Radio Luminosities and Classificatory Criteria of BL Lacertae Objects

Abstract

Using the sample of radio selected BL Lacertae objects (RBLs) and X-ray selected BL Lacertae objects (XBLs) presented by Sambruna et al. (1996), we calculated the luminosities of radio, optical and X-ray of each source and made the statistical analysis among the luminosities at different wave-bands, broad-band spectral indices from radio to X-ray (${\alpha }_{\mathrm{rx}}$) and peak frequencies (${\nu }_p$). Our results are as follows: (i) there is a positive correlation between radio luminosity $L_{\mathrm{r}}$ and ${\alpha }_{\mathrm{rx}}$ and a negative correlation between $L_{\mathrm{r}}$ and ${\nu }_p$. High-energy peak BL Lacs (HBLs) and low-energy peak BL Lacs (LBLs) can be distinguished very well, the dividing lines are probably those of $\log L_{\mathrm{r}}=43.25$ (erg/sec) and ${\alpha }_{\mathrm{rx}}>$(or $\le$)0.75 for $L_{\mathrm{r}}$ - ${\alpha }_{\mathrm{rx}}$ plot and those of $\log L_{\mathrm{r}}\le 43.25$ (erg/sec) and $\log {\nu }_p>14.7$ for the $L_{\mathrm{r}}$ - ${\nu }_p$ plot; (ii) there is a weak positive correlation between optical luminosity $L_o$ and ${\alpha }_{\mathrm{rx}}$ and a negatively weak correlation between $L_{\mathrm{o}}$ and ${\nu }_p$; (iii) there is no correlation between X-ray luminosity $L_X$ and ${\alpha }_{\mathrm{rx}}$ or between $L_X$ and ${\nu }_p$. From our analysis, we find that synchrotron radiation is the main X-ray radiation mechanism for HBLs while inverse Compton scattering for LBLs.

9 pages, 3 figures. Submitted to A&A

References in corpus (2)

• A Unifying View of the Spectral Energy Distributions of Blazars
• Distinguishing RBL-like objects and XBL-like objects with the peak emission frequency of the overall energy spectrum

Cited by in corpus (1)

• The HRX-BL Lac sample - evolution of BL Lac objects