The distribution of metals in cosmological hydrodynamical simulations of dwarf disc galaxies

AbstractThe MUSE TIMER Survey has obtained high signal and high spatial resolution integral-field spectroscopy data of the inner ~ 6×6 kpc of 21 nearby massive disc galaxies. This allows studies of the stellar kinematics of the central regions of massive disc galaxies that are unprecedented in spatial resolution. We confirm previous predictions from numerical and hydrodynamical simulations of the effects of bars and inner bars on stellar and gaseous kinematics, and also identify box/peanuts via kinematical signatures in mildly and moderately inclined galaxies, including a box/peanut in a face-on inner bar. In 20/21 galaxies we find inner discs and show that their properties are fully consistent with the bar-driven secular evolution picture for their formation. In addition, we show that these inner discs have, in the region where they dominate, larger rotational support than the main galaxy disc, and discuss how their stellar population properties can be used to estimate when in cosmic history the main bar formed. Our results are compared with photometric studies in the context of the nature of galaxy bulges and we show that inner discs are identified in image decompositions as photometric bulges with exponential profiles (i.e., Sérsic indices near unity).

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The mass–size plane of EAGLE galaxies

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935162 ◽

2019 ◽

Vol 629 ◽

pp. L3 ◽

Cited By ~ 6

Author(s):

M. S. Rosito ◽

P. B. Tissera ◽

S. E. Pedrosa ◽

C. D. P. Lagos

Keyword(s):

Velocity Dispersion ◽

Bimodal Distribution ◽

Early Type ◽

Chemical Abundances ◽

Radial Profiles ◽

Mass Size ◽

Hydrodynamical Simulations ◽

Star Formation Histories ◽

Disc Galaxies ◽

Second Peak

Context. Current observational results show that both late- and early-type galaxies follow tight mass–size planes on which physical properties such as age, velocity dispersion, and metallicity correlate with the scatter on the plane. Aims. We study the mass–size plane of galaxies in cosmological hydrodynamical simulations, as a function of velocity dispersion, age, chemical abundances, ellipticity, and spin parameters with the aim of assessing to what extent the current cosmological paradigm can reproduce these observations and provide a physical interpretation of them. Methods. We selected a sample of well-resolved galaxies from the (100 Mpc)3 simulation of the EAGLE Project. This sample is composed of 508 spheroid-dominated galaxies and 1213 disc-dominated galaxies. The distributions of velocity dispersion, age, metallicity indicators and gradients, and spin parameters across the mass–size plane are analysed. Furthermore, we study the relation between shape and kinematic parameters. The results are compared with observations. Results. The mass-weighted ages of the EAGLE galaxies are found to vary along lines of constant velocity dispersion on the mass–size plane, except for galaxies with velocity dispersions higher than ∼150 km s−1. Negative age gradients tend to be found in extended disc galaxies in agreement with observations. However, the age distributions of early-type galaxies show a larger fraction with inverted radial profiles. The distribution of metallicity gradients does not show any clear dependence on this plane. Galaxies with similar spin parameters (λ) display larger sizes as their dynamical masses increase. Stellar-weighted ages are found to be good proxies for λ in galaxies with low ellipticity (ε). A bimodal distribution of λ is found so that the high-λ peak is dominated by discs with young stellar populations (SPs), while the second peak is mainly populated by slow rotators (λ < 0.2) with old stars. Our findings suggest that the physical processes that regulate the star formation histories in galaxies might also affect the angular moment budgets of gas and stars, and as a consequence their morphology.

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Galaxies that shine: radiation-hydrodynamical simulations of disc galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stv937 ◽

2015 ◽

Vol 451 (1) ◽

pp. 34-58 ◽

Cited By ~ 65

Author(s):

Joakim Rosdahl ◽

Joop Schaye ◽

Romain Teyssier ◽

Oscar Agertz

Keyword(s):

Hydrodynamical Simulations ◽

Disc Galaxies

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Massive disc galaxies too dominated by dark matter in cosmological hydrodynamical simulations

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038326 ◽

2020 ◽

Vol 640 ◽

pp. A70 ◽

Cited By ~ 2

Author(s):

A. Marasco ◽

L. Posti ◽

K. Oman ◽

B. Famaey ◽

G. Cresci ◽

...

Keyword(s):

Dark Matter ◽

Rotation Curve ◽

Curve Analysis ◽

Rotation Curves ◽

Mass Ratios ◽

Hydrodynamical Simulations ◽

Halo Masses ◽

Global And Local ◽

Disc Galaxies

We investigated the disc-halo connection in massive (M⋆ > 5 × 1010 M⊙) disc galaxies from the cosmological hydrodynamical simulations EAGLE and IllustrisTNG, and compared this connection with that inferred from the study of H I rotation curves in nearby massive spirals from the Spitzer Photometry and Accurate Rotation Curves dataset. We find that discrepancies between the simulated and observed discs arise both on global and local scales. Globally, the simulated discs inhabit halos that are a factor ∼4 (in EAGLE) and ∼2 (in IllustrisTNG) more massive than those derived from the rotation curve analysis of the observed dataset. We also used synthetic rotation curves of the simulated discs to demonstrate that the recovery of the halo masses from rotation curves are not systematically biased. We find that the simulations predict systems dominated by dark matter with stellar-to-total enclosed mass ratios that are a factor of 1.5−2 smaller than real galaxies at all radii. This is an alternative manifestation of the ‘failed feedback problem,’ since it indicates that simulated halos hosting massive discs have been too inefficient at converting their baryons into stars, possibly owing to an overly efficient stellar and/or AGN feedback implementation.

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Fast galaxy bars continue to challenge standard cosmology

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab2553 ◽

2021 ◽

Vol 508 (1) ◽

pp. 926-939

Author(s):

Mahmood Roshan ◽

Neda Ghafourian ◽

Tahere Kashfi ◽

Indranil Banik ◽

Moritz Haslbauer ◽

...

Keyword(s):

Dark Matter ◽

Cold Dark Matter ◽

Dark Matter Halo ◽

Dynamical Friction ◽

Statistical Population ◽

Barred Galaxies ◽

Corotation Radius ◽

Pattern Speeds ◽

Hydrodynamical Simulations ◽

Disc Galaxies

ABSTRACT Many observed disc galaxies harbour a central bar. In the standard cosmological paradigm, galactic bars should be slowed down by dynamical friction from the dark matter halo. This friction depends on the galaxy’s physical properties in a complex way, making it impossible to formulate analytically. Fortunately, cosmological hydrodynamical simulations provide an excellent statistical population of galaxies, letting us quantify how simulated galactic bars evolve within dark matter haloes. We measure bar strengths, lengths, and pattern speeds in barred galaxies in state-of-the-art cosmological hydrodynamical simulations of the IllustrisTNG and EAGLE projects, using techniques similar to those used observationally. We then compare our results with the largest available observational sample at redshift z = 0. We show that the tension between these simulations and observations in the ratio of corotation radius to bar length is 12.62σ (TNG50), 13.56σ (TNG100), 2.94σ (EAGLE50), and 9.69σ (EAGLE100), revealing for the first time that the significant tension reported previously persists in the recently released TNG50. The lower statistical tension in EAGLE50 is actually caused by it only having five galaxies suitable for our analysis, but all four simulations give similar statistics for the bar pattern speed distribution. In addition, the fraction of disc galaxies with bars is similar between TNG50 and TNG100, though somewhat above EAGLE100. The simulated bar fraction and its trend with stellar mass both differ greatly from observations. These dramatic disagreements cast serious doubt on whether galaxies actually have massive cold dark matter haloes, with their associated dynamical friction acting on galactic bars.

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NIHAO-UHD: High-resolution Simulations of MW mass galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317006573 ◽

2017 ◽

Vol 13 (S334) ◽

pp. 209-212

Author(s):

Tobias Buck ◽

Andrea Macciò ◽

Melissa Ness ◽

Aura Obreja ◽

Aaron Dutton

Keyword(s):

High Resolution ◽

Milky Way ◽

Satellite System ◽

The Galaxy ◽

First Results ◽

History Of ◽

Galaxy Center ◽

Hydrodynamical Simulations ◽

Very High ◽

Disc Galaxies

AbstractHigh resolution cosmological and hydrodynamical simulations have reached a resolution able to resolve in a self consistent way the disc of our galaxy, the galaxy center and the satellites orbiting around it. We present first results from the NIHAO-UHD project, a set of very high-resolution baryonic zoom-in simulations of Milky Way mass disc galaxies. These simulations model the full cosmological assembly history of the galaxies and their satellite system using the same, well tested physics as the NIHAO project. We show that these simulations can self-consistently reproduce the observed kinematical and morphological features of the X-shaped bulge observed in our own Milky Way.

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Chandra survey of nearby highly inclined disc galaxies – III. Comparison with hydrodynamical simulations of circumgalactic coronae

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stu329 ◽

2014 ◽

Vol 440 (1) ◽

pp. 859-869 ◽

Cited By ~ 18

Author(s):

Jiang-Tao Li ◽

Robert A. Crain ◽

Q. Daniel Wang

Keyword(s):

Hydrodynamical Simulations ◽

Disc Galaxies

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On the origin of the chemical bimodality of disc stars: a tale of merger and migration

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3289 ◽

2019 ◽

Vol 491 (4) ◽

pp. 5435-5446 ◽

Cited By ~ 19

Author(s):

Tobias Buck

Keyword(s):

Large Scale ◽

Age Dating ◽

Solar Neighbourhood ◽

Stellar Disc ◽

Spatial Properties ◽

Hydrodynamical Simulations ◽

Early Galaxies ◽

And Migration ◽

Two Populations ◽

Disc Galaxies

ABSTRACT The Milky Way’s (MW) stellar disc exhibits a bimodality in the [Fe/H] versus [α/Fe] plane, showing a distinct high- and low-α sequences whose origin is still under debate. We examine the [Fe/H]–[α/Fe] abundance plane in cosmological hydrodynamical simulations of MW-like galaxies from the NIHAO-UHD project and show that the bimodal α-sequence is a generic consequence of a gas-rich merger at some time in the Galaxy’s evolution. The high-α sequence evolves first in the early galaxies, extending to high metallicities, while it is the low-α sequence that is formed after the gas-rich merger. The merger brings in fresh metal-poor gas diluting the interstellar medium’s metallicity while keeping the [α/Fe] abundance almost unchanged. The kinematic, structural, and spatial properties of the bimodal α-sequence in our simulations reproduces that of observations. In all simulations, the high-α disc is old, radially concentrated towards the galaxy’s centre and shows large scale heights. In contrast, the low-α disc is younger, more radially extended and concentrated to the disc mid-plane. Our results show that the abundance plane is well described by these two populations that have been distributed radially across the disc by migration: at present day in the solar neighbourhood, low-α stars originate from both the inner and outer discs, while most of the high-α stars have migrated from the inner disc. We show that age dating the stars in the [Fe/H]–[α/Fe] plane can constrain the time of the low-α sequence forming merger and conclude that α-bimodality is likely a not uncommon feature of disc galaxies.

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Drivers of disc tilting I: correlations and possible drivers for Milky Way analogues

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2109 ◽

2019 ◽

Vol 488 (4) ◽

pp. 5728-5738

Author(s):

Samuel W F Earp ◽

Victor P Debattista ◽

Andrea V Macciò ◽

Liang Wang ◽

Tobias Buck ◽

...

Keyword(s):

Correlation Coefficients ◽

Dark Halo ◽

Significant Extent ◽

Entire Sample ◽

Stellar Disc ◽

Gas Cooling ◽

Hydrodynamical Simulations ◽

Disc Galaxies ◽

Cold Gas

ABSTRACT The direction of the spin vectors of disc galaxies change over time. We present the tilting rate of a sample of galaxies in the NIHAO suite of cosmological hydrodynamical simulations. Galaxies in our sample have been selected to be isolated and to have well-determined spins. We compare the tilting rates to the predicted observing limit of Gaia, finding that our entire sample lies above the limit, in agreement with previous work. To test the role of dark matter and of gas, we compare the weighted Pearson’s correlation coefficients between the tilting rates and various properties. We find no correlation between the dark halo’s tilting rate, shape, or misalignment with respect to the disc, and the tilting rate of the stellar disc. Therefore, we argue that, in the presence of gas, the dark halo plays a negligible role in the tilting of the stellar disc. On the other hand, we find a strong correlation between the tilting rate of the stellar disc and the misalignment of the cold gas warp. Adding the stellar mass fraction improves the correlation, while none of the dark matter’s properties together with the cold gas misalignment improves the correlation to any significant extent. This implies that the gas cooling on to the disc is the principal driver of disc tilting.

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Internal Kinematics of Modelled Isolated and Interacting Disc Galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306006223 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 216-216

Author(s):

T. Kronberger ◽

W. Kapferer ◽

S. Schindler ◽

A. Böhm ◽

E. Kutdemir ◽

...

Keyword(s):

Velocity Field ◽

Spiral Galaxies ◽

Rotation Velocity ◽

Systematic Investigation ◽

Velocity Fields ◽

The Galaxy ◽

History Of ◽

Hydrodynamical Simulations ◽

Interaction History ◽

Disc Galaxies

AbstractWe present a systematic investigation of the velocity fields of both isolated and interacting spiral galaxies in combined N-body/hydrodynamical simulations. Closely mimicking the procedures applied in observations of distant, small, and faint galaxies we extract rotation curves (RCs) and compare the results of the simulation directly to observations. Irregularities in the velocity field reflect disturbances in the gravitational potential of the galaxy. They can be used to trace the recent interaction history of a galaxy and give possible clues to the type of the respective interaction. In addition, identifying disturbances in the RCs is important for Tully-Fisher studies in order to accurately derive the maximum rotation velocity.

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