What Millisecond Pulsars Can Tell Us About Matter In The Galaxy

TL;DR

Precision timing of millisecond pulsars can detect gravitational effects of galactic substructure, providing a novel method to probe dark matter and baryonic matter distributions within our galaxy.

Contribution

This paper introduces a new approach using pulsar timing to detect and analyze the gravitational influence of various forms of galactic substructure, including dark matter and baryonic objects.

Findings

Pulsar timing can reveal signatures of intervening galactic matter.

Observable signals of substructure are characterized and templates provided.

Potential to distinguish different types of dark matter and baryonic objects.

Abstract

I demonstrate that precision timing of millisecond pulsars possess the capabilities of detecting the gravitational effects of intervening galactic substructure. This analysis is applicable to all types of collapsed baryons including stars, planets, and MACHOs, as well as many types of dark matter, including primordial black holes, scalar miniclusters, and sufficiently dense clumps of cold dark matter. The physical signal is quantified and decomposed into observable and unobservable components; templates for the observable signals are also presented. Additionally, I calculate the expected changes in the observed period and period derivatives that will result from intervening matter. I find that pulsar timing is potentially a very useful tool for probing the nature of dark matter and to learn more about the substructure present within our galaxy.