scholarly journals Statistics of Weak Gravitational Lensing in Cold Dark Matter Models: Magnification Bias on Quasar Luminosity Functions

2000 ◽  
Vol 529 (1) ◽  
pp. 56-68 ◽  
Author(s):  
Takashi Hamana ◽  
Hugo Martel ◽  
Toshifumi Futamase
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
Weak Gravitational Lensing ◽  
Luminosity Functions

scholarly journals Understanding the large inferred Einstein radii of observed low-mass galaxy clusters

2020 ◽  
Vol 494 (4) ◽  
pp. 4706-4712 ◽  
Author(s):  
Andrew Robertson ◽  
Richard Massey ◽  
Vincent Eke
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
Baryonic Matter ◽  
Analysis Method ◽  
Critical Curves ◽  
Hydrodynamical Simulation ◽  
Low Mass ◽  
Main Effects

ABSTRACT We assess a claim that observed galaxy clusters with mass ${\sim}10^{14} \mathrm{\, M_\odot }$ are more centrally concentrated than predicted in lambda cold dark matter (ΛCDM). We generate mock strong gravitational lensing observations, taking the lenses from a cosmological hydrodynamical simulation, and analyse them in the same way as the real Universe. The observed and simulated lensing arcs are consistent with one another, with three main effects responsible for the previously claimed inconsistency. First, galaxy clusters containing baryonic matter have higher central densities than their counterparts simulated with only dark matter. Secondly, a sample of clusters selected because of the presence of pronounced gravitational lensing arcs preferentially finds centrally concentrated clusters with large Einstein radii. Thirdly, lensed arcs are usually straighter than critical curves, and the chosen image analysis method (fitting circles through the arcs) overestimates the Einstein radii. After accounting for these three effects, ΛCDM predicts that galaxy clusters should produce giant lensing arcs that match those in the observed Universe.

scholarly journals CFHTLenS: the relation between galaxy dark matter haloes and baryons from weak gravitational lensing

2013 ◽  
Vol 437 (3) ◽  
pp. 2111-2136 ◽  
Author(s):  
Malin Velander ◽  
Edo van Uitert ◽  
Henk Hoekstra ◽  
Jean Coupon ◽  
Thomas Erben ◽  
...  
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Weak Gravitational Lensing

scholarly journals Detection of weak gravitational lensing distortions of distant galaxies by cosmic dark matter at large scales

Nature ◽  
2000 ◽  
Vol 405 (6783) ◽  
pp. 143-148 ◽  
Author(s):  
David M. Wittman ◽  
J. Anthony Tyson ◽  
David Kirkman ◽  
Ian Dell'Antonio ◽  
Gary Bernstein
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Weak Gravitational Lensing ◽  
Distant Galaxies

scholarly journals Dark and luminous satellites of LMC-mass galaxies in the FIRE simulations

2019 ◽  
Vol 489 (4) ◽  
pp. 5348-5364 ◽  
Author(s):  
Ethan D Jahn ◽  
Laura V Sales ◽  
Andrew Wetzel ◽  
Michael Boylan-Kolchin ◽  
T K Chan ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Dwarf Galaxies ◽  
Large Magellanic Cloud ◽  
Proper Motions ◽  
New Members ◽  
Cosmological Context ◽  
Luminosity Functions ◽  
In Fire ◽  
Number Counts

ABSTRACT Within lambda cold dark matter ($\Lambda$CDM), dwarf galaxies like the Large Magellanic Cloud (LMC) are expected to host numerous dark matter subhaloes, several of which should host faint dwarf companions. Recent Gaia proper motions confirm new members of the LMC system in addition to the previously known SMC, including two classical dwarf galaxies ($M_\ast$$\gt 10^5$ M$_{\odot }$; Carina and Fornax) as well as several ultrafaint dwarfs (Car2, Car3, Hor1, and Hyd1). We use the Feedback In Realistic Environments (FIRE) simulations to study the dark and luminous (down to ultrafaint masses, $M_\ast$$\sim$6$\times 10^ {3}$ M$_{\odot }$) substructure population of isolated LMC-mass hosts ($M_{\text{200m}}$ = 1–3$\times 10^ {11}$ M$_{\odot }$) and place the Gaia  + DES results in a cosmological context. By comparing number counts of subhaloes in simulations with and without baryons, we find that, within 0.2 $r_{\text{200m}}$, LMC-mass hosts deplete $\sim$30 per cent of their substructure, significantly lower than the $\sim$70 per cent of substructure depleted by Milky Way (MW) mass hosts. For our highest resolution runs ($m_\text{bary}$  = 880 M$_{\odot }$), $\sim 5\!-\!10$ subhaloes form galaxies with $M_\ast$$\ge 10^{4}$ M$_{\odot }$ , in agreement with the seven observationally inferred pre-infall LMC companions. However, we find steeper simulated luminosity functions than observed, hinting at observation incompleteness at the faint end. The predicted DM content for classical satellites in FIRE agrees with observed estimates for Carina and Fornax, supporting the case for an LMC association. We predict that tidal stripping within the LMC potential lowers the inner dark matter density of ultrafaint companions of the LMC. Thus, in addition to their orbital consistency, the low densities of dwarfs Car2, Hyd1, and Hyd2 reinforce their likelihood of Magellanic association.

scholarly journals CONSTRAINING TEVES GRAVITY AS EFFECTIVE DARK MATTER AND DARK ENERGY

2007 ◽  
Vol 16 (12a) ◽  
pp. 2055-2063 ◽  
Author(s):  
HONGSHENG ZHAO
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
High Redshift ◽  
Elliptical Galaxies ◽  
Dual Roles ◽  
Acceleration Of The Universe ◽  
The Universe

The phenomena customarily described with the standard ΛCDM model are broadly reproduced by an extremely simple model in TeVeS, Bekenstein's1 modification of general relativity motivated by galaxy phenomenology. Our model can account for the acceleration of the Universe seen at SNeIa distances without a cosmological constant, and the accelerations seen in rotation curves of nearby spiral galaxies and gravitational lensing of high-redshift elliptical galaxies without cold dark matter. The model is consistent with BBN and the neutrino mass between 0.05 eV to 2 eV. The TeVeS scalar field is shown to play the effective dual roles of dark matter and dark energy, with the amplitudes of the effects controlled by a μ function of the scalar field, called the μ essence here. We also discuss outliers to the theory's predictions on multiimaged galaxy lenses and outliers on the subgalaxy scale.

scholarly journals Deflection Angle of Photon Through Dark Matter by Black Holes/Wormholes Using the Gauss-Bonnet Theorem

2019 ◽  
Author(s):  
Ali Övgün
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Near Field ◽  
Compact Objects ◽  
Weak Gravitational Lensing ◽  
Optical Geometry ◽  
Field Information ◽  
Bonnet Theorem ◽  
Fish Eye ◽  
Excellent Tool

Maxwell's fish eye has been known to be a perfect lens in optics. In this letter, using the Gibbons-Werner method, namely Gauss-Bonnet theorem on optical geometry of black hole, we extend the calculation of the weak gravitational lensing within the Maxwell's fisheye as a perfect lensing in medium composed of an isotropic refractive index that near-field information can be obtained from far-field distances. Moreover, these results provide an excellent tool to observe compact massive object by weak gravitational lensing within the dark matter medium and to understand the nature of the dark matter that may effect the gravitational waves. Moreover, we show that Gauss-Bonnet theorem is a global effect and this method can be used as a new tool on any optical geometry of compact objects in dark matter medium.

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