Constraining Dark matter annihilation with Dark Energy Survey Y3 LSBG sample

TL;DR

This paper uses the Dark Energy Survey Year 3 low-surface brightness galaxy sample to set new constraints on dark matter annihilation cross sections by cross-correlating galaxy positions with gamma-ray data, improving limits on particle properties.

Contribution

It applies a novel cross-correlation method to a large LSBG sample with unknown redshifts, providing updated constraints on dark matter annihilation rates.

Findings

Upper limit on annihilation cross section is 3×10^-25 cm^3/s at 100 GeV.

Removing galaxies near gamma-ray sources weakens constraints by 30%.

Method demonstrates effectiveness with large, redshift-uncertain galaxy samples.

Abstract

To reveal natures of the dark matter (DM) particles, a gamma-ray signal produced in annihilation processes of DM into the standard model particles has been one of the major probes. The cross-correlation between highly DM dominated structures, such as local dwarf galaxies, and observed photons in the direction of the structures, has been explored and provided stringent constraints on the annihilation rate. In our previous work, we have shown that it is sufficient to know the distance distribution of the galaxy sample and individual distance measurement is not required for constraining the annihilation rate. In this work, we apply the method to low-surface brightness galaxies (LSBGs) with unknown individual redshifts provided from the Dark Energy Survey (DES) Year 3 data. With all DES-LSBGs of about 24,000 objects, we find that the upper limits of the cross section for bb channel with 95% C.L. is 3*10^-25 cm^3/s at DM mass of 100 GeV. To be more conservative, we remove about 7000 LSBGs within 1 degree from resolved gamma-ray point sources and then the constraint becomes 30 % weaker than the one with all samples in all DM mass ranges.