Line profiles from hot star winds; absorption of X-rays from hot star winds.

These models address two related problems in X-ray emission from hot star winds.

The first group of models (windprof et al.) calculate the shape of emission lines from hot star winds, taking into account the distributed X-ray emission and the absorption by the cool component of the wind. These are additive models.

The second group of models (windtabs et al.) calculate the broadband absorption of X-rays emitted from hot star winds. This in analogy with wabs or tbabs, but taking into account the wind geometry and ionization. These are multiplicative models.

The line profile models implement physics described in Owocki & Cohen (2001), Owocki & Cohen (2006), Leutenegger et al. (2006), and Leutenegger et al. (2007).

The wind absorption models are described in Leutenegger et al. (2010).

The source code may obtained with subversion with the command:

svn co https://svn.code.sf.net/p/windprofile/code/ windprofile-code

The models require the GNU scientific library (libgsl) The installation procedures for OS X and Gnu/Linux are different.

  • OS X: GSL can be installed from either fink or macports. If macports is used, the 32 bit version of GSL must be installed:
    sudo port install gsl +universal
    Then run the script addGSL_OSX from $HEADAS/../BUILD_DIR. You must first edit addGSL_OSX to give the correct path to your GSL installation. This step can either be performed during a fresh build of heasoft from source, or on an existing install. For a fresh build, run addGSL_OSX after configure but before make. For an existing install, after running addGSL_OSX, run the script rebuildInitpackage.
  • Linux: GSL is available with most well-known GNU/Linux distributions. Because GSL must be statically linked, it is necessary to rebuild XSPEC from source with a modified makefile. The easiest way to do this is to run addGSL_linux from $HEADAS/../BUILD_DIR after ./configure and before make during the HEAsoft installation process. It is also possible to rebuild only the XSPEC binary (see the XSPEC FAQ #10). For further instructions on building XSPEC from source, please see the installation page.

The wind absorption models require the user to supply two data files, an opacity file, and a transmission file. These files are specified using xset, as in the following example:
xset WINDTABSDIRECTORY /path/to/local/model/data/
xset KAPPAFILENAME kappa.fits
xset TRANSMISSIONFILENAME tau_transmission.fits
The opacity file for the fiducial solar abundance wind described in Leutenegger et al (2010) can be downloaded as kappa.fits), or the user can generate their own, or request modification from the model authors. The transmission file can be generated by following the instructions in ./WindAbsorption.

Summary of models:

  • windprof: basic line profile model, rest wavelength is a parameter
  • hwind: same model for ly alpha lines, with rest wavelength determined by Z
  • hewind: model including f/i ratio dependence for He like triplets, as described in Leutenegger et al. (2006)
  • windtabs: broadband absorption of X-rays emitted from wind

Examples of typical parameters:

    1    1   windprof   q                   0.0          frozen
    2    1   windprof   taustar             1.00000      frozen
    3    1   windprof   u0                  0.500000     frozen
    4    1   windprof   h                   0.0          frozen
    5    1   windprof   tau0star            0.0          frozen
    6    1   windprof   beta                1.00000      frozen
    7    1   windprof   betaSob             0.0          frozen
    8    1   windprof   numerica            0            frozen
    9    1   windprof   anisotro            0            frozen
   10    1   windprof   rosselan            0            frozen
   11    1   windprof   expansio            0            frozen
   12    1   windprof   thick               0            frozen
   13    1   windprof   waveleng   A        24.7810      frozen
   14    1   windprof   shift      mA       0.0          frozen
   15    1   windprof   velocity   km/s     2485.00      frozen
   16    1   windprof   verbose             0            frozen
   17    1   windprof   norm                1.00000      
  • q gives the exponent of the radial dependence of the filling factor, f~r^{-q}
  • taustar (\tau_*) is the characteristic continuum optical depth of the wind as defined in Owocki & Cohen (2001)
  • u0 is the inverse radius (R_* / R_0) where the onset of X-ray emission occurs
  • h is the porosity length
  • tau0star (\tau_0,*) is the characterisic optical depth to resonance scattering
  • beta is the exponent in the wind velocity law
  • betaSob (\beta_sob) is a parameter in the resonance scattering calculation
  • numerica is a switch; if set to 1, the continuum optical depth integral is evaluated numerically, otherwise it is calculated analytically
  • anisotro: if set to 1, the porosity is "anisotropic", i.e. from pancake shaped clumps, otherwise the clumps are blobs
  • rosselan: if set to 1, the porosity is calculated using the approximate bridging law given in OC 2006, otherwise it uses the "correct" bridging law expansio: if set to 1, the porosity length scales as h~r, otherwise it goes as h~v(r)
  • thick: if set to 1, resonance scattering is evaluated in the optically thick limit, otherwise it is evaluted using tau0star
  • waveleng: the rest wavelength of the emission line
  • shift: a shift in the rest wavelength, to allow for calibration problems in the wavelength scale
  • velocity: the wind terminal velocity
  • verbose: if set to 1, models will produce extra output
  • norm: in photons/cm2/s
    1    1   hwind      q                   0.0          frozen
    2    1   hwind      taustar             1.00000      frozen
    3    1   hwind      u0                  0.500000     frozen
    4    1   hwind      h                   0.0          frozen
    5    1   hwind      tau0star            0.0          frozen
    6    1   hwind      beta                1.00000      frozen
    7    1   hwind      betaSob             0.0          frozen
    8    1   hwind      numerica            0            frozen
    9    1   hwind      anisotro            0            frozen
   10    1   hwind      rosselan            0            frozen
   11    1   hwind      expansio            0            frozen
   12    1   hwind      thick               0            frozen
   13    1   hwind      Z                   8            frozen
   14    1   hwind      shift      mA       0.0          frozen
   15    1   hwind      velocity   km/s     2485.00      frozen
   16    1   hwind      verbose             0            frozen
   17    1   hwind      norm                1.00000      
Parameters are as for windprof; except
  • Z: atomic number. The rest wavelength is chosen to be Lyman alpha for the hyrodgenic species with this value of Z.
    1    1   hewind     q                   0.0          frozen
    2    1   hewind     taustar             1.00000      frozen
    3    1   hewind     u0                  0.500000     frozen
    4    1   hewind     h                   0.0          frozen
    5    1   hewind     tau0star            0.0          frozen
    6    1   hewind     beta                1.00000      frozen
    7    1   hewind     betaSob             0.0          frozen
    8    1   hewind     G                   0.700000     frozen
    9    1   hewind     numerica            0            frozen
   10    1   hewind     anisotro            0            frozen
   11    1   hewind     rosselan            0            frozen
   12    1   hewind     expansio            0            frozen
   13    1   hewind     thick               0            frozen
   14    1   hewind     Z                   12           frozen
   15    1   hewind     shift      mA       0.0          frozen
   16    1   hewind     velocity   km/s     2485.00      frozen
   17    1   hewind     phiratio            131.000      frozen
   18    1   hewind     verbose             0            frozen
   19    1   hewind     norm                1.00000      
Parameters are as for hwind; except
  • G: the ratio G = (f+i)/r for the complex
  • phiratio: called "P" in Leutenegger et al. (2006), this gives the characteristic strength of UV photoexcitation of the forbidden line
    1    1   windtabs   Sigma*     g/cm2   1.00000E-02  frozen
The only free parameter of windtabs is
  • Sigma* (\Sigma_*): The characteristic mass column density of the wind. It is proportional to the wind mass loss rate.

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

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Last modified: Wednesday, 11-Sep-2013 15:25:56 EDT