The connection between black hole mass and Doppler boosted emission in BL Lacertae type objects

Abstract

We investigate the relationship between black hole mass (MBH) and Doppler boosted emission for BL Lacertae type objects (BL Lacs) detected in the Sloan Digital Sky Survey and Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) surveys. The synthesis of stellar population and two-dimensional decomposition methods allows us to disentangle the components of the host galaxy from that of the nuclear black hole in their optical spectra and images, respectively. We derive estimates of black hole masses via stellar velocity dispersion and bulge luminosity. We find that masses delivered by both methods are consistent within errors. There is no difference between the black hole mass ranges for high-synchrotron peaked BL Lacs (HBL) and low-synchrotron peaked BL Lacs (LBL). A correlation between the black hole mass and radio, optical and X-ray luminosity has been found at a high significance level. The optical continuum emission correlates with the jet luminosity as well. Besides, X-ray and radio emission are correlated when HBLs and LBLs are considered separately. Results presented in this work (i) show that the black hole mass does not decide the spectral energy distribution shapes of BL Lacs, (ii) confirm that X-ray and optical emission is associated to the relativistic jet and (iii) present evidence of a relation between MBH and Doppler boosted emission, which among BL Lacs may be understood as a close relation between faster jets and more massive black holes. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.