Three Pulsars Discovered by FAST in the Globular Cluster NGC 6517 with a Pulsar Candidate Sifting Code Based on Dispersion Measure to Signal-to-Noise Ratio Plots

Abstract

We report the discovery of three new pulsars in the Globular Cluster (GC) NGC6517, namely NGC 6517 E, F, and G, made with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The spin periods of NGC 6517 E, F, and G are 7.60~ms, 24.89~ms, and 51.59~ms, respectively. Their dispersion measures are 183.29, 183.713, and 185.3~pc~cm${}^{-3}$, respectively, all slightly larger than those of the previously known pulsars in this cluster. The spin period derivatives are at the level of 1$\times$10${}^{-18}$~s~s${}^{-1}$, which suggests these are recycled pulsars. In addition to the discovery of these three new pulsars, we updated the timing solutions of the known isolated pulsars, NGC 6517 A, C, and D. The solutions are consistent with those from Lynch et al. (2011) and with smaller timing residuals. From the timing solution, NGC 6517 A, B (position from Lynch et al. 2011), C, E, and F are very close to each other on the sky and only a few arcseconds from the optical core of NGC 6517. With currently published and unpublished discoveries, NGC6517 now has 9 pulsars, ranking 5${}^{th}$ of the GCs with the most pulsars. The discoveries take advantage of the high sensitivity of FAST and a new algorithm used to check and filter possible candidate signals.

10 pages, 3 figure, 2 tables, accepted by RAA, comments are always welcomed!

References in corpus (4)

• The Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) Project
• A 1.4-GHz Arecibo Survey for Pulsars in Globular Clusters
• Six New Recycled Globular Cluster Pulsars Discovered with the Green Bank Telescope
• Constraining the luminosity function parameters and population size of radio pulsars in globular clusters

Cited by in corpus (12)

• Dark photon superradiance: Electrodynamics and multimessenger signals
• TRAPUM discovery of thirteen new pulsars in NGC 1851 using MeerKAT
• A Census of X-ray Millisecond Pulsars in Globular Clusters
• FAST Discovery of Eight Isolated Millisecond Pulsars in NGC 6517
• Gamma-ray spectral properties of the Galactic globular clusters: constraint on the numbers of millisecond pulsars
• The FAST Globular Cluster Pulsar Survey (GC FANS)
• Timing of millisecond pulsars in NGC\,6752 -- III. On the presence of non-luminous matter in the cluster's core
• FAST Observations of Four Comets to Search for the Molecular Line Emissions between 1.0 and 1.5 GHz Frequencies
• The FAST Discovery of a Millisecond Pulsar M15O (PSR J2129+1210O) Hidden in the Harmonics of M15A (PSR J2129+1210A)
• Radio pulse search from Aql X-1
• Illuminating Hidden Pulsars: Scintillation-Enhanced Discovery of Two Binary Millisecond Pulsars in M13 with FAST
• FAST Observation and Results for Core Collapse Globular Cluster M15 and NGC 6517