New High-z BL Lacs Using the Photometric Method with Swift and SARA
New High-z BL Lacs Using the Photometric Method with Swift and SARA
Abstract BL Lacertae (BL Lac) objects are prominent members of the third Fermi Large Area Telescope catalog of γ -ray sources. Half of the members of the BL Lac population (∼300) lack redshift measurements, which is due to the absence of lines in their optical spectra, thereby making it difficult …