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Search for Periodic Radio Signals from Double Neutron Star System Companions Using the Fast Folding Algorithm

Wenze Li, Zhichen Pan, Lei Qian, Liyun Zhang, Yujie Chen, Dejiang Yin, Baoda Li, Yinfeng Dai, Yaowei Li, Dongyue Jiang, Qiaoli Hao, Menglin Huang, Xingyi Wang, Xianghua Niu, Minglei Guo, Jinyou Song, Shuangyuan Chen

Abstract

As most of the companions in the double neutron star systems should be normal pulsars, the Fast Folding Algorithm (FFA), which is suitable for finding these long spin period pulsars, was used to search their possible radio signals. A time domain resampling code PYSOLATOR was used to maximize the available data length by removing the orbital modulation. We collected and processed 272.2 hours observational data taken by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) for the 13 double neutron star systems in its sky. The signal-to-noise ratios of known pulsar signals are obviously improved by this search method, including the detection of a faint pulsar signal which only saw by folding the data. Unfortunately, no companion signals were found among all the 197962 candidates. Geodetic precession of the orbit could enhance detectability in future observations.

Search for Periodic Radio Signals from Double Neutron Star System Companions Using the Fast Folding Algorithm

Abstract

As most of the companions in the double neutron star systems should be normal pulsars, the Fast Folding Algorithm (FFA), which is suitable for finding these long spin period pulsars, was used to search their possible radio signals. A time domain resampling code PYSOLATOR was used to maximize the available data length by removing the orbital modulation. We collected and processed 272.2 hours observational data taken by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) for the 13 double neutron star systems in its sky. The signal-to-noise ratios of known pulsar signals are obviously improved by this search method, including the detection of a faint pulsar signal which only saw by folding the data. Unfortunately, no companion signals were found among all the 197962 candidates. Geodetic precession of the orbit could enhance detectability in future observations.
Paper Structure (14 sections, 4 equations, 4 figures, 7 tables)

This paper contains 14 sections, 4 equations, 4 figures, 7 tables.

Table of Contents

  1. Introduction
  2. Data and Data Reduction
  3. Data
  4. Data Reduction
  5. Results
  6. The Timing Solution for J1946+2052
  7. The Search Results
  8. Discussion
  9. The Search Sensitivities
  10. FFA Plus PYSOLATOR
  11. The Narrow Radiation Beam of Companion Star
  12. Geodetic Precession
  13. Other newly discovered DNS Systems
  14. Conclusion

Figures (4)

  • Figure 1: The orbital phase coverage.
  • Figure 2: The pulse profile (upper subplot) and the timing residual as a function of MJD and orbital phase from the best-fit timing model (lower subplot) with PSR J1946+2052.
  • Figure 3: The pulse profiles of the primary stars in 12 DNS systems, the results of FFA search after the orbital effects were removed.
  • Figure 4: Survey sensitivity as a function of pulsar period and DM when the observation time is 2 hours for all the telescopes, assuming an intrinsic pulse width of 3 $\%$. The solid line, dash-dot line, and dash line in every colour represent the DM values of 10, 200, and 350 $\text{pc cm}^{-3}$, respectively, as these three numbers are the lowest, median, and highest DM values among all the selected 13 pulsars in our study. The shaded area represents the searched pulsar period range.