The spectrum and magnitude of the galaxy associated with BL Lacertae
Аннотация
Spectroscopic observations of BL Lacertae performed through an annular aperture attached to a 3-m reflector are reported which demonstrate unequivocally that the prototype of the BL Lac class of objects is located in a luminous elliptical galaxy with a redshift of 0.0695 + or - 0.001. The general continuum level of the galaxy (with scattered light removed) is determined as 9.21 by 10 to the -28th power erg/sec per Hz at 5480 A and 3.13 by 10 to the -28th power erg/sec per Hz at 4400 A, which correspond to magnitudes of 19.00 and 20.17, respectively. The absolute magnitude of the galaxy associated with BL Lac is estimated to be -21.7, and the spectrum of this galaxy is shown to be entirely normal for a luminous elliptical. It is noted that the central source varies from a luminosity roughly comparable to that of the galaxy to an amount over 10 times greater.