The optical-gamma correlation in BL Lacertae

Claudia M. Raiteri, Massimo Villata, Filippo D'Ammando, Valeri M. Larionov, Mark A. Gurwell, Davron O. Mirzaqulov, Paul S. Smith, Maria Isabel Carnerero

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations


We present multifrequency light curves of BL Lacertae from February 2008 to October 2012. Lowenergy data (optical and millimetre) were acquired in the framework of a GASP-WEBT project. High-energy data (ultraviolet, X-ray, and γ-ray) come from observations of the Swift, RXTE, and Fermi satellites. After a period of moderate activity, in May 2011 the source suddenly started to flare at γ and optical-UV frequencies. Activity at millimetre wavelengths and X rays began 3-4 months later. This behaviour offered a good opportunity to study the correlation among flux variability in different bands, in particular between the best-sampled optical and γ-ray light curves. However, even in this fortuitous case, we can only define a general correlation with likely no time lag, but with a lag uncertainty of ±1 day. Indeed, the data reveal a complex relationship between the γ and optical fluxes, which cannot be unveiled because of the small gaps in the sampling of this extremely variable source.

Original languageEnglish (US)
Article number04014
JournalEPJ Web of Conferences
StatePublished - 2013
EventInternational Symposium on the Innermost Regions of Relativistic Jets and Their Magnetic Fields - Granada, Spain
Duration: Jun 10 2013Jun 14 2013

ASJC Scopus subject areas

  • General Physics and Astronomy


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