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The POLNA project

Linear polarization of electromagnetic radiation is caused by scattering processes in the atmospheres of stars and interstellar space. Such polarization has a noticeable effect on the structure of stars' atmospheres and their spectra observed in natural light.

The POLNA project aims to theoretically study the linear polarization of relativistic space objects in the X-ray range. This project deals with the polarization caused by Compton scattering of photons on free electrons in a hot gas with temperatures T = 108-109K. The influence of magnetic fields is not considered here.

    The scientific objectives of the POLNA project are:
  • calculations of the grid of atmosphere models, X-ray spectra and the degree of polarization of hot neutron stars (X-ray bursters),
  • calculations of the total luminosity, X-ray spectra and degree of polarization of hot neutron stars flattened by a rapid rotation where the effective temperature changes across the star's surface (Von Zeipel's theorem),
  • calculations of the atmosphere models, spectra and polarization of X-ray irradiated accretion disks around neutron stars and black holes.
Fig. Distribution of the local effective temperature on the surface of a rapidly rotating neutron star seen at an angle of i=30o to the equator plane. The mass of the neutron star M=0.92M was assumed. The equatorial radius is equal to Req=6.98 km whereas polar radius Req=5.02 km.
Graphical design: Agnieszka Majczyna; Created by: Agnieszka Majczyna; Background: APOD/NASA; Baner: pixabay/TheDigitalArtist