Answers are grounded in this paper and cite their sources.
New observations of the very red quasar or BL Lac object PKS 1413 + 135 are presented. Optical imaging and spectroscopy confirm the claim that the host galaxy to this BL Lac is a spiral, and H-band imaging shows the point source centered in the galaxy to within 0.1". A reanalysis of Einstein X-ray data finds evidence for an extremely large column density in this source of n(H)>= 2 x 10^22^ cm^2^. The A_v_>= 30 mag suggested by this n(H) can produce the unusual near-IR exponential decline in the spectrum of PKS 1413 + 135, at variance with previous interpretations. While the astrometric evidence supports the hypothesis that PKS 1413 + 135 is the very unusual case of a BL Lac object in a spiral galaxy, a highly extincted nuclear source would produce other observable features in this galaxy that are not observed: narrow emission-line region and large thermal IR flux. Their absence argues for this source being background to the spiral.
No takes yet. Share an insight, caveat, or question.
Stocke et al. (1992) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: