Internal Kinematics of the Fornax Dwarf Spheroidal Galaxy

By Matthew G. Walker, Mario Mateo, E. Olszewski, Rebecca Bernstein, Xiao Wang, Michael Woodroofe. 2005

184 citations recorded by the source corpus.

We present new radial velocity results for 176 stars in the Fornax dwarf spheroidal galaxy, of which at least 156 are probable Fornax members. We combine with previously published data to obtain a radial velocity sample with 206 stars, of which at least 176 are probable Fornax members. We detect the hint of rotation about an axis near Fornax's morphological minor axis, although the significance of the rotation signal in the galactic rest frame is sensitive to the adopted value of Fornax's proper motion. Regardless, the observed stellar kinematics is dominated by random motions, and we do not find kinematic evidence of tidal disruption. The projected velocity dispersion profile of the binned data set remains flat over the sampled region, which reaches a maximum angular radius of 65′. Single-component King models in which mass follows light fail to reproduce the observed flatness of the velocity dispersion profile. Two-component (luminous plus dark matter) models can reproduce the data, provided that the dark component extends sufficiently beyond the luminous component and the central dark matter density is of the same order as the central luminous density. These requirements suggest a more massive, darker Fornax than standard core-fitting analyses have previously concluded, with M/LV over the sampled region reaching 10-40 times the M/LV of the luminous component. We also apply a nonparametric mass estimation technique, introduced in a companion paper. Although it is designed to operate on data sets containing velocities for >1000 stars, the estimation yields preliminary results suggesting M/LV ∼ 15 inside r < 1.5 kpc.

View Paper: https://www.semanticscholar.org/paper/0f12d6d9ccab06cc643eb52b0bf757d2fd80ed5b

How researchers see this paper

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

Citations in the corpus

THE NUCLEUS OF THE SAGITTARIUS DSPH GALAXY AND M54: A WINDOW ON THE PROCESS OF GALAXY NUCLEATION (2008, methodology): “Sgr galaxy, that is found to be flat out to large radii (Ibata et al. 1997), as typical of dwarf spheroidals (see Walker et al. 2006; Muñoz, Majewski & Johnston 2007, and references therein).”
Estimating a Polya frequency function$_2$ (2007, background): “The full data set can be found in [13].”
Farthest Neighbor: The Distant Milky Way Satellite Eridanus II (2016, methodology): “…we calculated the systemic velocity and the velocity dispersion of Eri II using a 2-parameter Gaussian likelihood function similar to that of Walker et al. (2006): logL = −1 2 [ N∑ n=1 log(σ2vhel+σ 2 vi)+ N∑ n=1 (vi−vhel)2 σ2vi+σ 2 vhel ] , (2) where vhel and σvhel are the systemic velocity…”
Thin, thick and dark discs in ΛCDM (2008, background): “…for our satellite: Fornax, LMC and LLMC. Fornax, with dark matter contribution to the peak circular velocity vmax = 25 km s−1, models the satellite on the Fornax dwarf spheroidal galaxy which has a visible mass of ∼5 × 107 M , and a dynamical mass of M(<1.5 kpc) ∼ 7.5 × 108 M (Walker et al. 2006).”
THE LEAST-LUMINOUS GALAXY: SPECTROSCOPY OF THE MILKY WAY SATELLITE SEGUE 1 (2008, methodology): “Velocity Dispersion We measure the mean velocity and velocity dispersion of Segue 1 using the maximum-likelihood method described by Walker et al. (2006).”
Velocity Dispersion Profiles of Seven Dwarf Spheroidal Galaxies (2007, methodology): “…in the observed dSphs (Carina: Mateo et al. 2 1993; Muñoz et al. 2006; Draco: Armandroff et al. 1995; Kleyna et al. 2002; Fornax: Mateo et al. 1991; Walker et al. 2006a; Leo I: Mateo et al. 1998; Koch et al. 2007b; Leo II: Vogt et al. 1995; Koch et al. 2007a; Sculptor: Westfall et al. 2006;…”
A UNIVERSAL MASS PROFILE FOR DWARF SPHEROIDAL GALAXIES? (2009, methodology): “We estimate the velocity dispersion in each bin using the maximum-likelihood technique described by Walker et al. (2006).”
The DART Imaging And CaT Survey of the Fornax Dwarf Spheroidal Galaxy (2006, methodology): “The Fornax dSph is one of the most massive and luminous of the dwarf galaxy satellites of our Galaxy, second only to Sagittarius, with a total (dynamical) mass in the range 108-109 M⊙ (Mateo et al. 1991; Łokas 2002; Walker et al. 2006; Battaglia et al. 2006a).”
The Kinematic Status and Mass Content of the Sculptor Dwarf Spheroidal Galaxy (2008, result): “Other techniques such as bisection (Walker et al. 2006) support these results.”
A COMPLETE SPECTROSCOPIC SURVEY OF THE MILKY WAY SATELLITE SEGUE 1: THE DARKEST GALAXY (2010, methodology): “(Note that we calculate the velocity dispersion using a maximum likelihood method following Walker et al. 2006.)”
Dark matter annihilation and decay in dwarf spheroidal galaxies: the classical and ultrafaint dSphs (2015, methodology): “For each bin, we estimate velocity dispersion using the maximum-likelihood procedure described by Walker et al. (2006), with membership probabilities introduced as weights on each star.”
The Velocity Dispersion Profile of the Remote Dwarf Spheroidal Galaxy Leo I: A Tidal Hit and Run? (2007, methodology): “Repeat measurements can also be used to estimate the individual velocity errors as described by Walker et al. (2006a).”
The hidden giant: discovery of an enormous Galactic dwarf satellite in Gaia DR2 (2018, background): “The grey filled circle shows the proper motion inferred from the radial velocity gradient (Walker et al. 2006).”
Redefining the Missing Satellites Problem (2007, methodology): “We use the following data sets: Wilkinson et al. (2004); Munoz et al. (2005, 2006); Westfall et al. (2006); Walker et al. (2005, 2006); Sohn et al. (2006); Siegal et al. in preparation.”
The Most Dark-Matter-dominated Galaxies: Predicted Gamma-Ray Signals from the Faintest Milky Way Dwarfs (2007, background): “This has been shown to be a good description of the well-studied dwarfs with line-of-sight velocities from several hundred stars (Walker et al. 2006).”
The Masses of the Milky Way and Andromeda galaxies (2010, unknown): “…et al. (2007); 21, Belokurov et al. (2008); 22, Cioni et al. (2000); 23, Harris & Zaritsky (2006); 24, Ibata et al. (1997); 25, Kaluzny et al. (1995); 26, Queloz, Dubath & Pasquini (1995); 27, Geha et al. (2009); 28, Belokurov et al. (2009); 29, Walker et al. (2006b); 30, Zucker et al. (2006b).”
The star formation and chemical evolution history of the Fornax dwarf spheroidal galaxy (2012, methodology): “The National Optical Astronomy Observatory is operated by AURA, Inc., under cooperative agreement with the National Science Foundation. mass of ≈1.6 × 108 M , from modelling of kinematic data out to a radius of 1.9 kpc (Walker et al. 2006; Klimentowski et al. 2007; Łokas 2009).”
Kinematics in Young Star Clusters and Associations with Gaia DR2 (2018, methodology): “We use maximum likelihood to estimate the intrinsic velocity dispersion in the presence of measurement error (cf. Walker et al. 2006).”