Chapter 7 Dark Matter Particle Astrophysics Cosmology SS

Chapter 7 Dark Matter Particle Astrophysics & Cosmology SS 2008 1

Galaxies: face-on view NGC 1232 a galaxy like our Milky Way: 1011 stars, ~ 50 kpc diameter Particle Astrophysics & Cosmology SS 2008 2

Galaxies: edge-on view NGC 4565 central stellar bulge, stellar disk, interstellar medium (gas and dust) Particle Astrophysics & Cosmology SS 2008 3

Galaxy groups a few up to ~ 100 galaxies Particle Astrophysics & Cosmology SS 2008 4

Galaxy clusters up to a few 1000 galaxies a few Mpc total size Particle Astrophysics & Cosmology SS 2008 5

Density fluctuations without DM Particle Astrophysics & Cosmology SS 2008 6

Rotation curves of galaxies rotating gaseous disk (HI) rotation velocity v(r) from Doppler shift Particle Astrophysics & Cosmology SS 2008 7

Galaxy kinematics Isovelocity contours v(x, y) movie Particle Astrophysics & Cosmology SS 2008 8

Galaxy kinematics a real galaxy (NGC 2541) optical image column density of neutral hydrogen (grey/white) and isovelocity contours Particle Astrophysics & Cosmology SS 2008 9

A movie of v(x, y) model galaxy real galaxy (NGC 2541) Particle Astrophysics & Cosmology SS 2008 10

Measured rotation curve radial distribution of stellar light rotation curve with stellar and gaseous contribution Particle Astrophysics & Cosmology SS 2008 11

NFW profile vs. observation NFW Burkert + obs. points dark An extreme case: dwarf galaxy DDO 47 with mass M 1010 M NFW overpredicts central velocities gas stars “cusp problem” Particle Astrophysics & Cosmology SS 2008 12

X-ray halos of galaxy clusters Cluster A 3528 black ellipses: optically visible galaxies colour: X-ray emission Particle Astrophysics & Cosmology SS 2008 13

Total mass in galaxy clusters distribution of mass in a galaxy clusters Particle Astrophysics & Cosmology SS 2008 14

Total mass in galaxy clusters rotation curve of a dwarf galaxy Particle Astrophysics & Cosmology SS 2008 15

Gravitational lensing by galaxy clusters Particle Astrophysics & Cosmology SS 2008 16

Gravitational lensing by galaxy clusters Particle Astrophysics & Cosmology SS 2008 17

Numerical CDM simulations Simulated large-scale structure for different cosmologies Particle Astrophysics & Cosmology SS 2008 18

Numerical CDM simulations cluster large galaxy Particle Astrophysics & Cosmology SS 2008 19

Observations Particle Astrophysics & Cosmology SS 2008 20

Simulations and observations simulations and observations agree on large scales Particle Astrophysics & Cosmology SS 2008 21

Tully-Fisher relation Particle Astrophysics & Cosmology SS 2008 22

‘Missing satellites’ galaxy cluster Virgo Cluster : agreement Milky Way : large discrepancy Particle Astrophysics & Cosmology SS 2008 23

Web sites for numerical simulations http: //www. mpa-garching. mpg. de/~volker/gadget/index. html http: //www. aip. de/People/MSteinmetz/Movies. html Particle Astrophysics & Cosmology SS 2008 24

WIMP search Particle Astrophysics & Cosmology SS 2008 25