inspiralDistance.c

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/*
*  Copyright (C) 2007 B.S. Sathyaprakash, Thomas Cokelaer
*
*  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 2 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 with program; see the file COPYING. If not, write to the
*  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
*  MA  02110-1301  USA
*/
 
/* This programme expects six inputs at the command line:
 *
 * m1: mass of the first object in the binary source,
 * m2: mass of the second object in the binary source,
 * rhorms: rms SNR required from the source,
 * flow: lower frequency cutoff,
 * LO: Last orbit in units of M (either 6, for LSO, or 2.8, for light ring)
 * ispec: an integer indicating the nature of input data: power (0) or amplitude (1) spectrum is input
 *
 * reads a data from a file contianing two columns of frequency
 * and power/amplitude spectral density. It outputs the distance in Kpc
 * for a source with the given rms SNR.
 */
 
#include <stdlib.h>
#include <math.h>
#include <stdio.h>
 
int main (int argc, char **argv)
{
        double m1, m2, totalMass, eta, flso, lso, fOld, sevenBy3 = 7.L/3.L;
        double x, pwrSpec;
        double freq, flow;
        double rhorms, rmsD, Crms, integral;
        double MTSUN_SI=4.925e-6, pi=3.14159, PC_SI=3.e19, C_SI=3.e8;
        double SNRat1Mpc;
        int ispec;
 
        if (argc !=7 )
        {
                fprintf(stderr, "-----------------------------\n");
                fprintf(stderr, "Usage:%s mass1/solarMass mass2/solarMass rhoRMS fLow LO ispec < PSD_File\n",argv[0]);
                fprintf(stderr, "-----------------------------\n");
                exit(1);
        }
 
        m1 = atof(argv[1]);
        m2 = atof(argv[2]);
        rhorms = atof(argv[3]);
        flow = atof(argv[4]);
        lso = atof(argv[5]);
        ispec = atoi(argv[6]);
 
        totalMass = (m1+m2);
        eta = m1*m2/(totalMass*totalMass);
        totalMass *= MTSUN_SI;
        Crms = pow(totalMass,5./6.) * pow(2.*eta/15.,0.5) / (rhorms * pow(pi,2./3.));
 
        flso = 1.L/ ( pow(lso, 1.5) * pi * totalMass);
 
        /*
        printf("%e %e %e %e \n",totalMass, eta, Crms, flso );
        */
 
        integral = 0.;
        if (scanf("%le %le\n", &freq, &x) == EOF)
        {
                fprintf(stderr, "No data in file\n");
                return 1;
        }
        fOld = freq;
 
        while ( scanf("%le %le\n", &freq, &x) != EOF)
        {
 
                if (freq > flso) break;
                if (x && freq > flow)
                {
                        if (ispec)
                                pwrSpec = x*x;
                        else
                                pwrSpec = x;
                        integral += (freq - fOld) * pow(freq, -sevenBy3)/pwrSpec;
                }
                fOld = freq;
        }
 
        rmsD = Crms * sqrt(integral) / PC_SI * C_SI;
        SNRat1Mpc = 1.e-3 * 2.5 * rmsD*rhorms;
        fprintf(stdout, "%e %e %e %e %e %e %e\n", totalMass/MTSUN_SI, SNRat1Mpc, flow, rmsD, m1, m2, flso);
        return 0;
}