Рубрика: Новости

Astronomer’s Telegram #4122 ;

Svetlana Jorstad (Boston Univ., USA and St. Petersburg Univ. Russia),Valeri Larionov, and Evgenia Kopatskaya (St. Petersburg Univ., Russia)
on 23 May 2012; 08:45 UT

According to our optical observations at the 1.8 m Perkins telescope of Lowell observatory (Flagstaff, AZ) and at the 70-cm AZT-8 (CrAO, Ukraine) the quasar B2 1156+295 (4C +29.45 = Ton 599) has entered a new phase of a high optical activity. The source had an optical flare along with a moderate increase of the gamma-ray activity in the end of April 2012 (Atel #4051) when the quasar reached R~15.1 and then faded up to R~16. Our recent observations show that on May 19 the source was R=15.99+-0.02 while tonight, on May 23, its brightness reached R=14.774+-0.007. The source appears to continue to brighten. The optical polarization is very variable. Three other gamma-ray blazars, 1749+096 (OT +081), 1222+216 (4C +21.35), and 3C279, show an interesting optical activity as well. The brightness of the BLLac object 1749+096 increased by ~1mag and for the quasars, 1222+216 and 3C279, by ~0.5mag with respect to their brightness in R band in the end of April. The multifrequency observations are encouraged.

Astronomer’s Telegram #4068
T. Konstantinova, D. Blinov (St. Petersburg Univ.)
on 25 Apr 2012; 13:02 UT

We report on the recent optical activity of the high-mass X-ray binary system SAX J2103.5+4545. The source was monitored by 70-cm AZT-8 (CrAO, Ukraine) and 0.4-m LX-200 (St.Petersburg, Russia) telescopes. In the night of 2012-04-22 the brightness of the optical counterpart reached R= 13.27+/-0.02, as compared to R= 13.48+/-0.02 in the night 2012-03-23 and R= 13.65+/-0.02 in the night 2011-11-20. Last year, since ~ 2011-03-29, the system was in optical quiescent state. The previous optical activity observed from July 2010 to March 2011 was followed by onset of X-ray activity of the source (ATel #2925 and ATel #2928). New spectral observations of the system are desirable for monitoring a recent disc formation around the Be star.

Astronomer’s Telegram #4051
S. Jorstad (Boston Univ., USA and St. Petersburg Univ., Russia), V. Larionov, D. Blinov, D. Morozova, E. Kopatskaya, T. Konstantinova, Yu. Pavlova, A. Mokrushina (St. Petersburg Univ.)
on 18 Apr 2012; 13:31 UT

We perform optical photometric and R-band polarimetric monitoring of FSRQ B2 1156+29 = 4C +29.45 = Ton 599 using 1.8-m Perkins telescope (Az,USA), 70-cm AZT-8 (CrAO, Ukraine) and 0.4-m LX-200 (St.Petersburg, Russia) telescopes, partly in the frames of GASP project. Our data show that starting from 2012 April 2 this blazar entered a phase of violent optical activity. In the night of 2012-04-11 its brightness reached R=15.1, as compared to R=16.6 in the night 2012-04-09. The quasar faded almost to usual level of R=16.7 in subsequent nights, and brightened again to R=15.5 in the night of 2012-04-18UT07:00, becoming 1 magnitude brighter than during previous night. Both optical brightening events were accompanied with increased level of linear polarization ~10%, as compared to usual level of 3-5%. We encourage multi-wavelength observations of B2 1156+29.

По результатам последних наблюдений отправили Atel #4031 со следующим содержанием.

We perform optical photometric and R-band polarimetric monitoring of BL Lac using 70-cm AZT-8 (CrAO, Ukraine) and 0.4-m LX-200 (St.Petersburg, Russia) telescopes, as a part of GASP project. As reported in Atel #4028, this blazar was found by Fermi LAT in active state on 2012 April 9. Our data show that a sharp optical maximum was reached on the date 2012-04-08UT02:20, R=13.10, while on 2012-04-11UT01:30 R=13.40. Optical maximum occurring one day before gamma-ray one suggest negative time lag between two energy ranges. However, this conclusion may be spurious due to the lack of dense optical coverage. Our preliminary light curve may be seen here. Current high activity state of BL Lac deserves close attention in all wavelengths.

Подобная вспышка, где максимум в оптическом диапазоне предшествовал максимуму в гамма, наблюдалась нами ранее у блазара OJ287. Такие события противоречат некоторым моделям джетов, где считается, что излучение в гамма-диапазоне рождается в ближайшей окрестности черной дыры, поэтому представляют существенный интерес.

Наша группа присоединилась к фотометрическим наблюдениям яркой сверхновой SN2012aw, вспыхнувшей в галактике M95.