Characterizing the Gamma-Ray Emission Properties of the Globular Cluster M5 with the Fermi-LAT

X. Hou; W. Zhang; P. C. C. Freire; D. F. Torres; J. Ballet; D. A. Smith; T. J. Johnson; M. Kerr; C. C. Cheung; L. Guillemot; J. Li; L. Zhang; A. Ridolfi; P. Wang; D. Li; J. Yuan; N. Wang

doi:10.3847/1538-4357/ad3210

The Astrophysical Journal (Jan 2024)

Characterizing the Gamma-Ray Emission Properties of the Globular Cluster M5 with the Fermi-LAT

X. Hou,
W. Zhang,
P. C. C. Freire,
D. F. Torres,
J. Ballet,
D. A. Smith,
T. J. Johnson,
M. Kerr,
C. C. Cheung,
L. Guillemot,
J. Li,
L. Zhang,
A. Ridolfi,
P. Wang,
D. Li,
J. Yuan,
N. Wang

Affiliations

X. Hou: ORCiD; Yunnan Observatories, Chinese Academy of Sciences , Kunming 650216, People's Republic of China ; [email protected]; Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences , Kunming 650216, People's Republic of China; Center for Astronomical Mega-Science, Chinese Academy of Sciences , Beijing 100012, People's Republic of China
W. Zhang: ORCiD; Institute of Space Sciences (ICE, CSIC) , Campus UAB, 08193 Barcelona, Spain ; [email protected]; Institut d’Estudis Espacials de Catalunya (IEEC) , 08034 Barcelona, Spain
P. C. C. Freire: ORCiD; Max-Planck Institut für Radioastronomie , Auf dem Hügel 69, D-53121 Bonn, Germany
D. F. Torres: ORCiD; Institute of Space Sciences (ICE, CSIC) , Campus UAB, 08193 Barcelona, Spain ; [email protected]; Institut d’Estudis Espacials de Catalunya (IEEC) , 08034 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA) , E-08010 Barcelona, Spain
J. Ballet: ORCiD; Université Paris Saclay and Université Paris Cité , CEA, CNRS, AIM, F-91191 Gif-sur-Yvette, France
D. A. Smith: ORCiD; Laboratoire d’Astrophysique de Bordeaux, Université de Bordeaux , CNRS, B18N, allée Geoffroy Saint-Hilaire, F-33615 Pessac, France
T. J. Johnson: ORCiD; College of Science, George Mason University , Fairfax, VA 22030, resident at Naval Research Laboratory, Washington, DC 20375, USA
M. Kerr: ORCiD; Space Science Division, Naval Research Laboratory , Washington, DC 20375-5352, USA
C. C. Cheung: ORCiD; Space Science Division, Naval Research Laboratory , Washington, DC 20375-5352, USA
L. Guillemot: ORCiD; Laboratoire de Physique et Chimie de l’Environnement et de l’Espace—Université d’Orléans/CNRS , F-45071 Orléans Cedex 02, France; Station de radioastronomie de Nançay, Observatoire de Paris, CNRS/INSU , F-18330 Nançay, France
J. Li: ORCiD; CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China , Hefei 230026, People's Republic of China; School of Astronomy and Space Science, University of Science and Technology of China , Hefei 230026, People's Republic of China
L. Zhang: ORCiD; National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People's Republic of China; Centre for Astrophysics and Supercomputing, Swinburne University of Technology , P.O. Box 218, Hawthorn, VIC 3122, Australia
A. Ridolfi: ORCiD; Max-Planck Institut für Radioastronomie , Auf dem Hügel 69, D-53121 Bonn, Germany; INAF—Osservatorio Astronomico di Cagliari , Via della Scienza 5, I-09047 Selargius (CA), Italy
P. Wang: ORCiD; National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People's Republic of China; Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People's Republic of China
D. Li: ORCiD; National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People's Republic of China; University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100101, People's Republic of China; Zhijiang Lab , Hangzhou 311121, People's Republic of China
J. Yuan: ORCiD; Xinjiang Astronomical Observatory, Chinese Academy of Sciences , Urumqi, Xinjiang 830011, People's Republic of China
N. Wang: ORCiD; Xinjiang Astronomical Observatory, Chinese Academy of Sciences , Urumqi, Xinjiang 830011, People's Republic of China

DOI: https://doi.org/10.3847/1538-4357/ad3210
Journal volume & issue: Vol. 964, no. 2
p. 118

Abstract

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We analyzed the globular cluster M5 (NGC 5904) using 15 yr of gamma-ray data from the Fermi Large Area Telescope (LAT). Using rotation ephemerides generated from Arecibo and FAST radio telescope observations, we searched for gamma-ray pulsations from the seven millisecond pulsars (MSPs) identified in M5. We detected no significant pulsations from any of the individual pulsars. In addition, we searched for possible variations of the gamma-ray emission as a function of orbital phase for all six MSPs in binary systems, but we did not detect any significant modulations. The gamma-ray emission from the direction of M5 is well described by an exponentially cutoff power-law spectral model, although other models cannot be excluded. The phase-averaged emission is consistent with being steady on a timescale of a few months. We estimate the number of MSPs in M5 to be between 1 and 10, using the gamma-ray conversion efficiencies for well-characterized gamma-ray MSPs in the Third Fermi-LAT Catalog of Gamma-ray Pulsars, suggesting that the sample of known MSPs in M5 is (nearly) complete, even if it is not currently possible to rule out a diffuse component of the observed gamma rays from the cluster.

Published in The Astrophysical Journal

ISSN: 1538-4357 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Science: Astronomy: Astrophysics
Website: https://iopscience.iop.org/journal/0004-637X

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