NOAO >   Observing Info >   Approved Programs >   2003A-0302

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Proposal Information for 2003A-0302


PI: Travis A. Rector, NRAO, trector@nrao.edu
Address: P.O. Box O, Socorro, NM 87801, USA

CoI: Diana Londish, University of Sydney

Title: The Discovery of a New Class of AGN?

Abstract: We propose a photometric study of a new class of object discovered by the 2dF QSO redshift survey (2QZ). The 2QZ has discovered 56 objects which exhibit a featureless optical continuum, a steep number-magnitude relation and lack detectable proper motions, suggesting they are extragalactic and likely BL Lac objects. However, unlike any BL Lac objects known, these sources are not detected at radio and X-ray wavelengths. If indeed AGN, they are the first radio- and X-ray-quiet BL Lacs ever discovered. We propose to determine whether these objects are BL Lacs or instead Galactic continuum DC white dwarfs by photometrically measuring their continuum shape in the optical and the near-IR. Because they lack molecular absorption bands, DC white dwarfs closely match a blackbody spectrum throughout the optical and near-IR and will be readily differentiated from the nonthermal continuum plus host galaxy spectrum of BL Lacs. If indeed BL Lacs, these objects populate a new parameter space of broadband spectral energy distributions. And if they do obey the same evolution model as other QSOs in the 2QZ they are at much higher redshift than prior samples of BL Lacs, contradicting BL Lac emission models which predict that BL Lacs evolve from more radio luminous at high-z to less radio luminous in the local Universe. This proposal is a resubmission of 02A-0070, which was awarded time but was all but completely lost to poor weather.


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