arXiv subjects

Andisheh Mahdavi

Publications and source records attributed to Andisheh Mahdavi.

21 records · Page 2Linked to original sources

arXiv2001

The LX-sigma Relation for Galaxies and Clusters of Galaxies

We demonstrate that individual elliptical galaxies and clusters of galaxies form a continuous X-ray luminosity---velocity dispersion (LX-sigma) relation. Our samples of 280 clusters and 57 galaxies have LX ~ sigma^4.4 and LX ~ sigma^10, respectively. This unified LX - sigma relation spans 8 orders of magnitude in LX and is fully consistent with the observed and theoretical luminosity---temperature scaling laws. Our results support the notion that galaxies and clusters of galaxies are the luminous tracers of similar dark matter halos.

astro-ph↗

arXiv2000

The Orbital Structure of Dark Matter Halos with Gas

With the success of the Chandra and XMM missions and the maturation of gravitational lensing techniques, powerful constraints on the orbital structure of cluster dark matter halos are possible. I show that the X-ray emissivity and mass of a galaxy cluster uniquely specify the anisotropy and velocity dispersion profiles of its dark matter halo. I consider hydrostatic as well as cooling flow scenarios, and apply the formalism to the lensing cluster CL0024+16 and the cooling flow cluster Abell 2199. In both cases, the model predicts a parameter-free velocity dispersion profile that is consistent with independent optical redshift surveys of the clusters.

astro-ph↗

arXiv1999

The Cluster LX-sigma Relation Has Implications for Scale-Free Cosmologies

I show that the cluster LX-sigma relation should be sensitive to cosmologies with a scale-free power spectrum of initial density fluctuations, P(k) ~ k^n. I derive the dependence, and argue that a conservative interpretation of current observations implies n < -2.0 and n < -1.1 at the one-sided 90% and 99% confidence levels, respectively. This result, which agrees with constraints on n from the x-ray cluster temperature function, should be roughly independent of the value of Omega or Lambda.

astro-ph↗