Calibrating stellar velocity dispersions based on spatially resolved h-band spectra for improving the mbh–σ∗ relation

Kang, Wol-Rang and Woo, Jong-Hak and Schulze, Andreas and Riechers, Dominik A. and Kim, Sang Chul and Daeseong, Park and Smolčić, Vernesa (2013) Calibrating stellar velocity dispersions based on spatially resolved h-band spectra for improving the mbh–σ∗ relation. Astrophysical Journal, 767 (1). p. 11. ISSN 0004-637X

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Abstract

To calibrate stellar velocity dispersion measurements from optical and near-IR stellar lines, and to improve the black hole mass (MBH)–stellar velocity dispersion (σ∗) relation, we measure σ∗ based on high-quality H-band spectra for a sample of 31 nearby galaxies, for which dynamical MBH is available in the literature. By comparing velocity dispersions measured from stellar lines in the H-band with those measured from optical stellar lines, we find no significant difference, suggesting that optical and near-IR stellar lines represent the same kinematics and that dust effect is negligible for early-type galaxies. Based on the spatially resolved rotation and velocity dispersion measurements along the major axis of each galaxy, we find that a rotating stellar disk is present for 80% of galaxies in the sample. For galaxies with a rotation component, σ∗ measured from a single aperture spectrum can vary by up to ∼20%, depending on the size of the adopted extraction aperture. To correct for the rotational broadening, we derive luminosity-weighted σ∗ within the effective radius of each galaxy, providing uniformly measured velocity dispersions to improve the MBH–σ∗ relation.

Item Type: Article
Keywords: galaxies: bulges – galaxies: kinematics and dynamics – infrared: galaxies – techniques: spectroscopic Online-only material: color figures
Date: 2013
Subjects: NATURAL SCIENCES > Physics > Astronomy and Astrophysics
Additional Information: © 2013 American Astronomical Society. Received 2013 January 20; accepted for publication 2013 February 19; published 2013 March 21.
Divisions: Faculty of Science > Department of Physics
Publisher: IOP Publishing
Depositing User: Vernesa Smolčić
Date Deposited: 21 Apr 2015 18:29
Last Modified: 22 Apr 2015 14:10
URI: http://digre.pmf.unizg.hr/id/eprint/3852

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