Broad emission line of 4FGL blazars

For the 278 objects, we made a crossmatch from three catalogs, the Fermi Large Area Telescope Fourth Source Catalog (4FGL), the Sloan Digital Sky Survey, and the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, and calculated the broad-line region (BLR) luminosity.

Then, we estimated the Doppler factor and studied the correlations between the BLR luminosities and the {gamma}-ray luminosities, the synchrotron peak frequency ({nu}p), and Doppler factor ({delta}) for the whole sample. Our analyses and discussions came to the following main conclusions: For the 278 blazars, their BLR luminosity (log LBLR) ranges from 40.44 to 45.45erg/s, with a mean value of 43.39erg/s. The Doppler factor ranges from {delta}=0.45 to {delta}=88.52, with a mean value of 12.99 for the 979 Fermi blazars, which is consistent with the results in the literature.