Astrophysics & Cosmology

Sabine Schindler Institute for Astrophysics

University of Innsbruck

Currently most active field of research in Innsbruck:Clusters of Galaxies

Largest bound structures Size ~ a few Mpc Mass ~ 1015 Msun

Observable to large distances

Ideal tools for cosmology

Cluster Components

GalaxiesIntra-cluster gas

– Density ~ 10-2 – 10-4 cm-3

– Temperature ~ 107-108 K – Thermal bremsstrahlung

X-ray emission

luminosity ~ 1043-45 erg/s

optical

X-rays

Mass fraction

Observable in

Galaxies 3 – 5 % Optical

Intra-cluster gas 15 – 20 % X-rays

Dark matter Rest -

We can measure amount of dark matter distribution of dark matterbut nature of dark matter still unknown!!!

Matter Density m of the Universe

Assumption: ratio of visible matter to Assumption: ratio of visible matter to dark matter in clusters is representative dark matter in clusters is representative for the universe as a whole for the universe as a whole

3.0min units of thecritical density

Structure Formation

Observations only snapshots (time scales ~ 109 yrs)

Numerical simulations follow the evolution

Different componentsgalaxies, dark matter N-bodygas hydrodynamic simulations

For movies see http://astro.uibk.ac.at/astroneu/hydroskiteam/index.htm

Comparison with Observations

X-rays:XMM-Newton (ESA)

De Filippis, Schindler, Castillo-Morales, 2003

optical:VLT (ESO)Erben, Miralles,

Schindler, Schneider, in prep.

From observations and simulations:• Dynamics • Evolution• Interaction of components• Heavy element enrichment• .....

Structure Formation and Evolution

Cosmology

Galaxy clusters – the largest bound structures in the universe