Equilibrium Disk‐Bulge‐Halo Models for the Milky Way and Andromeda Galaxies

Widrow, Lawrence M.; Dubinski, John

doi:10.1086/432710

Cited by 248 publications

(340 citation statements)

References 85 publications

(133 reference statements)

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“…To calculate S dm for the Milky Way halo in the directions of the two Chandra CXB observations, we use mass models from Galactic dynamics measures presented in Klypin et al [57] and Battaglia et al [58], which are both consistent with each other and with Ref. [59]. We use the Navarro-Frenk-White (NFW) profile [60] ρ(r) = ρ s r r s…”

Section: The Dark Matter Modelmentioning

confidence: 99%

Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds

et al. 2007

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We present upper limits on line emission in the Cosmic X-ray background (CXB) that would be produced by decay of sterile neutrino dark matter. We employ the spectra of the unresolved component of the CXB in the Chandra Deep Fields North and South obtained with the Chandra CCD detector in the E = 0.8 − 9 keV band. The expected decay flux comes from the dark matter on the lines of sight through the Milky Way galactic halo. Our constraints on the sterile neutrino decay rate are sensitive to the modeling of the Milky Way halo. The highest halo mass estimates provide a limit on the sterile neutrino mass of ms < 2.9 keV in the Dodelson-Widrow production model, while the lowest halo mass estimates provide the conservative limit of ms < 5.7 keV (2σ). We also discuss constraints from a short observation of the softer (E < 1 keV) X-ray background with a rocket-borne calorimeter by McCammon and collaborators.

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Section: The Dark Matter Modelmentioning

confidence: 99%

Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds

et al. 2007

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“…We set up initial conditions using GalactICS (Widrow et al 2008;Widrow & Dubinski 2005;Kuijken & Dubinski 1995). We construct a model consisting of an exponential disc and a Navarro-Frenk-White (NFW) halo , with no bulge component.…”

Section: Co-spatial Discsmentioning

confidence: 99%

Separation of stellar populations by an evolving bar: implications for the bulge of the Milky Way

Debattista

Ness

Gonzalez

et al. 2017

Monthly Notices of the Royal Astronomical Society

148

255

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We present a novel interpretation of the previously puzzling different behaviours of stellar populations of the Milky Way's bulge. We first show, by means of pure N -body simulations, that initially co-spatial stellar populations with different in-plane random motions separate when a bar forms. The radially cooler populations form a strong bar, and are vertically thin and peanut-shaped, while the hotter populations form a weaker bar and become a vertically thicker box. We demonstrate that it is the radial, not the vertical, velocity dispersion that dominates this evolution. Assuming that early stellar discs heat rapidly as they form, then both the in-plane and vertical random motions correlate with stellar age and chemistry, leading to different density distributions for metal-rich and metal-poor stars. We then use a high-resolution simulation, in which all stars form out of gas, to demonstrate that this is what happens. When we apply these results to the Milky Way we show that a very broad range of observed trends for ages, densities, kinematics and chemistries, that have been presented as evidence for contradictory paths to the formation of the bulge, are in fact consistent with a bulge which formed from a continuum of disc stellar populations which were kinematically separated by the bar. For the first time we are able to account for the bulge's main trends via a model in which the bulge formed largely in situ. Since the model is generic, we also predict the general appearance of stellar population maps of external edge-on galaxies.

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“…The numerical realization of the dwarf galaxy is the same as used previously in simulations of tidal stirring by Lokas et al (2014b) and Lokas et al (2015). The model was generated following the method described in Widrow & Dubinski (2005) and Widrow et al (2008) which allows to create selfconsistent, equilibrium N -body models of galaxies with an exponential disk and an NFW halo (Navarro et al 1997).…”

Section: Simulationsmentioning

confidence: 99%

The Origin of Prolate Rotation in Dwarf Spheroidal Galaxies Formed by Mergers of Disky Dwarfs

Ebrová

Łokas

2015

ApJ

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Motivated by the discovery of prolate rotation of stars in Andromeda II, a dwarf spheroidal companion of M31, we study its origin via mergers of disky dwarf galaxies. We simulate merger events between two identical dwarfs changing the initial inclination of their disks with respect to the orbit and the amount of orbital angular momentum. On radial orbits the amount of prolate rotation in the merger remnants correlates strongly with the inclination of the disks and is well understood as due to the conservation of the angular momentum component of the disks along the merger axis. For non-radial orbits prolate rotation may still be produced if the orbital angular momentum is initially not much larger than the intrinsic angular momentum of the disks. The orbital structure of the remnants with significant rotation is dominated by box orbits in the center and long-axis tubes in the outer parts. The frequency analysis of stellar orbits in the plane perpendicular to the major axis reveals the presence of two families roughly corresponding to inner and outer long-axis tubes. The fraction of inner tubes is largest in the remnant forming from disks oriented most vertically initially and is responsible for the boxy shape of the galaxy. We conclude that prolate rotation results from mergers with a variety of initial conditions and no fine tuning is necessary to reproduce this feature. We compare the properties of our merger remnants to those of dwarfs resulting from the tidal stirring scenario and the data for Andromeda II.

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Equilibrium Disk‐Bulge‐Halo Models for the Milky Way and Andromeda Galaxies

Cited by 248 publications

References 85 publications

Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds

Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds

Separation of stellar populations by an evolving bar: implications for the bulge of the Milky Way

The Origin of Prolate Rotation in Dwarf Spheroidal Galaxies Formed by Mergers of Disky Dwarfs

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