model_image_orbiting_spot Class Reference

Defines an image model based on the semi-analytic shearing spot models employed in VRT2. More...

#include "model/model_image_orbiting_spot.h"

Inheritance diagram for model_image_orbiting_spot:

Collaboration diagram for model_image_orbiting_spot:

Public Member Functions
	model_image_orbiting_spot (double start_obs, double tobs, std::string sed_fit_parameter_file=Themis::utils::global_path("src/VRT2/DataFiles/2010_combined_fit_parameters.d"), double frequency=230e9, double M=VRT2::VRT2_Constants::M_SgrA_cm, double D=VRT2::VRT2_Constants::D_SgrA_cm)
	Constructor to make a shearing spot model. Takes the start time of the observation (UTC), time you are observing the spot at (UTC), the frequency (Hz), mass (cm), distance (cm).
virtual size_t	size () const
	Returns the number of the parameters the model expects.
virtual std::string	model_tag () const
	Return a string that contains a unique identifying tag for use with the ThemisPy plotting features.
void	set_image_resolution (int Nray)
void	set_screen_size (double Rmax)
void	add_background_riaf ()
double	frequency () const
	Returns the frequency at which this model is created.
double	obs_time () const
	Returns the start of the observation time in J2000 at which this model was created.
virtual void	set_mpi_communicator (MPI_Comm comm)
	Defines a set of processors provided to the model for parallel computation via an MPI communicator. Only facilates code parallelization if the model computation is parallelized via MPI.
Public Member Functions inherited from model_image
virtual void	generate_model (std::vector< double > parameters)
	A one-time generate function that permits model construction prior to calling the visibility_amplitude, closure_phase, etc. for each datum. Takes a vector of parameters.
virtual void	generate_complex_visibilities ()
	A one-time generate function that will generate the complex visibilities and store them. This must be called after generate_model has been called.
virtual std::complex< double >	visibility (datum_visibility &d, double accuracy)
	Returns complex visibility in Jy computed from the image given a datum_visibility_amplitude object, containing all of the accoutrements. While this provides access to the actual data value, the two could be separated if necessary. Also takes an accuracy parameter with the same units as the data, indicating the accuracy with which the model must generate a comparison value. Note that this can be redefined in child classes.
virtual double	visibility_amplitude (datum_visibility_amplitude &d, double accuracy)
	Returns visibility ampitudes in Jy computed from the image given a datum_visibility_amplitude object, containing all of the accoutrements. While this provides access to the actual data value, the two could be separated if necessary. Also takes an accuracy parameter with the same units as the data, indicating the accuracy with which the model must generate a comparison value. Note that this can be redefined in child classes.
virtual double	closure_phase (datum_closure_phase &d, double accuracy)
	Returns closure phase in degrees computed from the image given a datum_closure_phase object, containing all of the accoutrements. While this provides access to the actual data value, the two could be separated if necessary. Also takes an accuracy parameter with the same units as the data, indicating the accuracy with which the model must generate a comparison value. Note that this can be redefined in child classes.
virtual double	closure_amplitude (datum_closure_amplitude &d, double accuracy)
	Returns closure amplitude computed from the image given a datum_closure_phase object, containing all of the accoutrements. While this provides access to the actual data value, the two could be separated if necessary. Also takes an accuracy parameter with the same units as the data, indicating the accuracy with which the model must generate a comparison value. Note that this can be redefined in child classes.
void	output_image (std::string fname, bool rotate=false)
void	get_image (std::vector< std::vector< double > > &alpha, std::vector< std::vector< double > > &beta, std::vector< std::vector< double > > &I) const
	Provides direct access to the constructed image. Sets a 2D grid of angles (alpha, beta) in radians and intensities in Jy per steradian.
void	get_visibilities (std::vector< std::vector< double > > &u, std::vector< std::vector< double > > &v, std::vector< std::vector< std::complex< double > > > &V) const
	Provides direct access to the complex visibilities. Sets a 2D grid of baselines (u,v) in lambda, and visibilites in Jy.
void	get_visibility_amplitudes (std::vector< std::vector< double > > &u, std::vector< std::vector< double > > &v, std::vector< std::vector< double > > &V) const
	Provides direct access to the visibility amplitudes. Sets a 2D grid of baselines (u,v) in lambda, and visibilites in Jy.
void	use_spline_interp (bool use_spline)
	Provides ability to use bicubic spline interpolator (true) instead of regular bicubic. Code defaults to false.
void	write_model_tag_file (std::string tagfilename="model_image.tag") const
	Write a unique identifying tag for use with the ThemisPy plotting features. This calls the overloaded version with the outstream, which is the only function that need be rewritten in child classes.
virtual void	write_model_tag_file (std::ofstream &tagout) const
	Write a unique identifying tag for use with the ThemisPy plotting features. For most child classes, the default implementation is suffcient. However, should that not be the case, this is the only function that need be rewritten in child classes.

Protected Attributes
MPI_Comm	_comm
Protected Attributes inherited from model_image
MPI_Comm	_comm
bool	_generated_model
	True when a model is generated with generate_model.
bool	_generated_visibilities
	True when model visibilities have been computed.
bool	_use_spline
	True when want to use bicubic spline interpolator.
double	_position_angle
	Position angle of the image, assumed to be the last element of the parameter list passed to generate_model. Assumed to be in radians and defined E of N.
std::vector< double >	_current_parameters
	Last set of parameters passed to generate_image, useful to determine if it is necessary to recompute the model. Useful, e.g., if we are varying only position angle, or if recomputing for a number of different data sets at the same set of parameters.
std::vector< std::vector< double > >	_alpha
	2D grid of horizonal pixel locations in radians, relative to the fiducial direction of the image (i.e., unrotated by the position angle).
std::vector< std::vector< double > >	_beta
	2D grid of vertical pixel locations in radians, relative to the fiducial direction of the image (i.e., unrotated by the position angle).
std::vector< std::vector< double > >	_I
	2D grid of intensities at pixel locations in Jy/str.
Protected Attributes inherited from model_visibility
MPI_Comm	_comm
Protected Attributes inherited from model_visibility_amplitude
MPI_Comm	_comm
Protected Attributes inherited from model_closure_phase
MPI_Comm	_comm
Protected Attributes inherited from model_closure_amplitude
MPI_Comm	_comm

Private Member Functions
virtual void	generate_image (std::vector< double > parameters, std::vector< std::vector< double > > &I, std::vector< std::vector< double > > &alpha, std::vector< std::vector< double > > &beta)
	Generates and returns rectalinear grid of intensities associated with the shearing spot image model in Jy/pixel located at pixels centered on angular positions alpha and beta, both specified in radians and aligned with a fiducial direction. Note that the parameter vector has had the position removed.
void	open_error_streams ()
	Opens model-communicator-specific error streams for debugging output.

Private Attributes
const double	_start_obs
	Start time of the simulation in J2000.
const double	_tobs
	Observation time of spot in J2000 in seconds.
VRT2::SgrA_PolintDiskModelParameters2010	_sdmp
	Interpolation object to return.
const double	_frequency
	Internal frequency in Hz for the current model.
const double	_M
	Internal mass in cm.
const double	_D
	Internal distance in cm for the current model.
int	_Nray
	Image resolution.
double	_Rmax
	Default image sizes in M (note, not applied to flux estimates)
bool	_bkgd_riaf
	Specifies whether to include riaf model in radiative transfer scheme.
std::ofstream	_merr
	Model-specific error stream.

Detailed Description

Provides explicit implementation of the model_image object for the semi-analytic shearing spot models. There are additional tuning parameters that may impact accuracy, e.g., distance to the image screen, number of rays to produce, etc. See the appropriate parts of model_image_orbiting_spot.cpp for more. Parameter list:

• parameters[0] ... Black hole spin parameter (-1 to 1).
• parameters[1] ... Cosine of the inclincation relative to the line of sight.
• parameters[2] ... Spot electron density normalization \( n_0 \).
• parameters[3] ... Standard deviation of the Gaussian in M of initial shearing spot \( R_s \).
• parameters[4] ... Initial time of spot in observers time relative to start of observation time, in units of (M).
• parameters[5] ... Initial radius of spot in M.
• parameters[6] ... Initial azimuthal angle of spot around accretion disk.
• parameters[7] ... Infalling rate parameter \(\alpha_r\) of accretion flow \(u^r = u_K^r + \alpha_r(u_{ff}^r - u_K^r)\).
• parameters[8] ... Subkeplerian factor \(\kappa\) of accretion flow \(\Omega = u^{\phi}/u^t = \Omega_{ff} + \kappa(\Omega_K - \Omega_{ff})\).
  • parameters[9] ... Position angle (radians).

Warning

Model requires VRT2 to be installed and it explicitly time dependent. Model assumes one time is passed.

Member Function Documentation

void add_background_riaf

(

)

Adds background sed fitted riaf to model as specified by sed_fit_parameters_file that was given in the constructor.

void set_image_resolution

(

int

Nray

)

Sets model_image_orbiting_spot to generate production images with resolution Nray x Nray. The default is 128x128, which is probably larger than required in practice.

void set_screen_size

(

double

Rmax

)

Sets the screen size of the image in units M so that image has size Rmax x Rmax. The default is 15 which is probably larger than needed.

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

• model/model_image_orbiting_spot.h
• model/model_image_orbiting_spot.cpp