Reconstructing the velocity dispersion profiles from the line-of-sight kinematic data in disc galaxies

Abstract

We present a modification of the method for reconstructing the stellar velocity ellipsoid (SVE) in disc galaxies. Our version does not need any parametrization of the velocity dispersion profiles and uses only one assumption that the ratio ${\sigma }_z/{\sigma }_R$ remains constant along the profile or along several pieces of the profile. The method was tested on two galaxies from the sample of other authors and for the first time was applied to three lenticular galaxies NGC~1167, NGC~3245 and NGC~4150 as well as to one Sab galaxy NGC~338. We found that for galaxies with a high inclination ($i>55-60^{\circ }$) it is difficult or rather impossible to extract the information about SVE while for galaxies at an intermediate inclination the procedure of extracting is successful. For NGC~1167 we managed to reconstruct SVE, provided that the value of ${\sigma }_z/{\sigma }_R$ is piecewise constant. We found ${\sigma }_z/{\sigma }_R=0.7$ for the inner parts of the disc and ${\sigma }_z/{\sigma }_R=0.3$ for the outskirts. We also obtained a rigid constrain on the value of the radial velocity dispersion ${\sigma }_R$ for highly inclined galaxies and tested the result using the asymmetric drift equation, provided that the gas rotation curve is available.

References in corpus (11)

• Triaxial orbit based galaxy models with an application to the (apparent) decoupled core galaxy NGC 4365
• The mass distribution in early-type disk galaxies: declining rotation curves and correlations with optical properties
• NMAGIC: Fast Parallel Implementation of a Chi-Squared-Made-to-Measure Algorithm for Modelling Observational Data
• Dark matter content and internal dynamics of NGC 4697: NMAGIC particle models from slit data and planetary nebulae velocities
• A clear age-velocity dispersion correlation in Andromeda's stellar disk
• An Iterative Method for Constructing Equilibrium Phase Models of Stellar Systems
• The stellar mass distribution in early-type disk galaxies: surface photometry and bulge-disk decompositions
• Cold gas in group-dominant elliptical galaxies
• An Iterative Method for the Construction of Equilibrium N-Body Models for Stellar Disks
• Exploring Disk Galaxy Dynamics Using IFU Data
• Kinematics and Stellar Disk Modeling of Lenticular Galaxies

Cited by in corpus (3)

• The specific angular momentum of disc galaxies and its connection with galaxy morphology, bar structure and disc gravitational instability
• Local variations of the Stellar Velocity Ellipsoid-I: the disc of galaxies in the Auriga simulations
• Gravitational instability and spatial regularity of the gas clouds and young stellar population in spiral arms of NGC 628