ar X iv : a st ro - p h / 00 02 43 1 v 1 2 3 Fe b 20 00 CONSTRAINTS TO THE SSC MODEL FOR MKN 501

ar X iv : a st ro - p h / 00 02 25 5 v 1 1 1 Fe b 20 00 Multiwavelength observations of Mkn 501 during the 1997 high state

During the observation period 1997, the nearby Blazar Mkn 501 showed extremely strong emission and high variability. We examine multiwavelength aspects of this event using radio, optical, soft and hard X-ray and TeV data. We concentrate on the medium-timescale variability of the broadband spectra, averaged over weekly intervals. We confirm the previously found correlation between soft and hard ...

ar X iv : a st ro - p h / 02 12 56 6 v 1 3 0 D ec 2 00 2 Dark Energy : Is it Q or Λ ?

New observations of Cosmic Microwave Background Anisotropies, Su-pernovae luminosity distances and Galaxy Clustering are sharpening our knowledge about dark energy. Here we present the latest constraints.

ar X iv : a st ro - p h / 02 04 03 6 v 1 2 A pr 2 00 2 Investigating the Flame Microstructure in Type

ar X iv : a st ro - p h / 99 10 53 6 v 1 2 9 O ct 1 99 9 Effect of intergalactic absorption in the TeV γ - ray spectrum of Mkn 501

We discuss an effect of the intergalactic absorption of the TeV γ-rays in time-averaged spectrum of Mkn 501 measured by the HEGRA collaboration. Analysis of the spectral behavior, variability time scale and relevant calculations of TeV γ-ray emission allow to conclude the presence of a noticeable absorption of the TeV γ-rays in the Mkn 501 energy spectrum.

ar X iv : a st ro - p h / 98 10 43 0 v 1 2 7 O ct 1 99 8 VLBI Observations of Mkn 501 and Mkn 421

We present here two epochs of Space VLBI Observations at 18 cm of the BL-Lac type object Mkn 501. Thanks to the high resolution of these new data we have found that the inner jet is centrally brightened at its beginning but becomes extended and limb brightened at ∼ 8 mas from the core. Moreover a comparison between the two epochs shows the presence of a possible proper motion with apparent velo...