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btapec, bvtapec, bvvtapec: velocity broadened APEC emission spectrum with separate continuum and line temperatures

A velocity- and thermally-broadened emission spectrum from collisionally-ionized diffuse gas calculated from the AtomDB atomic database. More information can be found at http://atomdb.org/which should be consulted by anyone running this model. This version of the model allows different temperatures for the continuum and lines. This default version number can be changed by modifiying the ATOMDB_VERSION string in your Xspec.init file.

By default this model reads atomic physics continuum and line data from the files apec_v[version]_coco.fits and apec_v[version]_line.fits in the $HEADAS/../spectral/modelData directory. Different files can be specified by using the command xset APECROOT. There are three options. APECROOT can be set to a version number (eg 1.10, 1.2.0, 1.3.1, 2.0.1, 3.0.2, 3.0.3). In this case the value of APECROOT will be used to replace the default version number in the name of the standard files and the resulting files will be assumed to be in the modelData directory. Alternatively, a filename root (eg apec_v1.2.0) can be given. This root will be used as a prefix for the _coco.fits and _line.fits files. Finally, if neither of these work then the model will assume that the APECROOT value gives the complete directory path, e.g.

XSPEC12> xset APECROOT /foo/bar/apec_v1.2.0

will use the input files

/foo/bar/apec_v1.2.0_coco.fits 
/foo/bar/apec_v1.2.0_line.fits.

The btapec model uses abundances set by the abund command. The bvtapec and bvvtapec variants allow the user to set the abundance using additional parameters. For btapec and bvtapec the abundances of the trace elements (ie Li, Be, B, F, Na, P, Cl, K, Sc, Ti, V, Cr, Mn, Co, Cu, Zn) can be set using xset APEC_TRACE_ABUND. These trace element abundances can be set either to the abundance of one of the main elements or to a numerical value (relative to Solar). For instance,

XSPEC12> xset APEC_TRACE_ABUND Fe
sets trace element abundances to that of iron while
XSPEC12> xset APEC_TRACE_ABUND 1.0
sets them to Solar.

For the btapec model the parameters are:

par1=$kT$ continuum temperature, keV
par2=$kTi$ line temperature, keV
par3 Metal abundances (He fixed at cosmic). The elements included are C, N, O, Ne, Mg, Al, Si, S, Ar, Ca, Fe, Ni. Relative abundances are set by the abund command. The trace element abundances are from xset APEC_TRACE_ABUND, the default is 1.0.
par4 Redshift, z
par5 Gaussian sigma for velocity broadening (km/s)
norm ${10^{-14}\over{4\pi[D_A(1+z)]^2}}\int n_en_HdV$, where $D_A$ is the angular diameter distance to the source (cm), $n_e$ and $n_H$ are the electron and H densities (cm$^{-3}$), respectively

For the bvtapec variant the parameters are as follows.

par1=$kT$ continuum temperature, keV
par2=$kTi$ line temperature, keV
par3-par15 Abundances for He, C, N, O, Ne, Mg,Al, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command). The trace element abundances are from xset APEC_TRACE_ABUND, the default is 1.0.
par16 redshift, z
par17 Gaussian sigma for velocity broadening (km/s)
norm ${10^{-14}\over{4\pi[D_A(1+z)]^2}}\int n_en_HdV$, where $D_A$ is the angular diameter distance to the source (cm), $n_e$ and $n_H$ are the electron and H densities (cm$^{-3}$), respectively

For the bvvtapec variant the parameters are as follows.

par1=$kT$ continuum temperature, keV
par2=$kTi$ line temperature, keV
par3-par32 Abundances for H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn wrt Solar (defined by the abund command)
Par33 redshift, z
Par34 Gaussian sigma for velocity broadening (km/s)
norm ${10^{-14}\over{4\pi[D_A(1+z)]^2}}\int n_en_HdV$, where $D_A$ is the angular diameter distance to the source (cm), $n_e$ and $n_H$ are the electron and H densities (cm$^{-3}$), respectively


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Next: c6mekl, c6vmekl, c6pmekl, c6pvmkl: Up: Additive Model Components Previous: bremss, vbremss, zbremss: thermal