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The SKIRT project
advanced radiative transfer for astrophysics
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The SKIRT project
advanced radiative transfer for astrophysics
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#include <FlatUniverseCosmology.hpp>
Public Member Functions | |
| double | angularDiameterDistance () const override |
| double | luminosityDistance () const override |
| double | matterDensityFraction () const |
| double | modelRedshift () const override |
| double | redshift () const |
| double | reducedHubbleConstant () const |
| double | relativeExpansionRate () const override |
| Public Member Functions inherited from SimulationItem | |
| template<class T> | |
| T * | find (bool setup=true) const |
| template<class T> | |
| T * | interface (int levels=-999999, bool setup=true) const |
| virtual string | itemName () const |
| void | setup () |
| string | typeAndName () const |
| Public Member Functions inherited from Item | |
| Item (const Item &)=delete | |
| virtual | ~Item () |
| void | addChild (Item *child) |
| const vector< Item * > & | children () const |
| virtual void | clearItemListProperty (const PropertyDef *property) |
| void | destroyChild (Item *child) |
| virtual bool | getBoolProperty (const PropertyDef *property) const |
| virtual vector< double > | getDoubleListProperty (const PropertyDef *property) const |
| virtual double | getDoubleProperty (const PropertyDef *property) const |
| virtual string | getEnumProperty (const PropertyDef *property) const |
| virtual int | getIntProperty (const PropertyDef *property) const |
| virtual vector< Item * > | getItemListProperty (const PropertyDef *property) const |
| virtual Item * | getItemProperty (const PropertyDef *property) const |
| virtual string | getStringProperty (const PropertyDef *property) const |
| int | getUtilityProperty (string name) const |
| virtual void | insertIntoItemListProperty (const PropertyDef *property, int index, Item *item) |
| Item & | operator= (const Item &)=delete |
| Item * | parent () const |
| virtual void | removeFromItemListProperty (const PropertyDef *property, int index) |
| virtual void | setBoolProperty (const PropertyDef *property, bool value) |
| virtual void | setDoubleListProperty (const PropertyDef *property, vector< double > value) |
| virtual void | setDoubleProperty (const PropertyDef *property, double value) |
| virtual void | setEnumProperty (const PropertyDef *property, string value) |
| virtual void | setIntProperty (const PropertyDef *property, int value) |
| virtual void | setItemProperty (const PropertyDef *property, Item *item) |
| virtual void | setStringProperty (const PropertyDef *property, string value) |
| void | setUtilityProperty (string name, int value) |
| virtual string | type () const |
Protected Member Functions | |
| FlatUniverseCosmology () | |
| Protected Member Functions inherited from Cosmology | |
| Cosmology () | |
| Protected Member Functions inherited from SimulationItem | |
| SimulationItem () | |
| virtual bool | offersInterface (const std::type_info &interfaceTypeInfo) const |
| virtual void | setupSelfAfter () |
| virtual void | setupSelfBefore () |
| Protected Member Functions inherited from Item | |
| Item () | |
Private Types | |
| using | BaseType |
| using | ItemType |
Private Attributes | |
| double | _matterDensityFraction |
| double | _redshift |
| double | _reducedHubbleConstant |
Friends | |
| class | ItemRegistry |
An instance of the FlatUniverseCosmology class represents a cosmology where the simulated model resides at a given redshift \(z\) in a standard spatially-flat \(\Lambda\mathrm{CDM}\) universe. The allowed redshift range is \(0\le z\le 15\), i.e. including the epoch of reionization. If \(z=0\), the behavior is the same as that of a LocalUniverseCosmology.
In addition to the redshift, this cosmology has two parameters, namely the reduced Hubble constant \(h=H_0/(100\,\mathrm{km}\,\mathrm{s}^{-1}\,\mathrm{Mpc}^{-1})\) and the matter density fraction \(\Omega_\mathrm{m}\). The default values for these parameters are compatible with the latest observations and close to the values used by many recent cosmological simulations.
For a spatially-flat cosmology, the line-of-sight and transverse comoving distances are identical. We further ignore the radiation density, which is justified for the allowed redshift range \(z\le15\). With these assumptions, the comoving distance \(d_\mathrm{M}(z)\) corresponding to redshift $z$ can be obtained from the matter density fraction \(\Omega_\mathrm{m}\) and the Hubble constant \(H_0=h \times 100\,\mathrm{km}\,\mathrm{s}^{-1}\,\mathrm{Mpc}^{-1}\) using
\[ d_\mathrm{M}(z) = \frac{c}{H_0} \int_0^z \frac{\mathrm{d}z'}{\sqrt{\Omega_\mathrm{m}(1+z')^3 + (1-\Omega_\mathrm{m})}} \]
where \(c\) is the speed of light.
The angular-diameter distance \(d_\mathrm{A}(z)\) and the luminosity distance \(d_\mathrm{L}(z)\) are then obtained from
\[ d_\mathrm{A}(z) = (1+z)^{-1} \, d_\mathrm{M}(z) \]
and
\[ d_\mathrm{L}(z) = (1+z) \, d_\mathrm{M}(z). \]
Finally, the relative expansion rate of the universe \(H=\dot{a}/a\), usually called the Hubble parameter, is given by
\[ H(z) = H_0 \sqrt{\Omega_\mathrm{m}(1+z')^3 + (1-\Omega_\mathrm{m})}. \]
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inlineprotected |
Default constructor for concrete Item subclass FlatUniverseCosmology: "the model is at a given redshift in a flat universe".
When a value is entered for this property, the names provided by the conditional value expression "redshift:NonZeroRedshift" are inserted into the name sets used for evaluating Boolean expressions.
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overridevirtual |
This function returns the angular-diameter distance \(d_\mathrm{A}(z)\), calculated from the user-configured cosmology parameters as described in the class header. The integral is evaluated numerically. We don't worry about performance because this function is called just once during simulation setup.
Implements Cosmology.
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overridevirtual |
This function returns the luminosity distance. For this class, calculated from the user-configured cosmology parameters as described in the class header. The integral is evaluated numerically. We don't worry about performance because this function is called just once during simulation setup.
Implements Cosmology.
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inline |
This function returns the value of the discoverable double property matterDensityFraction: "the cosmological matter density fraction Ω_m".
The minimum value for this property is "0.1".
The maximum value for this property is "0.9".
The default value for this property is given by the conditional value expression "0.310".
This property is relevant only if the Boolean expression "redshift" evaluates to true after replacing the names by true or false depending on their presence.
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overridevirtual |
This function returns the redshift at which the model resides.
Implements Cosmology.
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inline |
This function returns the value of the discoverable double property redshift: "the redshift z of the model coordinate frame".
The minimum value for this property is "[0".
The maximum value for this property is "15]".
The default value for this property is given by the conditional value expression "1".
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inline |
This function returns the value of the discoverable double property reducedHubbleConstant: "the reduced Hubble constant h".
The minimum value for this property is "0.3".
The maximum value for this property is "1".
The default value for this property is given by the conditional value expression "0.675".
This property is relevant only if the Boolean expression "redshift" evaluates to true after replacing the names by true or false depending on their presence.
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overridevirtual |
This function returns the relative expansion rate of the universe, \(H=\dot{a}/a\), often called the Hubble parameter. The function returns the value in SI units, i.e. \(\mathrm{s}^{-1}\).
Implements Cosmology.