We present multifrequency light curves of BL Lacertae from February 2008 to October 2012. Low-energy data (optical and millimetre) were acquired in the framework of a GASP-WEBT project. High-energy data (ultraviolet, X-ray, and gamma-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 gamma 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 gamma-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 gamma and optical fluxes, which cannot be unveiled because of the small gaps in the sampling of this extremely variable source.
The optical-gamma correlation in BL Lacertae / Raiteri CM; Villata M; DAmmando F; Larionov VM; Gurwell MA; Mirzaqulov DO; Smith PS; Carnerero MI. - In: EPJ WEB OF CONFERENCES. - ISSN 2100-014X. - STAMPA. - 61:(2013), pp. 04014.1-04014.4. (Intervento presentato al convegno International Symposium on the Innermost Regions of Relativistic Jets and Their Magnetic Fields tenutosi a Granada, Spain nel 2013 June 10-14) [10.1051/epjconf/20136104014].
The optical-gamma correlation in BL Lacertae
D'AMMANDO, FILIPPO;
2013
Abstract
We present multifrequency light curves of BL Lacertae from February 2008 to October 2012. Low-energy data (optical and millimetre) were acquired in the framework of a GASP-WEBT project. High-energy data (ultraviolet, X-ray, and gamma-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 gamma 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 gamma-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 gamma and optical fluxes, which cannot be unveiled because of the small gaps in the sampling of this extremely variable source.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
