Ten new BL lacertae objects discovered by an efficient X-ray/radio/optical technique

Jonathan F. Schachter, John T. Stocke, Eric Perlman, Martin Elvis, Ron Remillard, Arno Granados, Jane Luu, John P. Huchra, Roberta Humphreys, C. Megan Urry, John Wallin

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116 Scopus citations


We report the recent discovery of 10 BL Lac objects in the Einstein IPC Slew Survey by means of X-ray/ radio versus X-ray/optical color-color diagrams and confirming optical spectroscopy. These 10 BL Lac objects were discovered using a technique proposed by Stocke et al. which exploits the characteristic broad-band spectra of BL Lac objects. New VLA detections provide accurate fluxes [limiting f(6 cm) ∼ 0.5 mJy] and ∼1″ positions, facilitating the determination of an optical counterpart. All 10 new BL Lac objects show essentially featureless optical spectra and lie within the range of radio/X-ray/optical colors of known X-ray-selected BL Lac objects, when ∼1 mag optical variability is included. We expect ∼50 new BL Lac objects in total, from complete optical follow-up of our now completed VLA work and recent Australia Telescope observations, yielding a complete Slew Survey sample of ∼90 BL Lac objects.

Original languageEnglish (US)
Pages (from-to)541-549
Number of pages9
JournalAstrophysical Journal
Issue number2
StatePublished - Aug 1 1993


  • BL Lacertae objects: general
  • Galaxies: active
  • Galaxies: nuclei
  • Methods: observational
  • Surveys
  • X-rays: galaxies


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