This directory contains two sample XSPEC spectra of cooling neutron stars with analytic envelopes. Both files are in FITS format suitable for use as additive table models with the XSPEC software:

• p0.fits depicts the observed spectra from the surface of a neutron star looking down the axis of the dipole. The gravitational field of the neutron star effectively defocuses the radiation pattern on the surface.
• p90.fits depicts the observed spectra from the surface of a neutron star looking a right angle to the dipole. This Java Applet demonstrates the defocusing from this vantage point.

Each model has a single interpolation parameter equal to R_s/R where R_s is the Schwartzschild radius of the neutron star and R is the circumferential radius at its surface. This parameter ranges from 0 where general relativistic corrections may be neglected to 0.6601 where the neutron star surfaces lies just outside the photon sphere.

For further details please see the appendix of ``Almost Analytic Models of Ultramagnetized Neutron Star Envelopes.''

The XSPEC software itself is available at ftp://legacy.gsfc.nasa.gov/software/xanadu , and an online manual is provided at http://www.merate.mi.astro.it/~xanadu/xspec/u_manual.html .