LyaDoublePeakedSED Class Reference

#include <LyaDoublePeakedSED.hpp>

Inheritance diagram for LyaDoublePeakedSED:

Public Member Functions
double	generateWavelength () const override
double	integratedLuminosity (const Range &wavelengthRange) const override
Range	intrinsicWavelengthRange () const override
double	scale () const
double	specificLuminosity (double wavelength) const override
void	specificLuminosityArray (Array &lambdav, Array &pv, const Range &wavelengthRange) const override
virtual double	specificLuminosity (double wavelength) const =0
virtual void	specificLuminosityArray (Array &lambdav, Array &pv, const Range &wavelengthRange) const =0
Public Member Functions inherited from SED
virtual double	generateWavelength () const =0
virtual double	integratedLuminosity (const Range &wavelengthRange) const =0
virtual Range	intrinsicWavelengthRange () const =0
Range	normalizationWavelengthRange () const
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
	LyaDoublePeakedSED ()
void	setupSelfBefore () override
Protected Member Functions inherited from ContSED
	ContSED ()
Protected Member Functions inherited from SED
	SED ()
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 = ContSED
using	ItemType = LyaDoublePeakedSED

Private Attributes
double	_scale
double	_wavelengthCenter
Range	_wavelengthRange
double	_wavelengthScale

Friends
class	ItemRegistry

Detailed Description

The LyaDoublePeakedSED class implements a double-peaked SED, centered on the Lyman-alpha line wavelength ${\lambda }_{\alpha }$, and corresponding to the spectrum that emerges from a static sphere of hydrogen gas surrounding a Lyman-alpha point source. This SED can be used as a simple model to represent sub-grid gas embedded in the source.

The spectrum can be expressed analytically (see Dijkstra et al. 2006a, ApJ, 649, 14-36). Using the photon velocity shift

$$v=\frac{\lambda -{\lambda }_{\alpha }}{{\lambda }_{\alpha }}c$$

as the spectral variable and a velocity scale $s$ configured by the user, the normalized spectrum can be written as

$$L_v(v)=\frac{3v^2}{2s^3[1+\cosh (v^3/s^3)]}.$$

The two peaks of this profile are situated at $v_{\ast }\approx \pm 1.06938s$.

The cumulative distribution is

$${\int }_{-\mathrm{\infty }}^v{L}_v(v^{\prime })\mathrm{d}{v}^{\prime }=\frac{1}{1+\exp (-v^3/s^3)},$$

which can be inverted so that we can obtain a sample from the distribution through

$$v=s{(\ln \frac{\mathcal{X}}{1-\mathcal{X}})}^{1/3},$$

where $\mathcal{X}$ is a uniform deviate.

To simplify some numerical operations, such as tabulating the SED, we limit the intrinsic range of the SED to $\pm 3.6s$ from the center. We have $L_v(3.6s)/L_v(v_{\ast })<4\times {10}^{-19}$ so that values outside this range will never contribute to the results anyway.

To simplify normalization of this SED, the source wavelength range configured by the user must fully contain the intrinsic wavelength range defined by

$${\lambda }_{\alpha }(1\pm \frac{3.6s}{c})$$

This item type is displayed only if the Boolean expression "Lya|Level3" evaluates to true after replacing the names by true or false depending on their presence.

Constructor & Destructor Documentation

LyaDoublePeakedSED()

LyaDoublePeakedSED::LyaDoublePeakedSED ( )

inlineprotected

Default constructor for concrete Item subclass LyaDoublePeakedSED : "a double-peaked spectrum around the central Lyman-alpha wavelength" .

Member Function Documentation

generateWavelength()

double LyaDoublePeakedSED::generateWavelength ( ) const

overridevirtual

This function draws a random wavelength from the normalized spectral energy distribution.

Implements SED.

integratedLuminosity()

double LyaDoublePeakedSED::integratedLuminosity ( const Range &  wavelengthRange ) const

overridevirtual

This function returns the normalized integrated luminosity $L$ (i.e. radiative power) over the specified wavelength range.

Implements SED.

intrinsicWavelengthRange()

Range LyaDoublePeakedSED::intrinsicWavelengthRange ( ) const

overridevirtual

This function returns the intrinsic wavelength range of the SED. For our double-peaked spectrum, we limit the range to $\pm 3.6s$ from the Lyman-alpha line center, as decribed in the class header.

Implements SED.

scale()

LyaDoublePeakedSED::scale ( ) const

inline

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

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

The minimum value for this property is "]0 km/s" .

The maximum value for this property is "1000 km/s]" .

The default value for this property is given by the conditional value expression "50 km/s" .

setupSelfBefore()

void LyaDoublePeakedSED::setupSelfBefore ( )

overrideprotectedvirtual

This function precalculates some values for later use.

Reimplemented from SimulationItem.

specificLuminosity()

double LyaDoublePeakedSED::specificLuminosity ( double  wavelength ) const

overridevirtual

This function returns the normalized specific luminosity $L_{\lambda }$ (i.e. radiative power per unit of wavelength) at the specified wavelength.

Implements ContSED.

specificLuminosityArray()

void LyaDoublePeakedSED::specificLuminosityArray ( Array &  lambdav, Array &  pv, const Range &  wavelengthRange  ) const

overridevirtual

This function returns the normalized specific luminosity $L_{\lambda }$ (i.e. radiative power per unit of wavelength) at a number of wavelength points within the specified wavelength range. The intrinsic wavelength range $\pm 3.6s$ of the SED is covered by 720 wavelength points on a regular linear grid.

Implements ContSED.

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

• LyaDoublePeakedSED.hpp