Contribution of young massive star clusters to Galactic diffuse $\gamma$-ray emission

Abstract

Context: Young massive stellar clusters (YMSCs) have emerged as potential $\gamma$-ray sources, after the recent association of a dozen YMSCs with extended $\gamma$-ray emission. The large size of the detected halos, comparable to that of the wind-blown bubble expected around YMSCs, makes the $\gamma$-ray detection of individual YMSCs rather challenging. As a result, the emission from most of the Galactic YMSCs could be unresolved, thus contributing to the diffuse $\gamma$-ray radiation observed along the Galactic Plane. Aims: In this study, we estimate the possible contribution to the Galactic diffuse $\gamma$-ray emission from a synthetic population of YMSCs, and we compare it with observations obtained with different experiments, from 1 GeV to hundreds of TeV, in two regions of the Galactic Plane. Methods: As the population of galactic YMSCs is only known locally, we evaluate the contribution of $\gamma$-ray emission relying on the simulation of synthetic populations of YMSCs based on the observed properties of local clusters. We compute the $\gamma$-ray emission from each cluster assuming that the radiation is purely hadronic in nature and produced by cosmic rays accelerated at the cluster's collective wind termination shock. Results: We find that the $\gamma$-ray emission from unresolved YMSCs can significantly contribute to the observed Galactic diffuse flux, especially in the inner part of the Galaxy, and that an important role is played by the power injected by Wolf-Rayet stellar winds. The predicted $\gamma$-ray flux should be considered as a lower limit, given that our calculation neglects the contribution of supernovae exploding in YMSCs.

arXiv commentAccepted for publication on A&A (20/01/2025)

References in corpus (47)

• On the variation of the Initial Mass Function
• Embedded Clusters in Molecular Clouds
• Fermi Large Area Telescope Fourth Source Catalog
• Toward Understanding Massive Star Formation
• Physical Properties of Wolf-Rayet Stars
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• Birth and Evolution of Isolated Radio Pulsars
• Diffuse continuum gamma rays from the Galaxy
• The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 Msun stellar mass limit
• Painting a portrait of the Galactic disc with its stellar clusters
• Planck Early Results: All sky temperature and dust optical depth from Planck and IRAS: Constraints on the "dark gas" in our galaxy
• Parametrization of gamma-ray production cross-sections for pp interactions in a broad proton energy range from the kinematic threshold to PeV energies
• The observed spiral structure of the Milky Way
• The First LHAASO Catalog of Gamma-Ray Sources
• Implications of the metallicity dependence of Wolf-Rayet winds
• Do O-stars form in isolation?
• Non-thermal high-energy emission from colliding winds of massive stars
• Measurement of ultra-high-energy diffuse gamma-ray emission of the Galactic plane from 10 TeV to 1 PeV with LHAASO-KM2A
• Particle acceleration in winds of star clusters
• Spatial distribution of Galactic Wolf-Rayet stars and implications for the global population
• Nuclear enhancement factor in calculation of Galactic diffuse gamma-rays: A new estimate with DPMJET-3
• Discovery of extended VHE γ-ray emission from the vicinity of the young massive stellar cluster Westerlund 1
• Kinematic Distances: A Monte Carlo Method
• HAWC observations of the acceleration of very-high-energy cosmic rays in the Cygnus Cocoon
• Diffuse Galactic gamma ray flux at very high energy
• Identification of the TeV Gamma-ray Source ARGO J2031+4157 with the Cygnus Cocoon
• Efficiently Cooled Stellar Wind Bubbles in Turbulent Clouds II. Validation of Theory with Hydrodynamic Simulations
• Study of the diffuse gamma-ray emission from the Galactic plane with ARGO-YBJ
• High-energy particles and radiation in star-forming regions
• An Ultrahigh-energy $\gamma$-ray Bubble Powered by a Super PeVatron
• Revisiting the Westerlund 2 Field with the H.E.S.S. Telescope Array
• Diffuse gamma-ray emission in the vicinity of young star cluster Westerlund 2
• Cosmic ray production in superbubbles
• Constraining the star formation rate in the Solar neighbourhood with star clusters
• Major structures of the inner Galaxy delineated by 6.7-GHz methanol masers
• The shape of the cosmic ray proton spectrum
• Ultraviolet Properties of Primeval Galaxies: Theoretical Models from Stellar Population Synthesis
• How Significant is Radiation Pressure in the Dynamics of the Gas Around Young Stellar Clusters?
• A deep spectromorphological study of the $\gamma$-ray emission surrounding the young massive stellar cluster Westerlund 1
• Detection of diffuse gamma-ray emission near the young massive cluster NGC 3603
• Galactic diffuse gamma-ray emission from GeV to PeV energies in light of up-to-date cosmic ray measurements
• The contribution of winds of star clusters to the Galactic cosmic-ray population
• Global survey of star clusters in the Milky Way VI. Age distribution and cluster formation history
• Gamma-ray observation towards the young massive star cluster NGC 6618 in the M17 region
• Multiple emission components in the Cygnus cocoon detected from Fermi-LAT observations
• Probing the galactic cosmic-ray density with current and future $\gamma$-ray instruments
• Mass and wind luminosity of young Galactic open clusters in Gaia DR2

Cited by in corpus (7)

• The Origin of the Very-High-Energy Diffuse $\gamma$-Ray Emission: The Case for Galactic Source Cocoons
• Hadronic acceleration in the young star cluster NGC 6611 inside the M16 region unveiled by Fermi-LAT: constraints on the acceleration efficiency
• Massive Star Clusters as sources of high-energy gamma radiation
• Exploring non-thermal emission from the star-forming region NGC 3603 through a realistic modelling of its environment
• How interacting winds shape the mechanical feedback of massive star clusters over millions of years
• Low-frequency spectra of neutron star + OB supergiant binaries: Does wind density drive persistent and flaring modes of accretion?
• Interpreting the LHAASO Galactic diffuse emission data