Long-term optical and radio variability of BL Lacertae

Abstract

Well-sampled optical and radio light curves of BL Lacertae in B, V, R, I bands and 4.8, 8.0, 14.5 GHz from 1968 to 2014 were presented in this paper. A possible $1.26\pm 0.05$ yr period in optical bands and a $7.50\pm 0.15$ yr period in radio bands were detected based on discrete correlation function, structure function as well as Jurkevich method. Correlations among different bands were also analyzed and no reliable time delay was found between optical bands. Very weak correlations were detected between V band and radio bands. However, in radio bands the variation at low frequency lagged that at high frequency obviously. The spectrum of BL Lacertae turned mildly bluer when the object turned brighter, and stronger bluer-when-brighter trends were found for short flares. A scenario including a precessing helical jet and periodic shocks was put forward to interpret the variation characteristics of BL Lacertae.

arXiv comment7 pages, 11 figures, submitted

References in corpus (18)

• Optical and radio behaviour of the BL Lacertae object 0716+714
• Optical and radio variability of the BL Lac object AO 0235+16: a possible 5-6 year periodicity
• The WEBT BL Lac Campaign 2000
• Multi-colour optical monitoring of eight red blazars
• On the geometrical origin of periodicity in blazar-type sources
• Near Infrared Intraday Variability of Mrk 421
• The correlated optical and radio variability of BL Lacertae. WEBT data analysis 1994-2005
• Optical Flux and Spectral Variability of Blazars
• Spectral Slope Variability of BL Lac Objects in the Optical Band
• Optical Monitoring of BL Lacertae Object S5 0716+714 with a Novel Multi-Peak Interference Filter
• Multi-band optical micro-variability observations of BL Lacertae
• Another look at the BL Lacertae flux and spectral variability
• The Cross-Wavelet Transform and Analysis of Quasiperiodic Behavior in the Pearson-Readhead VLBI Survey Sources
• The stellar content of low redshift BL Lac host galaxies from multicolour imaging
• Multi-color Optical Variability of the TeV Blazar Mrk 501 in the Low-State
• Optical observations of BL Lacertae from 1997 to 1999
• Optical Photometrical Observations and Variability for Quasar 4C 29.45
• Variability and spectral variation of 3C 66A

Cited by in corpus (2)

• Optical and Radio Variability of BL Lacertae
• Study of variability in long-term multiwavelength optical lightcurves of blazar AO 0235+164