The intracluster light as a tracer of the total matter density distribution: a view from simulations

ABSTRACT By using deep observations of clusters of galaxies, it has been recently found that the projected stellar mass density closely follows the projected total (dark and baryonic) mass density within the innermost ∼140 kpc. In this work, we aim to test these observations using the Cluster-EAGLE simulations, comparing the projected densities inferred directly from the simulations. We compare the iso-density contours using the procedure of Montes & Trujillo, and find that the shape of the stellar mass distribution follows that of the total matter even more closely than observed, although their radial profiles differ substantially. The ratio between stellar and total matter density profiles in circular apertures shows a slope close to −1, with a small dependence on the cluster’s total mass. We propose an indirect method to calculate the halo mass and mass density profile from the radial profile of the intracluster stellar mass density.

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THE SL2S GALAXY-SCALE LENS SAMPLE. IV. THE DEPENDENCE OF THE TOTAL MASS DENSITY PROFILE OF EARLY-TYPE GALAXIES ON REDSHIFT, STELLAR MASS, AND SIZE

The Astrophysical Journal ◽

10.1088/0004-637x/777/2/98 ◽

2013 ◽

Vol 777 (2) ◽

pp. 98 ◽

Cited By ~ 103

Author(s):

Alessandro Sonnenfeld ◽

Tommaso Treu ◽

Raphaël Gavazzi ◽

Sherry H. Suyu ◽

Philip J. Marshall ◽

...

Keyword(s):

Density Profile ◽

Total Mass ◽

Mass Density ◽

Stellar Mass ◽

Early Type ◽

Mass Density Profile

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A missing outskirts problem? Comparisons between stellar haloes in the Dragonfly Nearby Galaxies Survey and the TNG100 simulation

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1164 ◽

2020 ◽

Vol 495 (4) ◽

pp. 4570-4604 ◽

Cited By ~ 2

Author(s):

Allison Merritt ◽

Annalisa Pillepich ◽

Pieter van Dokkum ◽

Dylan Nelson ◽

Lars Hernquist ◽

...

Keyword(s):

Surface Brightness ◽

Ad Hoc ◽

Mass Density ◽

Stellar Mass ◽

Density Profiles ◽

Mass Fractions ◽

Stellar Halo ◽

Particle Level ◽

Nearby Galaxies ◽

Halo Masses

ABSTRACT Low surface brightness galactic stellar haloes provide a challenging but promising path towards unravelling the past assembly histories of individual galaxies. Here, we present detailed comparisons between the stellar haloes of Milky Way-mass disc galaxies observed as part of the Dragonfly Nearby Galaxies Survey (DNGS) and stellar mass-matched galaxies in the TNG100 run of the IllustrisTNG project. We produce stellar mass maps as well as mock g- and r-band images for randomly oriented simulated galaxies, convolving the latter with the Dragonfly point spread function (PSF) and taking care to match the background noise, surface brightness limits, and spatial resolution of DNGS. We measure azimuthally averaged stellar mass density and surface brightness profiles, and find that the DNGS galaxies generally have less stellar mass (or light) at large radii (>20 kpc) compared to their mass-matched TNG100 counterparts, and that simulated galaxies with similar surface density profiles tend to have low accreted mass fractions for their stellar mass. We explore potential solutions to this apparent ‘missing outskirts problem’ by implementing several ad hoc adjustments within TNG100 at the stellar particle level. Although we are unable to identify any single adjustment that fully reconciles the differences between the observed and simulated galaxy outskirts, we find that artificially delaying the disruption of satellite galaxies and reducing the spatial extent of in-situ stellar populations result in improved matches between the outer profile shapes and stellar halo masses, respectively. Further insight can be achieved with higher resolution simulations that are able to better resolve satellite accretion, and with larger samples of observed galaxies.

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Effects of environment on stellar metallicity profiles of late-type galaxies in the CALIFA survey

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038774 ◽

2020 ◽

Vol 642 ◽

pp. A132 ◽

Cited By ~ 1

Author(s):

Valeria Coenda ◽

Damián Mast ◽

Hernán Muriel ◽

Héctor J. Martínez

Keyword(s):

Surface Density ◽

Mass Density ◽

Stellar Mass ◽

Late Type ◽

Surface Mass ◽

Characteristic Radius ◽

Radial Profiles ◽

Stellar Masses ◽

Evolutionary Paths ◽

Negative Gradient

Aims. We explore the effects of environment in the evolution of late-type galaxies by studying the radial profiles of light- and mass-weighted metallicities of galaxies in two discrete environments: field and groups. Methods. We used a sample of 167 late-type galaxies with stellar masses of 9 ≤ log(M⋆/M⊙) ≤ 12 drawn from the Calar Alto Legacy Integral Field Area (CALIFA) survey. Firstly, we obtained light- and mass-weighted stellar metallicity profiles and stellar mass density profiles of these galaxies using publicly available data. We then classified them according to their environment into field and group galaxies. Finally, we studied the metallicity of galaxies in these two environments, including a comparison of the metallicity as a function of radius, at a characteristic scale, and as a function of stellar mass surface density. As metallicity depends on galaxy mass, we took special care throughout the study to compare, in all cases, subsamples of galaxies in groups and in the field that have similar masses. Results. We find significant differences between group and field late-type galaxies in terms of their metallicity: group galaxies are systematically higher in metallicity than their field counterparts. We find that field galaxies, in general, have metallicity profiles that show a negative gradient in their inner regions and a shallower profile at larger radii. This is in contrast to the metallicity profiles of galaxies in groups, which tend to be flat in the inner regions and to have a negative gradient in the outer parts. Regarding the metallicity at the characteristic radius of the luminosity profiles, we consistently find that it is higher for group galaxies irrespective of galaxy mass. At fixed local stellar surface mass density, group galaxies are again higher in metallicity, also the dependence of metallicity on surface density is less important for group galaxies. Conclusions. The evidence of a clear difference in metallicity between group and field galaxies as a function of mass, spatial scale, and local stellar mass density is indicative of the different evolutionary paths followed by galaxies in groups and in the field. We discuss some possible implications of the observed differences.

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CLASH-VLT: The stellar mass function and stellar mass density profile of thez= 0.44 cluster of galaxies MACS J1206.2-0847

Astronomy and Astrophysics ◽

10.1051/0004-6361/201424102 ◽

2014 ◽

Vol 571 ◽

pp. A80 ◽

Cited By ~ 39

Author(s):

M. Annunziatella ◽

A. Biviano ◽

A. Mercurio ◽

M. Nonino ◽

P. Rosati ◽

...

Keyword(s):

Density Profile ◽

Mass Density ◽

Mass Function ◽

Stellar Mass ◽

Cluster Of Galaxies ◽

Mass Density Profile

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NIHAO – XXIII. Dark matter density shaped by black hole feedback

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/slaa058 ◽

2020 ◽

Vol 495 (1) ◽

pp. L46-L50 ◽

Cited By ~ 7

Author(s):

Andrea V Macciò ◽

Samuele Crespi ◽

Marvin Blank ◽

Xi Kang

Keyword(s):

Black Hole ◽

Dark Matter ◽

Stellar Mass ◽

Matter Density ◽

Matter Distribution ◽

Density Profiles ◽

Systematic Analysis ◽

Dark Matter Density ◽

Dark Matter Distribution ◽

Halo Masses

ABSTRACT We present a systematic analysis of the reaction of dark matter distribution to galaxy formation across more than eight orders of magnitude in stellar mass. We extend the previous work presented in the NIHAO-IV paper by adding 46 new high-resolution simulations of massive galaxies performed with the inclusion of black hole feedback. We show that outflows generated by the active galactic nucleus (AGN) are able to partially counteract the dark matter contraction due to the large central stellar component in massive haloes. The net effect is to relax the central dark matter distribution that moves to a less cuspy density profiles at halo mass larger than ≈3 × 1012 M⊙. The scatter around the mean value of the density profile slope (α) is fairly constant (Δα ≈ 0.3), with the exception of galaxies with halo masses around 1012 M⊙, at the transition from stellar to AGN feedback dominated systems, where the scatter increases by almost a factor of 3. We provide useful fitting formulae for the slope of the dark matter density profiles at few per cent of the virial radius for the whole stellar mass range: 105–1012 M⊙ (2 × 109 to 5 × 1013 M⊙ in halo mass).

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TDCOSMO

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038861 ◽

2020 ◽

Vol 643 ◽

pp. A165 ◽

Cited By ~ 9

Author(s):

S. Birrer ◽

A. J. Shajib ◽

A. Galan ◽

M. Millon ◽

T. Treu ◽

...

Keyword(s):

Density Profile ◽

Gravitational Lensing ◽

Mass Density ◽

Hubble Constant ◽

Potential Effect ◽

Hierarchical Analysis ◽

Stellar Kinematics ◽

Density Profiles ◽

Mass Profile ◽

Mass Density Profile

The H0LiCOW collaboration inferred via strong gravitational lensing time delays a Hubble constant value of H0 = 73.3−1.8+1.7 km s−1 Mpc−1, describing deflector mass density profiles by either a power-law or stars (constant mass-to-light ratio) plus standard dark matter halos. The mass-sheet transform (MST) that leaves the lensing observables unchanged is considered the dominant source of residual uncertainty in H0. We quantify any potential effect of the MST with a flexible family of mass models, which directly encodes it, and they are hence maximally degenerate with H0. Our calculation is based on a new hierarchical Bayesian approach in which the MST is only constrained by stellar kinematics. The approach is validated on mock lenses, which are generated from hydrodynamic simulations. We first applied the inference to the TDCOSMO sample of seven lenses, six of which are from H0LiCOW, and measured H0 = 74.5−6.1+5.6 km s−1 Mpc−1. Secondly, in order to further constrain the deflector mass density profiles, we added imaging and spectroscopy for a set of 33 strong gravitational lenses from the Sloan Lens ACS (SLACS) sample. For nine of the 33 SLAC lenses, we used resolved kinematics to constrain the stellar anisotropy. From the joint hierarchical analysis of the TDCOSMO+SLACS sample, we measured H0 = 67.4−3.2+4.1 km s−1 Mpc−1. This measurement assumes that the TDCOSMO and SLACS galaxies are drawn from the same parent population. The blind H0LiCOW, TDCOSMO-only and TDCOSMO+SLACS analyses are in mutual statistical agreement. The TDCOSMO+SLACS analysis prefers marginally shallower mass profiles than H0LiCOW or TDCOSMO-only. Without relying on the form of the mass density profile used by H0LiCOW, we achieve a ∼5% measurement of H0. While our new hierarchical analysis does not statistically invalidate the mass profile assumptions by H0LiCOW – and thus the H0 measurement relying on them – it demonstrates the importance of understanding the mass density profile of elliptical galaxies. The uncertainties on H0 derived in this paper can be reduced by physical or observational priors on the form of the mass profile, or by additional data.

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Are ultra-diffuse galaxies Milky Way-sized?

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936821 ◽

2020 ◽

Vol 633 ◽

pp. L3 ◽

Cited By ~ 5

Author(s):

Nushkia Chamba ◽

Ignacio Trujillo ◽

Johan H. Knapen

Keyword(s):

Star Formation ◽

Milky Way ◽

Size Range ◽

Mass Density ◽

Effective Radius ◽

Density Profiles ◽

Gas Density ◽

Undesirable Consequence ◽

Definition Of ◽

Density Threshold

Now almost 70 years since its introduction, the effective or half-light radius has become a very popular choice for characterising galaxy size. However, the effective radius measures the concentration of light within galaxies and thus does not capture our intuitive definition of size which is related to the edge or boundary of objects. For this reason, we aim to demonstrate the undesirable consequence of using the effective radius to draw conclusions about the nature of faint ultra-diffuse galaxies (UDGs) when compared to dwarfs and Milky Way-like galaxies. Instead of the effective radius, we use a measure of galaxy size based on the location of the gas density threshold required for star formation. Compared to the effective radius, this physically motivated definition places the sizes much closer to the boundary of a galaxy. Therefore, considering the sizes and stellar mass density profiles of UDGs and regular dwarfs, we find that the UDGs have sizes that are within the size range of dwarfs. We also show that currently known UDGs do not have sizes comparable to Milky Way-like objects. We find that, on average, UDGs are ten times smaller in extension than Milky Way-like galaxies. These results show that the use of size estimators sensitive to the concentration of light can lead to misleading results.

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Molecular Dynamics Simulation Study of Lecithin Inhibiting Hydrate-Dissociation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.890.252 ◽

2017 ◽

Vol 890 ◽

pp. 252-259

Author(s):

Le Wang ◽

Guan Cheng Jiang ◽

Xin Lin ◽

Xian Min Zhang ◽

Qi Hui Jiang

Keyword(s):

Molecular Dynamics ◽

Water Movement ◽

Simulation Analysis ◽

Mass Density ◽

Dynamics Simulation ◽

Dissociation Process ◽

Hydrate Dissociation ◽

Hydrocarbon Chains ◽

Dynamics Simulations ◽

Mass Density Profile

Molecular dynamics simulations are used to study the dissociation inhibiting mechanism of lecithin for structure I hydrates. Adsorption characteristics of lecithin and PVP (poly (N-vinylpyrrolidine)) on the hydrate surfaces were performed in the NVT ensemble at temperatures of 277K and the hydrate dissociation process were simulated in the NPT ensemble at same temperature. The results show that hydrate surfaces with lecithin is more stable than the ones with PVP for the lower potential energy. The conformation of lecithin changes constantly after the balanced state is reached while the PVP molecular dose not. Lecithin molecule has interaction with lecithin nearby and hydrocarbon-chains of lecithin molecules will form a network to prevent the diffusion of water and methane molecules, which will narrow the available space for hydrate methane and water movement. Compared with PVP-hydrate simulation, analysis results (snapshots and mass density profile) of the dissociation simulations show that lecithin-hydrate dissociates more slowly.

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