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Correlations of Mass Distributions between Dark Matter and Visible MatterPowerPoint Presentation

Correlations of Mass Distributions between Dark Matter and Visible Matter

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### Correlations of Mass Distributionsbetween Dark Matter and Visible Matter

KIAS-APCTP-DMRC Workshop on

“The Dark Side of the Universe”

May 24, 2005

Yuriy Mishchenko and Chueng-Ryong Ji

NC State University Raleigh, NC

Motivation

- Universal Rotation Curves in Spiral Galaxies and
Strong Gravitational Lensing in Galaxy Clusters

provide convincing evidences of Dark Matter.

- High Resolution Mass Map of CL0024+1654 is now available from the deep imaging with the Hubble Space Telescope.
- Two dramatically different systems seem to exhibit a consistency in correlations of mass distributions between Dark Matter and Visible Matter.
Y.Mishchenko and C.Ji, PRD68, 063503 (2003)

Outline

- Gravitational Lensing
-Galaxy Clusters CL0024+1654

-Mass Map by Tyson et al.

-Simple but general theromodynamic analysis

- Universal Rotation Curves
-Spiral Galaxies with different luminosities

-Consistency with the thermodynamic analysis

- Discussions and Conclusions

Gravitational Lensing Effect

- gravitational lensing is phenomenon of light deflection in gravitational field
- allows to restore 2D projected mass distribution

Einstein Cross Q2237+0305

Dark vs. Visible in Galaxy Clusters

from J. Tyson, G. Kochanski, I. Dell’Antonio, astro-ph/9801193

Dark vs. Visible in Galaxy Clusters

J. Tyson, G. Kochanski, I. Dell’Antonio, 1998:

- presented analysis of Hubble telescope images of strong gravitational lensing in galaxy cluster CL0024+1654
- presented detailed mass map and radial “averaged” profiles for total and visible matter
- primary conclusion was about inconsistency with Cold Dark Matter simulations (soft core)

- projected density radial profiles presented on log-log scale for the total and visible matter distribution

- if profiles were re-plotted on log-linear scale, one would observe exponential decay

anomalous flat region at about 100kpc in the visible mass profile

Thermodynamic Principle

Log-Log Linear Correlation

Dark Matter in Spiral Galaxies

Rotation Curve represents gas/stars circular orbit velocity as function of distance from the galaxy’s center

spiral galaxy NGC2403

Dark vs. Visible in Spiral Galaxies

M. Persic, P. Salucci, F. Stel, 1996:

- presented analysis of a sample of spiral galaxies’ Rotation Curves classified by galaxy luminosities and normalized to vopt and ropt .
- found that majority of normalized RC in given luminosity group follow universal profiles (Universal Rotation Curves).
- described URC in terms of simple mass model: dark spherical halo + exponential thin stellar disk.

Universal Rotation Curves in Spiral Galaxies

- In Persic, Salucci, Stel visible mass contribution is known but approximated with an analytical fit,
- Dark halo contribution is parameterized,
- Final Rotation Curve is described with

Correlation of Mass Density

- URC can be fit in the region 0 r/ropt 2 with exponential dark hallo for all luminosities
- For larger r and are linearly correlated

Exponential Thin Disk

It corresponds to T~105 K consistent with the temperature

of the interstellar gas.

Dark vs. Visible in Spiral Galaxies

Log-Log-Linear Correlation in Spiral Galaxies

best fit values of a for different luminositiesM

…remember obtained for CL0024+1654,

Dark vs. Visible Matter

We observed Log-Log-Linear correlation with essentially the same correlation coefficient in different spiral galaxies and a galaxy cluster.

This is a remarkable coincidence…

How do we interprete?

Interpretation of Results

- Local Thermodynamic Equilibrium since it is unlikely
that the molar mass ratio varies in a precise correlation

with the temperature ratio to make kappa constant both

for the galaxy clusters and the spiral galaxies.

- Visible matter primarily consists of H, H2 and He.

Massive neutrinos and/or axions < 25MeV

WIMP ~ 10GeV-1TeV

SUSY lightest particles(e.g. neutralino)>30GeV

Discussions and Conclusions

- Correlations of mass distributions between dark matter and visible matter in two dramatically different systems, galaxy cluster and spiral galaxies, are remarkably consistent with each other.
- Based on an almost isothermal Boltzmann
distribution, we find K = 2.1~4.4 which indicate

the typical mass scale of dark matter particles

around the order of 100 MeV.

- Since this is right around the QCD mass scale,
any relation between the dark matter and QCD vacuum

condensates?

- Experimental – improve “statistics”
- large survey of dark vs. visible matter in galaxy clusters…

- Theoretical – investigate different possibilities
- role of gravity in thermalization processes…
- better understanding of galaxy cluster dynamics…
- better understanding of spiral galaxy dynamics…

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