Enhanced exploration for primordial black holes using pulsar timing arrays

TL;DR

This paper explores how pulsar timing arrays can detect primordial black holes, especially heavier ones, by analyzing timing residuals, with future facilities like SKA potentially identifying PBHs constituting a small fraction of dark matter.

Contribution

It demonstrates the complementary effectiveness of pulsar timing arrays in detecting heavier primordial black holes and assesses future detection prospects with SKA.

Findings

PTAs are effective for detecting heavier PBHs than Earth-based probes.

Future SKA observations could identify PBHs with masses around 10^{22-28} g.

Detection is possible even if PBHs make up less than 1% of dark matter.

Abstract

We investigate the capability of pulsar timing arrays (PTAs) as a probe of primordial black holes (PBHs), which might constitute the Galactic dark matter. A PBH passing nearby the Earth or a pulsar gives an impulse acceleration and induces residuals on otherwise orderly pulsar timing data. We show that the timing residuals induced at pulsars are optimal for searching heavier PBHs than those at the Earth, and the two probes are highly complemental. Future facilities like SKA could detect PBHs with masses around 10^(22-28) g even if only a small fraction (< 1%) of the Galactic dark matter consists of these PBHs.