For refcode 2006ApJ...637...96N: Retrieve 12 NED objects in this reference. Please click here for ADS abstract
NED Abstract
Copyright by American Astronomical Society.
Reproduced by permission
2006ApJ...637...96N
On the Correlations of Massive Black Holes with Their Host Galaxies
Gregory S. Novak, S. M. Faber, and Avishai Dekel
Abstract. We address the correlations of black hole (BH) mass with four
different hostgalaxy properties from 11 existing data sets. For the
purpose of guiding theoretical understanding, we first try to quantify
the tightness of the intrinsic correlations. We assume that all of the
relations are power laws and perform linear regressions that are
symmetric in the two variables on the logarithms of the data points.
Given the estimated measurement errors, we evaluate the probability
distribution of the residual variance in excess of that expected from
the measurement errors. Our central result is that the current data sets
do not allow definite conclusions regarding the quality of the true
correlations because the obtained probability distributions for the
residual variance overlap for most quantities. Velocity dispersion as
collected by Merritt & Ferrarese ({sigma}_MF_) and galaxy light
concentration as measured by Graham and coworkers (C_Re_) are consistent
with zero residual variance. Taken at face value, this means that these
two correlations are better than the others, but this conclusion is
highly sensitive to the assumed measurement errors and would be undone
if the present estimated errors were too large. We then consider which
of the relations offer the best inferences of BH mass when there is no
direct measurement available. As with the residual variances, we find
that the probability distribution of expected uncertainty in inferred BH
masses overlaps significantly for most of the relations. Photometric
methods would then be preferred because the data are easier to obtain,
as long as bulgedisk decomposition or detailed modeling of the
photometric profile (as studied by Graham and coworkers) do not present
problems. Determining which correlation offers the best inferences
requires reducing the uncertainty in the expected error in the inferred
BH masses (the "error on the error"). This uncertainty is currently
limited by uncertainty in the residual variance for all of the
relations. The only quantities for which BH mass inferences are limited
by measurement error are {sigma}_MF_ and C_Re_. Therefore, if these
relations are truly better than the others, then new, improved
measurements should allow improved inferences of BH masses. If they do
not, the conclusion must be that the present low residual variances for
these two relations result from overestimated error bars.
Key words: Black Hole Physics, Galaxies: Bulges, Galaxies: Fundamental
Parameters, Galaxies: Kinematics and Dynamics, Galaxies: Nuclei
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