AAS 205th Meeting, 9-13 January 2005
Session 110 Active Galaxies
Poster, Wednesday, January 12, 2005, 9:20am-6:30pm, Exhibit Hall

## [110.11] The Scatter in the M\bullet-\sigma Relation

C. Siopis, M. C. Aller (U. Michigan), R. Bender (U. Sternwarte, Munich), G. A. Bower (STScI), A. Dressler (Carnegie Obs.), S. M. Faber (UCSC), A. V. Filippenko (UCB), K. Gebhardt (UT), R. Green (NOAO), L. C. Ho (Carnegie Obs.), J. Kormendy (UT), T. R. Lauer (KPNO), J. Magorrian (U. Oxford), J. Pinkney (Ohio Northern U.), D. Richstone (U. Michigan), S. Tremaine (Princeton)

One of the most interesting findings from the search for supermassive black holes (BH) has been the discovery of the M\bullet-\sigma relation, a remarkably tight correlation between BH mass and the velocity dispersion of the stars in the galactic bulge outside of the BH sphere of influence''. The M\bullet-\sigma relation has a scatter which is < 0.3 dex in M\bullet, and consistent with zero. Several theories that try to explain the connection between galaxy formation and black hole growth predict the existence of a second parameter. We investigate the scatter in the M\bullet-\sigma relation and the role of a possible second parameter by examining a disparate set of ~0 galaxies at a narrow range of velocity dispersions \sigma = 200 ±20 km s-1. This approach ensures that we can establish the real scatter in the M\bullet-\sigma relation, without confusion due to errors in the slope or some undetected curvature. The sample spans a wide range of central surface brightness, Hubble type, luminosity, and local galaxy number density. Preliminary results for a subset of the sample are consistent with the absence of a strong correlation involving a second parameter. However, a more firm conclusion cannot be reached before the entire sample is analyzed.

Support for this work was provided by NASA through grants from STScI which is operated by AURA, under NASA contract NAS 5-26555.

Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.