Multiwavelength Variability of BL Lacertae Measured with High Time Resolution

Spectral variability and multiwavelength studies of the high-frequency-peaked BL Lacertae object 1ES 0806+524 with the MAGIC telescopes

SAX and multiwavelength observations of BL Lacertae in 2000

We present two BeppoSAX observations of BL Lac (2200+420) as part of a multiwavelength campaign performed in 2000. The source was in different states of activity: in June, the X–ray spectrum was faint and hard (α ∼ 0.8), with positive residuals towards low energies. In October we detected the highest [2–10] keV flux ever measured for the source. During this observation, the spectrum was soft (α...

High-resolution imaging of Einstein Slew Survey BL Lacertae objects

High-resolution images of 7 newly identified BL Lac objects (among them one BL Lac candidate) at z ≤ 0.2 from the Einstein Slew Survey are presented for the first time. In all cases we were able to resolve the host galaxy. Our 2−dimensional analysis of the host galaxies shows that all these BL Lac objects are embedded in elliptical galaxies with an average MR = −23.1 and re = 10 kpc. One BL Lac...

Modeling the Multiwavelength Spectra and Variability of BL Lacertae in 2000

BL Lacertae was the target of an extensive multiwavelength monitoring campaign in the second half of 2000. The campaign had revealed optical and X-ray intraday variability on time scales of ∼ 1.5 hours and evidence for significant spectral variability both at optical and X-ray frequencies. During the campaign, BL Lacertae was observed in two different activity states: A quiescent state with rel...

The long-term optical spectral variability of BL Lacertae

Context. We present the results from a study of the long-term optical spectral variations of BL Lacertae, using the long and wellsampled B and R-band light curves of the Whole Earth Blazar Telescope (WEBT) collaboration, binned on time intervals of 1 day. Aims. To study the relation between the long-term spectral variations and the respective flux variations of the source. Methods. We use cross...