skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: THE NEAREST MILLISECOND PULSAR REVISITED WITH XMM-NEWTON: IMPROVED MASS-RADIUS CONSTRAINTS FOR PSR J0437-4715

Abstract

I present an analysis of the deepest X-ray exposure of a radio millisecond pulsar (MSP) to date, an X-ray Multi Mirror-Newton European Photon Imaging Camera spectroscopic and timing observation of the nearest known MSP, PSR J0437-4715. The timing data clearly reveal a secondary broad X-ray pulse offset from the main pulse by {approx}0.55 in rotational phase. In the context of a model of surface thermal emission from the hot polar caps of the neutron star, this can be plausibly explained by a magnetic dipole field that is significantly displaced from the stellar center. Such an offset, if commonplace in MSPs, has important implications for studies of the pulsar population, high energy pulsed emission, and the pulsar contribution to cosmic-ray positrons. The continuum emission shows evidence for at least three thermal components, with the hottest radiation most likely originating from the hot magnetic polar caps and the cooler emission from the bulk of the surface. I present pulse phase-resolved X-ray spectroscopy of PSR J0437-4715, which for the first time properly accounts for the system geometry of a radio pulsar. Such an approach is essential for unbiased measurements of the temperatures and emission areas of polar cap radiation from pulsars. Detailed modelingmore » of the thermal pulses, including relativistic and atmospheric effects, provides a constraint on the redshift-corrected neutron star radius of R > 11.1 km (at 3{sigma} conf.) for the current radio timing mass measurement of 1.76 M {sub Sun }. This limit favors 'stiff' equations of state.« less

Authors:
 [1];  [2]
  1. Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)
  2. (Canada)
Publication Date:
OSTI Identifier:
22167281
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 762; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; CAMERAS; COMPUTERIZED SIMULATION; COSMIC PHOTONS; COSMIC POSITRONS; EQUATIONS OF STATE; MAGNETIC DIPOLES; MASS; NEUTRON STARS; PHOTON EMISSION; PULSARS; PULSES; RED SHIFT; RELATIVISTIC RANGE; X RADIATION; X-RAY SPECTROSCOPY

Citation Formats

Bogdanov, Slavko, E-mail: slavko@astro.columbia.edu, and Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8. THE NEAREST MILLISECOND PULSAR REVISITED WITH XMM-NEWTON: IMPROVED MASS-RADIUS CONSTRAINTS FOR PSR J0437-4715. United States: N. p., 2013. Web. doi:10.1088/0004-637X/762/2/96.
Bogdanov, Slavko, E-mail: slavko@astro.columbia.edu, & Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8. THE NEAREST MILLISECOND PULSAR REVISITED WITH XMM-NEWTON: IMPROVED MASS-RADIUS CONSTRAINTS FOR PSR J0437-4715. United States. doi:10.1088/0004-637X/762/2/96.
Bogdanov, Slavko, E-mail: slavko@astro.columbia.edu, and Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8. Thu . "THE NEAREST MILLISECOND PULSAR REVISITED WITH XMM-NEWTON: IMPROVED MASS-RADIUS CONSTRAINTS FOR PSR J0437-4715". United States. doi:10.1088/0004-637X/762/2/96.
@article{osti_22167281,
title = {THE NEAREST MILLISECOND PULSAR REVISITED WITH XMM-NEWTON: IMPROVED MASS-RADIUS CONSTRAINTS FOR PSR J0437-4715},
author = {Bogdanov, Slavko, E-mail: slavko@astro.columbia.edu and Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8},
abstractNote = {I present an analysis of the deepest X-ray exposure of a radio millisecond pulsar (MSP) to date, an X-ray Multi Mirror-Newton European Photon Imaging Camera spectroscopic and timing observation of the nearest known MSP, PSR J0437-4715. The timing data clearly reveal a secondary broad X-ray pulse offset from the main pulse by {approx}0.55 in rotational phase. In the context of a model of surface thermal emission from the hot polar caps of the neutron star, this can be plausibly explained by a magnetic dipole field that is significantly displaced from the stellar center. Such an offset, if commonplace in MSPs, has important implications for studies of the pulsar population, high energy pulsed emission, and the pulsar contribution to cosmic-ray positrons. The continuum emission shows evidence for at least three thermal components, with the hottest radiation most likely originating from the hot magnetic polar caps and the cooler emission from the bulk of the surface. I present pulse phase-resolved X-ray spectroscopy of PSR J0437-4715, which for the first time properly accounts for the system geometry of a radio pulsar. Such an approach is essential for unbiased measurements of the temperatures and emission areas of polar cap radiation from pulsars. Detailed modeling of the thermal pulses, including relativistic and atmospheric effects, provides a constraint on the redshift-corrected neutron star radius of R > 11.1 km (at 3{sigma} conf.) for the current radio timing mass measurement of 1.76 M {sub Sun }. This limit favors 'stiff' equations of state.},
doi = {10.1088/0004-637X/762/2/96},
journal = {Astrophysical Journal},
number = 2,
volume = 762,
place = {United States},
year = {Thu Jan 10 00:00:00 EST 2013},
month = {Thu Jan 10 00:00:00 EST 2013}
}