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GalElSpectrum.h

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// $Header: /nfs/slac/g/glast/ground/cvs/flux/flux/GalElSpectrum.h,v 1.6 2001/10/18 03:30:16 srobinsn Exp $
// Original author: P. L. Nolan, pln@egret1.Stanford.EDU
//
/*! The spectrum is the power law found in Barwick et al., ApJ 498, 779 (1998).
    The low-energy rollover is ignored.
    Also ignored are the east-west effect and the gradual nature of the
    geomagnetic cutoff.  The power law is cut off sharply at the cutoff
    energy and directions are isotropic above the  horizon.
    The cutoff energy is obtained by querying a CHIMESpectrum object and
    adjusting for the smaller mass of the electron.  (Actually the electron
    mass is assumed to be zero.)

    As with CHIMESpectrum, the flux normalization is handled in a screwy
    way.  We should come up with a better way to handle this.
    The value returned is in electrons/(m^2 sec ster), as if it was
    isotropic.  This value is obtained by taking the observed isotropic
    flux and multiplying by a correction factor for the fraction of the
    sky blocked by the earth.  Thus the total integrated flux in
    electrons/(m^2 sec) can be obtained by multiplying by 4*pi.
    */
/*
    Notation: probably one of those things is called "flux" and the other
    is something else.  Can someone look it up?
*/
// P. L. Nolan, April 1999

#ifndef GAL_EL_SPECTRUM_H
#define GAL_EL_SPECTRUM_H


#include "flux/Spectrum.h"
#include "flux/CHIMESpectrum.h"
#include "facilities/Observer.h"
#include <string>

class GalElSpectrum : public Spectrum
{
  
 public:
    GalElSpectrum(const std::string& params);
    virtual ~GalElSpectrum();

    virtual double calculate_rate(double old_rate);

    virtual double flux() const;
    
    virtual double solidAngle()const;

    float flux(float cut) const;
 
    virtual float flux(float lat, float lon) const;
    virtual float flux(std::pair<double, double> coords) const;

    virtual float operator() (float)const;

    float cutoff () const {return m_cutoff;};

    virtual void setPosition(float lat, float lon);
    virtual void setPosition(std::pair<double,double> coords);
 
    int askGPS();

    float findCutoff(float rflux) const;

    float findCutoff(float lat, float lon) const;
    float findCutoff(std::pair<double,double> coords) const;

    virtual std::pair<float,float> dir(float energy)const;


    virtual std::string title() const;
    virtual const char * particleName() const;
    inline  const char * nameOf() const {return "GalElSpectrum";}
    //   use default destructor, copy constructor, and assignment op.

    void setParticleName(std::string name);
 
 private:
    CHIMESpectrum m_pspec;
    void init(float lat, float lon);
    float m_expo;   // exponent of power-law spectrum (integral)
    float m_norm;
    float m_normfact; // fraction of sky not blocked by earth
    float m_cutoff; // current cutoff energy
    float m_coscutoff;  // zenith angle of horizon
    float m_flux;   // current flux (set when cutoff changes)

    static const float m_rearth;    // radius of earth in km
    static const float m_altitude;  // altitude of circular orbit

    std::string m_particle_name;
    ObserverAdapter< GalElSpectrum > m_observer; //obsever tag
};

#endif // GAL_EL_SPECTRUM_H

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