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Globular clusters host large populations of millisecond pulsars (MSPs) due to their high gravitational encounter rates, producing many binary systems and thus MSPs via the recycling process. Seven pulsars with spin periods ranging from 3 ms…

High Energy Astrophysical Phenomena · Physics 2024-12-17 Justine Singleton , Megan DeCesar , Shi Dai , Deven Bhakta , Scott Ransom , Jay Strader , Laura Chomiuk , James Miller-Jones

The luminosity distribution of Galactic radio pulsars is believed to be log-normal in form. Applying this functional form to populations of pulsars in globular clusters, we employ Bayesian methods to explore constraints on the mean and…

Solar and Stellar Astrophysics · Physics 2015-06-11 Jayanth Chennamangalam , D. R. Lorimer , Ilya Mandel , Manjari Bagchi

We analyze deterministic and random temporal variations in dispersion measure (DM) from the full three-dimensional velocities of pulsars with respect to the solar system, combined with electron-density variations on a wide range of length…

High Energy Astrophysical Phenomena · Physics 2016-09-29 Michael T. Lam , James M. Cordes , Shami Chatterjee , Megan L. Jones , Maura A. McLaughlin , John W. Armstrong

Terzan 5 is the only Galactic globular cluster that has plausibly been detected at very-high energies by the High Energy Stereoscopic System. It has an unexpectedly asymmetric very-high-energy morphology that is offset from the cluster…

High Energy Astrophysical Phenomena · Physics 2019-07-31 Hambeleleni Ndiyavala , Christo Venter , Tyrel J. Johnson , Alice K. Harding , David A. Smith , Peter Eger , Andreas Kopp , Johan van Der walt

Terzan 5 is a stellar system located in the Galactic Bulge, at a distance of 5.9 kpc. Recent discoveries show that it hosts two stellar populations with different iron abundance ({\Delta}[Fe/H]=0.5). Such a large difference has been…

Astrophysics of Galaxies · Physics 2013-01-14 D. Massari , F. R. Ferraro , E. Dalessandro , B. Lanzoni , A. Mucciarelli , L. Origlia

We report on the follow-up observations of circularly polarized sources identified in the MeerKAT image-based survey of the Galactic bulge. Using the Parkes radio telescope, we observed sixteen circularly polarized sources with the UWL…

High Energy Astrophysical Phenomena · Physics 2026-03-17 Rahul Sengar , Akash Anumarlapudi , David L. Kaplan , Dale A. Frail , Scott D. Hyman , Emil Polisensky

Terzan 5 is a globular cluster-like stellar system in the Galactic Bulge which has been recently found to harbor two stellar populations with different iron content and probably different ages (Ferraro et al. 2009). This discovery suggests…

Up to November 2022, 267 pulsars have been discovered in 36 globular clusters (GCs). In this paper, we present our studies on the distribution of GC pulsar parameters and the detection efficiency. The power law relation between the average…

High Energy Astrophysical Phenomena · Physics 2023-03-20 De-Jiang Yin , Li-Yun Zhang , Bao-Da Li , Ming-Hui Li , Lei Qian , Zhichen Pan

We used near-infrared spectroscopy at medium-high resolution (R=8,000$-$25,000) to perform the first comprehensive chemical study of the intermediate luminosity bulge globular cluster Terzan~6. We derived detailed abundances and abundance…

Astrophysics of Galaxies · Physics 2024-06-12 C. Fanelli , L. Origlia , A. Mucciarelli , F. R. Ferraro , R. M. Rich , B. Lanzoni , D. Massari , C. Pallanca , E. Dalessandro , M. Loriga

We report here on the timing of 597 pulsars over the last four years with the MeerKAT telescope. We provide Times-of-Arrival, pulsar ephemeris files and per-epoch measurements of the flux density, dispersion measure (DM) and rotation…

High Energy Astrophysical Phenomena · Physics 2024-04-03 M. J. Keith , S. Johnston , A. Karastergiou , P. Weltevrede , M. E. Lower , A. Basu , B. Posselt , L. S. Oswald , A. Parthasarathy , A. D. Cameron , M. Serylak , S. Buchner

Recent radio surveys have revealed pulsars with dispersion and scattering delays induced by ionized gas that are larger than the rest of the observed pulsar population, in some cases with electron column densities (or dispersion measures;…

Astrophysics of Galaxies · Physics 2024-08-05 S. K. Ocker , L. D. Anderson , T. J. W. Lazio , J. M. Cordes , V. Ravi

We report the detection of ionized intracluster gas in the globular cluster 47 Tucanae. Pulsars in this cluster with a negative period derivative, which must lie in the distant half of the cluster, have significantly higher measured…

Astrophysics · Physics 2009-10-05 P. C. Freire , M. Kramer , A. G. Lyne , F. Camilo , R. N. Manchester , N. D'Amico

We present here the results from an extensive scintillation study of twenty pulsars in the dispersion measure (DM) range 3 - 35 pc cm^-3 caried out using the Ooty Radio Telescope (ORT) at 327 MHz, to investigate the distribution of ionized…

Astrophysics · Physics 2009-10-30 N. D. Ramesh Bhat , Yashwant Gupta , A. Pramesh Rao

Optical depth variations in the Galactic neutral interstellar medium (ISM) with spatial scales from hundreds to thousands of astronomical units have been observed through HI absorption against pulsars and continuum sources, while extremely…

Using three-dimensional non-equilibrium ionization (NEI) hydrodynamical simulation of the interstellar medium (ISM), we study the electron density, $n_{e}$, in the Galactic disk and compare it with the values derived from dispersion…

Astrophysics of Galaxies · Physics 2015-06-04 M. A. de Avillez , A. Asgekar , D. Breitschwerdt , E. Spitoni

Variations of dispersion measure (DM) have been observed in some binary pulsars, which can not be well explained by the propagation effects, such as turbulence of the interstellar media (ISM) between the Earth and the pulsar. This paper…

Astrophysics · Physics 2007-05-23 B. P. Gong

We report the discovery of gamma-ray emission from the Galactic globular cluster Terzan 5 using data taken with the Fermi Gamma-ray Space Telescope, from 2008 August 8 to 2010 January 1. Terzan 5 is clearly detected in the 0.5-20 GeV band…

High Energy Astrophysical Phenomena · Physics 2015-05-18 A. K. H. Kong , C. Y. Hui , K. S. Cheng

Using the NIRSPEC spectrograph at Keck II, we have obtained infrared echelle spectra covering the range $1.5-1.8 \mu \rm m$ for the highly reddened bulge globular clusters Terzan 4 and Terzan 5. The clusters are of interest because a blue…

Astrophysics · Physics 2009-11-10 Livia Origlia , R. Michael Rich

We report detections of scintillation arcs for pulsars in globular clusters M5, M13 and M15 for the first time using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). From observations of these arcs at multiple epochs, we…

Astrophysics of Galaxies · Physics 2023-08-14 Dandan Zhang , Zhenzhao Tao , Mao Yuan , Jumei Yao , Pei Wang , Qijun Zhi , Weiwei Zhu , Xun Shi , Michael Kramer , Di Li , Lei Zhang , Guangxing Li

The Parkes telescope has been monitoring 286 radio pulsars approximately monthly since 2007 at an observing frequency of 1.4 GHz. The wide dispersion measure (DM) range of the pulsar sample and the uniformity of the observing procedure make…

High Energy Astrophysical Phenomena · Physics 2021-01-06 H. Kumamoto , S. Dai , S. Johnston , M. Kerr , R. M. Shannon , P. Weltevrede , C. Sobey , R. N. Manchester , G. Hobbs , K. Takahashi