Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Illuminating Hidden Pulsars: Scintillation-Enhanced Discovery of Two Binary Millisecond Pulsars in M13 with FAST

Dejiang Yin, Lin Wang, Li-yun Zhang, Lei Qian, Baoda Li, Kuo Liu, Bo Peng, Yinfeng Dai, Yaowei Li, Zhichen Pan

TL;DR

This study uses 84 FAST observations of the globular cluster M13 and Fourier-domain acceleration searches with overlapping segmentation to reveal two binary millisecond pulsars, M13G and M13H, that were previously undetected due to scintillation and high orbital acceleration. M13G yields a phase-connected timing solution spanning $6.4$ years and is classified as a black widow with $P_b=0.12$ d and a very low-mass companion $M_c o 9.9 imes10^{-3} M_f$; M13H shows strong apparent acceleration but could not be timing-solved due to limited detections. The results underscore the role of interstellar scintillation and acceleration in GC pulsar detectability and suggest a potentially larger hidden MSP population in M13, highlighting the need for advanced search techniques and multi-epoch monitoring. Overall, the work demonstrates that scintillation-enhanced observations with FAST can uncover faint, dynamically interesting pulsars in globular clusters, with implications for cluster dynamics and binary evolution.

Abstract

We conducted a sensitive acceleration search using Fast Fourier Transform (FFT) techniques on full-length and segmented data from 84 observations of the globular cluster M13 with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Employing a low detection threshold (2 $σ$) to maximize sensitivity to faint pulsars, here we report the discovery of two binary millisecond pulsars: J1641+3627G (M13G) and J1641+3627H (M13H). Both pulsars were detected during scintillation-brightened states, revealing systems that would otherwise remain undetected. For M13G, we obtained a phase-connected timing solution spanning 6.4 years, identifying it as a black widow system with an orbital period of 0.12 days hosting an extremely low-mass companion ($\sim 9.9\times 10^{-3}~{ M}_\odot$), though no eclipses were observed. M13H, however, shows significant apparent acceleration but was detected in only 2 of 84 observations; its extremely low detection rate currently prevents constraints on orbital parameters or classification.

Illuminating Hidden Pulsars: Scintillation-Enhanced Discovery of Two Binary Millisecond Pulsars in M13 with FAST

TL;DR

This study uses 84 FAST observations of the globular cluster M13 and Fourier-domain acceleration searches with overlapping segmentation to reveal two binary millisecond pulsars, M13G and M13H, that were previously undetected due to scintillation and high orbital acceleration. M13G yields a phase-connected timing solution spanning years and is classified as a black widow with d and a very low-mass companion ; M13H shows strong apparent acceleration but could not be timing-solved due to limited detections. The results underscore the role of interstellar scintillation and acceleration in GC pulsar detectability and suggest a potentially larger hidden MSP population in M13, highlighting the need for advanced search techniques and multi-epoch monitoring. Overall, the work demonstrates that scintillation-enhanced observations with FAST can uncover faint, dynamically interesting pulsars in globular clusters, with implications for cluster dynamics and binary evolution.

Abstract

We conducted a sensitive acceleration search using Fast Fourier Transform (FFT) techniques on full-length and segmented data from 84 observations of the globular cluster M13 with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Employing a low detection threshold (2 ) to maximize sensitivity to faint pulsars, here we report the discovery of two binary millisecond pulsars: J1641+3627G (M13G) and J1641+3627H (M13H). Both pulsars were detected during scintillation-brightened states, revealing systems that would otherwise remain undetected. For M13G, we obtained a phase-connected timing solution spanning 6.4 years, identifying it as a black widow system with an orbital period of 0.12 days hosting an extremely low-mass companion (), though no eclipses were observed. M13H, however, shows significant apparent acceleration but was detected in only 2 of 84 observations; its extremely low detection rate currently prevents constraints on orbital parameters or classification.

Paper Structure

This paper contains 13 sections, 2 equations, 2 figures.

Table of Contents

  1. Introduction
  2. Observation and data reduction
  3. FAST Observation
  4. Previous Pulsar searches for GC M13
  5. Data Reduction
  6. Results
  7. new discoveries
  8. The timing of M13G
  9. discussion
  10. Properties of new discoveries
  11. The flux estimation of new pulsars
  12. The detection significance of weak pulsars
  13. Conclusions

Figures (2)

  • Figure 1: The average pulse profile and timing residual of M13G. The left panel is the integrated pulse profile obtained by summing all 57 detections over 128 pulse phase bins. The timing residual as a function of MJD (upper subplot) and orbital phase (lower subplot) from the best-fit timing model are shown in the right panel.
  • Figure 2: The median companion mass vs. orbital period (zoomed in on the range of $M_{\rm c, med}$ = $8\times 10^{-4}$ - $1\times10^{-1}$${\rm M}_\odot$. The data was taken from the ATNF pulsar catalogue 2005AJ....129.1993M and GC pulsar catalog (As of 2025 February 22) with the psrqpy package 2018JOSS....3..538P.