ReadFitsGeometry Class Reference

#include <ReadFitsGeometry.hpp>

Inheritance diagram for ReadFitsGeometry:

Public Member Functions
double	centerX () const
double	centerY () const
double	density (Position bfr) const override
string	filename () const
Position	generatePosition () const override
double	inclination () const
int	numPixelsX () const
int	numPixelsY () const
double	pixelScale () const
double	positionAngle () const
double	scaleHeight () const
double	SigmaX () const override
double	SigmaY () const override
double	SigmaZ () const override
Public Member Functions inherited from GenGeometry
int	dimension () 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 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
	ReadFitsGeometry ()
void	setupSelfBefore () override
Protected Member Functions inherited from GenGeometry
	GenGeometry ()
Protected Member Functions inherited from Geometry
	Geometry ()
Random *	random () 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 = GenGeometry
using	ItemType = ReadFitsGeometry

Private Member Functions
void	deproject (double &x) const
void	derotate (double &x, double &y) const
void	project (double &x) const
void	rotate (double &x, double &y) const

Private Attributes
double	_C1x
double	_C1y
double	_C2x
double	_C2y
double	_C3x
double	_C3y
double	_C4x
double	_C4y
double	_centerX
double	_centerY
double	_cosi
double	_cospa
double	_deltax
string	_filename
Array	_image
double	_inclination
int	_numPixelsX
int	_numPixelsY
int	_nx
int	_ny
int	_nz
double	_pixelScale
double	_positionAngle
double	_scaleHeight
double	_sini
double	_sinpa
double	_xmax
double	_xmin
Array	_Xv
double	_ymax
double	_ymin

Friends
class	ItemRegistry

Detailed Description

The ReadFitsGeometry class is a subclass of the GenGeometry class, and describes a geometry characterized by observations. A 2D observed image FITS file is read into SKIRT, and deprojected assuming a certain position angle and inclination. The density is assumed to follow a exponential profile in the vertical directions,

$$\rho (z)={\rho }_0\exp (-\frac{|z|}{h_z}).$$

By running a SKIRT simulation with inclination of 0 degrees and position angle of the simulated galaxy, the SKIRT model images can be compared with the observations. The model geometry is set by nine parameters: the input filename, the pixel scale $pix$, the position angle $pa$, the inclination $incl$, the number of pixels in x and y direction $n_x$ and $n_y$, the center of galaxy in (x,y) image coordinates $x_c$ and $y_c$ and the vertical scale height $h_z$.

This item type is displayed only if the Boolean expression "Level2" evaluates to true after replacing the names by true or false depending on their presence.

Constructor & Destructor Documentation

ReadFitsGeometry()

ReadFitsGeometry::ReadFitsGeometry ( )

inlineprotected

Default constructor for concrete Item subclass ReadFitsGeometry : "a geometry read from a 2D FITS file" .

Member Function Documentation

centerX()

ReadFitsGeometry::centerX ( ) const

inline

This function returns the value of the discoverable double property centerX : "x coordinate of the center (in pixels)" .

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

centerY()

ReadFitsGeometry::centerY ( ) const

inline

This function returns the value of the discoverable double property centerY : "y coordinate of the center (in pixels)" .

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

density()

double ReadFitsGeometry::density ( Position  bfr ) const

overridevirtual

This function returns the density $\rho (x,y,z)$ at the position (x,y,z).

Implements Geometry.

deproject()

void ReadFitsGeometry::deproject ( double &  x ) const

private

This function deprojects the x coordinate of a point in the inclined plane into the x coordinate of that point in the world coordinate system. The following operation is applied:

$$x=\frac{x^{\prime }}{\cos \theta }$$

where $\theta$ is the inclination.

derotate()

void ReadFitsGeometry::derotate ( double &  x, double &  y  ) const

private

This function transforms a set of x and y coordinates in the plane of the image into the x and y coordinates in the (derotated) inclined plane. The transformation matrix is the inverse of the matrix used for the rotate function.

filename()

string ReadFitsGeometry::filename ( ) const

inline

This function returns the value of the discoverable string property filename : "the name of the input image file" .

generatePosition()

Position ReadFitsGeometry::generatePosition ( ) const

overridevirtual

This function generates a random position $(x,y,z)$ from the geometry, by drawing a random point from the appropriate probability density distribution function. The $(x,y)$ coordinates are derived from the normalized cumulative luminosity vector of the observed 2D projection. The z coordinate is derived from the vertical exponential probability distribution function.

Implements Geometry.

inclination()

ReadFitsGeometry::inclination ( ) const

inline

This function returns the value of the discoverable double property inclination : "the inclination angle θ of the system" .

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

The minimum value for this property is "[0 deg" .

The maximum value for this property is "90 deg[" .

The default value for this property is given by the conditional value expression "0 deg" .

numPixelsX()

ReadFitsGeometry::numPixelsX ( ) const

inline

This function returns the value of the discoverable integer property numPixelsX : "number of pixels in the x direction" .

The minimum value for this property is "1" .

numPixelsY()

ReadFitsGeometry::numPixelsY ( ) const

inline

This function returns the value of the discoverable integer property numPixelsY : "number of pixels in the y direction" .

The minimum value for this property is "1" .

pixelScale()

ReadFitsGeometry::pixelScale ( ) const

inline

This function returns the value of the discoverable double property pixelScale : "the physical scale of the image (length per pixel)" .

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

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

positionAngle()

ReadFitsGeometry::positionAngle ( ) const

inline

This function returns the value of the discoverable double property positionAngle : "the position angle ω of the system" .

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

The minimum value for this property is "-360 deg" .

The maximum value for this property is "360 deg" .

The default value for this property is given by the conditional value expression "0 deg" .

project()

void ReadFitsGeometry::project ( double &  x ) const

private

This function projects the x coordinate of a point in the world coordinate system into the x coordinate of that point in the inclined plane. The following operation is applied:

$$x^{\prime }=x\cdot \cos \theta$$

where $\theta$ is the inclination.

rotate()

void ReadFitsGeometry::rotate ( double &  x, double &  y  ) const

private

This function transform a set of x and y coordinates in the inclined plane into the x and y coordinates in the (rotated) plane of the image. The transformation matrix $\mathbf{T}$ is given by:

$$\mathbf{T}=\left(\begin{array}{ccc}\cos \omega & -\sin \omega & 0\\ \sin \omega & \cos \omega & 0\\ 0& 0& 1\end{array}\right)\left(\begin{array}{ccc}0& 1& 0\\ -1& 0& 0\\ 0& 0& 1\end{array}\right)$$

where $\omega$ is the position angle.

scaleHeight()

ReadFitsGeometry::scaleHeight ( ) const

inline

This function returns the value of the discoverable double property scaleHeight : "the scale height" .

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

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

setupSelfBefore()

void ReadFitsGeometry::setupSelfBefore ( )

overrideprotectedvirtual

This function verifies the validity of the pixel scale, the inclination angle, the number of pixels in the x and y direction, the center of the image in x and y coordinates and the vertical scale height $h_z$. A vector of normalized cumulative pixel luminosities is computed, satisfying the condition that the total mass equals 1.

Reimplemented from Geometry.

SigmaX()

double ReadFitsGeometry::SigmaX ( ) const

overridevirtual

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

$${\mathrm{\Sigma }}_X={\int }_{-\mathrm{\infty }}^{\mathrm{\infty }}\rho (x,0,0)\text{d}x$$

Implements Geometry.

SigmaY()

double ReadFitsGeometry::SigmaY ( ) const

overridevirtual

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

$${\mathrm{\Sigma }}_Y={\int }_{-\mathrm{\infty }}^{\mathrm{\infty }}\rho (0,y,0)\text{d}y$$

Implements Geometry.

SigmaZ()

double ReadFitsGeometry::SigmaZ ( ) const

overridevirtual

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

$${\mathrm{\Sigma }}_Z={\int }_{-\mathrm{\infty }}^{\mathrm{\infty }}\rho (0,0,z)\text{d}z$$

Implements Geometry.

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

• ReadFitsGeometry.hpp