A Spectral Study of Four X-Ray--selected BL Lacertae Objects with EXOSAT

Abstract

We present new EXOSAT spectral results for four X-ray-selected BL Lac objects (H0323+022, H0414+009, H1426+428, and H1722+ 119). The data were retrieved from the EXOSAT data base. A spectral analysis was performed on the overall low-energy plus medium-energy distributions, which were modeled with a single, absorbed power law. In one case (H1426+428), an indication of a spectral break at ~5 keV is found. For H0323 + 022 and H0414 + 428, for which more than one observation is available, the spectral index is found to vary with intensity, in the sense of a hardening of the spectrum when the source brightens.