• Hard X-ray spectrum of Mkn 421 during the active phase

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      https://www.ias.ac.in/article/fulltext/joaa/022/02-03/0145-0154

    • Keywords

       

      X-rays, AGNs; BL Lac sources, massive black hole candidates, jet emission, individual; Mkn 421

    • Abstract

       

      Spectral measurement of Mkn 421 were made in the hard X-ray energy band of 20–200 keV using a high sensitivity, large area scintillation counter telescope on November 21, 2000 and these coincided with the onset of an active X-ray phase as seen in the ASM counting rates on board RXTE. The observed spectrum can not be fitted to a single power law similar to the PDS data of BeppoSAX. The data can be fitted both by a two component power-law function or a combination of an exponential function with a power law component at the high energies above 80 keV. We identify these components with those arising from the synchrotron self compton and the high energy power-law tail arising from the upgrading of the thermal photons due to multiple Compton scattering a la Cyg X-1. A comparison with the earlier data clearly suggests a spectral variability in the hard X-ray spectrum of the source. We propose a continuously flaring geometry for the source as the underlying mechanism for energy release.

    • Author Affiliations

       

      R. K. Manchanda1

      1. Tata Institute of Fundamental Research, Colaba, Mumbai - 400005, India
    • Dates

       
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