Asymmetric Drift and the Stellar Velocity Ellipsoid

Kyle B. Westfall; Matthew A. Bershady; Marc A. W. Verheijen; David R. Andersen; Rob A. Swaters

doi:10.1007/978-1-4020-5573-7_27

Asymmetric Drift and the Stellar Velocity Ellipsoid

Kyle B. Westfall, Matthew A. Bershady, Marc A. W. Verheijen, David R. Andersen, Rob A. Swaters

Astronomy

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Academic › peer-review

5 Citations (Scopus)

Abstract

We present the decomposition of the stellar velocity ellipsoid using stellar velocity dispersions within a 40° wedge about the major-axis (smaj), the epicycle approximation, and the asymmetric drift equation. Thus, we employ no fitted forms for smaj and escape interpolation errors resulting from comparisons of the major and minor axes. We apply the theoretical construction of the method to integral field data taken for NGC 3949 and NGC 3982. We derive the vertical-to-radial velocity dispersion ratio (σz/σR) and find (1) our decomposition method is accurate and reasonable, (2) NGC 3982 appears to be rather typical of an Sb type galaxy with σz/σR = 0.73+0.13 -0.11 despite its high surface brightness and small size, and (3) NGC 3949 has a hot disk with σz/σR = 118+0.36 -0.28

Original language	English
Title of host publication	ISLAND UNIVERSES
Subtitle of host publication	Astrophysics and Space Science Proceedings
Publisher	Springer
Pages	157-160
Number of pages	4
ISBN (Print)	978-1-4020-5572-0
DOIs	https://doi.org/10.1007/978-1-4020-5573-7_27
Publication status	Published - 2007

Keywords

Physics

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http://adsabs.harvard.edu/abs/2007iuse.book..157W

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Asymmetric Drift and the Stellar Velocity Ellipsoid
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title = "Asymmetric Drift and the Stellar Velocity Ellipsoid",

abstract = "We present the decomposition of the stellar velocity ellipsoid using stellar velocity dispersions within a 40° wedge about the major-axis (smaj), the epicycle approximation, and the asymmetric drift equation. Thus, we employ no fitted forms for smaj and escape interpolation errors resulting from comparisons of the major and minor axes. We apply the theoretical construction of the method to integral field data taken for NGC 3949 and NGC 3982. We derive the vertical-to-radial velocity dispersion ratio (σz/σR) and find (1) our decomposition method is accurate and reasonable, (2) NGC 3982 appears to be rather typical of an Sb type galaxy with σz/σR = 0.73+0.13 -0.11 despite its high surface brightness and small size, and (3) NGC 3949 has a hot disk with σz/σR = 118+0.36 -0.28",

keywords = "Physics",

author = "Westfall, {Kyle B.} and Bershady, {Matthew A.} and Verheijen, {Marc A. W.} and Andersen, {David R.} and Swaters, {Rob A.}",

year = "2007",

doi = "10.1007/978-1-4020-5573-7_27",

language = "English",

isbn = "978-1-4020-5572-0",

pages = "157--160",

booktitle = "ISLAND UNIVERSES",

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T1 - Asymmetric Drift and the Stellar Velocity Ellipsoid

AU - Westfall, Kyle B.

AU - Bershady, Matthew A.

AU - Verheijen, Marc A. W.

AU - Andersen, David R.

AU - Swaters, Rob A.

PY - 2007

Y1 - 2007

N2 - We present the decomposition of the stellar velocity ellipsoid using stellar velocity dispersions within a 40° wedge about the major-axis (smaj), the epicycle approximation, and the asymmetric drift equation. Thus, we employ no fitted forms for smaj and escape interpolation errors resulting from comparisons of the major and minor axes. We apply the theoretical construction of the method to integral field data taken for NGC 3949 and NGC 3982. We derive the vertical-to-radial velocity dispersion ratio (σz/σR) and find (1) our decomposition method is accurate and reasonable, (2) NGC 3982 appears to be rather typical of an Sb type galaxy with σz/σR = 0.73+0.13 -0.11 despite its high surface brightness and small size, and (3) NGC 3949 has a hot disk with σz/σR = 118+0.36 -0.28

AB - We present the decomposition of the stellar velocity ellipsoid using stellar velocity dispersions within a 40° wedge about the major-axis (smaj), the epicycle approximation, and the asymmetric drift equation. Thus, we employ no fitted forms for smaj and escape interpolation errors resulting from comparisons of the major and minor axes. We apply the theoretical construction of the method to integral field data taken for NGC 3949 and NGC 3982. We derive the vertical-to-radial velocity dispersion ratio (σz/σR) and find (1) our decomposition method is accurate and reasonable, (2) NGC 3982 appears to be rather typical of an Sb type galaxy with σz/σR = 0.73+0.13 -0.11 despite its high surface brightness and small size, and (3) NGC 3949 has a hot disk with σz/σR = 118+0.36 -0.28

KW - Physics

U2 - 10.1007/978-1-4020-5573-7_27

DO - 10.1007/978-1-4020-5573-7_27

M3 - Conference contribution

SN - 978-1-4020-5572-0

SP - 157

EP - 160

BT - ISLAND UNIVERSES

PB - Springer

ER -

Asymmetric Drift and the Stellar Velocity Ellipsoid

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