scholarly journals Basilisk: Bayesian hierarchical inference of the galaxy–halo connection using satellite kinematics – I. Method and validation

2019 ◽  
Vol 488 (4) ◽  
pp. 4984-5013 ◽  
Author(s):  
Frank C van den Bosch ◽  
Johannes U Lange ◽  
Andrew R Zentner
Keyword(s):  
Luminosity Function ◽  
Velocity Dispersion ◽  
Dynamic Range ◽  
Radial Profile ◽  
Summary Statistics ◽  
Bayesian Hierarchical ◽  
The Galaxy ◽  
Satellite Velocity ◽  
Galaxy Halo ◽  
Satellite Galaxies

ABSTRACT We present a Bayesian hierarchical inference formalism (Basilisk) to constrain the galaxy–halo connection using satellite kinematics. Unlike traditional methods, Basilisk does not resort to stacking the kinematics of satellite galaxies in bins of central luminosity, and does not make use of summary statistics, such as satellite velocity dispersion. Rather, Basilisk leaves the data in its raw form and computes the corresponding likelihood. In addition, Basilisk can be applied to flux-limited, rather than volume-limited samples, greatly enhancing the quantity and dynamic range of the data. And finally, Basilisk is the only available method that simultaneously solves for halo mass and orbital anisotropy of the satellite galaxies, while properly accounting for scatter in the galaxy–halo connection. Basilisk uses the conditional luminosity function to model halo occupation statistics, and assumes that satellite galaxies are a relaxed tracer population of the host halo’s potential with kinematics that obey the spherical Jeans equation. We test and validate Basilisk using mocks of varying complexity, and demonstrate that it yields unbiased constraints on the galaxy–halo connection and at a precision that rivals galaxy–galaxy lensing. In particular, Basilisk accurately recovers the full PDF of the relation between halo mass and central galaxy luminosity, and simultaneously constrains the orbital anisotropy of the satellite galaxies. Basilisk ’s inference is not affected by potential velocity bias of the central galaxies, or by slight errors in the inferred, radial profile of satellite galaxies that arise as a consequence of interlopers and sample impurity.

scholarly journals Updated results on the galaxy–halo connection from satellite kinematics in SDSS

2019 ◽  
Vol 487 (3) ◽  
pp. 3112-3129 ◽  
Author(s):  
Johannes U Lange ◽  
Frank C van den Bosch ◽  
Andrew R Zentner ◽  
Kuan Wang ◽  
Antonio S Villarreal
Keyword(s):  
Dark Matter ◽  
Radial Profile ◽  
Sloan Digital Sky Survey ◽  
Galaxy Clustering ◽  
Sky Survey ◽  
The Galaxy ◽  
Blue Galaxies ◽  
Galaxy Halo ◽  
Satellite Galaxies ◽  
The Relationship

ABSTRACT We present new results on the relationship between central galaxies and dark matter haloes inferred from observations of galaxy abundances and satellite kinematics in the Sloan Digital Sky Survey (SDSS) DR7. We employ an updated analysis framework that includes detailed mock catalogues to model observational effects in SDSS. Our results constrain the colour-dependent conditional luminosity function of dark matter haloes, as well as the radial profile of satellite galaxies. Confirming previous results, we find that red central galaxies live in more massive haloes than blue galaxies at a fixed luminosity. Additionally, our results suggest that satellite galaxies have a radial profile less centrally concentrated than dark matter but not as cored as resolved subhaloes in dark-matter-only simulations. Compared to previous works using satellite kinematics by More et al., we find much more competitive constraints on the galaxy–halo connection, on par with those derived from a combination of galaxy clustering and galaxy–galaxy lensing. This improvement stems from also modelling the abundance of galaxies as well as a larger sample size and more realistic observational uncertainties. We compare our results on the galaxy–halo connection to other studies using galaxy clustering and group catalogues, showing a reasonable agreement between these different techniques. We discuss future applications of satellite kinematics in the context of constraining cosmology and the relationship between galaxies and dark matter haloes.

scholarly journals The galaxy–halo connection in modified gravity cosmologies: environment dependence of galaxy luminosity function

2019 ◽  
Vol 488 (1) ◽  
pp. 782-802 ◽  
Author(s):  
N Chandrachani Devi ◽  
Aldo Rodríguez-Puebla ◽  
O Valenzuela ◽  
Vladimir Avila-Reese ◽  
César Hernández-Aguayo ◽  
...  
Keyword(s):  
Modified Gravity ◽  
Luminosity Function ◽  
Cold Dark Matter ◽  
Density Field ◽  
High Density ◽  
Gravity Models ◽  
The Galaxy ◽  
Galaxy Halo ◽  
Environment Dependence ◽  
Galaxy Luminosity Function

Abstract We investigate the dependence of the galaxy–halo connection and galaxy density field in modified gravity models using the N-body simulations for f(R) and nDGP models at z = 0. Because of the screening mechanisms employed by these models, chameleon and Vainshtein, haloes are clustered differently in the non-linear regime of structure formation. We quantify their deviations in the galaxy density field from the standard Λ cold dark matter (ΛCDM) model under different environments. We populate galaxies in haloes via the (sub)halo abundance matching. Our main results are as follows: (1) The galaxy–halo connection strongly depends on the gravity model; a maximum variation of ${\sim }40{{\ \rm per\ cent}}$ is observed between halo occupational distribution (HOD) parameters; (2) f(R) gravity models predict an excess of galaxies in low-density environments of ${\sim }10{{\ \rm per\ cent}}$ but predict a deficit of ${\sim }10{{\ \rm per\ cent}}$ at high-density environments for |fR0| = 10−4 and 10−6 while |fR0| = 10−5 predicts more high-density structures; nDGP models are consistent with ΛCDM; (3) different gravity models predict different dependences of the galaxy luminosity function (GLF) with the environment, especially in void-like regions we find differences around ${\sim }10{{\ \rm per\ cent}}$ for the f(R) models while nDPG models remain closer to ΛCDM for low-luminosity galaxies but there is a deficit of ${\sim }11{{\ \rm per\ cent}}$ for high-luminosity galaxies in all environments. We conclude that the dependence of the GLF with environment might provide a test to distinguish between gravity models and their screening mechanisms from the ΛCDM. We provide HOD parameters for the gravity models analysed in this paper.

scholarly journals The Three Hundred project: shapes and radial alignment of satellite, infalling, and backsplash galaxies

2020 ◽  
Vol 495 (3) ◽  
pp. 3002-3013 ◽  
Author(s):  
Alexander Knebe ◽  
Matías Gámez-Marín ◽  
Frazer R Pearce ◽  
Weiguang Cui ◽  
Kai Hoffmann ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Galaxy Cluster ◽  
Cluster Radius ◽  
Dynamical State ◽  
The Galaxy ◽  
Radial Orbit ◽  
Galaxy Halo ◽  
Satellite Galaxies

ABSTRACT Using 324 numerically modelled galaxy clusters, we investigate the radial and galaxy–halo alignment of dark matter subhaloes and satellite galaxies orbiting within and around them. We find that radial alignment depends on distance to the centre of the galaxy cluster but appears independent of the dynamical state of the central host cluster. Furthermore, we cannot find a relation between radial alignment of the halo or galaxy shape with its own mass. We report that backsplash galaxies, i.e. objects that have already passed through the cluster radius but are now located in the outskirts, show a stronger radial alignment than infalling objects. We further find that there exists a population of well radially aligned objects passing very close to the central cluster’s centre that were found to be on highly radial orbit.

THE LINK BETWEEN GALAXIES AND DARK MATTER

2011 ◽  
Vol 20 (10) ◽  
pp. 1771-1777
Author(s):  
HOUJUN MO
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Luminosity Function ◽  
The Other ◽  
Dark Matter Halos ◽  
Galaxy Formation And Evolution ◽  
The Galaxy ◽  
Galaxy Halo ◽  
Formation And Evolution ◽  
The Universe

Given that dark matter is gravitationally dominant in the universe, and that galaxy formation is closely related to dark matter halos, a key first step in understanding galaxy formation and evolution in the CDM paradigm is to quantify the galaxy-halo connection for galaxies of different properties. Here I will present results about the halo/galaxy connection obtained from two different methods. One is based on the conditional luminosity function, which describes the occupation of galaxies in halos of different masses, and the other is based on galaxy systems properly selected to represent dark halos.

scholarly journals Revealing the galaxy–halo connection in IllustrisTNG

2019 ◽  
Vol 490 (4) ◽  
pp. 5693-5711 ◽  
Author(s):  
Sownak Bose ◽  
Daniel J Eisenstein ◽  
Lars Hernquist ◽  
Annalisa Pillepich ◽  
Dylan Nelson ◽  
...  
Keyword(s):  
Strong Predictor ◽  
Stellar Mass ◽  
High Mass ◽  
Angular Momenta ◽  
Central Galaxy ◽  
Wide Range ◽  
The Galaxy ◽  
Best Fitting ◽  
Galaxy Halo ◽  
Satellite Galaxies

ABSTRACT We use the IllustrisTNG (TNG) simulations to explore the galaxy–halo connection as inferred from state-of-the-art cosmological, magnetohydrodynamical simulations. With the high-mass resolution and large volume achieved by combining the 100 Mpc (TNG100) and 300 Mpc (TNG300) volumes, we establish the mean occupancy of central and satellite galaxies and their dependence on the properties of the dark matter haloes hosting them. We derive best-fitting HOD parameters from TNG100 and TNG300 for target galaxy number densities of $\bar{n}_g = 0.032\,$  and $\bar{n}_g = 0.016\, h^3$ Mpc−3, respectively, corresponding to a minimum galaxy stellar mass of $M_\star \sim 1.9\times 10^9\, $ and $M_\star \sim 3.5\times 10^9\, {\rm M}_\odot$, respectively, in hosts more massive than $10^{11}\, {\rm M}_\odot$. Consistent with previous work, we find that haloes located in dense environments, with low concentrations, later formation times, and high angular momenta are richest in their satellite population. At low mass, highly concentrated haloes and those located in overdense regions are more likely to contain a central galaxy. The degree of environmental dependence is sensitive to the definition adopted for the physical boundary of the host halo. We examine the extent to which correlations between galaxy occupancy and halo properties are independent and demonstrate that HODs predicted by halo mass and present-day concentration capture the qualitative dependence on the remaining halo properties. At fixed halo mass, concentration is a strong predictor of the stellar mass of the central galaxy, which may play a defining role in the fate of the satellite population. The radial distribution of satellite galaxies, which exhibits a universal form across a wide range of host halo mass, is described accurately by the best-fitting NFW density profile of their host haloes.

scholarly journals The Luminosity Function of Galaxies in Some Nearby Clusters

2021 ◽  
Vol 5 (2) ◽  
pp. 1-10
Author(s):  
Mariwan Ahmed Rasheed ◽  
Khalid K. Mohammad
Keyword(s):  
Luminosity Function ◽  
Velocity Dispersion ◽  
Absolute Magnitude ◽  
Normalization Constant ◽  
Minimization Method ◽  
Redshift Range ◽  
Magnitude Distribution ◽  
The Galaxy ◽  
The Absolute ◽  
Galaxy Luminosity Function

In the present work, the galaxy luminosity function (LF) has been studied for a sample of seven clusters in the redshift range (0.0 ≲ z ≲ 0.1), within Abell radius (1.5 h−1 Mpc), in the five SDSS passbands ugriz. In each case, the absolute magnitude distribution is found and then fitted with a Schechter function. The fitting is done, using the χ2 – minimization method to find the best values of Schechter parameters Ф* (normalization constant), M* (characteristic absolute magnitude), and α (faint-end slope). No remarkable changes are found in the values of M* and α, for any cluster, in any passband. Furthermore, the LF does not seem to vary with such cluster parameters as richness, velocity dispersion, and Bautz–Morgan morphology. Finally, it is found that M* becomes brighter toward redder bands, whereas almost no variation is seen in the value of α with passband, being around (−1.00).

scholarly journals KiDS+GAMA: The weak lensing calibrated stellar-to-halo mass relation of central and satellite galaxies

2020 ◽  
Vol 642 ◽  
pp. A83 ◽  
Author(s):  
Andrej Dvornik ◽  
Henk Hoekstra ◽  
Konrad Kuijken ◽  
Angus H. Wright ◽  
Marika Asgari ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Stellar Mass ◽  
Weak Lensing ◽  
Mass Relation ◽  
Overlapping Data ◽  
The Galaxy ◽  
Galaxy Halo ◽  
Satellite Galaxies ◽  
Mass Assembly ◽  
Halo Masses

We simultaneously present constraints on the stellar-to-halo mass relation for central and satellite galaxies through a weak lensing analysis of spectroscopically classified galaxies. Using overlapping data from the fourth data release of the Kilo-Degree Survey (KiDS), and the Galaxy And Mass Assembly survey (GAMA), we find that satellite galaxies are hosted by halo masses that are 0.53 ± 0.39 dex (68% confidence, 3σ detection) smaller than those of central galaxies of the same stellar mass (for a stellar mass of log(M⋆/M⊙) = 10.6). This is consistent with galaxy formation models, whereby infalling satellite galaxies are preferentially stripped of their dark matter. We find consistent results with similar uncertainties when comparing constraints from a standard azimuthally averaged galaxy-galaxy lensing analysis and a two-dimensional likelihood analysis of the full shear field. As the latter approach is somewhat biased due to the lens incompleteness and as it does not provide any improvement to the precision when applied to actual data, we conclude that stacked tangential shear measurements are best-suited for studies of the galaxy-halo connection.

scholarly journals Fossil group origins

2019 ◽  
Vol 631 ◽  
pp. A16
Author(s):  
S. Zarattini ◽  
J. A. L. Aguerri ◽  
A. Biviano ◽  
M. Girardi ◽  
E. M. Corsini ◽  
...  
Keyword(s):  
Velocity Dispersion ◽  
Radial Profile ◽  
Relative Magnitude ◽  
Small Magnitude ◽  
Groups Of Galaxies ◽  
Cluster Galaxies ◽  
Radial Profiles ◽  
Significant Difference ◽  
Satellite Galaxies ◽  
Flat Profile

Aims. We aim to study how the velocity segregation and the radial profile of the velocity dispersion depend on the prominence of the brightest cluster galaxies (BCGs). Methods. We divided a sample of 102 clusters and groups of galaxies into four bins of magnitude gap between the two brightest cluster members. We then computed the velocity segregation in bins of absolute and relative magnitude. Moreover, for each bin of magnitude gap we computed the radial profile of the velocity dispersion. Results. When using absolute magnitudes, the segregation in velocity is limited to the two brightest bins and no significant difference is found for different magnitude gaps. However, when we use relative magnitudes, a trend appears in the brightest bin: the larger the magnitude gap, the larger the velocity segregation. We also show that this trend is mainly due to the presence, in the brightest bin, of satellite galaxies in systems with small magnitude gaps: in fact, if we study central galaxies and satellites separately, this trend is mitigated and central galaxies are more segregated than satellites for any magnitude gap. A similar result is found in the radial velocity dispersion profiles: a trend is visible in central regions (where the BCGs dominate) but, if we analyse the profile using satellites alone, the trend disappears. In the latter case, the shape of the velocity dispersion profile in the centre of the systems with different magnitude gaps shows three types of behaviour: systems with the smallest magnitude gaps have an almost flat profile from the centre to the external regions; systems with the largest magnitude gaps show a monothonical growth from the low values of the central part to the flat ones in the external regions; and finally, systems with 1.0 <  Δm12 ≤ 1.5 show a profile that peaks in the centre and then decreases towards the external regions. Conclusions. We suggest that two mechanisms could be responsible for the observed differences in the velocity segregation of the BCGs: an earlier formation of systems with a larger magnitude gap or a more centrally concentrated halo. However, the radial profiles of the velocity dispersion confirm that central galaxies are more relaxed, but that the satellite galaxies do not seem to be affected by the magnitude gap.

scholarly journals Galaxy alignment on large and small scales

2014 ◽  
Vol 11 (S308) ◽  
pp. 448-451
Author(s):  
X. Kang ◽  
W.P. Lin ◽  
X. Dong ◽  
Y.O. Wang ◽  
A. Dutton ◽  
...  
Keyword(s):  
Dark Matter ◽  
Major Axis ◽  
Dark Matter Halo ◽  
Central Galaxy ◽  
Small Scales ◽  
The Galaxy ◽  
Galaxy Halo ◽  
Satellite Galaxies ◽  
Red Galaxies ◽  
Inner Region

AbstractGalaxies are not randomly distributed across the universe but showing different kinds of alignment on different scales. On small scales satellite galaxies have a tendency to distribute along the major axis of the central galaxy, with dependence on galaxy properties that both red satellites and centrals have stronger alignment than their blue counterparts. On large scales, it is found that the major axes of Luminous Red Galaxies (LRGs) have correlation up to 30Mpc/h. Using hydro-dynamical simulation with star formation, we investigate the origin of galaxy alignment on different scales. It is found that most red satellite galaxies stay in the inner region of dark matter halo inside which the shape of central galaxy is well aligned with the dark matter distribution. Red centrals have stronger alignment than blue ones as they live in massive haloes and the central galaxy-halo alignment increases with halo mass. On large scales, the alignment of LRGs is also from the galaxy-halo shape correlation, but with some extent of mis-alignment. The massive haloes have stronger alignment than haloes in filament which connect massive haloes. This is contrary to the naive expectation that cosmic filament is the cause of halo alignment.

scholarly journals Limitations to the ‘basic’ HOD model and beyond

2020 ◽  
Vol 493 (4) ◽  
pp. 5506-5519 ◽  
Author(s):  
Boryana Hadzhiyska ◽  
Sownak Bose ◽  
Daniel Eisenstein ◽  
Lars Hernquist ◽  
David N Spergel
Keyword(s):  
Velocity Dispersion ◽  
Local Environment ◽  
Real Space ◽  
Space Correlation ◽  
Redshift Surveys ◽  
The Galaxy ◽  
Systematic Effects ◽  
Galaxy Halo ◽  
Hydrodynamical Simulations ◽  
Halo Occupation Distribution

ABSTRACT We use the IllustrisTNG cosmological, hydrodynamical simulations to test fundamental assumptions of the mass-based halo occupation distribution (HOD) approach to modelling the galaxy–halo connection. By comparing the clustering of galaxies measured in the 300 Mpc TNG box (TNG300) with that predicted by the standard (basic) HOD model, we find that, on average, the ‘basic’ HOD model underpredicts the real-space correlation function in the TNG300 box by ∼15 per cent on scales of $1 \,\,\lt\,\, r \,\,\lt\,\, 20 \ {\rm Mpc}\, h^{-1}$, which is well beyond the target precision demanded of next-generation galaxy redshift surveys. We perform several tests to establish the robustness of our findings to systematic effects, including the effect of finite box size and the choice of halo finder. In our exploration of ‘secondary’ parameters with which to augment the ‘basic’ HOD, we find that the local environment of the halo, the velocity dispersion anisotropy, β, and the product of the half-mass radius and the velocity dispersion, σ2Rhalfmass, are the three most effective measures of assembly bias that help reconcile the ‘basic’ HOD-predicted clustering with that in TNG300. In addition, we test other halo properties such as halo spin, formation epoch, and halo concentration. We also find that at fixed halo mass, galaxies in one type of environment cluster differently from galaxies in another. We demonstrate that a more complete model of the galaxy–halo connection can be constructed if we combine both mass and local environment information about the halo.

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