2003A&A...412..711T -
Astronomy and Astrophysics, volume 412, 711-720 (2003/12-4)
Wide band X-ray and optical observations of the BL Lac object 1ES 1959+650 in high state.
TAGLIAFERRI G., RAVASIO M., GHISELLINI G., TAVECCHIO F., GIOMMI P., MASSARO E., NESCI R. and TOSTI G.
Abstract (from CDS):
The blazar 1ES1959+650 was observed twice by BeppoSAX in September 2001 simultaneously with optical observations. We report here the X-ray data together with the optical, RC magnitude light curve since August 1995. The BeppoSAX observations were triggered by an active X-ray status of the source. The X-ray spectra are brighter than the previously published X-ray observations, although the source was in an even higher state a few months later, as monitored by the ASM onboard RossiXTE, when it was also detected to flare in the TeV band. Our X-ray spectra are well represented by a continuosly curved model up to 45keV and are interpreted as synchrotron emission, with the peak moving to higher energies. This is also confirmed by the slope of the X-ray spectrum which is harder than in previous observations. Based on our optical and X-ray data, the synchrotron peak turns out to be in the range 0.1-0.7keV. We compare our data with non-simultaneous radio to TeV data and model the spectral energy distribution with a homogeneous, one-zone synchrotron inverse Compton model. We derive physical parameters that are typical of low power High Energy peaked Blazars, characterised by a relatively large beaming factor, low luminosity and absence of external seed photons.
Abstract Copyright:
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Journal keyword(s):
galaxies: BL Lacertae objects: general - galaxies: BL Lacertae objects: individual: 1ES 1959+650 - X-rays: galaxies
Simbad objects:
11
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