Aberration/Retardation Analysis of PSR B1451-68’s Profiles from Decimeter to Meter Wavelengths: Emission Heights and Implications for ‘Radius-to-Frequency Mapping’
- 1Curtin University
- 2University of Vermont
Abstract
Measurements of pulse profiles over a large frequency range can be used to investigate the frequency dependence of emission heights using aberration/retardation (A/R) analysis. A recent analysis using PSR B1237+25, a pulsar with a core/double-cone profile, shows no evidence for an increase in emission height with wavelength in observations made across a large range in frequencies from 5 GHz–30 MHz. Motivated by this intriguing result, we undertook a similar analysis of PSR B1451−68, a bright southern-sky pulsar with a somewhat different core/double-cone profile. We used eight profiles at six different frequencies—four from the Parkes/Murriyang telescope and four from the Murchison Widefield Array—spanning 8 GHz–80 MHz. Each profile was modeled with five Gaussian components, and these were used to measure the profile asymmetries attributable to A/R, and hence to estimate the emission heights. Our results show a dramatic increase in the outer conal width and height as predicted by “radius-to-frequency mapping” (RFM). However, the A/R emission heights decrease significantly at frequencies below 1 GHz, which is inconsistent with the RFM behavior. The fact that the outer conal emission heights apparently decrease at lower frequencies remains a mystery to be further investigated.
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BibTeX
@article{bhat2026aberrationretardation,
title = {{Aberration/Retardation Analysis of PSR B1451-68’s Profiles from Decimeter to Meter Wavelengths: Emission Heights and Implications for ‘Radius-to-Frequency Mapping’}},
author = {N. D. Ramesh Bhat and Christopher P. Lee and Joanna M. Rankin},
journal = {The Astrophysical Journal},
year = {2026},
month = oct,
doi = {10.3847/1538-4357/ae8f3e},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/ae8f3e},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Aberration/Retardation Analysis of PSR B1451-68’s Profiles from Decimeter to Meter Wavelengths: Emission Heights and Implications for ‘Radius-to-Frequency Mapping’
AU - N. D. Ramesh Bhat
AU - Christopher P. Lee
AU - Joanna M. Rankin
PY - 2026
DA - 2026/10/01
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/ae8f3e
UR - https://iopscience.iop.org/article/10.3847/1538-4357/ae8f3e
AB - Measurements of pulse profiles over a large frequency range can be used to investigate the frequency dependence of emission heights using aberration/retardation (A/R) analysis. A recent analysis using PSR B1237+25, a pulsar with a core/double-cone profile, shows no evidence for an increase in emission height with wavelength in observations made across a large range in frequencies from 5 GHz–30 MHz. Motivated by this intriguing result, we undertook a similar analysis of PSR B1451−68, a bright southern-sky pulsar with a somewhat different core/double-cone profile. We used eight profiles at six different frequencies—four from the Parkes/Murriyang telescope and four from the Murchison Widefield Array—spanning 8 GHz–80 MHz. Each profile was modeled with five Gaussian components, and these were used to measure the profile asymmetries attributable to A/R, and hence to estimate the emission heights. Our results show a dramatic increase in the outer conal width and height as predicted by “radius-to-frequency mapping” (RFM). However, the A/R emission heights decrease significantly at frequencies below 1 GHz, which is inconsistent with the RFM behavior. The fact that the outer conal emission heights apparently decrease at lower frequencies remains a mystery to be further investigated.
SN - 0004-637X
SN - 1538-4357
ER -