To find and download HEASARC data in the cloud, you can use astroquery.heasarc or download our new tool, hark.
The HEASARC and NuSTAR teams are greatly saddened by the sudden passing of Katja Pottschmidt. Most recently Katja was the lead scientist for the NuSTAR Guest Observer Facility (GOF), a role she had supported for many years. During her science career she worked on many other high energy astrophysics missions and played an integral role in advancing our knowledge of the universe. She was a wonderful colleague and friend and will be keenly missed by all who knew her.
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hatm: Nonmagnetic hydrogen atmosphere of a neutron star
This model provides the spectra emitted from a nonmagnetic hydrogen atmosphere of a neutron star. The model spectra in a 0 - 20 keV range of (unredshifted) photon energy are computed on a grid of surface gravity accelerations log(g)=13.7 - 14.9 (in cgs units) and effective temperatures T = 0.5 - 10 MK. For a given set of the fitting parameters, the surface gravity g and the gravitational redshift z are derived from the mass M and radius R of the star. The trial spectra are computed using a linear interpolation between the nearest model spectra on the T-log(g) grid, and the boundaries of the energy bins and the number of photons in each bin are divided by (1+z). The details of the model can be found in Suleimanov et al. (2017) and Klochkov et al. (2015).
The directory used for the files required by this model can be changed by using the xset command to set HATM.
The parameters are:
| par1 | Effective temperature T (MK) |
| par2 | Neutron star mass M (M ) |
| par3 | Neutron star radius R (km) |
| par4 | Normalization K = A/(d kpc) where dkpc is the distance to the source in units of 10 kpc and A characterizes the fraction of the surface emitting the radiation (A=1 corresponds to the case when the radiation is emitted from the entire surface). |