The distribution of mass components in simulated disc galaxies

Santos-Santos, Isabel; Brook, Chris; Stinson, Greg; Cintio, Arianna Di; Wadsley, James; Domínguez-Tenreiro, R.; Gottlöber, Stefan; Yepes, Gustavo

doi:10.1093/mnras/stv2335

Cited by 63 publications

(48 citation statements)

References 67 publications

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“…The simulations fall reasonably within the range of observed galaxies, giving some confidence in the mass distributions of the baryons (see also Santos-Santos et al 2016). Larger, uniform samples of simulations and observations are required to make careful statistical comparisons including determination of scatter.…”

Section: The Simulationssupporting

confidence: 57%

The different baryonic Tully–Fisher relations at low masses

Santos-Santos

Stinson

2016

Mon. Not. R. Astron. Soc.

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We compare the Baryonic Tully-Fisher relation (BTFR) of simulations and observations of galaxies ranging from dwarfs to spirals, using various measures of rotational velocity V rot . We explore the BTFR when measuring V rot at the flat part of the rotation curve, V flat , at the extent of HI gas, V last , and using 20% (W 20 ) and 50% (W 50 ) of the width of HI line profiles. We also compare with the maximum circular velocity of the parent halo, V DM max , within dark matter only simulations. The different BTFRs increasingly diverge as galaxy mass decreases. Using V last one obtains a power law over four orders of magnitude in baryonic mass, with slope similar to the observed BTFR. Measuring V flat gives similar results as V last when galaxies with rising rotation curves are excluded. However, higher rotation velocities would be found for low mass galaxies if the cold gas extended far enough for V rot to reach a maximum. W 20 gives a similar slope as V last but with slightly lower values of V rot for low mass galaxies, although this may depend on the extent of the gas in your galaxy sample. W 50 bends away from these other relations toward low velocities at low masses. By contrast, V DM max bends toward high velocities for low mass galaxies, as cold gas does not extend out to the radius at which halos reach V DM max . Our study highlights the need for careful comparisons between observations and models: one needs to be consistent about the particular method of measuring V rot , and precise about the radius at which velocities are measured.

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Section: The Simulationssupporting

confidence: 57%

The different baryonic Tully–Fisher relations at low masses

Santos-Santos

Stinson

2016

Mon. Not. R. Astron. Soc.

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“…This work significantly increases the statistics and mass range with respect to Santos-Santos et al (2016) and Keller & Wadsley (2016), but present several problems:…”

Section: Comparison With Hydrodynamical Simulationsmentioning

confidence: 99%

One Law to Rule Them All: The Radial Acceleration Relation of Galaxies

Lelli

McGaugh

Schombert

et al. 2017

ApJ

405

604

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We study the link between baryons and dark matter in 240 galaxies with spatially resolved kinematic data. Our sample spans 9 dex in stellar mass and includes all morphological types. We consider (i) 153 late-type galaxies (LTGs; spirals and irregulars) with gas rotation curves from the SPARC database; (ii) 25 early-type galaxies (ETGs; ellipticals and lenticulars) with stellar and H I data from ATLAS 3D or X−ray data from Chandra; and (iii) 62 dwarf spheroidals (dSphs) with individual-star spectroscopy. We find that LTGs, ETGs, and "classical" dSphs follow the same radial acceleration relation: the observed acceleration (g obs ) correlates with that expected from the distribution of baryons (g bar ) over 4 dex. The relation coincides with the 1:1 line (no dark matter) at high accelerations but systematically deviates from unity below a critical scale of ∼10 −10 m s −2 . The observed scatter is remarkably small ( 0.13 dex) and largely driven by observational uncertainties. The residuals do not correlate with any global or local galaxy property (baryonic mass, gas fraction, radius, etc.). The radial acceleration relation is tantamount to a Natural Law: when the baryonic contribution is measured, the rotation curve follows, and vice versa. Including ultrafaint dSphs, the relation may extend by another 2 dex and possibly flatten at g bar 10 −12 m s −2 , but these data are significantly more uncertain. The radial acceleration relation subsumes and generalizes several well-known dynamical properties of galaxies, like the Tully-Fisher and Faber-Jackson relations, the "baryon-halo" conspiracies, and Renzo's rule.

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“…Like the g14 suite, the MaGICC galaxies were generated using GASOLINE (Wadsley et al 2004); however, instead of disabling cooling at early times, the MaGICC implementation includes early stellar feedback from massive stars, which is purely thermal and operates much like an ultraviolet ionization source. The early heating of the gas suppresses a higher fraction of star formation prior to z=1 than supernovae feedback alone; thus, the MaGICC galaxies do not suffer from overcooling, and have realistic rotation curves (see Figure1 of Santos-Santos et al 2016) with smaller central bulges in the MW host galaxies and more realistic stellar content in satellite galaxies.…”

Section: Magicc Suitementioning

confidence: 99%

Beta Dips in the Gaia Era: Simulation Predictions of the Galactic Velocity Anisotropy Parameter (β) for Stellar Halos

Loebman

Valluri

Hattori

et al. 2018

ApJ

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The velocity anisotropy parameter, β, is a measure of the kinematic state of orbits in the stellar halo, which holds promise for constraining the merger history of the Milky Way (MW). We determine global trends for β as a function of radius from three suites of simulations, including accretion-only and cosmological hydrodynamic simulations. We find that the two types of simulations are consistent and predict strong radial anisotropy ( b á ñ~0.7) for Galactocentric radii greater than 10 kpc. Previous observations of β for the MW's stellar halo claim a detection of an isotropic or tangential "dip" at r∼20 kpc. Using the N-body+SPH simulations, we investigate the temporal persistence, population origin, and severity of "dips" in β. We find that dips in the in situ stellar halo are long-lived, while dips in the accreted stellar halo are short-lived and tied to the recent accretion of satellite material. We also find that a major merger as early as z∼1 can result in a present-day low (isotropic to tangential) value of β over a broad range of radii and angles. While all of these mechanisms are plausible drivers for the β dip observed in the MW, each mechanism in the simulations has a unique metallicity signature associated with it, implying that future spectroscopic surveys could distinguish between them. Since an accurate knowledge of β(r) is required for measuring the mass of the MW halo, we note that significant transient dips in β could cause an overestimate of the halo's mass when using spherical Jeans equation modeling.

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The distribution of mass components in simulated disc galaxies

Cited by 63 publications

References 67 publications

The different baryonic Tully–Fisher relations at low masses

The different baryonic Tully–Fisher relations at low masses

One Law to Rule Them All: The Radial Acceleration Relation of Galaxies

Beta Dips in the Gaia Era: Simulation Predictions of the Galactic Velocity Anisotropy Parameter (β) for Stellar Halos

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