The archive contains files that give net cooling rates due to various
elements as a function of density, temperature, and redshift. Each
file is encoded using the HDF5 format
(http://hdf.ncsa.uiuc.edu/HDF5/).

For a description of the methods used, see 

Wiersma, R. P. C., Schaye, J., and Smith, B. D. 2008, MNRAS, submitted
(arxiv:0807.3748)

The gas was exposed to the (redshift-dependent) Haardt & Madau (2001,
hereafter HM01) UV/X-ray background from quasars and galaxies and the
(redshift-dependent) cosmic microwave background (CMB). The gas was
assumed to be optically thin and in ionization equilibrium.

The redshift range is identical to that of the HM01 model: z = 0
through z = 8.989. Every file is named for the redshift it represents,
with the exception of the following files:

-z_8.989nocompton.hdf5: This file contains net cooling rates for the z
       = 8.989 UV/X-ray background, but without the CMB. Such a table
       could be used in a pre z=9, but post-reionization universe (one
       should then add redshift-dependent Compton cooling off the CMB
       analytically).

-z_photodis.hdf5: This file contains net cooling rates computed using
       a soft, non-ionizing UV background. It was computed for the z =
       8.989 HM01 background but with the spectrum cut-off at 1
       Ryd. The CMB was not included. This background dissociates
       molecules, but does not contain H-ionizing radiation. It could
       for example be used in the pre-reionization universe (one
       should then add redshift-dependent Compton cooling off the CMB
       analytically).

In addition, we provide the following redshift-independent file:

-z_collis.hdf5: This file contains net cooling rates computed assuming
       collisional ionization equilbrium and no CMB. Note that 'no induced 
       processes' was not used in this table (all other tables were made with 
       this command) since it caused cloudy to crash.

Each file contains groups corresponding to the different elements
(e.g., "/Carbon"). Hydrogen and helium are considered simultaneously
in the group "/Metal_free". The different contributions to the cooling
rates can be combined and scaled to the desired abundances as
described in WSS08 (eq. 3).

All metals (not just the ones we do separately) are considered
simultaneously in the group "/Total_Metals". This latter table is useful if
the metallicity is known, but not the abundances of individual
elements.  The metal and H&He contributions to the cooling rates can
be combined and scaled to the desired metallicity as described in
WSS08 (eq. 4).

The group "/Header" contains some useful meta-data and the group
"/Solar" considers all elements simultaneously (assuming solar
abundances).

The tables were prepared using the Haardt and Madau (2001) quasars and
galaxies spectrum, and CLOUDY (last described in Ferland et al. 1998)
version 07.02. 

The ranges of the tables are as follows:
Temperature: 100 K - 9.5907002E8 K
Hydrogen density: 1 cm^-3 - 1e-8 cm^-3
Redshift: 0 - 8.989
Helium mass fraction (Helium number ratio): 0.238 - 0.298 (0.07865282 - 
0.10689845)
Energy density: 1e10 erg/g - 1e18 erg/g

References:

Haardt, F. and Madau, P., 2001, Clusters of galaxies and the high
redshift universe observed in X-rays, Recent results of XMM-Newton and
Chandra, XXXVIth Rencontres de Moriond , XXIst Moriond Astrophysics
Meeting, March 10-17, 2001 Savoie, France.   

Ferland et al., 1998, PASP, 110, 761

______________________________________________________________________________

What follows is a item-by-item description of each entry in the table,
complete with units.

/Header (Group)                            
       Contains meta data.

/Header/Abundances (Group)                 
       Abundances subgroup

/Header/Abundances/Abund_names             
       Names of all the elements in the list
       /Header/Abundances/Solar_abundances and
       /Header/Abundances/Solar_number_abundances

/Header/Abundances/Number_of_abundances
       Number of entries in /Header/Abundances/Solar_abundances and
       /Header/Abundances/Solar_number_abundances 

/Header/Abundances/Solar_mass_fractions
       Solar abundances used (mass fractions)

/Header/Abundances/Solar_number_ratios
       Solar abundances used (number density relative to hydrogen)

/Header/Metal_names		   
       Names of the metals for which cooling rates are included
       (correspond to group names).

/Header/Number_of_density_bins    
       Number of density bins

/Header/Number_of_helium_fractions
       Number of helium fraction bins

/Header/Number_of_metals	  
       Number of metals for which cooling rates are included.

/Header/Number_of_temperature_bins
       Number of temperature bins 

/Header/Redshift                  
       The redshift to which the data in this file corresponds.

-----

/Metal_free (Group)
       Includes only hydrogen and helium

/Metal_free/Electron_density_over_n_h 
       Ratio of free electron and hydrogen number densities (n_e/n_H)
       as a function of /Metal_free/Hydrogen_density_bins,
       /Metal_free/Temperature_bins, and helium abundance
       (/Metal_free/Helium_mass_fraction_bins or
       /Metal_free/Helium_number_ratio_bins)

/Metal_free/Helium_mass_fraction_bins       
       Helium mass fraction bins 

/Metal_free/Helium_number_ratio_bins 
       Ratio of helium and hydrogen number density bins (n_He/n_H)

/Metal_free/Hydrogen_density_bins
       Hydrogen number density bins (n_H [cm^-3]) 

/Metal_free/Mean_particle_mass 
       Mean particle mass as a function of
       /Metal_free/Hydrogen_density_bins,
       /Metal_free/Temperature_bins, and helium abundance
       (/Metal_free/Helium_mass_fraction_bins or
       /Metal_free/Helium_number_ratio_bins) (mu [m_H])

/Metal_free/Net_cooling 
       Normalized net cooling rate (pos for cooling, neg for heating)
       as a function of /Metal_free/Hydrogen_density_bins,
       /Metal_free/Temperature_bins, and helium abundance
       (/Metal_free/Helium_mass_fraction_bins or
       /Metal_free/Helium_number_ratio_bins) (Lambda/n_H^2 [erg s^-1
       cm^3])

/Metal_free/Temperature_bins
       Temperature bins (T [K])

-----

/Metal_free/Temperature (Group)
       Contains data needed to convert energy per unit mass into
       temperature 

/Metal_free/Temperature/Energy_density_bins
       Internal energy density per unit mass bins [erg g^-1]

/Metal_free/Temperature/Helium_mass_fraction_bins        
       Helium mass fraction bins

/Metal_free/Temperature/Helium_number_ratio_bins
       Ratio of helium and hydrogen number density bins (n_He/n_H)

/Metal_free/Temperature/Hydrogen_density_bins
       Hydrogen number density bins (n_H [cm^-3]) 

/Metal_free/Temperature/Temperature 
       Temperature as a function of
       /Metal_free/Temperature/Hydrogen_density_bins,
       /Metal_free/Temperature/Energy_density_bins, and helium
       abundance (/Metal_free/Temperature/Helium_mass_fraction_bins or
       /Metal_free/Temperature/Helium_number_ratio_bins) (T [K])

-----

/Total_Metals (Group)
       Contains contribution to the net cooling due to elements from 
       Li to Zn combined (for solar abundances)

/Total_Metals/Hydrogen_density_bins
       Hydrogen number density bins (n_H [cm^-3]) 

/Total_Metals/Net_cooling 
       Normalized net cooling rate (pos for cooling, neg for heating)
       as a function of /Total_Metals/Hydrogen_density_bins and
       /Total_Metals/Temperature_bins (Lambda/n_H^2 [erg s^-1 cm^3])

/Total_Metals/Temperature_bins
       Temperature bins (T [K])

-----

/X (Group)
       Contains contribution to the net cooling due to element X (for
       solar abundances)

/X/Hydrogen_density_bins
       Hydrogen number density bins (n_H [cm^-3])

/X/Net_cooling
       Normalized, net cooling rate (pos for cooling, neg for heating)
       due to element X as a function of /X/Hydrogen_density_bins and
       /X/Temperature_bins (Lambda/n_H^2 [erg s^-1 cm^3])

/X/Temperature_bins
       Temperature bins (T [K])

-----

/Solar (Group)
       All elements - H to Zn - are considered simultaneously (assuming 
       solar abundances) 

/Solar/Electron_density_over_n_h
       Ratio of free electron and hydrogen number densities (n_e/n_H)
       as a function of /Solar/Hydrogen_density_bins and
       /Solar/Temperature_bins for solar abundances

/Solar/Hydrogen_density_bins
       Hydrogen number density bins (n_H [cm^-3])

/Solar/Mean_particle_mass
       Mean particle mass as a function of /Solar/Hydrogen_density_bins and
       /Solar/Temperature_bins for solar abundances (mu [m_H]) 

/Solar/Net_Cooling       
       Normalized, net cooling rate (pos for cooling, neg for heating)
       as a function of /Solar/Hydrogen_density_bins and
       /Solar/Temperature_bins for solar abundances (Lambda/n_H^2 [erg
       s^-1 cm^3]) 

/Solar/Temperature_bins	 	 
       Temperature bins (T [K])
