/***************************************************************************
* GModelSpatialRadialProfileDMBurkert.cpp - Burkert radial profile class *
* ----------------------------------------------------------------------- *
* copyright (C) 2016-2018 by Nathan Kelley-Hoskins *
* ----------------------------------------------------------------------- *
* *
* This program is free software: you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation, either version 3 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program. If not, see . *
* *
***************************************************************************/
/**
* @file GModelSpatialRadialProfileDMBurkert.cpp
* @brief Radial DM Burkert profile model class implementation
* @author Nathan Kelley-Hoskins
*/
/* __ Includes ___________________________________________________________ */
#ifdef HAVE_CONFIG_H
#include
#endif
#include "GException.hpp"
#include "GTools.hpp"
#include "GMath.hpp"
#include "GXmlElement.hpp"
#include "GModelSpatialRadialProfileDMBurkert.hpp"
#include "GModelSpatialRegistry.hpp"
/* __ Constants __________________________________________________________ */
/* __ Globals ____________________________________________________________ */
const GModelSpatialRadialProfileDMBurkert g_radial_disk_seed;
const GModelSpatialRegistry g_radial_disk_registry(&g_radial_disk_seed);
/* __ Method name definitions ____________________________________________ */
#define G_READ "GModelSpatialRadialProfileDMBurkert::read(GXmlElement&)"
#define G_WRITE "GModelSpatialRadialProfileDMBurkert::write(GXmlElement&)"
/* __ Macros _____________________________________________________________ */
/* __ Coding definitions _________________________________________________ */
/* __ Debug definitions __________________________________________________ */
/*==========================================================================
= =
= Constructors/destructors =
= =
==========================================================================*/
/***********************************************************************//**
* @brief Void constructor
*
* Constructs empty radial DMBurkert profile
***************************************************************************/
GModelSpatialRadialProfileDMBurkert::GModelSpatialRadialProfileDMBurkert(void) :
GModelSpatialRadialProfile()
{
// Initialise members
init_members();
// Return
return;
}
/***********************************************************************//**
* @brief XML constructor
*
* @param[in] xml XML element.
*
* Constructs radial DMBurkert profile model by extracting information from
* an XML element. See the read() method for more information about the
* expected structure of the XML element.
***************************************************************************/
GModelSpatialRadialProfileDMBurkert::GModelSpatialRadialProfileDMBurkert(const GXmlElement& xml) :
GModelSpatialRadialProfile()
{
// Initialise members
init_members();
// Read information from XML element
read(xml);
// Return
return;
}
/***********************************************************************//**
* @brief Copy constructor
*
* @param[in] model Radial DMBurkert profile model.
*
* Copies radial DMBurkert profile model from another radial profile model.
***************************************************************************/
GModelSpatialRadialProfileDMBurkert::GModelSpatialRadialProfileDMBurkert(const GModelSpatialRadialProfileDMBurkert& model) :
GModelSpatialRadialProfile(model)
{
// Initialise members
init_members();
// Copy members
copy_members(model);
// Return
return;
}
/***********************************************************************//**
* @brief Destructor
*
* Destructs radial DMBurkert profile model.
***************************************************************************/
GModelSpatialRadialProfileDMBurkert::~GModelSpatialRadialProfileDMBurkert(void)
{
// Free members
free_members();
// Return
return;
}
/*==========================================================================
= =
= Operators =
= =
==========================================================================*/
/***********************************************************************//**
* @brief Assignment operator
*
* @param[in] model Radial DMBurkert profile model.
* @return Radial DMBurkert profile model.
*
* Assigns radial DMBurkert profile model.
***************************************************************************/
GModelSpatialRadialProfileDMBurkert& GModelSpatialRadialProfileDMBurkert::operator=(const GModelSpatialRadialProfileDMBurkert& model)
{
// Execute only if object is not identical
if (this != &model) {
// Copy base class members
this->GModelSpatialRadialProfile::operator=(model);
// Free members
free_members();
// Initialise members
init_members();
// Copy members
copy_members(model);
} // endif: object was not identical
// Return
return *this;
}
/*==========================================================================
= =
= Public methods =
= =
==========================================================================*/
/***********************************************************************//**
* @brief Clear radial DMBurkert profile model
*
* Clears radial DMBurkert profile model.
***************************************************************************/
void GModelSpatialRadialProfileDMBurkert::clear(void)
{
// Free class members
free_members();
this->GModelSpatialRadialProfile::free_members();
this->GModelSpatialRadial::free_members();
this->GModelSpatial::free_members();
// Initialise members
this->GModelSpatial::init_members();
this->GModelSpatialRadial::init_members();
this->GModelSpatialRadialProfile::init_members();
init_members();
// Return
return;
}
/***********************************************************************//**
* @brief Clone radial DMBurkert profile model
*
* @return Pointer to deep copy of radial DMBurkert profile model.
*
* Returns a deep copy of the radial DMBurkert profile model.
***************************************************************************/
GModelSpatialRadialProfileDMBurkert* GModelSpatialRadialProfileDMBurkert::clone(void) const
{
// Clone radial disk model
return new GModelSpatialRadialProfileDMBurkert(*this);
}
/***********************************************************************//**
* @brief Return minimum model radius (in radians)
*
* @return Minimum model radius (in radians).
***************************************************************************/
double GModelSpatialRadialProfileDMBurkert::theta_min(void) const
{
// update precomputation cache
update();
// Return value
return m_theta_min.value();
}
/***********************************************************************//**
* @brief Return maximum model radius (in radians)
*
* @return Maximum model radius (in radians).
***************************************************************************/
double GModelSpatialRadialProfileDMBurkert::theta_max(void) const
{
// Update
update();
// initialize value
double theta = 0.0;
// If Earth is within the significant radius, then we must integrate
// the entire profile ...
if (m_halo_distance.value() < m_mass_radius) {
theta = gammalib::pi;
}
// ... otherwise, if the halo is far enough away (further than the
// significant radius) then we just need to deal with the angles within
// the sphere of the significant radius
else {
theta = std::atan(m_mass_radius / m_halo_distance.value());
}
// Always chose the lesser of mass_radius theta and theta_max
double theta_max = m_theta_max.value() * gammalib::deg2rad;
if (theta > theta_max) {
theta = theta_max;
}
// Return value
return theta;
}
/***********************************************************************//**
* @brief Read model from XML element
*
* @param[in] xml XML element.
*
* Reads the DMBurkert radial profile model information from an XML element.
* The XML element shall have the format
*
*
*
*
*
*
*
*
*
*
*
*
***************************************************************************/
void GModelSpatialRadialProfileDMBurkert::read(const GXmlElement& xml)
{
// Read DMBurkert location
GModelSpatialRadial::read(xml);
const GXmlElement* par1 = gammalib::xml_get_par(G_READ, xml, "ScaleRadius");
m_scale_radius.read(*par1);
const GXmlElement* par2 = gammalib::xml_get_par(G_READ, xml, "ScaleDensity");
m_scale_density.read(*par2);
const GXmlElement* par3 = gammalib::xml_get_par(G_READ, xml, "HaloDistance");
m_halo_distance.read(*par3);
const GXmlElement* par4 = gammalib::xml_get_par(G_READ, xml, "ThetaMin");
m_theta_min.read(*par4);
const GXmlElement* par5 = gammalib::xml_get_par(G_READ, xml, "ThetaMax");
m_theta_max.read(*par5);
const GXmlElement* par6 = gammalib::xml_get_par(G_READ, xml, "CoreRadius");
m_core_radius.read(*par6);
// Return
return;
}
/***********************************************************************//**
* @brief Write model into XML element
*
* @param[in] xml XML element into which model information is written.
*
* Writes the DMBurkert radial profile model information into an XML element.
* The XML element will have the format
*
*
*
*
*
*
*
*
*
*
*
***************************************************************************/
void GModelSpatialRadialProfileDMBurkert::write(GXmlElement& xml) const
{
// Write DMBurkert location
GModelSpatialRadial::write(xml);
// Write Scale Radius parameter
GXmlElement* par1 = gammalib::xml_need_par(G_WRITE, xml, "ScaleRadius");
m_scale_radius.write(*par1);
// Write Scale Radius parameter
GXmlElement* par2 = gammalib::xml_need_par(G_WRITE, xml, "ScaleDensity");
m_scale_density.write(*par2);
// Write Halo Distance parameter
GXmlElement* par3 = gammalib::xml_need_par(G_WRITE, xml, "HaloDistance");
m_halo_distance.write(*par3);
// Write Halo Distance parameter
GXmlElement* par4 = gammalib::xml_need_par(G_WRITE, xml, "ThetaMin");
m_theta_min.write(*par4);
// Write Halo Distance parameter
GXmlElement* par5 = gammalib::xml_need_par(G_WRITE, xml, "ThetaMax");
m_theta_max.write(*par5);
// Write Core Radius parameter
GXmlElement* par6 = gammalib::xml_need_par(G_WRITE, xml, "CoreRadius");
m_core_radius.write(*par6);
// Return
return;
}
/***********************************************************************//**
* @brief Print information
*
* @param[in] chatter Chattiness.
* @return String containing model information.
***************************************************************************/
std::string GModelSpatialRadialProfileDMBurkert::print(const GChatter& chatter) const
{
// Initialise result string
std::string result;
// Continue only if chatter is not silent
if (chatter != SILENT) {
// Append header
result.append("=== GModelSpatialRadialProfileDMBurkert ===");
// Append parameters
result.append("\n"+gammalib::parformat("Number of parameters"));
result.append(gammalib::str(size()));
for (int i = 0; i < size(); ++i) {
result.append("\n"+m_pars[i]->print(chatter));
}
} // endif: chatter was not silent
// Return result
return result;
}
/*==========================================================================
= =
= Private methods =
= =
==========================================================================*/
/***********************************************************************//**
* @brief Initialise class members
***************************************************************************/
void GModelSpatialRadialProfileDMBurkert::init_members(void)
{
// Initialise scale radius
m_scale_radius.clear();
m_scale_radius.name("ScaleRadius");
m_scale_radius.unit("kpc");
m_scale_radius.value(21.5); // default to GC scale radius
m_scale_radius.min(1.0e-6); // arbitrarily chosen :/
m_scale_radius.free();
m_scale_radius.scale(1.0);
m_scale_radius.gradient(0.0);
m_scale_radius.has_grad(false); // Radial components never have gradients
// Initialise scale density
m_scale_density.clear();
m_scale_density.name("ScaleDensity");
m_scale_density.unit("GeV/cm^3");
m_scale_density.value(0.2); // GeV/cm3, default to GC scale density
m_scale_density.min(1.0e-6);
m_scale_density.fix();
m_scale_density.scale(1.0);
m_scale_density.gradient(0.0);
m_scale_density.has_grad(false); // Radial components never have gradients
// Initialise halo distance
m_halo_distance.clear();
m_halo_distance.name("HaloDistance");
m_halo_distance.unit("kpc");
m_halo_distance.value(7.94); // default to GC halo distance
m_halo_distance.min(1.0e-6); // arbitrarily chosen
m_halo_distance.free();
m_halo_distance.scale(1.0);
m_halo_distance.gradient(0.0);
m_halo_distance.has_grad(false); // Radial components never have gradients
// Initialise theta max
m_theta_min.clear();
m_theta_min.name("ThetaMin");
m_theta_min.unit("degrees");
m_theta_min.value(1.0e-6);
m_theta_min.min(1.0e-10); // arbitrarily chosen
m_theta_min.fix(); // should always be fixed!
m_theta_min.scale(1.0);
m_theta_min.gradient(0.0);
m_theta_min.has_grad(false); // Radial components never have gradients
// Initialise theta max
m_theta_max.clear();
m_theta_max.name("ThetaMax");
m_theta_max.unit("degrees");
m_theta_max.value(180.0); // can only go from halo center to opposite halo center
m_theta_max.min(1.0e-6); // arbitrarily chosen
m_theta_max.fix(); // should always be fixed!
m_theta_max.scale(1.0);
m_theta_max.gradient(0.0);
m_theta_max.has_grad(false); // Radial components never have gradients
// Initialise core radius
m_core_radius.clear();
m_core_radius.name("CoreRadius");
m_core_radius.unit("kpc");
m_core_radius.value(0.5); // example: galactic center core
m_core_radius.min(0.0);
m_core_radius.fix();
m_core_radius.scale(1.0);
m_core_radius.gradient(0.0);
m_core_radius.has_grad(false); // Radial components never have gradients
// Set parameter pointer(s)
m_pars.push_back(&m_scale_radius);
m_pars.push_back(&m_halo_distance);
m_pars.push_back(&m_theta_max);
m_pars.push_back(&m_theta_min);
m_pars.push_back(&m_core_radius);
// Initialize precomputation cache. Note that zero values flag
// uninitialised, as a zero radius is not meaningful
m_last_scale_radius = 0.0;
m_last_scale_density = 0.0;
m_mass_radius = 0.0;
m_scale_density_squared = 0.0;
// Return
return;
}
/***********************************************************************//**
* @brief Copy class members
*
* @param[in] model Radial DMBurkert model.
*
* Copies class members from another radial profile model.
***************************************************************************/
void GModelSpatialRadialProfileDMBurkert::copy_members(const GModelSpatialRadialProfileDMBurkert& model)
{
// Copy members. We do not have to push back the members on the parameter
// stack as this should have been done by init_members() that was called
// before. Otherwise we would have sigma twice on the stack.
m_scale_radius = model.m_scale_radius;
m_scale_density = model.m_scale_density;
m_halo_distance = model.m_halo_distance;
m_theta_min = model.m_theta_min;
m_theta_max = model.m_theta_max;
m_core_radius = model.m_core_radius;
// copy cache values
m_last_scale_radius = model.m_last_scale_radius;
m_last_scale_density = model.m_last_scale_density;
m_mass_radius = model.m_mass_radius;
m_scale_density_squared = model.m_scale_density_squared;
// Return
return;
}
/***********************************************************************//**
* @brief Delete class members
***************************************************************************/
void GModelSpatialRadialProfileDMBurkert::free_members(void)
{
// Return
return;
}
/***********************************************************************//**
* @brief Radial profile
*
* @param[in] theta Angular distance from DMBurkert centre (radians).
* @return Profile value.
***************************************************************************/
double GModelSpatialRadialProfileDMBurkert::profile_value(const double& theta) const
{
// Update precompuation cache
update();
// Initialize integral value
double value = 0.0;
// Set up integration limits
double los_min = m_halo_distance.value() - m_mass_radius;
double los_max = m_halo_distance.value() + m_mass_radius;
// Handle case where observer is within halo mass radius
if (los_min < 0.0) {
los_min = 0.0;
}
// Set up integral
halo_kernel_los integrand(m_scale_radius.value(),
m_halo_distance.value(),
theta,
m_core_radius.value());
GIntegral integral(&integrand);
// Compute value
value = integral.romberg(los_min, los_max) * m_scale_density_squared;
// Return value
return value;
}
/***********************************************************************//**
* @brief Kernel for halo density profile squared
*
* @param[in] los Distance from observer to point in space (meters).
* @return Halo density.
*
* Computes the value of an einasto halo density profile squared,
* at distance l from observer, at angle \f[\theta\f] from the halo center:
*
* \f[
* f(\theta, l) = \frac{r_{scale}^3}{ \left( r + r_{scale} \right)
* \left( r^2 + r_{scale}^2 \right)}
* \f]
*
* where
*
* \f[
* r = \sqrt{l^2+d^2-2ldCos(\theta)}
* \f]
*
* This profile is detailed in:
* Burkert, 1995
* "The Structure Of Dark Matter Halos In Dwarf Galaxies"
* The Astrophysical Journal, 447: L25–L28
* http://iopscience.iop.org/article/10.1086/309560/pdf
* Equation 2
*
***************************************************************************/
double GModelSpatialRadialProfileDMBurkert::halo_kernel_los::eval(const double &los)
{
// Calculate the scale distance r, the ( distance from integration point
// to the halo center ) divided by ( the halo scale radius )
// first calculate the distance of the integration point from the halo
// center via the law of cosines
double r = los * los;
r += m_halo_distance * m_halo_distance;
r -= 2.0 * los * m_halo_distance * std::cos(m_theta);
r = std::sqrt(r);
// If we have a core radius specified, all halo values inside this core
// radius should be the same as at the core radius itself.
if (r < m_core_radius) {
r = m_core_radius;
}
// Now that we've found out how far we are from the halo center,
// feed this radius to the burkert formula
double bot = (m_scale_radius + r);
bot *= (m_scale_radius*m_scale_radius) + (r*r);
double f = m_scale_radius * m_scale_radius * m_scale_radius;
f /= bot;
// Squared, for annihilating DM, would just be f if it was decaying dm
f = f * f;
// Return function value
return f;
}
/***********************************************************************//**
* @brief Update precomputation cache
*
* Computes the mass_radius calculation, determining the radius around
* the halo that contains 99.99% of the mass. For an Burket halo profile,
* this is just 80.0 * scale_radius.
***************************************************************************/
void GModelSpatialRadialProfileDMBurkert::update() const
{
// Update if scale radius has changed
if (m_last_scale_radius != scale_radius() ||
m_last_scale_density != scale_density() ) {
// Store last values
m_last_scale_radius = scale_radius();
m_last_scale_density = scale_density();
// perform precomputations
// set the mass radius to 80*scale_radius, meaning
// 99.99% of the mass is contained within the mass radius,
// and integration only needs to worry about whats inside this radius.
m_mass_radius = 80.0 * scale_radius();
m_scale_density_squared = scale_density() * scale_density() ;
}
// Return
return;
}
/***********************************************************************//**
* @brief Calculate Halo Mass Density
*
* @param[in] radius Distance from halo centre (kpc).
* @return Halo mass density.
*
* Calculates the halo's mass density at a given radial distance from the
* halo centre.
***************************************************************************/
double GModelSpatialRadialProfileDMBurkert::mass_density(const double& radius) const
{
// Initialize halo kernel with stored values. We use theta=0 to effectivly
// sample the halo radially
halo_kernel_los halo_shape(m_scale_radius.value(),
m_halo_distance.value(),
0.0,
m_core_radius.value());
// eval produces a unitless density^2, so we must take its square root
double density = std::sqrt(halo_shape.eval(m_halo_distance.value() + radius));
// Multiply in the missing scale density
density *= m_scale_density.value();
// Return halo mass density
return density;
}
/***********************************************************************//**
* @brief Calculate J-factor
*
* @param[in] angle Angle from halo center (radians).
* @return J-factor.
*
* Calculates the halo's J-factor at an angle from the halo center.
***************************************************************************/
double GModelSpatialRadialProfileDMBurkert::jfactor(const double& angle) const
{
// Integration settings
double minradian = 0.0;
int npoints = 200;
// Initialize other variables
double jfactor = 0.0 ;
double dr = (angle - minradian) / npoints ;
double r = 0.0;
// Loop over different radii in the profile
for (int i = 0; i < npoints; ++i) {
// integration: Int[ profile(r) * r * dr ]
r = minradian + (i * dr);
jfactor += profile_value(r) * r * dr;
}
// J-Factor = 2 * pi * Int[ profile(r) * r * dr , {r,minradian,angle} ]
jfactor *= gammalib::twopi;
// Return J-factor
return jfactor;
}