Polytropic dark haloes of elliptical galaxies

Massive Elliptical Galaxies : from Cores to Haloes

In the context of recent observational results that show massive ellipticals were in place at high redshifts, we reassess the status of monolithic collapse in a ΛCDM universe. Using a sample of over 2000 galaxies from the Sloan Digital Sky Survey, by comparing the dynamical mass and stellar mass (estimated from colours) we find that ellipticals have 'cores' which are baryon-dominated within the...

Gravitational Flexion by Elliptical Dark Matter Haloes

We present equations for the gravitational lensing flexion expected for an elliptical lens mass distribution. These can be reduced to one-dimensional finite integrals, thus saving significant computing time over a full two-dimensional calculation. We estimate constraints on galaxy halo ellipticities for a range of potential future surveys, finding that the constraints from the two different typ...

Dark Matter in Elliptical Galaxies?

Spectroscopic Constraints on Cooling Flow Models of Clusters of Galaxies and Gaseous Haloes Around Elliptical Galaxies

In many clusters of galaxies, the cooling time at the core of the intracluster medium is much less than the age of the system, suggesting that the the gas should continually lose energy by radiation. Simple thermodynamic arguments then require that the expected " cooling flow " should exhibit a specific spectroscopic signature, characterized by a differential emission measure distribution that ...

Prevalence and Properties of Dark Matter in Elliptical Galaxies

Given the recently deduced relationship between X-ray temperatures and stellar velocity dispersions (the “T–σ relation”) in an optically complete sample of elliptical galaxies (Davis & White 1996), we demonstrate that L > L∗ ellipticals contain substantial amounts of dark matter in general. We present constraints on the dark matter scale length and on the dark-to-luminous mass ratio within the ...