EGRET gamma-ray source 2EG J0809+5117, a quasar with redshift of 1.14?

Abstract

The low dispersion (400$Å$/mm) spectrum of the optical counterpart of a flat-spectrum radio source 87GB 080315.5+512613, which is one of two possible radio counterparts of 2EG J0809+5117, was obtained recently. The optical counterpart, which is $2.02''$ away from 87GB 080315.5+512613 and $19.3'$ away from 2EG J0809+5117, was identified as a quasar with redshift of 1.14. We noted that Mattox et al. (1997) suggested the other radio counterpart 87GB 080459.4+495915 (OJ 508), which is $87.1'$ away from 2EG J0809+5117, is the more potential identification, though it was previously suggested to be the identification (with low confidence) of another nearby EGRET source 2EG J0807+4849. Our observation suggests that it is quite possible that 87GB 080315.5+512613 is the identification of 2EG J0809+5117 rather than 87GB 080459.4+495915. But we still can not exclude the possibility of 87GB 080459.4+495915 at present. Moreover, in order to determine whether or not 87GB 080315.5+512613 is a blazar type quasar, the optical polarization and variability measures of its optical counterpart are strongly encouraged.