Measuring the inclination and mass-to-light ratio of axisymmetric galaxies via anisotropic Jeans models of stellar kinematics

By M. Cappellari. 2008

360 citations recorded by the source corpus.

We present a simple and efficient anisotropic generalization of the semi-isotropic (two-integral) axisymmetric Jeans formalism, which is used to model the stellar kinematics of galaxies. The following is assumed: (i) a constant mass-to-light ratio (MIL) and (ii) a velocity ellipsoid that is aligned with cylindrical coordinates (R, z) and characterized by the classic anisotropy parameter β z = 1 - υ 2 z /υ 2 R . Our simple models are fit to SAURON integral-field observations of the stellar kinematics for a set of fast-rotator early-type galaxies. With only two free parameters (β z and the inclination), the models generally provide remarkably good descriptions of the shape of the first (V) and second (V rms ≡ √V 2 + σ 2 ) velocity moments, once a detailed description of the surface brightness is given. This is consistent with previous findings on the dynamical structure of these objects. With the observationally motivated assumption that β z ≥0, the method is able to recover the inclination. The technique can be used to determine the dynamical MIL and angular momenta of early-type fast-rotators and spiral galaxies, especially when the quality of the data does not justify more sophisticated modelling approaches. This formalism allows for the inclusion of dark matter, supermassive black holes, spatially varying anisotropy and multiple kinematic components.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/89a1500f9dac1386da54e16654932ea676dc5a17

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. M. Cappellari
2. P. Hopkins
3. C. Conroy
4. L. Hernquist
5. T. Naab
6. Simon D. M. White
7. T. Treu
8. Volker Springel

In Instrumentation

1. M. Cappellari
2. C. Conroy
3. P. Hopkins
4. L. Hernquist
5. T. Naab
6. T. Treu
7. Simon D. M. White
8. P. V. van Dokkum

Citations in the corpus

• Structure and Kinematics of Early-Type Galaxies from Integral Field Spectroscopy (2016, methodology): “The input MGE surface brightness was taken from Cappellari et al. (2006) and Scott et al. (2009) respectively, while the adopted model parameters from Cappellari (2008).”
• Galaxy Masses: A Review (2013, methodology): “This is also true for the general case σR 6= σz 6= σφ, and for all the six projected second moments, including radial velocities and proper motions, as demonstrated by Cappellari (2008). This flexibility can be more practically witnessed when using an implementation of the “Jeans Anisotropic MGE” (J”
• OVERVIEW OF THE SDSS-IV MaNGA SURVEY: MAPPING NEARBY GALAXIES AT APACHE POINT OBSERVATORY (2014, methodology): “Figure 15 shows successful Jeans axisymmetric modelling (JAM, Cappellari 2008) applied to two P-MaNGA galaxies, with derived constraints on the intrinsic axis ratio, anisotropy, dark matter fraction (assuming a generalized NavarroFrenk-White (NFW), with free inner slope), and inner dark matter…”
• The Tully-Fisher relations of early-type spiral and S0 galaxies (2010, methodology): “The solution of the Jeans equations under these assumptions is described in Cappellari (2008).”
• DISCOVERY OF AN ACTIVE GALACTIC NUCLEUS DRIVEN MOLECULAR OUTFLOW IN THE LOCAL EARLY-TYPE GALAXY NGC 1266 (2011, methodology): “We used this MGE model to build an axisymmetric dynamical model of the stellar kinematics based on the JAM formalism (Cappellari 2008).”
• The ATLAS3D project - VII. A new look at the morphology of nearby galaxies: the kinematic morphology-density relation (2011, background): “A recent dynamical modeling study suggests that the stellar dynamics of the fast rotators appear to be indistinguishable from that of spiral galaxies of comparable flattening (Williams et al. 2009), both being well described by the simple anisotropic Jeans models of Cappellari (2008).”
• The ATLAS3D project - XIV. The extent and kinematics of the molecular gas in early-type galaxies (2012, methodology): “Until recently, only a small number of ETGs had been mapped with mminterferometers (e.g. Wrobel & Kenney 1992; Young 2002; Young, Bureau & Cappellari 2008; Schinnerer & Scoville 2002; Crocker et al. 2008, 2009; Wei et al. 2010; Crocker et al. 2011), hence drawing conclusions based on a few objects h”
• The ATLAS3D project XV: benchmark for early-type galaxies scaling relations from 260 dynamical models: mass-to-light ratio, dark matter, fundamental plane and mass plane (2012, methodology): “The MGE models are used as input for the JAM method1 (Cappellari 2008) which calculates a prediction of the LOS second velocity moments 〈v2los〉1/2 for given model parameters and compare this to the observed Vrms.”
• The ATLAS3D project – XX. Mass–size and mass–σ distributions of early-type galaxies: bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function (2012, methodology): “We verified that the JAM inclination agrees with the one inferred from the geometry of the dust, for 26 galaxies with regular dusts discs (see also Cappellari 2008).”
• TDCOSMO IV: Hierarchical time-delay cosmography -- joint inference of the Hubble constant and galaxy density profiles (2020, background): “These approximations are sufficient given the current uncertainties and constraints, but future work should consider at least axissymmetric Jeans modeling (e.g., Cappellari 2008; Barnabè et al. 2012; Posacki et al. 2015; Yıldırım et al. 2020), and consider alternate parameterizations of anisotropy.”
• THE NGC 404 NUCLEUS: STAR CLUSTER AND POSSIBLE INTERMEDIATE-MASS BLACK HOLE (2010, methodology): “The adopted dynamical model uses the Jeans Anisotropic MGE (JAM) software10 which implements an axisymmetric solution of the Jeans equations which allow for orbital anisotropy (Cappellari 2008).”
• THE DENSITY PROFILES OF MASSIVE, RELAXED GALAXY CLUSTERS. I. THE TOTAL DENSITY OVER THREE DECADES IN RADIUS (2012, background): “We assume the BCGs are completely pressure-supported, consistent with the lack of observed rotation (Section 6.1): Σ∗σ 2 los(R) = 2G ∫ ∞ R ν∗(r)M(r)F(r) r2−2βaniso dr. (12) By default we consider isotropic orbits with βaniso = 0 and F(r) = √ r2 −R2 (Cappellari 2008).”
• The ATLAS3D project – III. A census of the stellar angular momentum within the effective radius of early‐type galaxies: unveiling the distribution of fast and slow rotators (2011, methodology): “…accurate dynamical masses, Mdyn, were derived via MultiGaussian Expansion (Emsellem, Monnet & Bacon 1994) of the galaxies’ photometry followed by detailed Jeans anisotropic dynamical models (Cappellari 2008; Scott et al. 2009) of the ATLAS3D SAURON stellar kinematics (Cappellari et al. 2010).”
• The Sydney-AAO Multi-object Integral field spectrograph (2011, methodology): “The stellar and emission line kinematic data that SAMI can provide will allow dynamical mass estimates within maximum radius probed, using techniques such as anisotropic Jeans modelling (Cappellari 2008).”
• The ATLAS3D project – IV. The molecular gas content of early-type galaxies (2011, methodology): “The dynamical mass used here is, however, derived from stellar dynamical models of the SAURON stellar kinematics (Cappellari et al. 2010), using the Jeans anisotropic modelling technique of Cappellari (2008).”