The HEASARC welcomes your participation in a brief survey to capture how users access and utilize HEASARC data, software, and services. The outcome(s) of this survey will be used to guide, prioritize, and plan our activities and development in the coming years. It contains 20 questions, generally takes just a few minutes to complete, and your answers will remain totally anonymous. The survey is open until Dec 18, 2023. We thank you in advance for your valuable feedback.

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NS Hydrogen Atmosphere model with electron conduction and self-irradiation

NOTE: This model is now in the Xspec release and this page is superceded by the Xspec manual

This model interpolates from a grid of NS atmosphere calculations provided by George Rybicki and Ramesh Narayan to output a NS atmosphere spectrum. The model grids cover a wide range of surface gravity and effective temperature, and incorporate thermal electron conduction and self-irradiation by photons from the compact object. This code assumes negligible (less than 10^9 G) magnetic fields and a pure hydrogen atmosphere. A detailed description of the model is given in Heinke et al. (2006), ApJ in press, astro-ph/0506563 (see also McClintock et al. 2004, ApJ, 615, 402).

The model parameters are :

par1     =  logTeff, (unredshifted) effective surface temperature
par2     =  Mns, neutron star gravitational mass (in units of solar mass)
par3     =  Rns, neutron star radius (in km)
par4     =  dist, distance to the neutron star (in kpc)

The source code, lmodel.dat entries and model data file are available. The model data file should either be placed in the $XANADU/spectral/modelIonData directory (for v12), $XANADU/spectral/xspec/manager directory (for v11), or the environment variable NSATMOS_FILE set to the full pathname of the model data file (for v11 or v12).

The normalization should normally be fixed at one, which corresponds to emission from the entire surface of the neutron star.

Keith Arnaud, Lab. for High Energy Astrophysics, NASA/Goddard Space Flight Center

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Last modified: Tuesday, 14-Feb-2023 16:42:06 EST

The HEASARC welcomes your participation in a brief survey to capture how users access and utilize HEASARC data, software, and services. The outcome(s) of this survey will be used to guide, prioritize, and plan our activities and development in the coming years. It contains 20 questions, generally takes just a few minutes to complete, and your answers will remain totally anonymous. The survey is open until Dec 18, 2023. We thank you in advance for your valuable feedback.