coolcurve_create 1.00

coolcurve_create project contains cooling curves (emissivities) for hydrodynamical simulations from XSPEC.

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GPL (GNU General Public License) 
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Dave Strickland
ROOT \ Science and Engineering \ Astronomy
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coolcurve_create project contains cooling curves (emissivities) for hydrodynamical simulations from XSPEC.

ccurve_create.tcl is a TCL script (plus associated csh-scripts) that make it is possible to calculate cooling curves (plasma emissivities, in units of erg cm^3 s^-1) as a function of plasma temperature using the hot plasma codes available in the XSPEC spectral fitting program. The ability to control the metal abundances in XSPEC, in particular the relative element abundances (e.g. alpha-elements to iron) and absolute abundances (with respect to hydrogen) is particularly useful for simulations considering metal-enrichment or chemically-different plasmas. Element-specific cooling functions can also be created.

These can be used in hydrodynamical simulations to assess the total cooling rate, calculate the luminosity in a specific wavelength/energy range, or more generally to calculate X-ray or UV line diagnostics.

These cooling function are equivalent to the cooling functions presented by Sutherland & Dopita (1993) or Orly & Gnat (2007), although they do not in any sense replace them.

These functions will be of most use if you wish to quickly and cheaply assess the X-ray luminosity of a hot plasma in a simulation (rather than calculating it post-facto after the simulation is completed), as the majority of the hot plasma codes available in XSPEC are best suited to X-ray emission, in particular conditions of collisional ionization equilibrium (CIE). This code and method is well-suited to line-or-ion specific cooling functions, e.g. the emission at E~6.7 keV from Fe XXV, or the O VI doublet at 1032 and 1038 Angstroms.

However bolometric cooling functions can still be calculated, in particular with the MEKAL plasma code (as it was designed to calculate FUV/EUV emission in addition to X-ray emission). The CIE bolometric emissivities will be larger than the NIE cooling rates, as you will find out if you compare the CIE emissivities to the Sutherland and Dopita NIE cooling function.

To calculate luminosities from these emissivities multiply by n_e * n_H * V, NOT n_tot**2 * V, where n_e is the electron number density (in cm^-3), n_H the proton number density and V the region volume (cm^3).

Last updated on June 18th, 2008

#cooling function #cooling curves #hydrodynamical simulations #cooling #function #curves #hydrodynamical

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