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EI2GYB > ASTRO 04.11.25 16:25l 48 Lines 4541 Bytes #999 (0) @ WW
BID : 47232_EI2GYB
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Subj: Two FAST-discovered pulsars
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Two FAST-discovered pulsars: Follow-up observations determine their fundamental parameters
Using the Green Bank Telescope (GBT), astronomers from West Virginia University and elsewhere have observed two distant pulsars identified with the Five-hundred-meter Aperture Spherical Radio Telescope (FAST). Results of the observational campaign, presented October 27 on the arXiv preprint server, deliver important insights into the properties of these two pulsars.
To date, over two hundred pulsars have been identified by FAST as part of the Commensal Radio Astronomy FasT Survey (CRAFTS). The detections include at least 74 millisecond pulsars (MSPs), approximately 141 non-recycled pulsars and about seven confirmed rotating radio transients (RRATs).
However, due to the large number of discoveries from CRAFTS, follow-up observations of newly discovered pulsars using other large radio telescopes are required to confirm and characterize these objects and to obtain timing solutions. Recently, a team of astronomers led by West Virginia University's Victoria A. Blackmon has performed such a follow-up study to investigate two CRAFTS-discovered pulsars.
"In this paper, we describe our efforts to produce combined FAST and GBT timing solutions spanning several years for two CRAFTS discoveries-PSRs J0535-0231 and J1816-0518-and present polarization profiles for both sources, based on FAST and GBT data at each observing frequency," the researchers explained.
The targets of these observations, PSR J0535-0231 and PSR J1816-0518, are non-recycled pulsars with spin periods of 0.415 and 1.93 seconds, respectively. By utilizing GBT's 800-MHz Prime Focus 1 Receiver at 820-MHz center frequency with a 200-MHz bandwidth, they managed to determine fundamental parameters of the pulsars.
According to the paper, PSR J0535-0231 has a dispersion measure of 117.55 pc/cm3 and a rotation measure of 77 rad/m2. The pulsar has a spin-down luminosity at a level of 3.3 nonillion erg/s and its characteristic age is estimated to be approximately 1.1 billion years. The surface dipole magnetic field strength of PSR J0535-0231 was calculated to be 50 billion Gauss.
Meanwhile, the dispersion measure of PSR J1816-0518 was found to be 137.19 pc/cm3, while its rotation measure was established to be around -0.21 rad/m2. It turned out that the pulsar has a characteristic age of some 2.6 million years, a spin-down luminosity of about 63 nonillion erg/s, and an estimated surface dipole magnetic field strength of 4.8 trillion Gauss.
In both pulsars, the astronomers found some noticeable profile evolution with frequency. For PSR J0535-0231, the relative fluxes and linear polarizations of the trailing components increase with frequency. In the case of PSR J1816-0518, it shows rather minimal profile evolution, with its leading component appearing to have slightly higher linear polarization and relative flux than the trailing component at higher frequencies.
Based on the results, the authors of the paper concluded that PSR J0535-0231 may be a partially recycled pulsar, likely a disrupted recycled pulsar (DRP), given its isolated nature.
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