scholarly journals Understanding the cosmic web

2014 ◽  
Vol 11 (S308) ◽  
pp. 47-56 ◽  
Author(s):  
Marius Cautun ◽  
Rien van de Weygaert ◽  
Bernard J. T. Jones ◽  
Carlos S. Frenk
Keyword(s):  
Time Evolution ◽  
Qualitative Agreement ◽  
Mass Density ◽  
Good Qualitative Agreement ◽  
Subsequent Evolution ◽  
Density Profiles ◽  
Surface Mass ◽  
Analysis Tools ◽  
Surface Mass Density ◽  
Hierarchical Pattern

AbstractWe investigate the characteristics and the time evolution of the cosmic web from redshift, z=2, to present time, within the framework of the \nexus{} algorithm. This necessitates the introduction of new analysis tools optimally suited to describe the very intricate and hierarchical pattern that is the cosmic web. In particular, we characterising filaments (walls) in terms of their linear (surface) mass density, which is very good in capturing the evolution of these structures. At early times the cosmos is dominated by tenuous filaments and sheets, which, during subsequent evolution, merge together, such that the present day web is dominated by fewer, but much more massive, structures. We show also that voids are more naturally described in terms of their boundaries and not their centres. We illustrate this for void density profiles, which, when expressed as a function of the distance from void boundary, show a universal profile in good qualitative agreement with the theoretical shell-crossing framework of expanding underdense regions.

scholarly journals The True Surface Mass density of Cold Dark Matter Halos

2007 ◽  
Vol 3 (S244) ◽  
pp. 358-359
Author(s):  
Janne Holopainen ◽  
E. Zackrisson ◽  
A. Knebe ◽  
P. Nurmi ◽  
P. Heinämaki ◽  
...  
Keyword(s):  
Dark Matter ◽  
Analytical Model ◽  
Light Propagation ◽  
Cold Dark Matter ◽  
Mass Density ◽  
Dark Matter Halos ◽  
Density Profiles ◽  
Surface Mass ◽  
Symmetric Density ◽  
Surface Mass Density

AbstractThe cold dark matter (CDM) scenario generically predicts the existence of triaxial dark matter halos which contain notable amounts of substructure. However, analytical halo models with smooth, spherically symmetric density profiles are routinely adopted in the modelling of light propagation effects through such objects. In this paper, we report the biases introduced by this procedure by comparing the surface mass densities of actual N-body halos against the widely used analytical model suggested by Navarro, Frenk and White (1996) (NFW). We conduct our analysis in the redshift range of 0.0 − 1.5.In cluster sized halos, we find that triaxiality can cause scatter in the surface mass density of the halos up to σ+= +60% and σ−= −70%, where the 1-σ limits are relative to the analytical NFW model given value. Subhalos can increase this scatter to σ+= +70% and σ−= −80%. In galaxy sized halos, the triaxial scatter can be as high as σ+= +80% and σ−= −70%, and with subhalos the values can change to σ+= +40% and σ−= −80%.We have developed an analytical model for the surface mass density scatter as a function of distance to the halo centre, halo redshift and halo mass. The analytical description enables one to investigate the reliability of results obtained with simplified halo models. Additionally, it provides the means to add simulated surface density scatter to analytical density profiles. We have tested our model on the calculation of microlensing optical depths for MACHOs in CDM halos.

scholarly journals Strong orientation dependence of surface mass density profiles of dark haloes at large scales

2018 ◽  
Vol 477 (2) ◽  
pp. 2141-2153 ◽  
Author(s):  
Ken Osato ◽  
Takahiro Nishimichi ◽  
Masamune Oguri ◽  
Masahiro Takada ◽  
Teppei Okumura
Keyword(s):  
Mass Density ◽  
Orientation Dependence ◽  
Density Profiles ◽  
Surface Mass ◽  
Strong Orientation ◽  
Surface Mass Density

scholarly journals The intriguing properties of local compact massive galaxies: What are they?

2012 ◽  
Vol 8 (S295) ◽  
pp. 240-240
Author(s):  
A. Ferré-Mateu ◽  
A. Vazdekis ◽  
I. Trujillo ◽  
P. Sánchez-Blázquez ◽  
E. Ricciardelli ◽  
...  
Keyword(s):  
Stellar Population ◽  
Mass Density ◽  
High Redshift ◽  
Imaging Data ◽  
Local Universe ◽  
Density Profiles ◽  
Surface Mass ◽  
Massive Galaxies ◽  
Surface Mass Density ◽  
Star Formation Histories

AbstractStudying the properties of the few compact massive galaxies that exist in the local Universe (Trujillo et al. 2009) might provide a closer look to the nature of their high redshift (z ≥ 1.0) massive counterparts. By this means we have characterized their main kinematics, structural properties, stellar populations and star formation histories with a set of new high quality spectroscopic and imaging data (Ferré-Mateu et al. 2012 and Trujillo et al. 2012). These galaxies seem to be truly unique, as they do not follow the characteristic kinematics, stellar surface mass density profiles and stellar population patterns of present-day massive ellipticals or spirals of similar mass. They are, instead, more alike their high-z analogs.Summarizing, local compact massive galaxies are rare, unique and the perfect laboratory to study their high redshift counterparts.

scholarly journals Gemini NIFS survey of feeding and feedback processes in nearby active galaxies – II. The sample and surface mass density profiles

2017 ◽  
Vol 474 (1) ◽  
pp. 1373-1389 ◽  
Author(s):  
R. A. Riffel ◽  
T. Storchi-Bergmann ◽  
R. Riffel ◽  
R. Davies ◽  
M. Bianchin ◽  
...  
Keyword(s):  
Mass Density ◽  
Active Galaxies ◽  
Density Profiles ◽  
Surface Mass ◽  
Surface Mass Density

scholarly journals The SAMI Galaxy Survey: stellar population and structural trends across the Fundamental Plane

2021 ◽  
Author(s):  
Francesco D’Eugenio ◽  
Matthew Colless ◽  
Nicholas Scott ◽  
Arjen van der Wel ◽  
Roger L Davies ◽  
...  
Keyword(s):  
Stellar Population ◽  
Mass Density ◽  
Empirical Relation ◽  
Zero Point ◽  
High Signal ◽  
Fundamental Plane ◽  
Surface Mass ◽  
Integral Field Spectroscopy ◽  
Surface Mass Density ◽  
Photometric Measurements

Abstract We study the Fundamental Plane (FP) for a volume- and luminosity-limited sample of 560 early-type galaxies from the SAMI survey. Using r −band sizes and luminosities from new Multi-Gaussian Expansion (MGE) photometric measurements, and treating luminosity as the dependent variable, the FP has coefficients a = 1.294 ± 0.039, b = 0.912 ± 0.025, and zero-point c = 7.067 ± 0.078. We leverage the high signal-to-noise of SAMI integral field spectroscopy, to determine how structural and stellar-population observables affect the scatter about the FP. The FP residuals correlate most strongly (8σ significance) with luminosity-weighted simple-stellar-population (SSP) age. In contrast, the structural observables surface mass density, rotation-to-dispersion ratio, Sérsic index and projected shape all show little or no significant correlation. We connect the FP residuals to the empirical relation between age (or stellar mass-to-light ratio ϒ⋆ ) and surface mass density, the best predictor of SSP age amongst parameters based on FP observables. We show that the FP residuals (anti-)correlate with the residuals of the relation between surface density and ϒ⋆ . This correlation implies that part of the FP scatter is due to the broad age and ϒ⋆ distribution at any given surface mass density. Using virial mass and ϒ⋆ we construct a simulated FP and compare it to the observed FP. We find that, while the empirical relations between observed stellar population relations and FP observables are responsible for most (75 per cent) of the FP scatter, on their own they do not explain the observed tilt of the FP away from the virial plane.

The surface mass density in the solar neighbourhood using red clumps stars in TGASxRAVE

2017 ◽  
Vol 13 (S334) ◽  
pp. 304-305
Author(s):  
Jorrit H. J. Hagen ◽  
Amina Helmi
Keyword(s):  
Vertical Velocity ◽  
Velocity Dispersion ◽  
Mass Density ◽  
Solar Neighbourhood ◽  
Local Distribution ◽  
Surface Mass ◽  
Preliminary Results ◽  
Combining Data ◽  
Surface Mass Density ◽  
Red Clump

AbstractWe investigate the kinematics of red clump stars in the Solar neighbourhood by combining data from the RAVE survey with the TGAS dataset presented in Gaia DR1. Our goal is to put new constraints on the (local) distribution of mass using the Jeans Equations. Here we show the variation of the vertical velocity dispersion as function of height above the mid-plane for both a thin and a thick disk tracer sample and present preliminary results.

scholarly journals Setting the scene for BUFFALO: a study of the matter distribution in the HFF galaxy cluster MACS J0416.1−2403 and its parallel field

2020 ◽  
Vol 494 (1) ◽  
pp. 349-362
Author(s):  
E J Gonzalez ◽  
M Chalela ◽  
M Jauzac ◽  
D Eckert ◽  
M Schaller ◽  
...  
Keyword(s):  
Mass Distribution ◽  
Mass Density ◽  
Galaxy Cluster ◽  
Field Of View ◽  
Evolutionary Stage ◽  
Matter Distribution ◽  
Surface Mass ◽  
X Ray ◽  
Parallel Field ◽  
Surface Mass Density

ABSTRACT In the context of the Beyond Ultradeep Frontier Fields And Legacy Observations (BUFFALO) survey, we present a new analysis of the merging galaxy cluster MACS J0416.1−2403 (z = 0.397) and its parallel field using Hubble Frontier Fields (HFF) data. We measure the surface mass density from a weak-lensing analysis and characterize the overall matter distribution in both the cluster and parallel fields. The surface mass distribution derived for the parallel field shows clumpy overdensities connected by filament-like structures elongated in the direction of the cluster core. We also characterize the X-ray emission in the parallel field and compare it with the lensing mass distribution. We identify five mass peaks at the >5σ level over the two fields, four of them being in the cluster one. Three of them are located close to galaxy overdensities and one is also close to an excess in the X-ray emission. Nevertheless, two of them have neither optical nor X-ray counterpart and are located close to the edges of the field of view, thus further studies are needed to confirm them as substructures. Finally, we compare our results with the predicted subhalo distribution of one of the Hydrangea/C-EAGLE simulated cluster. Significant differences are obtained suggesting the simulated cluster is at a more advanced evolutionary stage than MACS J0416.1−2403. Our results anticipate the upcoming BUFFALO observations that will link the two HFF fields, extending further the HST coverage.

scholarly journals Satellite galaxies in the Illustris-1 simulation: anisotropic locations around relatively isolated hosts

2019 ◽  
Vol 489 (1) ◽  
pp. 459-469 ◽  
Author(s):  
Tereasa G Brainerd ◽  
Masaya Yamamoto
Keyword(s):  
Dark Matter ◽  
Mass Density ◽  
Stellar Mass ◽  
Stellar Surface ◽  
Surface Mass ◽  
Degree Of Anisotropy ◽  
Surface Mass Density ◽  
The Mean ◽  
Satellite Galaxies ◽  
Stellar Masses

ABSTRACT We investigate the locations of satellite galaxies in the z = 0 redshift slice of the hydrodynamical Illustris-1 simulation. As expected from previous work, the satellites are distributed anisotropically in the plane of the sky, with a preference for being located near the major axes of their hosts. Due to misalignment of mass and light within the hosts, the degree of anisotropy is considerably less when satellite locations are measured with respect to the hosts’ stellar surface mass density than when they are measured with respect to the hosts’ dark matter surface mass density. When measured with respect to the hosts’ dark matter surface mass density, the mean satellite location depends strongly on host stellar mass and luminosity, with the satellites of the faintest, least massive hosts showing the greatest anisotropy. When measured with respect to the hosts’ stellar surface mass density, the mean satellite location is essentially independent of host stellar mass and luminosity. In addition, the satellite locations are largely insensitive to the amount of stellar mass used to define the hosts’ stellar surface mass density, as long as at least 50–70 per cent of the hosts’ total stellar mass is used. The satellite locations are dependent upon the stellar masses of the satellites, with the most massive satellites having the most anisotropic distributions.

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