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DonutGeometry Class Reference

#include <DonutGeometry.hpp>

Inheritance diagram for DonutGeometry:
Inheritance graph
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Public Member Functions

double density (double R, double z) const override
 
Position generatePosition () const override
 
double largeRadius () const
 
double SigmaR () const override
 
double SigmaZ () const override
 
double smallRadius () const
 
- Public Member Functions inherited from AxGeometry
virtual double density (double R, double z) const =0
 
double density (Position bfr) const override
 
int dimension () const override
 
virtual double SigmaR () const =0
 
double SigmaX () const override
 
double SigmaY () const override
 
virtual double density (Position bfr) const =0
 
virtual int dimension () const =0
 
virtual Position generatePosition () const =0
 
virtual double SigmaX () const =0
 
virtual double SigmaY () const =0
 
virtual double SigmaZ () const =0
 
- 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 ItemgetItemProperty (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)
 
Itemoperator= (const Item &)=delete
 
Itemparent () 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

 DonutGeometry ()
 
void setupSelfBefore () override
 
- Protected Member Functions inherited from AxGeometry
 AxGeometry ()
 
- Protected Member Functions inherited from Geometry
 Geometry ()
 
Randomrandom () const
 
void setupSelfBefore () override
 
- 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 = AxGeometry
 
using ItemType = DonutGeometry
 

Private Attributes

double _A
 
double _largeRadius
 
const double & _R0
 
const double & _r0
 
double _r02
 
double _smallRadius
 

Friends

class ItemRegistry
 

Detailed Description

The DonutGeometry class is a subclass of the AxGeometry class and describes the geometry of an axisymmetric ring torus (i.e. a doughnut geometry) of uniform density. This ring torus geometry is often used to model the dusty gas in the equatorial plane of active galactic nuclei (AGN), to explain the observed variety of AGN types as a distribution of observed system orientations relative to this obscuring torus of gas and dust; see Antonucci (1993, ARA&A, 31, 473), Urry & Padovani (1995, PASP, 107, 803) and Netzer (2015, ARA&A, 53, 365).

The ring torus geometry is obtained by revolving a circle of radius \(r_{\text{small}}\) about an axis that is co-planar with this circle, at a radius \(r_{\text{large}}\). Inside this surface of revolution the density has a constant value, and outside this surface the density is zero. In formula, this is easily expressed in cylindrical coordinates as

\[ \rho(R, z) = A\ \quad\text{for } \sqrt{(R-r_{\text{large}})^2 + z^2}<r_{\text{small}}. \]

There are two free parameters describing this torus geometry: the torus radius in the azimuthal plane \(r_{\text{small}}\) and the torus radius in the equatorial plane \(r_{\text{large}}\).

Constructor & Destructor Documentation

◆ DonutGeometry()

DonutGeometry::DonutGeometry ( )
inlineprotected

Default constructor for concrete Item subclass DonutGeometry : "a donut torus geometry" .

Member Function Documentation

◆ density()

double DonutGeometry::density ( double  R,
double  z 
) const
overridevirtual

This function returns the density \(\rho(R,z)\) at the cylindrical radius \(R\) and height \(z\). It just implements the geometry definition.

Implements AxGeometry.

◆ generatePosition()

Position DonutGeometry::generatePosition ( ) const
overridevirtual

This function generates a random position from the uniform ring torus geometry. A random azimuth angle \(\phi\) is readily found by choosing a random deviate \({\cal{X}}\) and setting \(\phi = 2\pi {\cal{X}}\). Then, a random position in the small circle in the azimuthal plane is found (in polar coordinates) as \( \theta' = 2\pi {\cal{X}}_1 \) and \( r' = r_{\text{small}} \sqrt{{\cal{X}}_2}\), with \( {\cal{X}}_1 \) and \( {\cal{X}}_2 \) two more random deviates. Finally, these small circle coordinates are transformed to global cylindrical coordinates as \(z = r' \sin(\theta')\) and \(R = r_{\text{large}} + r' \cos(\theta')\).

Implements Geometry.

◆ largeRadius()

DonutGeometry::largeRadius ( ) const
inline

This function returns the value of the discoverable double property largeRadius : "the radius of the torus circle in the equatorial plane" .

This property represents a physical quantity of type "length" .

The minimum value for this property is "]0" .

◆ setupSelfBefore()

void DonutGeometry::setupSelfBefore ( )
overrideprotectedvirtual

This function calculates some frequently used values. The normalization parameter \(A\) is set by the normalization condition that total mass equals one, i.e.

\[ A = \frac{1}{V} = \frac{1}{2 \pi^2 r_{\text{large}} r_{\text{small}}^2}. \]

Reimplemented from SimulationItem.

◆ SigmaR()

double DonutGeometry::SigmaR ( ) const
overridevirtual

This function returns the radial surface density, i.e. the integration of the density along a line in the equatorial plane starting at the centre of the coordinate system,

\[ \Sigma_R = \int_0^\infty \rho(R,0)\,{\text{d}}R. \]

For this geometry,

\[ \Sigma_R = A\,2 r_{\text{small}}. \]

Implements AxGeometry.

◆ SigmaZ()

double DonutGeometry::SigmaZ ( ) const
overridevirtual

This function returns the Z-axis surface density, i.e. the integration of the density along the entire Z-axis,

\[ \Sigma_Z = \int_{-\infty}^\infty \rho(0,z)\, {\text{d}}z. \]

For this geometry, the integral is simply zero.

Implements Geometry.

◆ smallRadius()

DonutGeometry::smallRadius ( ) const
inline

This function returns the value of the discoverable double property smallRadius : "the radius of the torus circle in the azimuthal plane" .

This property represents a physical quantity of type "length" .

The minimum value for this property is "]0" .


The documentation for this class was generated from the following file: