. Shurpakov, P. Balanutsa, D. Denisenko, V. Lipunov, E. Gorbovskoy, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, V. Yecheistov, D. Zimnukhov (Moscow State University, SAI), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov, A. Punanova (Ural Federal University), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress, A. Frolova, (Irkutsk State University), A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk solar station of the Pulkovo observatory RAS), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov (Blagoveshchensk Educational University), P. Podvorotny, V. Shumkov (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (OAFA)
on 4 May 2013; 11:03 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

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MASTER OT J075042.60+790918.2 - flaring QSO?

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 07h 50m 42.60s +79d 09m 18.2s on 2013-04-26.69442 UT. The OT unfiltered magnitude is 17.3m (limit 17.9m). The OT is seen in 2 images. We have reference image without OT on 2012-10-10.80939 UT with unfiltered magnitude limit 19.0m.

This area of sky is not covered by SDSS and CRTS. There is nothing at this position on six digitized Palomar plates and on their combination to the limiting magnitude ~21.5. However, there is a radio source NVSS J075043+790917 within 2" of the OT which is listed in the Large Quasar Astrometric Catalogue LQAC-2 (Souchay et al., 2012) and Flat-spectrum symmetric radio sources (Augusto et al., 2006). We suggest that MASTER OT J075042.60+790918.2 can be an optical flare of this quasar.

Multi-wavelength follow up observations are encouraged. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/075042.60790918.2.png

MASTER OT J210012.04+422802.0 - new red variable in Cygnus complex of nebulae

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 21h 00m 12.04s +42d 28m 02.0s on 2013-04-27.75375 UT. The OT unfiltered magnitude is 14.3m (limit 17.3m). The OT is seen in 2 images. We have unfiltered reference image on 2012-04-17.71211 UT with the object at 16.8m (limit 17.2m).

Nothing is present at this position in GCVS and AAVSO VSX. This area of sky in Cygnus is not covered by CRTS and SDSS. The OT is identical to the IR object 2MASS 21001201+4227599 (J=10.08+/-0.02 H=8.75+/-0.03 K=8.07+/-0.02) and to the red star USNO-B1.0 1324-0487086 (21 00 12.034 +42 28 00.12 B2=20.60 R2=17.17 I=13.86). It is showing large amplitude variability between POSS-II red plates obtained on 1990 Sep. 11, 1991 July 09 and 1992 Sep. 20. Color-combined DSS finder chart is uploaded to http://master.sai.msu.ru/static/OT/J210012+422802-BRIR.jpg (10'x10' FOV).

Follow up observations and search for variability in archival images are desirable. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/210012.04422802.0.png

MASTER OT J113550.80+341702.7 - PSN in PGC 35860

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 11h 35m 50.80s +34d 17m 02.7s on 2013-05-01.78745 UT. The OT unfiltered magnitude is 17.3m (limit 19.7m). The OT is seen in 3 images. There is no minor planet at this place. We have reference image without OT on 2011-11-22.00624 UT with unfiltered magnitude limit 20.4m.

The OT is located 4" west and 7" north of the center of PGC 35860 galaxy aka SDSS J113551.13+341655.9 with z=0.02102. The object is positionally coincident with a 21-mag blue spot (likely a star forming region) listed in SDSS as a separate galaxy: SDSS J113550.80+341701.9 (u=20.90 g=20.76 r=20.98 i=21.38 z=20.87).

The object was also found on the earlier 2013 MASTER-Kislovodsk images with the following unfiltered magnitudes: Mar. 06.921, 16.74; 06.952, 16.66; Mar. 30.893, 17.05; May 01.754, 17.23. It was not detected on 2013 Feb. 11.896 MASTER-Kislovodsk image (m_lim=19.2) and on Feb. 23.642 MASTER-Amur image (m_lim=17.5).

Based on the outburst duration (about 2 months) and gradual fading we suggest that MASTER OT J113550.80+341702.7 is most likely a supernova in PGC 35860. However, other scenarios (like LBV or a foreground cataclysmic variable) are possible. Spectral confirmation is required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/113550.80341702.7.png

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