AAS 205th Meeting, 9-13 January 2005
Session 30 Jets and Active Nuclei in Galaxies
Oral, Monday, January 10, 2005, 10:00-11:30am, Golden Ballroom

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[30.03] Investigating the nature of relativistic jets by studying the demographics of Blazars

G. Fossati (Rice University), S. Laurent-Muehleisen (IGPP), C.M. Urry (Yale University)

We present an overview and selected results of our on-going FIRST Flat Spectrum Sample (FFSS) project. The goal of the FFSS is to shed light on the true nature and physical properties of radio-loud AGN jets, and in turn their relationship with the SMBH and accretion disk from which they are ultimately powered, through the understanding of the demographics of blazars.

The FFSS is ``designed'' to give us a true(r) census of the different types of blazars, resolving a long-standing uncertainty, and the first step towards understanding how Nature makes jets. In order to do so, it is crucial to strive to select in an unprejudiced way all "flavors" of blazar (e.g. not distinguish a priori between BL Lac and FSRQ), and to be sensitive to the whole -broad- range of the SED "color" phenomenology.

The FFSS is now 95% identified. It comprises \approx 600 objects, selected from the FIRST radio survey, representing a very diverse mix of FSRQ (currently 60%), BL Lacs (20%), and ``galaxies" (15%). It spans across the full range of SED colors, with relatively uniform statistics.

The multiwavelength coverage is excellent. The optical spectroscopy coverage (new for \approx 40% of the sample) is >95% complete. The FIRST/SDSS overlap, ensures that for \approx 2/3 of the sample there will be homogeneous multiband photometry. Moreover, at the current match rate (as of SDSS-DR3) we will have SDSS spectra for 1/2 of the sources (DR3 yielded also 45 new redshifts). The 2MASS yields data for \approx 60% of the FFSS objects. X-ray data are available for 2/3 of the sample, including archival and new Chandra observations for about 60 objects.

We will report on our Chandra observations, and we will also discuss the modeling techniques that we are implementing, whose first goal is to test the current luminosity-color sequence paradigm, and to discriminate among competing unification schemes.

(GF acknowledges support from NASA/Chandra grant GO3-4147X)

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© 2004. The American Astronomical Society.