diff --git a/doc/RTD/source/SubgridModels/EAGLE/index.rst b/doc/RTD/source/SubgridModels/EAGLE/index.rst index 332524240b3d8933d6425c369ed1fc5ec9247a1b..b2a004955f88036dc4c36f6cb98731f6e628dd96 100644 --- a/doc/RTD/source/SubgridModels/EAGLE/index.rst +++ b/doc/RTD/source/SubgridModels/EAGLE/index.rst @@ -5,16 +5,23 @@ EAGLE model =========== +This section of the documentation gives a brief description of the +different components of the EAGLE subgrid model. We mostly focus on +the parameters and values output in the snapshots. + Chemical tracers ~~~~~~~~~~~~~~~~ The gas particles in the EAGLE model carry metal abundance information in the form of metal mass fractions. We follow the following 9 elements: `H`, `He`, `C`, `N`, `O`, `Ne`, `Mg`, `Si` and `Fe`. We -additionally follow the total metal mass fraction `Z`. This is -typically larger than the sum of the 7 metals that are individually -traced since this will also contain the contribution of all the -elements that are not individually followed. +additionally follow the total metal mass fraction (i.e. absolute +metallicity) `Z`. This is typically larger than the sum of the 7 +metals that are individually traced since this will also contain the +contribution of all the elements that are not individually followed. +We note that all of definitions are independent of any defitinio of +solar the solar metallicity :math:`Z_\odot` or of any solar abundance +pattern. As part of the diagnostics, we additionally trace the elements coming from the different stellar evolution channels. We store for each @@ -35,26 +42,107 @@ The chemistry module in ``src/chemistry/EAGLE`` includes all the arrays that are added to the particles and the functions used to compute the smoothed elements. -In the snapshots, we output: - -+------------------------------+--------------------------------+-----------+-----------------------------+ -| Name | Description | Units | Comments | -+==============================+================================+===========+=============================+ -| ``ElementAbundance`` | | Fraction of the gas mass | [-] | | Array of length | -| | | in the different elements | | | 9 for each particle | -+------------------------------+--------------------------------+-----------+-----------------------------+ -| ``SmoothedElementAbundance`` | | Fraction of the gas mass | [-] | | Array of length | -| | | in the different elements | | | 9 for each particle | -| | | smoothed over SPH neighbours | | | -+------------------------------+--------------------------------+-----------+-----------------------------+ -| ``Metallicity`` | | Fraction of the gas mass | [-] | | -| | | in *all* metals | | | -+------------------------------+--------------------------------+-----------+-----------------------------+ -| ``SmoothedMetallicity`` | | Fraction of the gas mass | [-] | | -| | | in *all* metals | | | -| | | smoothed over SPH neighbours | | | -+------------------------------+--------------------------------+-----------+-----------------------------+ - +When a star is formed (see below), it inherits all the chemical +tracers of its parent gas particle. + +In the snapshots, we output for each gas and star particle: + ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| Name | Description | Units | Comments | ++==================================+=====================================+===========+=============================+ +| ``ElementAbundance`` | | Fraction of the gas/star mass | [-] | | Array of length | +| | | in the different elements | | | 9 for each particle | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``SmoothedElementAbundance`` | | Fraction of the gas/star mass | [-] | | Array of length | +| | | in the different elements | | | 9 for each particle | +| | | smoothed over SPH neighbours | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``Metallicity`` | | Fraction of the gas/star mass | [-] | | +| | | in *all* metals | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``SmoothedMetallicity`` | | Fraction of the gas/star mass | [-] | | +| | | in *all* metals | | | +| | | smoothed over SPH neighbours | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``TotalMassFromSNIa`` | | Total mass of the gas/star | [U_M] | | +| | | that was produced by enrichment | | | +| | | from SNIa stars | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``MetalMassFracFromSNIa`` | | Fraction of the *total* gas/star | [-] | | +| | | mass that is in metals produced | | | +| | | by enrichment from SNIa stars | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``TotalMassFromAGB`` | | Total mass of the gas/star | [U_M] | | +| | | that was produced by enrichment | | | +| | | from AGB stars | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``MetalMassFracFromAGB`` | | Fraction of the *total* gas/star | [-] | | +| | | mass that is in metals produced | | | +| | | by enrichment from AGB star | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``TotalMassFromSNII`` | | Total mass of the gas/star | [U_M] | | +| | | that was produced by enrichment | | | +| | | from SNII stars | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``MetalMassFracFromSNII`` | | Fraction of the gas/star mass | [-] | | +| | | that is in metals produced by | | | +| | | enrichment from SNII stars | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``IronMassFracFromSNIa`` | | Fraction of the *total* gas/star | [-] | | +| | | mass in *iron* produced produced | | | +| | | by enrichment from SNIa stars | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ +| ``SmoothedIronMassFracFromSNIa`` | | Fraction of the *total* gas/star | [-] | | +| | | mass in *iron* produced produced | | | +| | | by enrichment from SNIa stars | | | +| | | smoothed over SPH neighbours | | | ++----------------------------------+-------------------------------------+-----------+-----------------------------+ + +The stars will lose mass over their lifetime (up to ~45%). The +fractions will remain unchanged but if one is interested in computing +an absolute metal mass (say) for a star, the ``InitialMass`` (see +below) of the star must be used. + +The chemistry model only requires a small number of parameters to be +specified in the YAML file. These are the initial values of the +metallicity and element mass fractions. These are then applied at the +start of a simulation to *all* the *gas* particles. All 9 elements have +to be specified An example section, for primordial abundances (typical +for a cosmological run), is: + +.. code:: YAML + + EAGLEChemistry: + Metallicity: 0. # Mass fraction in all metals + InitAbundance_Hydrogen: 0.755 # Mass fraction in Hydrogen + InitAbundance_Helium: 0.245 # Mass fraction in Helium + InitAbundance_Carbon: 0. # Mass fraction in Carbon + InitAbundance_Nitrogen: 0. # Mass fraction in Nitrogen + InitAbundance_Oxygen: 0. # Mass fraction in Oxygen + InitAbundance_Neon: 0. # Mass fraction in Neon + InitAbundance_Magnesium: 0. # Mass fraction in Magnesium + InitAbundance_Silicon: 0. # Mass fraction in Silicon + InitAbundance_Iron: 0. # Mass fraction in Iron + +Whilst one would use the following values for solar abundances +(typical for an idealised low-redshift run): + +.. code:: YAML + + EAGLEChemistry: + Metallicity: 0.014 # Mass fraction in all metals + InitAbundance_Hydrogen: 0.70649785 # Mass fraction in Hydrogen + InitAbundance_Helium: 0.28055534 # Mass fraction in Helium + InitAbundance_Carbon: 2.0665436e-3 # Mass fraction in Carbon + InitAbundance_Nitrogen: 8.3562563e-4 # Mass fraction in Nitrogen + InitAbundance_Oxygen: 5.4926244e-3 # Mass fraction in Oxygen + InitAbundance_Neon: 1.4144605e-3 # Mass fraction in Neon + InitAbundance_Magnesium: 5.907064e-4 # Mass fraction in Magnesium + InitAbundance_Silicon: 6.825874e-4 # Mass fraction in Silicon + InitAbundance_Iron: 1.1032152e-3 # Mass fraction in Iron + + + Cooling: Wiersma+2008a ~~~~~~~~~~~~~~~~~~~~~~