H I absorption line and anomalous dispersion in the radio pulses of PSR B1937+21
Feb 27, 2025Citations per year
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Abstract: (arXiv)
We use the Five-hundred-meter Aperture Spherical radio Telescope (FAST) to observe the bright millisecond pulsar (MSP) PSR B1937+21 (J1939+2134) and record the data in the band from 1.0 GHz to 1.5 GHz. We measure the neutral hydrogen (HI) emission and absorption lines near 1420 MHz ( cm). We derive the kinematic distance of the pulsar with the HI observation, and update the upper bound of kinematic distance from the previous npc in the Outer Arm to the nearer kpc in the Perseus Arm. By comparing with the archival absorption spectra observed decades ago, we notice possible variations in the absorption spectra towards this pulsar, which corresponds to a possible tiny-scale atomic structure (TSAS) of a few AU in size. We also verify the apparent faster-than-light anomalous dispersion at the HI absorption line of this pulsar previously reported.Note:
- 13 pages, 5 figures, 2 tables. Submitted to ApJ
References(81)
Figures(5)
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