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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Reflection of a blackbody from a constant density ionized accretion disk.

These table models provide the reflection spectrum from a constant density disk illuminated by a blackbody, as in the case of an accreting neutron star system. They were computed using the same version of the Ross reflection code as the AGN constant density ionized disk models.

Full details of the calculations can be found in Ballantyne (2004).

The author (david.ballantyne -at- physics.gatech.edu) is more than happy to collaborate with observers to produce grids if the ones below are not appropriate for a certain observation/dataset.

Model parameters are:

  • the LOG of the ionization parameter of the slab : Xi = 4 PI*F/n, where F=incident flux (in ergs/s/cm**2) and n=hydrogen number density of slab (cm**{-3}).

    The models were calculated with log n= 15, and the flux was varied to change the ionization parameter. Valid range: 1.0 -> 3.75. Stepsize: 0.05 (in the log)

  • The temperature (kT) of incident blackbody in keV. Valid range: 1.0 -> 3.15. Stepsize: 0.05

  • Reflection fraction, R. [For some table models] Model=Incident+R*Reflected. This describes how strong the reflection component is in the model spectrum. It is not necessarily related to the subtending solid angle of the slab, as that depends on geometric assumptions. Valid range: 0.0 -> 5.0. Stepsize: 0.05

    NB: a separate blackbody will need to be included in the model definition when using grids that only include the reflection spectrum

  • Normalization. As the model predicts flux per emitting area, this is a very small number (about 1e-20 or less). See Cackett et al. (arXiv:0908.1098) for more details.

  • Redshift

The following table models are available and will be useful in a wide variety of situations:

Fe AbundanceFilenameComments
1.0 Solarbbrefl_1xsolar_0-5r.fitsHas reflection fract. (440 Mb)
1.0 Solarbbrefl_1xsolar.fitsRefl. spectrum only. (4.4 Mb)
2.0 Solarbbrefl_2xsolar_0-5r.fitsHas reflection fract. (440 Mb)
2.0 Solarbbrefl_2xsolar.fitsRefl. spectrum only. (4.4 Mb)

Examples of usage:
(a)Model with reflection fraction:wabs*atable{bbrefl_1xsolar_0-5r.fits}
(b)Model with reflection spectrum only:wabs*(atable{bbrefl_1xsolar.fits}+bbody)
where the kT parameter of the blackbody is linked to the kT parameter of the table model.

In addition there are 2 table models that contain only reflection spectra and are likely for more specific purposes:

FilenameComments
bbrefl_Hestar.fitsModels were calculated with abundances appropriate for a He-star donor (see Ballantyne & Strohmayer 2004) (4.4 Mb)
bbrefl_varyFe.fitsA sparser grid in Xi and kT but with a variable Fe abundance. log n =18 for these models. (0.6 Mb)

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

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Last modified: Tuesday, 13-Nov-2012 12:47:20 EST

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.