School of Astronomy (SoA) - Weekly Seminar 

Prospects for detecting Dark Matter Halo substructure with Pulsar Timing

Shant Baghramian (SUT & IPM)

Abstract:

One of the open questions of modern cosmology is the nature and
properties of Dark Matter halo and its substructures. In this work
we study the gravitational effect of dark matter substructures on
the pulsar timing observations. As the millisecond pulsars are
stable and accurate emitters, they have been proposed  as plausible
astrophysical tools to probe the gravitational effects of dark
matter structures. We study this effect  on pulsar timing through
Shapiro time delay (or Integrated Sachs-Wolfe (ISW) effect) and
Doppler effects statistically. For this task we relate the power
spectrum of pulsar frequency change to the matter power spectrum and
in order to obtain the matter power spectrum on small scales we used
the stable clustering hypothesis in phase space and investigate the
effect of the free parameters of the model on pulsar timing such as
minimum mass of sub halos, the the mean fraction of bound particles
that can survive the tidal disruption period and also the spectral
index of matter power spectrum. Finally, we compare the
dimensionless power spectrum for these effects with the accuracy of
current and future observations of pulsar timing designed for
gravitational wave(GW) detection. Our results show that while
current observations are unable to detect these signals, error
projections for upcoming Square Kilometer Array (SKA), are only a
factor of few higher than our optimistic predictions.

Wednesday / 11-August-2010 / 20-Mordad-1389/ 2:00 PM

School of Astronomy- Laarak
Address: Larak Garden, opposite Araj, Artesh Highway,Tehran, Iran
E-mail: astro(at)ipm.ir