THE EINSTEIN SLEW SURVEY SAMPLE OF BL LACERTAE OBJECTS

We have used an efficient method of finding new BL Lacertae objects in the Einstein Slew Survey suggested by Stocke et al, By exploiting the unique broadband (radio / optical / X-ray) spectra of X-ray-selected BL Lac objects, we have identified 29 new BL Lac objects out of 32 can didates observed, effectively doubling the size of the Slew Survey BL Lac sample, which now includes 62 objects. Six more BL Lac candidates have yet to be observed, and seven blank field radio sources cannot be ruled out as optically faint BL Lac objects, although this is unlikel y. The correct classification of one BL Lac candidate remains uncertai n, We present finding charts, optical spectroscopy, radio images, and optical polarimetry for these new BL Lac objects, Based upon nearly co mplete radio imaging and optical spectroscopy observations, we present the northern, high-latitude Slew Survey BL Lac sample, in the area bo unded by delta greater than or equal to -40 degrees and \ b(II) \ grea ter than or equal to 15 degrees and excluding the region within 5 degr ees of M31, This sample contains 48 BL Lac objects, five BL Lac candid ates, and five blank fields which may contain possible BL Lac candidat es, This is considerably larger than any previous complete sample of B L Lac objects. We compare this sample with the X-ray-selected Extended Medium-Sensitivity Survey (EMSS) sample of BL Lac objects as well as the radio-selected 1 Jy sample.