We present the analysis of archival data from ROSAT and ASCA of a serendipitous BL Lac object PKS 2316-423 .
Because of its featureless non-thermal radio/optical continuum , PKS 2316-423 has been called as a BL Lac candidate in the literature .
PKS 2316-423 was evidently variable over the multiple X-ray observations , in particular , a variable high-energy tail of the synchrotron radiation is revealed .
The X-ray spectral analysis provides further evidence of the synchrotron nature of its broad-band spectrum : a steep and downward curving spectrum between 0.1–10 keV , typical of high-energy peaked BL Lacs ( HBL ) .
The spectral energy distribution ( SED ) through radio-to-X-ray yields the synchrotron radiation peak at frequency \nu _ { p } = 7.3 \times 10 ^ { 15 } Hz , with integrated luminosity of L _ { syn } = 2.1 \times 10 ^ { 44 } ergs s ^ { -1 } .
The averaged SED properties of PKS 2316-423 are very similar to those “ intermediate ” BL Lac objects ( IBL ) found recently in several deep surveys , such as Deep X-ray Radio Blazar , Radio-Emitting X-ray , and ROSAT-Green Bank surveys .
We suggest that PKS 2316-423 is an IBL though it also shows some general features of a HBL .
Actually , this double attribute of PKS 2316-423 provides a good test of the prediction that an IBL object can show either synchrotron or inverse-Compton characteristics in different variability states .