A Counterintuitive Correlation between Neutron Star Radii Inferred from Pulse Modeling and Surface Emission Beaming
Thermal X-ray emission from rotation-powered millisecond pulsars, shaped by gravitational lensing and the beaming of the surface radiation, provides critical insights into neutron star properties. This approach has been the focus of observations with the Neutron Star Interior Composition Explorer (N...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adb9ea |
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| author | Tong Zhao Dimitrios Psaltis Feryal Özel |
| author_facet | Tong Zhao Dimitrios Psaltis Feryal Özel |
| author_sort | Tong Zhao |
| collection | DOAJ |
| description | Thermal X-ray emission from rotation-powered millisecond pulsars, shaped by gravitational lensing and the beaming of the surface radiation, provides critical insights into neutron star properties. This approach has been the focus of observations with the Neutron Star Interior Composition Explorer (NICER) mission. Using a semianalytic model to calculate pulse profiles, we investigate the effects of adopting incorrect beaming models on the inferred compactness of neutron stars. We demonstrate that assuming a more centrally peaked beaming pattern when fitting data from a more isotropic emitter leads to an underestimation of compactness in the case of two antipodal polar caps. We present a detailed analysis of this counterintuitive result, offering both qualitative insights and quantitative estimates. If the atmospheric heating in the millisecond pulsars observed with NICER is shallow, the inferred radii for these sources could be significantly overestimated, with important implications for neutron star structure and equation-of-state constraints. |
| format | Article |
| id | doaj-art-b6ddec9a38d440ecafa70b6cfae43302 |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-b6ddec9a38d440ecafa70b6cfae433022025-08-20T03:41:56ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01982211210.3847/1538-4357/adb9eaA Counterintuitive Correlation between Neutron Star Radii Inferred from Pulse Modeling and Surface Emission BeamingTong Zhao0Dimitrios Psaltis1https://orcid.org/0000-0003-1035-3240Feryal Özel2https://orcid.org/0000-0003-4413-1523School of Physics, Georgia Institute of Technology , 837 State St. NW, Atlanta, GA 30332, USA; Departments of Astronomy and Physics, University of Arizona , 933 N. Cherry Ave., Tucson, AZ 85721, USASchool of Physics, Georgia Institute of Technology , 837 State St. NW, Atlanta, GA 30332, USASchool of Physics, Georgia Institute of Technology , 837 State St. NW, Atlanta, GA 30332, USAThermal X-ray emission from rotation-powered millisecond pulsars, shaped by gravitational lensing and the beaming of the surface radiation, provides critical insights into neutron star properties. This approach has been the focus of observations with the Neutron Star Interior Composition Explorer (NICER) mission. Using a semianalytic model to calculate pulse profiles, we investigate the effects of adopting incorrect beaming models on the inferred compactness of neutron stars. We demonstrate that assuming a more centrally peaked beaming pattern when fitting data from a more isotropic emitter leads to an underestimation of compactness in the case of two antipodal polar caps. We present a detailed analysis of this counterintuitive result, offering both qualitative insights and quantitative estimates. If the atmospheric heating in the millisecond pulsars observed with NICER is shallow, the inferred radii for these sources could be significantly overestimated, with important implications for neutron star structure and equation-of-state constraints.https://doi.org/10.3847/1538-4357/adb9eaMillisecond pulsarsX-ray astronomyNeutron stars |
| spellingShingle | Tong Zhao Dimitrios Psaltis Feryal Özel A Counterintuitive Correlation between Neutron Star Radii Inferred from Pulse Modeling and Surface Emission Beaming The Astrophysical Journal Millisecond pulsars X-ray astronomy Neutron stars |
| title | A Counterintuitive Correlation between Neutron Star Radii Inferred from Pulse Modeling and Surface Emission Beaming |
| title_full | A Counterintuitive Correlation between Neutron Star Radii Inferred from Pulse Modeling and Surface Emission Beaming |
| title_fullStr | A Counterintuitive Correlation between Neutron Star Radii Inferred from Pulse Modeling and Surface Emission Beaming |
| title_full_unstemmed | A Counterintuitive Correlation between Neutron Star Radii Inferred from Pulse Modeling and Surface Emission Beaming |
| title_short | A Counterintuitive Correlation between Neutron Star Radii Inferred from Pulse Modeling and Surface Emission Beaming |
| title_sort | counterintuitive correlation between neutron star radii inferred from pulse modeling and surface emission beaming |
| topic | Millisecond pulsars X-ray astronomy Neutron stars |
| url | https://doi.org/10.3847/1538-4357/adb9ea |
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