The Fundamental Plane of Gamma-ray Globular Clusters

Abstract

We have investigated the properties of a group of $\gamma$-ray emitting globular clusters (GCs) which have recently been uncovered in our Galaxy. By correlating the observed $\gamma$-ray luminosities $L_{\gamma }$ with various cluster properties, we probe the origin of the high energy photons from these GCs. We report $L_{\gamma }$ is positively correlated with the encounter rate ${\Gamma }_c$ and the metalicity $\left[Fe/H\right]$ which place an intimate link between the gamma-ray emission and the millisecond pulsar population. We also find a tendency that $L_{\gamma }$ increase with the energy densities of the soft photon at the cluster location. Furthermore, the two-dimensional regression analysis suggests that $L_{\gamma }$, soft photon densities, and ${\Gamma }_c$/$\left[Fe/H\right]$ possibly span fundamental planes which potentially provide better predictions for the $\gamma$-ray properties of GCs.

17 pages, 4 figures, 3 tables, published in ApJ

References in corpus (3)

• Chandra X-Ray Observations of Nineteen Millisecond Pulsars in the Globular Cluster 47 Tucanae
• The Origin of Gamma-Rays from Globular Clusters
• Diffuse X-ray emission in globular cluster cores

Cited by in corpus (29)

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• Detection of gamma-ray emission from globular clusters M 15, NGC 6397, NGC 5904, NGC 6218 and NGC 6139 with Fermi-LAT
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• TeV gamma-ray emission initiated by the population or individual millisecond pulsars within globular clusters
• The X-ray Emissivity of Low-Density Stellar Populations
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• A Search for Diffuse X-ray Emission from GeV Detected Galactic Globular Clusters
• Deep observations of the globular cluster M15 with the MAGIC telescopes
• Chandra detection of a new diffuse X-ray component from the globular cluster 47 Tucanae
• Discovery of gamma-ray pulsations of PSR J1835$-$3259B in the Globular Cluster NGC 6652
• Numerical modelling of gamma-ray emission produced by electrons originating from the magnetospheres of millisecond pulsars in globular clusters
• High energy gamma-ray emission from compact galactic sources in the context of observations with the next generation Cherenkov Telescope Arrays
• Gamma-ray spectral properties of the Galactic globular clusters: constraint on the numbers of millisecond pulsars
• Gamma-ray emission from high Galactic latitude globular clusters
• Likely detection of gamma-ray pulsations of PSR~J1717+4308A in NGC~6341 and implication of the gamma-ray millisecond pulsars in globular clusters
• Searches for Pulsar-like Candidates from Unidentified Objects in the Third Catalog of Hard Fermi-LAT (3FHL) sources with Machine Learning Techniques
• Millisecond Pulsar Kicks Cause Difficulties in Explaining the Galactic Center Gamma-Ray Excess
• Stacking Star Clusters in M51: Searching for Faint X-Ray Binaries
• High energy emission from the nebula around the Black Widow binary system containing millisecond pulsar B1957+20
• How the dynamical properties of globular clusters impact their $\gamma$-ray and X-ray emission
• A Fermi-LAT Study of Globular Cluster Dynamical Evolution in the Milky Way: Millisecond Pulsars as the Probe
• A possible GeV-TeV connection in the direction of the Globular Cluster UKS 1
• Characterizing the Gamma-ray Emission Properties of the Globular Cluster M5 with the Fermi-LAT
• A deep Chandra study verifies diffuse non-thermal X-ray emission from the globular cluster Terzan 5