AAS 205th Meeting, 9-13 January 2005
Session 143 Quasars
Poster, Thursday, January 13, 2005, 9:20am-4:00pm, Exhibit Hall

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[143.12] Spitzer Photometry of Lineless Quasars at High Redshift: BL Lacs or A New Class of Unbeamed Quasars?

A.M. Diamond-Stanic, X. Fan (Arizona), S.F. Anderson (Washington), W.N. Brandt (Penn State), J.S. Kim (Arizona), D.P Schneider (Penn State), M.A. Strauss (Princeton)

The Sloan Digital Sky Survey has recently discovered a class of high-redshift quasars with no or extremely weak optical emission lines. Their redshifts are determined by the presence of strong Lyman break and Lyman Limit Systems, but their nature remains unknown. They could be analogs of BL Lac objects at high redshift, a new type of unbeamed quasar whose broad emission-line region is very weak or absent, or a combination of both. We present Spitzer IRAC and MIPS 24 micron photometry of four lineless quasars at z = 4 4.6, two of which are radio/X-ray quiet and two of which are radio/X-ray loud. This Spitzer photometry probes the spectral region where there is a dramatic contrast between beamed synchrotron emission in BL Lac objects and thermal dust emission in unbeamed quasars. By revealing the nature of the IR emission mechanism, we can determine whether these lineless quasars are beamed sources similar to BL Lac objects or a new type of unbeamed quasar.

The author(s) of this abstract have provided an email address for comments about the abstract: adiamond@as.arizona.edu

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© 2004. The American Astronomical Society.