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Gyoto::Astrobj::PageThorneDisk Class Reference

Geometrically thin disk in Kerr metric. More...

#include <GyotoPageThorneDisk.h>

Inheritance diagram for Gyoto::Astrobj::PageThorneDisk:
Gyoto::Astrobj::ThinDisk Gyoto::Astrobj::Generic Gyoto::Functor::Double_constDoubleArray Gyoto::SmartPointee

List of all members.

Public Member Functions

 PageThorneDisk ()
 Standard constructor.
 PageThorneDisk (const PageThorneDisk &)
 Copy constructor.
virtual PageThorneDiskclone () const
 Cloner.
virtual ~PageThorneDisk ()
 Destructor.
virtual void setMetric (SmartPointer< Metric::Generic >)
 Set metric, checking that it is either KerrBL or KerrKS.
virtual void updateSpin ()
 Get spin from metric, which must be KerrBL or KerrKS.
virtual double emission (double nu_em, double dsem, double c_ph[8], double c_obj[8]) const
 INVARIANT emission j_{}/^{2}.
virtual void fillElement (FactoryMessenger *fmp) const
 called from Factory
virtual double getInnerRadius () const
 Get rin_.
virtual void setInnerRadius (double)
 Set rin_.
virtual double getOuterRadius () const
 Get rout_.
virtual void setOuterRadius (double)
 Set rout_.
virtual double getThickness () const
 Get thickness_.
virtual void setThickness (double)
 Set thickness_.
virtual int getDir () const
 Get dir_.
virtual void setDir (int)
 Set dir_.
virtual double operator() (double const coord[])
 theta-pi/2 or z
virtual double projectedRadius (double const coord[]) const
 projected radius of position coord on the equatorial plane
virtual double sphericalPhi (double const coord[]) const
 longitude
virtual void getVelocity (double const pos[4], double vel[4])
virtual int setParameter (std::string name, std::string content)
 Called from setParameters()
virtual int Impact (Gyoto::Photon *ph, size_t index, Astrobj::Properties *data=NULL)
 does a photon at these coordinates impact the object?
virtual SmartPointer
< Metric::Generic
getMetric () const
virtual double getRmax ()
 Get maximal distance from center of coordinate system.
const std::string getKind () const
 Get the kind of the Astrobj (e.g. "Star")
virtual void setRmax (double val)
 Set maximal distance from center of coordinate system.
virtual void unsetRmax ()
 Set rmax_set_ to 0.
void setFlag_radtransf (int flag)
 Set whether the object is optically thin.
int getFlag_radtransf () const
 Query whether object is optically thin.
virtual Quantity_t getDefaultQuantities ()
virtual void setParameters (FactoryMessenger *fmp)
 Main loop in Subcontractor_t function.
virtual void processHitQuantities (Photon *ph, double *coord_ph_hit, double *coord_obj_hit, double dt, Astrobj::Properties *data) const
virtual double integrateEmission (double nu1, double nu2, double dsem, double c_ph[8], double c_obj[8]=NULL) const
 ^nu2 I_nu dnu (or j_nu)
virtual double transmission (double nuem, double dsem, double coord[8]) const
 Transmission: exp( {} * dsem )
void checkPhiTheta (double coord[8]) const

Protected Types

typedef Gyoto::SmartPointer
< Gyoto::SmartPointee
Subcontractor_t (Gyoto::FactoryMessenger *)
 A subcontractor builds an object upon order from the Factory.

Protected Member Functions

void incRefCount ()
 Increment the reference counter. Warning: Don't mess with the counter.
int decRefCount ()
 Decrement the reference counter and return current value. Warning: Don't mess with the counter.
int getRefCount ()
 Get the current number of references.

Protected Attributes

double rin_
 disk inner radius
double rout_
 disk outer radius
double thickness_
 disk thickness
int dir_
 1 for corotating (default), -1 for counterrotating.
SmartPointer
< Gyoto::Metric::Generic
gg_
double rmax_
 Maximum distance to the center of the coordinate system.
int rmax_set_
 Never recompute rmax: it was externally set.
const std::string kind_
 Kind of object (e.g. "Star"...)
int flag_radtransf_
 1 if radiative transfer inside Astrobj, else 0

Private Attributes

double aa_
 Spin.
double aa2_
double x0_
double x1_
double x2_
double x3_

Friends

class Gyoto::SmartPointer< Gyoto::Astrobj::PageThorneDisk >

Detailed Description

Geometrically thin disk in Kerr metric.

This class describes a disk contained in the z=0 (equatorial) plane, extending from r=r_ISCO to r=infinity. The flux emitted at radius r is given by Page & Thorne (1974, ApJ 191:499, Eqs. 11b, 14, 15).

The metric must be either KerrBL or KerrKS.

Warning: The spin value and the inner radius are cached when the metric is assigned using setMetric(). If the spin is later changed in the metric, updateSpin() must be called.


Member Typedef Documentation

typedef Gyoto::SmartPointer<Gyoto::SmartPointee> Gyoto::SmartPointee::Subcontractor_t(Gyoto::FactoryMessenger *)
inherited

A subcontractor builds an object upon order from the Factory.

Various classes need to provide a subcontractor to be able to instanciate themselves upon order from the Factory. A subcontractor is a function (often a static member function) which accepts a pointer to a FactoryMessenger as unique parameter, communicates with the Factory using this messenger to read an XML description of the object to build, and returns this objet. SmartPointee::Subcontractor_t* is just generic enough a typedef to cast to and from other subcontractor types: Astrobj::Subcontractor_t, Metric::Subcontractor_t, Spectrum::Subcontractor_t. A subcontractor needs to be registered using the relevant Register() function: Astrobj::Register(), Metric::Register(), Spectrum::Register().


Member Function Documentation

void Gyoto::Astrobj::Generic::checkPhiTheta ( double  coord[8]) const
inherited

checkPhiTheta() Modifies coord if the corrdinates are spherical-like so that coord[2]=theta is in [0,pi] and coord[3]=phi is in [0,2pi]. Important to use in all astrobj in spherical coordinates to prevent "z-axis problems".

virtual double Gyoto::Astrobj::PageThorneDisk::emission ( double  nu_em,
double  dsem,
double  coord_ph[8],
double  coord_obj[8] 
) const
virtual

INVARIANT emission j_{}/^{2}.

 Called by the default implementation for processHitQuantities().

 emission() computes the intensity I_nu emitted by the small
 volume of length dsem. It should take self-absorption along dsem
 into account.

 Reminder :
  - intensity = I_nu [erg cm^-2 s^-1 ster^-1 Hz^-1];
  - invariant intensity = I_nu/nu^3, which has the same value in any frame;
  - emission coefficient = j_nu [erg cm^-3 s^-1 ster^-1 Hz^-1] ,
            defined by dI_nu = j_nu*ds, where ds is the distance
            travelled by the photon inside the object;
  - invariant emission coef = j_nu/nu^2, which has the same value
            in any frame.

 The equation used for radiative transfer (without absorption) is:
                      d(I_nu/nu^3)/dlambda = (j_nu/nu^2)  [*]
  where lambda is the integration parameter along the null geodesic.
NB: Let us consider a particular observer, 
    with nu being the frequency measured by this observer,
    and ds being the proper distance (as measured by the observer) 
    that the photon travels as it moves
    from lambda to lambda+dlambda along its geodesic.
    Then it can be shown that :
                    dlambda = ds/nu
    This shows that Eq. [*] is homogeneous.
 The default implementation returns 1. if optically thick and dsem
 if optically thin. It allows for a quick implementation of your
 object for visualization purposes.

 \param nu_em Frequency at emission
 \param dsem length over which to integrate inside the object
 \param coord_ph Photon coordinate
 \param coord_obj Emitter coordinate at current photon position

Reimplemented from Gyoto::Astrobj::Generic.

virtual Quantity_t Gyoto::Astrobj::Generic::getDefaultQuantities ( )
virtualinherited

Return a Gyoto::Quantity_t suitable as input to Gyoto::Scenery::setRequestedQuantities() to set de default quantities to compute for this object. The default of these defaults GYOTO_QUANTITY_INTENSITY.

int Gyoto::Astrobj::Generic::getFlag_radtransf ( ) const
inherited

Query whether object is optically thin.

See setFlag_radtransf(int flag).

virtual SmartPointer<Metric::Generic> Gyoto::Astrobj::Generic::getMetric ( ) const
virtualinherited

Get the Metric

Reimplemented in Gyoto::Astrobj::Star.

virtual double Gyoto::Astrobj::Generic::getRmax ( )
virtualinherited

Get maximal distance from center of coordinate system.

Get maximal distance from center of coordinate system at which a Photon may hit the object.

Child classes may use the rmax_ member to cache this value.

It can also be set using setRmax(). If setRmax has been used to set rmax_, getRmax() must not recompute it.

Reimplemented in Gyoto::Astrobj::Star, and Gyoto::Astrobj::Torus.

virtual void Gyoto::Astrobj::ThinDisk::getVelocity ( double const  pos[4],
double  vel[4] 
)
virtualinherited

Used by Standard::Impact().

Fill vel with the 4-vector velocity of the fluid at 4-position pos. getVelocity() should work at some distance from the equatorial plane. The default implementation calls Metric::Generic::circularVelocity().

Parameters:
posinput, 4-position at which to compute velocity;
veloutput, 4-velocity at pos.

Reimplemented in Gyoto::Astrobj::PatternDisk, Gyoto::Astrobj::DynamicalDisk, and Gyoto::Astrobj::PatternDiskBB.

virtual int Gyoto::Astrobj::ThinDisk::Impact ( Gyoto::Photon ph,
size_t  index,
Astrobj::Properties data = NULL 
)
virtualinherited

does a photon at these coordinates impact the object?

Impact() checks whether a Photon impacts the object between two integration steps of the photon's trajectory (those two steps are photon->getCoord(index, coord1) and photon->getCoord(index+1, coord2)). Impact returns 1 if the photon impacts the object between these two steps, else 0. In many cases of geometrically thick obects, the implementation Astrobj::Standard::Impact() will be fine.

Impact will call Generic::processHitQuantities() (which is virtual and may be re-implemented) to compute observable properties on demand: if the data pointer is non-NULL, the object will look in it for pointers to properties which apply to its kind. If a pointer to a property known to this object is present, then the property is computed and store at the pointed-to adress. For instance, all objects know the "intensity" property. If data->intensity != NULL, the instensity is computed and stored in *data->intensity.

If data is non-NULL and only in this case, processHitQuantities() will also call ph->transmit() to update the transmissions of the Photon (see Photon::transmit(size_t, double)). This must not be done if data is NULL (see Astrobj::Complex::Impact() for an explanation).

Parameters:
phGyoto::Photon aimed at the object;
indexIndex of the last photon step;
dataPointer to a structure to hold the observables at impact.
Returns:
1 if impact, 0 if not.

Implements Gyoto::Astrobj::Generic.

virtual double Gyoto::Astrobj::Generic::integrateEmission ( double  nu1,
double  nu2,
double  dsem,
double  c_ph[8],
double  c_obj[8] = NULL 
) const
virtualinherited

^nu2 I_nu dnu (or j_nu)

Compute the integral of emission() from nu1 to nu2. The default implementation is a numerical integrator which works well enough and is reasonably fast if emission() is a smooth function (i.e. no emission or absorption lines). If possible, it is wise to implement an analytical solution. It is used by processHitQuantities to compute the "BinSpectrum" quantity which is the most physical: it is the only quantity that can be actually measured directly by a real-life instrument.

Reimplemented in Gyoto::Astrobj::UniformSphere, and Gyoto::Astrobj::Torus.

virtual double Gyoto::Astrobj::ThinDisk::operator() ( double const  coord[])
virtualinherited

theta-pi/2 or z

A function which changes sign on the equatorial plane.

Implements Gyoto::Functor::Double_constDoubleArray.

virtual void Gyoto::Astrobj::Generic::processHitQuantities ( Photon ph,
double *  coord_ph_hit,
double *  coord_obj_hit,
double  dt,
Astrobj::Properties data 
) const
virtualinherited

processHitQuantities fills the requested data in Impact. To use it, you need to call it in the Impact() method for your object in case of hit. It will fill Redshift, Intensity, Spectrum, BinSpectrum and update the Photon's transmission by calling Photon::transmi(), only if data==NULL.

You can overload it for your Astrobj. The generic implementation calls emission(), integrateEmission() and transmission() below.

void Gyoto::Astrobj::Generic::setFlag_radtransf ( int  flag)
inherited

Set whether the object is optically thin.

Set flag indicating that radiative transfer should be integrated, i.e. the object is to be considered optically thin.

Parameters:
flag,:1 if optically thin, 0 if optically thick.
virtual int Gyoto::Astrobj::ThinDisk::setParameter ( std::string  name,
std::string  content 
)
virtualinherited

Called from setParameters()

 Assume MyKind is a sublcass of Astrobj::Generic which has towo
 members (a string StringMember and a double DoubleMember):
int MyKind::setParameter(std::string name, std::string content) {
if (name=="StringMember") setStringMember(content);
else if (name=="DoubleMember") setDoubleMemeber(atof(content.c_str()));
else return Generic::setParameter(name, content);
return 0;
}

If MyKind is not a direct subclass of Generic but is a subclass of e.g. Standard, UniformSphere of ThinDisk, it should call the corresponding setParameter() implementation instead of Generic::setParameter().

Parameters:
nameXML name of the parameter
contentstring representation of the value
Returns:
0 if this parameter is known, 1 if it is not.

Reimplemented from Gyoto::Astrobj::Generic.

Reimplemented in Gyoto::Astrobj::PatternDisk, Gyoto::Astrobj::DynamicalDisk, Gyoto::Astrobj::ThinDiskPL, and Gyoto::Astrobj::PatternDiskBB.

virtual void Gyoto::Astrobj::Generic::setParameters ( FactoryMessenger fmp)
virtualinherited

Main loop in Subcontractor_t function.

 The Subcontractor_t function for each Astrobj kind should look
 somewhat like this:
SmartPointer<Astrobj::Generic>
Gyoto::Astrobj::MyKind::Subcontractor(FactoryMessenger* fmp) {
SmartPointer<MyKind> ao = new MyKind();
ao -> setParameters(fmp);
return ao;
}
 Each object kind should implement setParameter(string name,
 string content) to interpret the individual XML
 elements. setParameters() can be overloaded in case the specific
 Astrobj class needs low level access to the FactoryMessenger. See
 UniformSphere::setParameters().

Reimplemented in Gyoto::Astrobj::PatternDisk, Gyoto::Astrobj::Disk3D, Gyoto::Astrobj::Star, Gyoto::Astrobj::UniformSphere, Gyoto::Astrobj::Complex, and Gyoto::Astrobj::Torus.

virtual void Gyoto::Astrobj::Generic::setRmax ( double  val)
virtualinherited

Set maximal distance from center of coordinate system.

Set maximal distance from center of coordinate system at which a Photon may hit the object.

Side effect: set rmax_set_ to 1.

virtual double Gyoto::Astrobj::Generic::transmission ( double  nuem,
double  dsem,
double  coord[8] 
) const
virtualinherited

Transmission: exp( {} * dsem )

transmission() computes the transmission of this fluid element or 0 if optically thick. The default implementation returns 1. (no attenuation) if optically thin, 0. if optically thick.

Parameters:
nuemfrequency in the fluid's frame
coordPhoton coordinate
dsemgeometrical length in geometrical units

Reimplemented in Gyoto::Astrobj::PatternDisk, and Gyoto::Astrobj::Torus.

virtual void Gyoto::Astrobj::Generic::unsetRmax ( )
virtualinherited

Set rmax_set_ to 0.

getRmax() will then be free to recompute rmax_. Astrobjs which cache rmax_ may need to update it when unsetRmax() is called.

Reimplemented in Gyoto::Astrobj::Star.


Member Data Documentation

SmartPointer<Gyoto::Metric::Generic> Gyoto::Astrobj::Generic::gg_
protectedinherited

The Metric in this end of the Universe

const std::string Gyoto::Astrobj::Generic::kind_
protectedinherited

Kind of object (e.g. "Star"...)

The kind should match the name of the class, e.g. "Star" for a Gyoto::Star.

double Gyoto::Astrobj::Generic::rmax_
protectedinherited

Maximum distance to the center of the coordinate system.

Maximum distance from the center of the coordinate system at which a photon may hit the object. Child classes may choose to update rmax at all time or to use it to cache the value, for instance when getRmax() is called. External classes (Photons in particular) must use getRmax() to access this information.

rmax_set_==1 means that rmax_ was set using setRmax() or the constructor. In this case, getRmax() must always return this value, not recompute it.

Reimplemented in Gyoto::Astrobj::PatternDiskBB.

int Gyoto::Astrobj::Generic::rmax_set_
protectedinherited

Never recompute rmax: it was externally set.

rmax_set_==1 means that rmax_ was set using setRmax() or the constructor. In this case, getRmax() must always return this value, not recompute it.

Use unsetRmax() to reset rmax_set_ to 0.

double Gyoto::Astrobj::ThinDisk::thickness_
protectedinherited

disk thickness

Geometrical thickness in geometrical units. Used only in the optically thin regime (flag_radtransf_==1). Should be << rin_. Default: 1e-3.


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