Observational constraints of the compactness of isolated neutron stars

2nd International Symposium on the Modern Physics of Compact Stars and Relativistic Gravity

物理学;天文学

Hambaryan, V.^1 ; Neuhäuser, R.^1 ; Suleimanov, V.^2 ; Werner, K.^2

Astrophysical Institute, University Observatory, Friedrich-Schiller University Jena, Schillergässchen 2-3, Jena Thüringen 07745, Germany^1

Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, 72076 Tubingen, Germany^2

关键词: Broad absorptions;    Distribution parameters;    General spectral;    Gravitational redshift;    Isolated neutron stars;    Magnetic field strengths;    Optical observations;    Phase resolved spectroscopy;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/496/1/012015/pdf
DOI  :  10.1088/1742-6596/496/1/012015

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

We report on our observational attempt to constrain the compactness of the isolated neutron stars via X-ray spin phase-resolved spectroscopy. There are seven thermally emitting neutron stars known from X-ray and optical observations, which are young (up to few Myrs), nearby (hundreds of pc), and radio-quiet with blackbody-like X-ray spectra. A model with a condensed iron surface and partially ionized hydrogen-thin atmosphere allows us to fit simultaneously the observed general spectral shape and the broad absorption feature (observed at 0.3 keV) in different spin phases. We constrain a number of physical properties of the X-ray emitting areas, including their temperatures, magnetic field strengths at the poles, and their distribution parameters. In addition, we place some constraints on the geometry of the emerging X-ray emission and the gravitational redshift of three isolated neutron stars.