Biomedical subjects

Chung-Pei Ma

Publications and source records attributed to Chung-Pei Ma.

2 recordsLinked to original sources

PubMed2004

Are halos of collisionless cold dark matter collisionless?

We study whether gravitational scattering of halo dark matter particles by subhalos can connect two seemingly independent problems: the abundance of subhalos in dark matter halos and the cuspiness of the halos' inner density profiles. Our numerical experiments indicate that subhalos can cause the collisionless dark matter particles in the centers of main halos to diffuse. Combined with tidal mass loss of the subhalos, this process introduces significant scatter in the inner density profiles and offers an explanation for the range of profiles seen in both observations and cosmological simulations.

Journal Article↗

PubMed2002

Nonlinear kinetic Sunyaev-Zeldovich effect.

We derive fully nonlinear expressions for temperature fluctuations from the kinetic Sunyaev-Zeldovich (SZ) effect, the scattering of cosmic microwave background photons off hot electrons in bulk motion. Our result reproduces the Ostriker-Vishniac effect to second order in perturbation theory but contains nonlinear corrections to the electron velocities and densities that were neglected previously. We use the recently developed halo model for nonlinear gravitational clustering to compute the nonlinear kinetic SZ power spectrum, which dominates the primary anisotropy on small angular scales.

Journal Article↗