#include <Band.hpp>
Public Member Functions | |
double | effectiveWidth () const |
double | meanSpecificLuminosity (const Array &lambdav, const Array &pv) const |
double | pivotWavelength () const |
double | transmission (double wavelength) const |
Range | wavelengthRange () 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 | |
Band () | |
virtual size_t | dataSize () const =0 |
void | setupSelfAfter () override |
virtual const double * | transmissionData () const =0 |
virtual const double * | wavelengthData () const =0 |
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 = SimulationItem |
using | ItemType = Band |
Private Attributes | |
const double * | _lambdav |
double | _pivot |
size_t | _size |
const double * | _transv |
double | _width |
Friends | |
class | ItemRegistry |
An instance of a Band subclass represents the transmission curve of a particular observational filter as a function of wavelength. Examples include the standard Johnson filters and the transmission curves in each broadband for actual observatories such as GALEX, SDSS or Herschel.
This abstract base class implements the key operations offered by all Band objects: obtaining the transmission at a given wavelength, calculating the mean specific luminosity for a given SED after convolving it with the transmission curve, and determining the pivot wavelength. Subclasses are responsible only for acquiring and serving the data points defining the transmission curve for the band.
Refer to the appendix in Camps et al. 2016 (MNRAS 462, 1057-1075) for a brief introduction of the relevant concepts and a derivation of the corresponding formulas. For the purposes of this class, a band is defined through its arbitrarily scaled transmission curve \(T(\lambda)\). The relative transmission at a given wavelength can then be written as
\[ T_\text{rel}(\lambda) = \frac{ T(\lambda) } { \max[ T(\lambda) ] }. \]
Given a spectral energy distribution \(L_\lambda(\lambda)\), the mean specific luminosity over the band \(\left<L_\lambda\right>\) can then be obtained through
\[ \left<L_\lambda\right> = \frac{ \int L_\lambda(\lambda)T(\lambda) \,\mathrm{d}\lambda } { \int T(\lambda) \,\mathrm{d}\lambda }. \]
The pivot wavelength of the band is defined as the wavelength at which the mean specific luminosity can be properly converted between wavelength and frequency representations. It is given by
\[ \lambda_\mathrm{pivot} = \sqrt{ \frac{ \int T(\lambda) \,\mathrm{d}\lambda } { \int T(\lambda) \,\mathrm{d}\lambda/\lambda^2 } }. \]
The effective width of the band is defined as the horizontal size of a rectangle with height equal to the maximum transmission and with the same area as the one covered by the band's transmission curve. It is given by
\[ W_\mathrm{eff} = \frac{ \int T(\lambda) \,\mathrm{d}\lambda } { \max[ T(\lambda) ] }. \]
As set forth by Camps et al. 2016, for energy measuring devices (bolometers) the total system transmission \(T(\lambda)\) is usually given by the instrument designers, and it can be used directly for this class. For photon counters (including all instruments in the UV, optical and near infrared), the total system response \(R(\lambda)\) is usually given instead. The transmission curve needed for this class can be derived from the response curve through
\[ T(\lambda) = \lambda\,R(\lambda). \]
This operation must be performed in a preprocessing step before handing the data to this class.
Also, to further simplify the above formulas, this class requires that the transmission curve provided by a subclass is normalized to unity, i.e.
\[ \int T(\lambda) \,\mathrm{d}\lambda = 1. \]
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inlineprotected |
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protectedpure virtual |
This function returns the number of elements in the wavelength and transmission data arrays held by a subclass.
Implemented in BroadBand, and TabulatedBand.
double Band::effectiveWidth | ( | ) | const |
This function returns the effective width for this band, i.e. the horizontal size of a rectangle with height equal to the maximum transmission and with the same area as the one covered by the band's transmission curve. See the class header for the relevant formulas.
This function returns the mean specific luminosity \(\left<L_\lambda\right>\) for a given SED after convolving it with the transmission curve for this band. See the class header for the relevant formulas.
double Band::pivotWavelength | ( | ) | const |
This function returns the pivot wavelength for this band, i.e. the wavelength at which the mean specific luminosity can be properly converted between wavelength and frequency representations. See the class header for the relevant formulas.
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overrideprotectedvirtual |
This function obtains pointers to the data representing the transmission curve from the subclass and precomputes various values for later use.
Reimplemented from SimulationItem.
double Band::transmission | ( | double | wavelength | ) | const |
This function returns the relative transmission \(T_\text{rel}(\lambda)\) for this band at the specified wavelength. See the class header for the relevant formulas.
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protectedpure virtual |
This function returns a pointer to the first transmission value in the corresponding array held by a subclass. The number of elements in this array can be obtained through the dataSize() function. The transmission values must be normalized as described in the class header.
Implemented in BroadBand, and TabulatedBand.
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protectedpure virtual |
This function returns a pointer to the first wavelength in the corresponding array held by a subclass. The number of elements in this array can be obtained through the dataSize() function.
Implemented in BroadBand, and TabulatedBand.
Range Band::wavelengthRange | ( | ) | const |
This function returns the wavelength range in which the transmission for this band may be nonzero.