bapec: velocity broadened APEC thermal plasma model

An emission spectrum from collisionally-ionized diffuse gas calculated using the APEC code v1.3.1. Lines are velocity broadened with a Gaussian sigma given by the velocity parameter. Lines are also broadened by the velocity parameter. Lines are also broadened by the thermal line width. More information on APEC can be found at  http://hea-www.harvard.edu/APEC/ which should be consulted by anyone running this model. By default this model reads atomic physics data from the files apec_v1.3.1_coco.fits and apec_v1.3.1_line.fits in the spectral/xspec/manager file. Different files can be specified by using the command xset set APECROOT. There are three options. APECROOT can be set to a version number (eg 1.2.0). In this case the value of APECROOT will be used to replace 1.3.1 in the name of the standard files and the resulting files will be assumed to be in the spectral/xspec/manager 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 in the manager directory. Finally, if neither of these work then the model will assume that the APECROOT value gives the complete directory path e.g. XSPEC> xset APECROOT /foo/bar/apec_v1.2.0 will use /foo/bar/apec_v1.2.0_coco.fits and /foo/bar/apec_v1.2.0_line.fits as input files.

 

 

 par1   = plasma temperature in keV

 par2   = Metal abundances (He fixed at cosmic). The elements

          included are C, N, O, Ne, Mg, Al, Si, S, Ar, Ca,

          Fe, Ni. Abundances are set by the abund command.

 par3   = redshift, z

 par4   = Gaussian sigma for velocity broadening (km/s)

 K      = 10**-14 / (4 pi (D_A*(1+z))**2) Int n_e n_H dV, where D_A is

          the angular size distance to the source (cm), n_e is the electron

          density (cm**-3), and n_H is the hydrogen density (cm**-3)