AAS 204th Meeting, June 2004
Session 60 Quasars
Poster, Wednesday, June 2, 2004, 10:00am-7:00pm, Ballroom

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[60.02] QSOs, Giant Black Holes, and Missing Host Galaxies

G. A. Shields, K. Gebhardt (U. Texas)

The most luminous quasars often contain black holes of mass greater than 4 billion solar masses. This value exceeds the largest black holes known in the local universe. Nevertheless, the reality of these large masses is supported by consistency with the Eddington limit and with the widths of the [O III] narrow lines (Shields et al. 2003, ApJ, 583, 124). Assuming the normal relationship between black hole mass and stellar velocity dispersion, we estimate a comoving space density of ~102 host galaxies per cubic Gpc with velocity dispersion exceeding 500 km/s. Such galaxies are absent from locally observed galaxy luminosity and velocity dispersion functions. However, galaxy clusters provide an ample number of dark matter halos with such large velocity dispersions. This suggests that the the largest black holes may exist in failed galaxies in massive dark matter halos.

This work was supported by Texas Advanced Research Program grant 003658-0177-2001 and by NSF grant AST-0098594.

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