Millisecond pulsar origin of the Galactic center excess and extended gamma-ray emission from Andromeda - a closer look

Abstract

A new measurement of a spatially extended gamma-ray signal from the center of the Andromeda galaxy (M31) has been recently published by the Fermi-LAT collaboration, reporting that the emission broadly resembles the so-called Galactic center excess (GCE) of the Milky Way (MW). At the same time, evidence is accumulating on a millisecond pulsar (MSPs) origin for the GCE. These elements prompt us to compare the mentioned observations with what is, perhaps, the simplest model for an MSP population, solely obtained by rescaling of the MSP luminosity function determined in the local MW disk via the respective stellar mass of the systems. It is remarkable that without free fitting parameters, this model can account for both the energetics and the morphology of the GCE within uncertainties. For M31, the estimated luminosity due to primordial MSPs is expected to contribute only about a quarter of the detected emission, although a dominant contribution cannot be excluded given the large uncertainties. If correct, the model predicts that the M31 disk emission due to MSP is not far below the present upper bound. We also discuss a few refinements of this simple model. In particular, we use the correlation between globular cluster gamma-ray luminosity and stellar encounter rate to gauge the dynamical MSP formation in the bulge. This component is expected to contribute to the GCE only at a level $\lesssim 5\%$, but it may be of some importance in explaining the signal's morphology in the inner region of the Galaxy. We also comment on some effects which may lead to violations of the simple scaling used, on alternative models, and on future perspectives for improved diagnostics.

arXiv comment12 pages, 5 figures, accepted for publication in ApJ

References in corpus (72)

• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• Fermi-LAT Observations of the Diffuse Gamma-Ray Emission: Implications for Cosmic Rays and the Interstellar Medium
• Pulsars as the Sources of High Energy Cosmic Ray Positrons
• The Characterization of the Gamma-Ray Signal from the Central Milky Way: A Compelling Case for Annihilating Dark Matter
• Improved Estimates of the Milky Way's Stellar Mass and Star Formation Rate from Hierarchical Bayesian Meta-Analysis
• Detection of a Gamma-Ray Source in the Galactic Center Consistent with Extended Emission from Dark Matter Annihilation and Concentrated Astrophysical Emission
• The Nuclear Bulge of the Galaxy. III. Large-Scale Physical Characteristics of Stars and Interstellar Matter
• Background model systematics for the Fermi GeV excess
• The Fermi Galactic Center GeV Excess and Implications for Dark Matter
• Fermi-LAT Observations of High-Energy Gamma-Ray Emission Toward the Galactic Center
• The Pulsar Kick Velocity Distribution
• GeV Observations of Star-forming Galaxies with \textit{Fermi} LAT
• Dynamical modelling of the Galactic bulge and bar: the Milky Way's bar pattern speed, stellar, and dark matter mass distribution
• Low mass X-ray binaries as a stellar mass indicator for the host galaxy
• Strong support for the millisecond pulsar origin of the Galactic center GeV excess
• Constraints on cosmic-ray propagation models from a global Bayesian analysis
• The Spectrum and Morphology of the Fermi Bubbles
• A Tale of Tails: Dark Matter Interpretations of the Fermi GeV Excess in Light of Background Model Systematics
• Evidence for Unresolved Gamma-Ray Point Sources in the Inner Galaxy
• X-ray Binary Evolution Across Cosmic Time
• The Milky Way's Stellar Disk
• Dark matter and visible baryons in M33
• The long bar as seen by the VVV survey: I. Colour-magnitude diagrams
• Stellar mass map and dark matter distribution in M31
• Surface Brightness Profile of the Milky Way's Nuclear Star Cluster
• The old nuclear star cluster in the Milky Way: dynamics, mass, statistical parallax, and black hole mass
• The Luminosity Profile and Structural Parameters of the Andromeda Galaxy
• Co-Evolution of Galactic Nuclei and Globular Cluster Systems
• Masses and Scaling Relations for Nuclear Star Clusters, and their Coexistence with Central Black Holes
• Neutron Star Population Dynamics.I: Millisecond Pulsars
• Cosmic Ray Protons in the Inner Galaxy and the Galactic Center Gamma-Ray Excess
• A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope
• Pulsars Cannot Account for the Inner Galaxy's GeV Excess
• Binary and Millisecond Pulsars
• Disrupted Globular Clusters Can Explain the Galactic Center Gamma Ray Excess
• The heating of dust by old stellar populations in the Bulge of M31
• Galactic Center gamma-ray "excess" from an active past of the Galactic Centre?
• Millisecond pulsars and the Galactic Center gamma-ray excess: the importance of luminosity function and secondary emission
• A New Photometric Model of the Galactic Bar using Red Clump Giants
• The Gaia-ESO Survey: radial distribution of abundances in the Galactic disc from open clusters and young field stars
• Fermi Large Area Telescope observations of Local Group galaxies: Detection of M31 and search for M33
• First AGILE Catalog of High Confidence Gamma-Ray Sources
• High-Energy Gamma Rays from the Milky Way: Three-Dimensional Spatial Models for the Cosmic-Ray and Radiation Field Densities in the Interstellar Medium
• Stellar Encounter Rate in Galactic Globular Clusters
• Observations of M31 and M33 with the Fermi Large Area Telescope: a galactic center excess in Andromeda?
• Herschel Exploitation of Local Galaxy Andromeda (HELGA) III: The Star Formation Law in M31
• Millisecond pulsar interpretation of the Galactic center gamma-ray excess
• A common solution to the cosmic ray anisotropy and gradient problems
• Dark matter vs. Pulsars: Catching the impostor
• Eccentric-disk models for the nucleus of M31
• Dynamical Formation of Millisecond Pulsars in Globular Clusters
• Disk-Bulge-Halo Models for the Andromeda Galaxy
• The High-Energy Tail of the Galactic Center Gamma-Ray Excess
• The Gamma-Ray Luminosity Function of Millisecond Pulsars and Implications for the GeV Excess
• Towards a realistic astrophysical interpretation of the gamma-ray Galactic center excess
• The Gamma-Ray Pulsar Population of Globular Clusters: Implications for the GeV Excess
• The dynamical formation of LMXBs in dense stellar environments: globular clusters and the inner bulge of M31
• Low Mass X-Ray Binaries in the Inner Galaxy: Implications for Millisecond Pulsars and the GeV Excess
• Testing the millisecond pulsar scenario of the Galactic center gamma-ray excess with very high energy gamma-rays
• Consistency Between the Luminosity Function of Resolved Millisecond Pulsars and the Galactic Center Excess
• The outer rotation curve of the Milky Way
• Cosmic-ray positrons from millisecond pulsars
• Galactic dark matter search via phenomenological astrophysics modeling
• Gamma-ray and X-ray emission from the Galactic Centre: hints on the nuclear star cluster formation history
• Disrupted Globular Clusters and the Gamma-Ray Excess in the Galactic Centre
• Putting Things Back Where They Belong: Tracing Cosmic-Ray Injection with H2
• The Fundamental Plane of Gamma-ray Globular Clusters
• Estimating the GeV Emission of Millisecond Pulsars in Dwarf Spheroidal Galaxies
• Probing the formation history of the nuclear star cluster at the Galactic Centre with millisecond pulsars
• Population synthesis of classical low-mass X-ray binaries in the Galactic Bulge
• The Contribution of Millisecond Pulsars to the Galactic Cosmic-Ray Lepton Spectrum

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• Search for $\gamma$-ray emission from dark matter particle interactions from Andromeda and Triangulum Galaxies with the Fermi Large Area Telescope
• Gamma-ray emission from the Sagittarius Dwarf Spheroidal galaxy due to millisecond pulsars
• Exploring A Cosmic-Ray Origin of the Multi-wavelength Emission in M31
• Millisecond Pulsars Modify the Radio-SFR Correlation in Quiescent Galaxies
• TeV Dark Matter Searches in the Extragalactic Gamma-Ray Sky
• Millisecond pulsars and the gamma-ray excess in Andromeda
• Inverse Compton emission from millisecond pulsars in the Galactic bulge
• Probing the Fermi-LAT GeV excess with gravitational waves
• Massive White Dwarfs in the Galactic Center: A Chandra X-ray Spectroscopy of Cataclysmic Variables
• Gamma-ray image reconstruction of the Andromeda galaxy
• Mind the gap: The discrepancy between simulation and reality drives interpretations of the Galactic Center Excess
• The Andromeda Gamma-Ray Excess: Background Systematics of the Millisecond Pulsars and Dark Matter Interpretations
• Searching for GeV gamma-ray emission from the bulge of M31
• Measuring the Mass of Missing Baryons in the Halo of Andromeda Galaxy with Gamma-Ray Observations
• Cosmic-ray transport and gamma-ray emission in M31
• Relativistic scattering of a fast spinning neutron star by a massive black hole
• On the Gamma-Ray Emission of the Andromeda Galaxy M31
• Millisecond Pulsar Kicks Cause Difficulties in Explaining the Galactic Center Gamma-Ray Excess
• CONGRuENTS (COsmic-ray, Neutrino, Gamma-ray and Radio Non-Thermal Spectra). I. A predictive model for galactic non-thermal emission
• The effect of kick velocities on the spatial distribution of millisecond pulsars and implications for the Galactic center excess
• Molecular ionization rates and ultracompact dark matter minihalos
• On the Gravitational Wave Counterpart to a Gamma-ray Galactic Center Signal from Millisecond Pulsars
• Prospects for annihilating dark matter from M31 and M33 observations with the Cherenkov Telescope Array
• A Fermi-LAT Study of Globular Cluster Dynamical Evolution in the Milky Way: Millisecond Pulsars as the Probe
• The contribution to Galactic Centre γ-ray excess from cluster-born millisecond pulsars. Constraints from direct N-body simulations
• Hunting Star-Forming Galaxies in the Gamma-Ray Domain