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NET COOLING TABLES — HM12 UV/X-RAY BACKGROUND
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Radiative cooling and heating tables for cosmological simulations, computed with
Cloudy v23.01 under the Haardt & Madau (2012) metagalactic UV/X-ray background.

Reference paper
  Di Federico, L., Dolag, K., Khabibullin, I., Sala, L., Karademir, G. S., Valentini, M.,
  "Net Cooling Tables for Cosmological Simulations under Multiple X-UV Background Models".

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1. CONTENTS OF THIS FOLDER
--------------------------

* z_<redshift>.hdf5 — one file per redshift (61 files), <redshift> with three decimals.
  Redshift range: 0.000 ≤ z ≤ 15.100.
  Up to z = 8.989 the redshifts are the same as Wiersma et al. (2009, W09), roughly uniform in
  log10(1+z) with Δlog10(1+z) ≈ 0.02; at higher z the spacing is Δz ≈ 0.2–0.7.
* z_collis.hdf5 — collisional-ionisation table 

2. PHYSICAL SETUP  (PAPER: SECTIONS 1.1, 2.1, 2.4; TABLE 1; APPENDIX A)
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* Code: Cloudy v23.01; UVB: Haardt & Madau (2012) (UVB spectrum distributed with Cloudy 23.01). 
The physical ingredients of the UVB model
  are summarized in Table 1 and Appendix A of the paper.
* Gas is optically thin and in ionization equilibrium, exposed to a spatially uniform UVB
  (plus CMB). No self-shielding, local stellar/AGN sources, dust, cosmic rays or
  non-equilibrium chemistry (paper, Section 5).
* Grid (same as W09; paper Section 2.4, Eqs. 8–9, and Section 2.5, Eqs. 10–11, Table 2):
  * hydrogen number density n_H: 81 bins, 10⁻⁸ ≤ n_H ≤ 1 cm⁻³, Δlog10 n_H = 0.1
  * temperature T: 352 bins, 10² ≤ T ≤ 9.6 × 10⁸ K, Δlog10 T = 0.0199
  * helium mass fraction Y (H+He tables only): 11 values, 0.238 ≤ Y ≤ 0.338, ΔY = 0.01
* All axis arrays are stored as linear values (NOT log10).

3. QUANTITIES AND UNITS  (PAPER: SECTION 2.2, EQS. 2–3; SECTION 2.7)
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All rates are normalized by n_H² and are in erg cm³ s⁻¹:

    Λ_cool = C / n_H²      Γ_heat = H / n_H²      Λ_net = Λ_cool − Γ_heat

where C and H are the Cloudy total volumetric cooling and heating rates (Ctot, Htot
of save cooling, in erg cm⁻³ s⁻¹), and n_H is in cm⁻³.
Λ_net > 0 means net cooling, Λ_net < 0 net heating, Λ_net = 0 thermal equilibrium.
Cooling and heating are stored separately as well as combined (paper, Section 2.7).

  Symbol                       Quantity                               Units
  --------------------------   ------------------------------------   -------------------
  n_H                          hydrogen number density                cm⁻³
  T                            temperature                            K
  u                            specific internal energy               erg g⁻¹
  Y                            helium mass fraction M_He/(M_H+M_He)   dimensionless
  n_He/n_H, n_i/n_H, n_e/n_H   number ratios relative to hydrogen     dimensionless
  X_i                          mass fraction                          dimensionless
  Λ_net, Λ_cool, Γ_heat        rates normalized by n_H²               erg cm³ s⁻¹
  μ                            mean particle mass                     m_H (dimensionless)
  x_HI, x_HII, x_H2            hydrogen fractions                     dimensionless

4. FILE STRUCTURE — DATASETS  (PAPER: SECTION 3, TABLE 4)
---------------------------------------------------------

N_nH = 81, N_T = 352, N_Y = 11. 

Header
~~~~~~
  Dataset                                  Shape    Content                                 
  --------------------------------------   ------   -------------------------------------  
  Header/Redshift                          (1)      redshift of the file                   
  Header/Number_of_density_bins            scalar   N_nH = 81 (stored as float)            
  Header/Number_of_temperature_bins        scalar   N_T = 352 (stored as float)             
  Header/Number_of_helium_fractions        scalar   N_Y = 11 (stored as float)             
  Header/Number_of_species                 scalar   N_s = 13 (stored as float)              
  Header/Species_names                     (13)     individually tabulated heavy elements   
  Header/Abundances/Abund_names            (15)     H, He + the 13 heavy elements           
  Header/Abundances/Number_of_abundances   scalar   N_el = 15 (stored as float)             
  Header/Abundances/Solar_number_ratios    (15)     (n_i/n_H)_⊙                             
  Header/Abundances/Solar_mass_fractions   (15)     X_i,⊙                                   

Solar reference abundances (paper, Section 2.6 and Table 3): Cloudy GASS10
(Grevesse et al. 2010, solar_GASS10.abn).
X_H,⊙ = 0.7374651, Y_⊙ = 0.2492176, Z_⊙ = 0.01332.

  Element   (n_i/n_H)_⊙   X_i,⊙
  -------   -----------   -------
  H         1.00          0.7375
  He        8.51e-2       0.2492
  C         2.69e-4       2.36e-3
  N         6.76e-5       6.93e-4
  O         4.90e-4       5.74e-3
  Ne        8.51e-5       1.26e-3
  Na        1.74e-6       2.93e-5
  Mg        3.98e-5       7.08e-4
  Al        2.82e-6       5.57e-5
  Si        3.24e-5       6.66e-4
  S         1.32e-5       3.10e-4
  Ar        2.51e-6       7.34e-5
  Ca        2.19e-6       6.42e-5
  Fe        3.16e-5       1.29e-3
  Ni        1.66e-6       7.13e-5

Metal_free — H + He only, for 11 helium mass fractions  (paper: Section 2.5)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Dataset                                            Shape              Content                              Units           Paper
  ------------------------------------------------   ----------------   ----------------------------------   -------------   ---------------
  Metal_free/Hydrogen_density_bins                   (N_nH)             n_H                                  cm⁻³            Eq. 8
  Metal_free/Temperature_bins                        (N_T)              T                                    K               Eq. 9
  Metal_free/Helium_mass_fraction_bins               (N_Y)              Y                                    dimensionless   Eq. 10, Table 2
  Metal_free/Helium_number_ratio_bins                (N_Y)              n_He/n_H = (m_H/m_He) · Y/(1−Y)      dimensionless   Eq. 11, Table 2
  Metal_free/Net_Cooling                             (N_Y, N_T, N_nH)   Λ_net,HHe                            erg cm³ s⁻¹     Eq. 3
  Metal_free/Cooling_only                            (N_Y, N_T, N_nH)   Λ_cool,HHe                           erg cm³ s⁻¹     Eq. 2
  Metal_free/Heating_only                            (N_Y, N_T, N_nH)   Γ_heat,HHe                           erg cm³ s⁻¹     Eq. 2
  Metal_free/Electron_density_over_n_h               (N_Y, N_T, N_nH)   n_e/n_H                              dimensionless   Eq. 6
  Metal_free/Mean_particle_mass                      (N_Y, N_T, N_nH)   μ                                    m_H             Sect. 4.5
  Metal_free/Hydrogen_fractions/HI                   (N_Y, N_T, N_nH)   x_HI = n_HI/n_H                      dimensionless   Sect. 3.2
  Metal_free/Hydrogen_fractions/HII                  (N_Y, N_T, N_nH)   x_HII = n_HII/n_H                    dimensionless   Sect. 3.2
  Metal_free/Hydrogen_fractions/H2                   (N_Y, N_T, N_nH)   x_H2 = 2 n_H2/n_H                    dimensionless   Sect. 3.2
  Metal_free/Temperature/Energy_density_bins         (N_T)              specific internal energy u           erg g⁻¹         Table 4
  Metal_free/Temperature/Temperature                 (N_Y, N_T, N_nH)   T(u, n_H, Y) = 2 μ m_H u / (3 k_B)   K               Table 4
  Metal_free/Temperature/Hydrogen_density_bins       (N_nH)             n_H (copy)                           cm⁻³            Table 4
  Metal_free/Temperature/Helium_mass_fraction_bins   (N_Y)              Y (copy)                             dimensionless   Table 4
  Metal_free/Temperature/Helium_number_ratio_bins    (N_Y)              n_He/n_H (copy)                      dimensionless   Table 4

Following the Cloudy convention, x_H2 counts hydrogen atoms bound in molecules, so
x_HI + x_HII + x_H2 = 1 (paper, Section 3.2).
In Metal_free/Temperature/Temperature the second axis is the energy grid
Energy_density_bins, not Temperature_bins.

Solar — Solar composition restricted to the 15 tracked elements  (paper: Sections 2.1, 2.6)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Dataset                           Shape         Content                           Units           Paper
  -------------------------------   -----------   -------------------------------   -------------   ---------
  Solar/Hydrogen_density_bins       (N_nH)        n_H                               cm⁻³            Eq. 8
  Solar/Temperature_bins            (N_T)         T                                 K               Eq. 9
  Solar/Net_Cooling                 (N_T, N_nH)   Λ_net,⊙ (total, incl. H and He)   erg cm³ s⁻¹     Eq. 3
  Solar/Cooling_only                (N_T, N_nH)   Λ_cool,⊙                          erg cm³ s⁻¹     Eq. 2
  Solar/Heating_only                (N_T, N_nH)   Γ_heat,⊙                          erg cm³ s⁻¹     Eq. 2
  Solar/Electron_density_over_n_h   (N_T, N_nH)   (n_e/n_H)_⊙                       dimensionless   Eq. 6
  Solar/Mean_particle_mass          (N_T, N_nH)   μ                                 m_H             Eq. 13–14

Individual elements  (paper: Section 2.3, Eq. 7)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Groups: Carbon, Nitrogen, Oxygen, Neon, Sodium, Magnesium, Aluminium,
Silicon, Sulphur, Argon, Calcium, Iron, Nickel (<El> below).

  Dataset                      Shape         Content      Units         Paper
  --------------------------   -----------   ----------   -----------   ----------------
  <El>/Hydrogen_density_bins   (N_nH)        n_H          cm⁻³          Eq. 8
  <El>/Temperature_bins        (N_T)         T            K             Eq. 9
  <El>/Net_Cooling             (N_T, N_nH)   Λ_net,i,⊙    erg cm³ s⁻¹   Eq. 7
  <El>/Cooling_only            (N_T, N_nH)   Λ_cool,i,⊙   erg cm³ s⁻¹   Eq. 7, Sect. 2.7
  <El>/Heating_only            (N_T, N_nH)   Γ_heat,i,⊙   erg cm³ s⁻¹   Eq. 7, Sect. 2.7

Contribution of element i at its Solar abundance (paper, Eq. 7), obtained as the difference
between a Cloudy run with the full Cloudy Solar mixture and an identical run without
element i:

    Λ_net,i,⊙ = Λ_net,⊙ − Λ_net,⊙,i=0

applied separately to cooling, heating and net rates.

Total_Metals — sum of the 13 element contributions  (paper: Table 4)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Dataset                              Shape         Content          Units         Paper
  ----------------------------------   -----------   --------------   -----------   -------
  Total_Metals/Hydrogen_density_bins   (N_nH)        n_H              cm⁻³          Eq. 8
  Total_Metals/Temperature_bins        (N_T)         T                K             Eq. 9
  Total_Metals/Net_Cooling             (N_T, N_nH)   Σ_i Λ_net,i,⊙    erg cm³ s⁻¹   Eq. 6–7
  Total_Metals/Cooling_only            (N_T, N_nH)   Σ_i Λ_cool,i,⊙   erg cm³ s⁻¹   Eq. 6–7
  Total_Metals/Heating_only            (N_T, N_nH)   Σ_i Γ_heat,i,⊙   erg cm³ s⁻¹   Eq. 6–7

5. CONTACT
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Laura Di Federico  (University Observatory, LMU Munich) : laudif@usm.lmu.de