Dark matter line emission constraints from NuSTAR observations of the Bullet Cluster

TL;DR

This study uses NuSTAR observations of the Bullet Cluster to search for dark matter line emissions in the 3-80 keV range, setting upper limits and constraining sterile neutrino models, but does not detect any significant lines.

Contribution

First search for dark matter line emission in the 3-80 keV range using NuSTAR observations of the Bullet Cluster, providing new constraints on dark matter candidates.

Findings

No significant line emission detected.

Upper limits set on flux at 95% confidence level.

Constraints improve on previous limits for 10-25 keV energies.

Abstract

Line emission from dark matter is well motivated for some candidates e.g. sterile neutrinos. We present the first search for dark matter line emission in the 3-80keV range in a pointed observation of the Bullet Cluster with NuSTAR. We do not detect any significant line emission and instead we derive upper limits (95% CL) on the flux, and interpret these constraints in the context of sterile neutrinos and more generic dark matter candidates. NuSTAR does not have the sensitivity to constrain the recently claimed line detection at 3.5keV, but improves on the constraints for energies of 10-25keV.