HEASARC Staff Scientist Position - Applications are now being accepted for a Staff Scientist with significant experience and interest in the technical aspects of astrophysics research, to work in the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA Goddard Space Flight Center (GSFC) in Greenbelt, MD. Refer to the AAS Job register for full details.

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nsx: neutron star with a non-magnetic atmosphere

The nsx model interpolates from a grid of neutron star (NS) atmosphere spectra to produce a final spectrum that depends on the parameters listed below. Atmosphere spectra are obtained using opacity tables computed by The Opacity Project and are for non-magnetic atmospheres (note that nsx is fully compatible with the magnetic atmosphere spectral tables of nsmaxg, and both nsx and nsmaxg spectral tables can easily be made compatible with other XSPEC NS fitting models). Atmosphere models are constructed by solving the radiative transfer equation, and the atmosphere is assumed to be in radiative and hydrostatic equilibrium. Atmosphere models depend on the surface effective temperature $T_{eff}$ and surface gravity $g = (1+z_g)GM/R^2$, where $1+z_g = \sqrt{1-2GM/R}$ is the gravitational redshift and $M$ and $R$ are the NS mass and radius, respectively. The parameters are:

par1 $\log T_{eff}$, surface (unredshifted) effective temperature
par2 $M$, neutron star gravitation mass (in units of Solar mass)
par3 $R$, neutron star radius (in km)
par4 $d$, distance to neutron star (in kpc)
par5 Switch indicating model to use
norm 1, normalization (though not strictly correct, can be varied to change the size of the emission region, $(R_{em}/R)^2$)

The models available by setting par5 are:

Switch Element $\log g$ (cm/s$^2$) $\log T_{eff}$ E (keV)
1 H 13.6 - 15.0 5.5 - 6.7 0.03 - 15
2 He 13.6 - 14.9 5.5 - 6.7 0.03 - 15
6 C 13.6 - 15.3 5.9 - 6.6 0.01 - 15

If you publish results obtained using nsx, please reference Ho & Heinke (2009).

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Next: nteea: non-thermal pair plasma Up: Additive Model Components Previous: nsmaxg: Neutron Star with
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Last modified: Friday, 23-Aug-2024 13:20:40 EDT

HEASARC Staff Scientist Position - Applications are now being accepted for a Staff Scientist with significant experience and interest in the technical aspects of astrophysics research, to work in the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA Goddard Space Flight Center (GSFC) in Greenbelt, MD. Refer to the AAS Job register for full details.