Likely detection of gamma-ray pulsations of PSR~J1717+4308A in NGC~6341 and implication of the gamma-ray millisecond pulsars in globular clusters

Abstract

We report our analysis results for the globular cluster (GC) NGC~6341 (M92), as a millisecond pulsar (MSP) J1717$+$4308A has recently been reported found in this GC. The data used are from the Large Area Telescope onboard the {\it Fermi Gamma-ray Space Telescope (Fermi)}. We detect $\gamma$-ray pulsations of the MSP at a $4.4\sigma$ confidence level (the corresponding weighted H-test value is $\sim$28.4). This MSP, the fourth $\gamma$-ray pulsar found in a GC, does not have significant off-pulse emission and has $\gamma$-ray luminosity and efficiency $1.3\times 10^{34}$\,erg\,s${}^{-1}$ and 1.7\% respectively. In order to have a clear view on the properties of the known GC $\gamma$-ray MSPs, we re-analyze the \fermi\ LAT data for the other three ones. These four MSPs share the properties of either having high $\dot{E}$ ($\sim 10^{36}$\,erg\,s${}^{-1}$) or being in the GCs that contain only limited numbers of known MSPs. In addition, we find that PSRs~J1823$-$3021A and B1821$-$24, in NGC~6624 and NGC~6626 respectively, have detectable off-pulse $\gamma$-ray emission and PSR J1835$-$3259B in NGC~6652 does not. Using the obtained off-pulse spectra or spectral upper limits, we constrain the numbers of other MSPs in the four GCs. The results are consistent with the numbers of the radio pulsars reported in them. While at least in NGC~6624 and NGC~6626, the contribution of other MSPs to their observed $\gamma$-ray emission can not be ignored, our study indicates that the presence of a bright MSP could be the dominant factor for whether a GC is detectable at $\gamma$-rays or not.

arXiv comment13 pages, 10 figures, 5 tables, appearing in ApJ; minor typos corrected

References in corpus (35)

• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• Fermi Large Area Telescope Fourth Source Catalog
• The Second Fermi Large Area Telescope Catalog of Gamma-ray Pulsars
• Incremental Fermi Large Area Telescope Fourth Source Catalog
• The Ages of 55 Globular Clusters as Determined Using an Improved delta V_TO^HB Method Along with Color-Magnitude Diagram Constraints, and Their Implications for Broader Issues
• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• Fermi Large Area Telescope Observations of the Crab Pulsar and Nebula
• Precise Gamma-Ray Timing and Radio Observations of 17 Fermi Gamma-Ray Pulsars
• A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope
• Improving Sensitivity to Weak Pulsations with Photon Probability Weighting
• Long-term observations of the pulsars in 47 Tucanae - II. Proper motions, accelerations and jerks
• FAST Globular Cluster Pulsar Survey: Twenty-Four Pulsars Discovered in Fifteen Globular Clusters
• Fermi Detection of a Luminous Gamma-ray Pulsar in a Globular Cluster
• Long-term observations of the pulsars in 47 Tucanae. I. A study of four elusive binary systems
• Broadband Pulsations from PSR B1821-24: Implications for Emission Models and the Pulsar Population of M28
• Fermi Discovery of Gamma-ray Emission from the Globular Cluster Terzan 5
• Gamma-ray emission from the globular clusters Liller 1, M80, NGC 6139, NGC 6541, NGC 6624, and NGC 6752
• Ages of the Bulge globular clusters NGC 6522 and NGC 6626 (M28) from HST Proper-motion-cleaned Color-Magnitude Diagrams
• A Highly Eccentric 3.9-Millisecond Binary Pulsar in the Globular Cluster NGC 6652
• The Fundamental Plane of Gamma-ray Globular Clusters
• The FAST discovery of an Eclipsing Binary Millisecond Pulsar in the Globular Cluster M92 (NGC 6341)
• Four pulsar discoveries in NGC 6624 by TRAPUM using MeerKAT
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XX. Ages of single and multiple stellar populations in seven bulge globular clusters
• Evidence for a high-energy tail in the gamma-ray spectra of globular clusters
• Search for pulsed gamma-ray emission from globular cluster M28
• Detection of gamma-ray emission from globular clusters M 15, NGC 6397, NGC 5904, NGC 6218 and NGC 6139 with Fermi-LAT
• Upgraded GMRT survey for pulsars in globular clusters. I: Discovery of a millisecond binary pulsar in NGC 6652
• Milky Way globular clusters in gamma-rays: analyzing the dynamical formation of millisecond pulsars
• Gamma-ray emission from globular clusters
• Two New Black Widow Millisecond Pulsars In M28
• A Search for Diffuse X-ray Emission from GeV Detected Galactic Globular Clusters
• Discovery of gamma-ray pulsations of PSR J1835$-$3259B in the Globular Cluster NGC 6652
• Gamma-ray spectral properties of the Galactic globular clusters: constraint on the numbers of millisecond pulsars
• Gamma-ray emission from globular clusters 2MS-GC01, IC 1257, NGC5904, NGC6656 and FSR1735
• A gamma-ray periodic modulation in Globular Cluster 47 Tucanae

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