Violent intra-night optical variability of the blazar S4 0954+65 during its unprecedented 2015 February outburst

Abstract

In this letter we present results from intra-night monitoring in three colors (BRI) of the blazar S4 0954+65 during its recent (2015 February) unprecedented high state. We find violent variations on very short time scales, reaching magnitude change levels of 0.1-0.2 mag/h. On some occasions, changes of ~0.1 mag are observed even within ~10 min. During the night of 14.02.2015 an exponential drop of ~0.7 magnitudes is detected for about 5 hours. Cross-correlation between the light curves does not reveal any detectable wavelength-dependent time delays, larger than ~5 min. Color changes "bluer-when-brighter" are observed on longer time scales. Possible variability mechanisms to explain the observations are discussed and a preference to the geometrical one is given.

arXiv commentMNRAS, accepted

References in corpus (8)

• Quasi-simultaneous two band optical variability of the blazars 1ES 1959+650 and 1ES 2344+514
• Simultaneous B'V'R' Monitoring of BL Lacertae Object S5~0716+714 and Detection of Inter-Band Time Delay
• The Outburst of the Blazar S40954+658 in March-April 2011
• Improved characterisation of intra-night optical variability of prominent AGN classes
• Short-term optical variability of high-redshift QSO's
• The nature of the intra-night optical variability in blazars
• Intranight variability of 3C 454.3 during its 2010 November outburst
• Multi-band optical micro-variability observations of the BL Lac object S4 0954+658

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