The TeV and X-ray Characteristics of Mkn 501 as Measured in 1998
with the HEGRA Cherenkov Telescopes and RXTE
H.Krawczynski, F.A.Aharonian for the HEGRA collaboration
R.M.Sambruna, L.Chou
C.M.Urry
Abstract
The HEGRA Cherenkov telescopes have been used in 1997
and in 1998 to intensively monitor the BL Lac object Mkn 501 on a regular
basis. After a period of exceptional activity in 1997 of continuous flares
and a mean flux roughly one order of magnitude stronger than in the
preceding years the source returned in 1998 to a state of moderate flux
levels with only very sparse flaring activity. We present detailed studies
of the 1998 TeV characteristics of the source and focus on a comparison of
its 1997 and 1998 TeV spectra. In June, 1998 we organized a joint
HEGRA/RXTE multiwavelength campaign, characterized by exactly simultaneous
observations with long integration times during approximately two weeks. A
strong flare occurred during the campaign yielding a possible signature
for time delays between the TeV and the X-ray emission as well as the high
and low energy X-ray radiation. We highlight the results of the
correlation studies and discuss the implications on emission scenaria and
the intergalactic extinction of the TeV radiation by the Diffuse
Extragalactic Background Radiation.
File translated from TEX by TTH, version 2.32.
On 16 Jul 1999, 09:19.