Constraining ultralight dark matter using the Fermi-LAT pulsar timing array

TL;DR

This study uses gamma-ray pulsar timing data from Fermi-LAT to search for ultralight dark matter effects, setting new constraints and demonstrating the method's potential for dark matter detection.

Contribution

First application of gamma-ray pulsar timing array data to constrain ultralight dark matter models, complementing radio PTA and direct detection efforts.

Findings

No significant ULDM signals detected.

Constraints on ULDM parameters at 95% confidence level.

Gamma-ray PTA offers a complementary approach to radio PTA for ULDM searches.

Abstract

Ultralight dark matter (ULDM) is proposed as a theoretical candidate of dark matter particles with masses of approximately $10^{-22}$ eV. The interactions between ULDM particles and standard model particles would cause variations in pulse arrival times of millisecond pulsars, which means that the pulsar timing array (PTA) can be used to indirectly detect ULDM. In this letter, we use the gamma-ray PTA composed of 29 millisecond pulsars observed by the Fermi Large Area Telescope (Fermi-LAT) to test four ULDM effects, including gravitational effects for generalized ULDM with different Spin-0/1, the fifth-force coupling effect of dark photon, and the modified gravitational effect of the Spin-2 ULDM. The gamma-ray pulsar timing is not affected by the ionized interstellar medium and suffers relatively simple noises, unlike that of the radio band. Our work is the first time that the gamma-ray PTA has been used to search for the ULDM. No significant signals of ULDM are found based on the Fermi-LAT PTA for all four kinds of ULDM models. Constraints on ULDM parameters are set with the 95% confidence level, which provides a complementary check of the nondetection of ULDM for radio PTAs and direct detection experiments.