nsa: neutron star atmosphere

This model provides the spectra in the X-ray range (0.05-10 keV) emitted from a hydrogen atmosphere of a neutron star. There are three options : nonmagnetized (B G) with a uniform surface (effective) temperature in the range of ; a field B = G with a uniform surface (effective) temperature in the range of ; a field B = G with a uniform surface (effective) temperature in the range of . The atmosphere is in radiative and hydrostatic equilibrium; sources of heat are well below the atmosphere. The Comptonization effects (significant at K) are taken into account. The model spectra are provided as seen by a distant observer, with allowance for the GR effects. The user is advised to keep and fixed and fit the temperature and the normalization. MagField must be fixed at one of 0, , or .

The values of the effective temperature and radius as measured by a
distant observer (“values at infinity”) are :

where

is the gravitational redshift parameter.

Please send your comments/questions to Slava Zavlin (vyacheslav.zavlin@msfc.nasa.gov) and/or George Pavlov (pavlov@astro.psu.edu). If you publish results obtained using these models, please reference Zavlin, Pavlov & Shibanov (1996) for nonmagnetic models, and Pavlov et al. (1995) for magnetic models.

par1 | , (unredshifted) effective temperature |

par2 | , neutron star gravitational mass (in units of solar mass) |

par3 | , neutron star radius (in km) |

par4 | neutron star magnetic field strength (0, , or G) |

norm | , where is the distance of the object in pc. |