A Search for Annihilating Dark Matter in 47 Tucanae and Omega Centauri

Abstract

A plausible formation scenario for the Galactic globular clusters 47 Tuc and Omega Cen is that they are tidally stripped remnants of dwarf galaxies, in which case they are likely to have retained a fraction of their dark matter cores. In this study, we have used the ultra-wide band receiver on the Parkes telescope (Murriyang) to place upper limits on the annihilation rate of exotic Light Dark Matter particles (X) via the XX/$e^{+}{e}^{-}$ channel using measurements of the recombination rate of positronium (Ps). This is an extension of a technique previously used to search for Ps in the Galactic Centre. However, by stacking of spectral data at multiple line frequencies, we have been able to improve sensitivity. Our measurements have resulted in 3-sigma flux density (recombination rate) upper limits of 1.7 mJy (1.4x10${}^{43}$ s${}^{-1}$) and 0.8 mJy (1.1x10${}^{43}$ s${}^{-1}$) for 47 Tuc and Omega Cen, respectively. Within the Parkes beam at the cluster distances, which varies from 10 to 23 pc depending on the frequency of the recombination line, we calculate upper limits to the dark matter mass and rms dark matter density of <1.2-1.3x10${}^5$ fn${}^{-0.5}$ (mX/MeV c${}^{-2}$) solar masses and <48-54 fn${}^{-0.5}$ (mX/MeV c${}^{-2}$) solar masses pc${}^{-3}$ for the clusters, where fn=Rn/Rp is the ratio of Ps recombination transitions to annihilations, estimated to be 0.01. The radio limits for Omega Cen suggest that, for a fiducial dark/luminous mass ratio of 0.05, any contribution from Light Dark Matter is small unless the cross section <7.9x10${}^{-28}$ (mX/MeV c${}^{-2}$)${}^2$ cm${}^3$ s${}^{-1}$. Owing to the compactness and proximity of the clusters, archival 511-keV measurements suggest even tighter limits than permitted by CMB anisotropies, <8.6x10${}^{-31}$ (mX/MeV c${}^{-2}$)${}^2$ cm${}^3$ s${}^{-1}$. Our recombination rate limits substantially improve on previous radio limits for the Milky Way.

arXiv comment11 pages, 4 figures, 3 tables; accepted by Publications of the Astronomical Society of Australia 2 May 2022; abbreviated arXiv abstract; minor corrections to match proofs; CUP open source publication

References in corpus (64)

• The Structure of Cold Dark Matter Halos
• Supersymmetric Dark Matter
• Ultralight scalars as cosmological dark matter
• A History of Dark Matter
• Is the Lightest Kaluza-Klein Particle a Viable Dark Matter Candidate?
• Observability of Gamma Rays from Dark Matter Neutralino Annihilations in the Milky Way Halo
• Microlensing constraints on primordial black holes with the Subaru/HSC Andromeda observation
• Dark and luminous matter in THINGS dwarf galaxies
• Light Dark Matter: Models and Constraints
• The SIMPlest Miracle
• The all-sky distribution of 511 keV electron-positron annihilation emission
• Constraining Light Dark Matter with Diffuse X-Ray and Gamma-Ray Observations
• A review of indirect searches for particle dark matter
• Multi-frequency analysis of neutralino dark matter annihilations in the Coma cluster
• Indirect Dark Matter Signatures in the Cosmic Dark Ages II. Ionization, Heating and Photon Production from Arbitrary Energy Injections
• Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects
• Light and Heavy Dark Matter Particles
• Enrichment by supernovae in globular clusters with multiple populations
• The origin of the double main sequence in Omega Centauri: Helium enrichment due to gas fueling from its ancient host galaxy ?
• Gamma-ray spectroscopy of Positron Annihilation in the Milky Way
• Detection of HI in distant galaxies using spectral stacking
• Long-term observations of the pulsars in 47 Tucanae - II. Proper motions, accelerations and jerks
• Baryon-induced dark matter cores in the EAGLE simulations
• Novel cosmic-ray electron and positron constraints on MeV dark matter particles
• A realistic assessment of the CTA sensitivity to dark matter annihilation
• The lives and deaths of positrons in the interstellar medium
• Simple J-Factors and D-Factors for Indirect Dark Matter Detection
• A pulsational distance to Omega Centauri based on Near-Infrared Period-Luminosity relations of RR Lyrae stars
• Prospects for indirect dark matter searches with MeV photons
• On The Gamma-Ray Emission From Reticulum II and Other Dwarf Galaxies
• Signatures of MRI-Driven Turbulence in Protoplanetary Disks: Predictions for ALMA Observations
• Axion-photon conversion in strongly magnetised plasmas
• Distances to the globular clusters 47 Tucanae and NGC 362 using Gaia DR2 parallaxes
• Radio constraints on dark matter annihilation in the galactic halo and its substructures
• Testing Newtonian Gravity with AAOmega: Mass-To-Light Profiles and Metallicity Calibrations From 47 Tuc and M55
• Dark matter in the Reticulum II dSph: a radio search
• MeV Dark Matter Complementarity and the Dark Photon Portal
• Search for 511 keV Emission in Satellite Galaxies of the Milky Way with INTEGRAL/SPI
• Mass estimates from stellar proper motions: The mass of $\omega$ Centauri
• Stellar envelopes of globular clusters embedded in dark mini-haloes
• Chandra studies of the globular cluster 47 Tucanae: A deeper X-ray source catalogue, five new X-ray counterparts to millisecond radio pulsars, and new constraints to r-mode instability window
• A Deep X-ray Survey of the Globular Cluster Omega Centauri
• Revisiting CMB constraints on dark matter annihilation
• Understanding hydrogen recombination line observations with ALMA and EVLA
• Synchrotron Emission from Dark Matter Annihilation: Predictions for Constraints from Non-detections of Galaxy Clusters with New Radio Surveys
• Positron Annihilation on Polycyclic Aromatic Hydrocarbon molecules in the Interstellar Medium
• Discovery of Millisecond Pulsars in the Globular Cluster Omega Centauri
• Spherical models of star clusters with potential escapers
• A Radio Astronomy Search for Cold Dark Matter Axions
• Reticulum II: Particle Dark Matter and Primordial Black Holes Limits
• Deep HST Imaging in 47 Tucanae: A Global Dynamical Model
• Dark and luminous mass components of Omega Centauri with stellar kinematics
• Annihilating Dark Matter Search with 12 Years of Fermi LAT Data in Nearby Galaxy Clusters
• Detecting Axion Dark Matter through the Radio Signal from Omega Centauri
• Learning credit assignment
• Simulations of globular clusters within their parent galaxies: multiple stellar populations and internal kinematics
• The first detection of radio recombination lines at cosmological distances
• Large-Scale Tides in General Relativity
• The orbital evolution of UFDs and GCs in an evolving Galactic potential
• Sensitivity of SKA to dark matter induced radio emission
• On the origin of the gamma-ray emission from Omega Centauri: Milisecond pulsars and dark matter annihilation
• Stringent constraint on the radio signal from dark matter annihilation in dwarf spheroidal galaxies using the TGSS
• Formation of massive globular clusters with dark matter and its implication on dark matter annihilation
• What Could be the Observational Signature of Dark Matter in Globular Clusters?

Cited by in corpus (2)

• Timing of Pulsars in the Globular Cluster Omega Centauri
• SKA sensitivity for possible radio emission from dark matter in Omega Centauri