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X-ray emitting BL Lacertae objects located by the scanning modulation collimator experiment on HEAO 1

DOI

41

Citations

0

References

1979

Year

D. A. Schwartz, R. E. Griffiths, J. Schwarz, R. Doxsey, Mark Johnston
The Astrophysical Journal

Abstract

It is established that BL Lacertae objects constitute a class of X-ray emitter by precisely locating X-ray sources identified with Mrk 421, PKS 0548-322, PKS 2155-304, and 2A 1219+305. Irregular variations of the order of 1 mag, characteristic of BL Lacertae objects, are reported for the last two objects. The measurement of an extremely steep X-ray spectrum from Mrk 421, in contrast to previous flat X-ray spectra above 3 keV, suggests that different structural states of an accretion disk are being observed.