ﻻ يوجد ملخص باللغة العربية
We analyzed the multi-band optical behaviour of the BL Lacertae object, S5 0716+714, during its outburst state from 2014 November - 2015 March. We took data on 23 nights at three observatories, one in India and two in Bulgaria, making quasi-simultaneous observations in B, V, R, and I bands. We measured multi-band optical fluxes, colour and spectral variations for this blazar on intraday and short timescales. The source was in a flaring state during the period analyzed and displayed intense variability in all wavelengths. R band magnitude of 11.6 was attained by the target on 18 Jan 2015, which is the brightest value ever recorded for S5 0716+714. The discrete correlation function method yielded good correlation between the bands with no measurable time lags, implying that radiation in these bands originate from the same region and by the same mechanism. We also used the structure function technique to look for characteristic timescales in the light curves. During the times of rapid variability, no evidence for the source to display spectral changes with magnitude was found on either of the timescales. The amplitude of variations tends to increase with increasing frequency with a maximum of $sim$ 22% seen during flaring states in B band. A mild trend of larger variability amplitude as the source brightens was also found. We found the duty cycle of our source during the analyzed period to be $sim$ 90%. We also investigated the optical spectral energy distribution of S5 0716+714 using B, V, R, and I data points for 21 nights. We briefly discuss physical mechanisms most likely responsible for its flux and spectral variations.
The BL Lac object S5~0716+714, a highly variable blazar, underwent an impressive outburst in January 2015 (Phase A), followed by minor activity in February (Phase B). The MAGIC observations were triggered by the optical flux observed in Phase A, corr
S5 0716+714 is a well known BL Lac object, one of the brightest and most active blazars. The discovery in the Very High Energy band (VHE, E > 100 GeV) by MAGIC happened in 2008. In January 2015 the source went through the brightest optical state ever
We present the results of a series of radio, optical, X-ray and gamma-ray observations of the BL Lac object S50716+714 carried out between April 2007 and January 2011. The multi-frequency observations were obtained using several ground and space base
The occurrence of low-amplitude flux variations in blazars on hourly timescales, commonly known as microvariability, is still a widely debated subject in high-energy astrophysics. Several competing scenarios have been proposed to explain such occurre
We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of January 2015. Observed almost simultaneously in the optical, X-rays and {gamma}-ray