Measuring Dark Matter Halos by Modeling Interacting Galaxies

2004 ◽  
Vol 220 ◽  
pp. 461-462 ◽  
Author(s):  
Christian Theis
Keyword(s):  
Genetic Algorithm ◽  
Dark Matter ◽  
Parameter Space ◽  
Matter Content ◽  
Interacting Galaxies ◽  
Dark Matter Halo ◽  
Dark Matter Halos ◽  
Characteristic Parameters ◽  
Galactic Dark Matter

The richness of tidal features seen in interacting galaxies allows for the determination of their characteristic parameters, provided one can deal with the extended parameter space. Genetic algorithm based methods – like our code minga – have proven to be such a tool. Here I discuss the implementation of dark matter halo descriptions in the restricted N-body simulations of minga. I show that the final morphology of a galaxy encounter strongly depends on the halo properties. Thus, modeling tidal features of interacting galaxies might allow also for conclusions on the galactic dark matter content.

Rotation Curve and Dark Matter Halo profile in Finsler Geometry

2020 ◽  
Author(s):  
Nupur Paul ◽  
Farook Rahaman ◽  
Nasarul Islam ◽  
S.S. De
Keyword(s):  
Dark Matter ◽  
Rotational Velocity ◽  
Finsler Geometry ◽  
Outer Region ◽  
Recent Time ◽  
Dark Matter Halo ◽  
Dark Matter Halos ◽  
Radial Profiles ◽  
Galactic Dark Matter ◽  
Specific Equation

Galactic dark matter is an active area of research in recent time. Several researchers proposed several descriptions of radial profiles of dark matter halos by using N-body simulations. Among them, Navarro, Frenk and White (NFW) dark matter profile provides the most accurate description of dark matter halos. It is believed that dark matter is smooth and distributed uniformly throughout space. Using Finslerian geometrical background and a specific equation of state, we propose a new way to estimate the rotational velocity of galaxies based on the NFW dark matter profile. On small scales the first few distances (about 30 kpc) the velocity increases whereas in the outer region of the galaxies, the rotational velocity is found to be more or less constant which supports observed rotational velocities.

scholarly journals GRAVITATIONAL WAVE ENHANCEMENT AS A TOOL TO DISTINGUISH DARK MATTER HALO PROFILES

2019 ◽  
Vol 55 (2) ◽  
pp. 231-235
Author(s):  
Sergio Grijalva Castillo ◽  
Carlos Calcáneo-Roldán
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Dark Matter Halo ◽  
Spherically Symmetric ◽  
Dark Matter Halos ◽  
Recent Success ◽  
Galactic Dark Matter ◽  
Matter Model ◽  
Invaluable Tool ◽  
Dark Matter Model

The recent success of the dark matter model has proven to be an invaluable tool for describing the formation, evolution and stability of galaxies. In this work we study the enhancement function, F , of the gravitational lensing of gravitational waves by galactic dark matter halos and show how this function may be used to distinguish between halo models. In particular we compare an isothermal sphere with an NFW type density distribution, both of which are assumed to be spherically symmetric, and find that our technique clearly distinguishes between the models.

scholarly journals Limits on the dark matter content of globular clusters

2009 ◽  
Vol 5 (S266) ◽  
pp. 365-365
Author(s):  
H. Baumgardt ◽  
P. Côté ◽  
M. Hilker ◽  
M. Rejkuba ◽  
S. Mieske ◽  
...  
Keyword(s):  
Dark Matter ◽  
Globular Clusters ◽  
Stellar Population ◽  
Velocity Dispersion ◽  
Large Mass ◽  
Matter Content ◽  
Dark Matter Halo ◽  
Dark Matter Halos ◽  
Galactocentric Distance ◽  
Rule Out

AbstractWe have measured the velocity dispersion of the Galactic globular cluster NGC 2419 to determine if a substantial amount of dark matter is present in this cluster. NGC 2419 is one of the best globular clusters to look for dark matter due to its large mass, long relaxation time and large Galactocentric distance, which makes tidal stripping of dark matter unlikely. Our results can be summarized as follows. (i) We found a global velocity dispersion of 4.14 ± 0.48 km s−1, which leads to a total cluster mass of (9.02 ± 2.22) × 105 M⊙ and implies a global mass-to-light ratio of 2.05 ± 0.50 M⊙/L⊙. (ii) Our derived mass-to-light ratio is completely consistent with the mass-to-light ratio of a standard stellar population at the metallicity and age of NGC 2419. In addition, the mass-to-light ratio of NGC 2419 does not increase towards the outer cluster parts. (iii) We can therefore rule out the presence of a dark-matter halo with a central density greater than about 0.02 M⊙ pc−3. Similar limits are found for other halo globular clusters, like Pal 14. These observations therefore indicate that NGC 2419 and other halo globular clusters did not form at the centers of dark-matter halos similar to those surrounding dwarf galaxies. Instead, an origin driven by gas-dynamical processes during mergers between galaxies or proto-galactic fragments seems to be the more likely explanation for the formation of even the lowest-metallicity globular clusters.

scholarly journals Precision Determination of the Mass Function of Dark Matter Halos

2006 ◽  
Vol 646 (2) ◽  
pp. 881-885 ◽  
Author(s):  
Michael S. Warren ◽  
Kevork Abazajian ◽  
Daniel E. Holz ◽  
Luis Teodoro
Keyword(s):  
Dark Matter ◽  
Mass Function ◽  
Dark Matter Halos ◽  
Precision Determination

scholarly journals The emergence of the red sequence at z~2 seen through galaxy clustering in the UKIDSS UDS

2012 ◽  
Vol 8 (S295) ◽  
pp. 105-108
Author(s):  
William G. Hartley ◽  
Omar Almaini ◽  
Alice Mortlock ◽  
Chris Conselice ◽  
Keyword(s):  
Dark Matter ◽  
Cross Correlation ◽  
Near Infrared ◽  
Correlation Technique ◽  
Dark Matter Halos ◽  
Star Forming ◽  
Deep Survey ◽  
Cross Correlation Technique ◽  
Infrared Survey

AbstractWe use the UKIDSS Ultra-Deep Survey, the deepest degree-scale near-infrared survey to date, to investigate the clustering of star-forming and passive galaxies to z ~ 3.5. Our new measurements include the first determination of the clustering for passive galaxies at z > 2, which we achieve using a cross-correlation technique. We find that passive galaxies are the most strongly clustered, typically hosted by massive dark matter halos with Mhalo > 1013 M⊙ irrespective of redshift or stellar mass. Our findings are consistent with models in which a critical halo mass determines the transition from star-forming to passive galaxies.

scholarly journals Recoiling black holes in static and evolving dark matter halo potential

2015 ◽  
pp. 17-28 ◽  
Author(s):  
M. Smole
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Critical Velocity ◽  
Complete Removal ◽  
Matter Density ◽  
Dark Matter Halo ◽  
Dark Matter Halos ◽  
Critical Amplitude ◽  
Density Distributions

We follow trajectories of kicked black holes in static and evolving dark matter halo potential. We explore both NFW and Einasto dark matter density distributions. Considered dark matter halos represent hosts of massive spiral and elliptical field galaxies. We study critical amplitude of kick velocity necessary for complete black hole ejection at various redshifts and find that ~40% lower kick velocities can remove black holes from their host haloes at z = 7 compared to z = 1. The greatest difference between static and evolving potential occurs near the critical velocity for black hole ejection and at high redshifts. When NFW and Einasto density distributions are compared ~30% higher kick velocities are needed for complete removal of BHs from dark matter halo described by NFW profile.

How Far Do They Go? The Outer Structure of Galactic Dark Matter Halos

2006 ◽  
Vol 645 (2) ◽  
pp. 1001-1011 ◽  
Author(s):  
Francisco Prada ◽  
Anatoly A. Klypin ◽  
Eduardo Simonneau ◽  
Juan Betancort‐Rijo ◽  
Santiago Patiri ◽  
...  
Keyword(s):  
Dark Matter ◽  
Dark Matter Halos ◽  
Galactic Dark Matter

scholarly journals Structure of Dark Matter Halo

1999 ◽  
Vol 183 ◽  
pp. 155-155
Author(s):  
Toshiyuki Fukushige ◽  
Junichiro Makino
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Temperature Inversion ◽  
Dark Matter Halo ◽  
Temperature Structure ◽  
Galactic Halos ◽  
Dark Matter Halos ◽  
Density Profiles ◽  
Order Of Magnitude ◽  
Special Purpose Computer

We performed N-body simulation on special-purpose computer, GRAPE-4, to investigate the structure of dark matter halos (Fukushige, T. and Makino, J. 1997, ApJL, 477, L9). Universal profile proposed by Navarro, Frenk, and White (1996, ApJ, 462, 563), which has cusp with density profiles ρ ∝r−1in density profile, cannot be reproduced in the standard Cold Dark Matter (CDM) picture of hierarchical clustering. Previous claims to the contrary were based on simulations with relatively few particles, and substantial softening. We performed simulations with particle numbers an order of magnitude higher, and essentially no softening, and found that typical central density profiles are clearly steeper than ρ ∝r−1, as shown in Figure 1. In addition, we confirm the presence of a temperature inversion in the inner 5 kpc of massive galactic halos, and give a natural explanation for formation of the temperature structure.

scholarly journals On measuring the Galactic dark matter halo with hypervelocity stars

2019 ◽  
Vol 487 (3) ◽  
pp. 4025-4036 ◽  
Author(s):  
O Contigiani ◽  
E M Rossi ◽  
T Marchetti
Keyword(s):  
Dark Matter ◽  
Dark Matter Halo ◽  
Galactic Dark Matter
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