New non-stellar BL Lacertae objects OY091 and PKS2335+03

Abstract

DURING the past year, opinions on the nature of the BL Lacertae objects have narrowed to the association of elliptical galaxies with non-thermal sources which display continuous optical spectra. The study of the objects B2 1101+38 (Markarian 421) and B2 1652+39 (Markarian 501) indicates that they, could be members of a sequence of elliptical galaxies ordered by the relative brightness of the BL Lac objects located in their nuclei¹. On the other hand, the proximity of B2 1215+30, ON231, PKS1205–008 and PKS0048–097 to galaxies or nebulosities, has prompted the suggestion that, at least these four BL Lac objects have been ejected from the nuclei of their companion galaxies (J. J. Condon and D. L. Jauncey, unpublished). Furthermore, an analysis of the optical energy distribution² of several BL Lac objects indicates that the decline of their optical spectra toward the ultraviolet becomes steeper because of the contribution of underlying elliptical galaxies. Typical examples are Markarian 501, AP Librae and BL Lac itself. In the case of AP Librae, the nebulosity was discovered with deep image tube photographs³.