void csurvey2gal(double lambda, double eta, double *glon, double *glat)
{
double ra, dec, g_lon, g_lat;
csurvey2eq(lambda,eta,&ra,&dec);
eq2gal(ra,dec,&g_lon,&g_lat);
if (g_lon > 360.0) g_lon -= 360.0;
*glon = g_lon;
*glat = g_lat;
}
/* dist (kpc) and returns proper motion in Galactic coordinates with errors */
int find_galcoord_equatorial(double ra2000,double dec2000,double pmra,double pmraerr,double pmdec,double pmdecerr, double dist,double *mul,double *mulerr,double *mub,double *muberr)
{
double l2000,b2000;
double cel2gal[3][3],cel[3],gal[3],covmat[3][3];
double covar=0.0,covmatgal[3][3],covargal;
double galcart[4],gcr,ddtemp,pmlerr,pmberr;
double p[4],q[4],r[4],vsl,vsb,vgal[4];
double pml,pmb,thetagal,vrgal,pmlrot,pmbrot,cosb;
int i;
/* angles in mas/yr to kms/s (along with distances in kpc) */
double dang2vel = 4.7405;
/* Oort's consts */
double a=14.5,b=-12.0,r0=8.5,v0gal,vsun[4];
/* Solar veloctiy */
vsun[1]=9.2; vsun[2]=10.5; vsun[3]=6.9;
/* Galactic rotation velocty at the Earth */
v0gal = 225.0; /* Using flat rotation curve */
/* Calculate L and B */
eq2gal(ra2000,dec2000,&l2000,&b2000,cel2gal);
cel[1]=pmra;
cel[2]=pmdec;
/* Calculate the position in galactic cartesian coordinates */
/* x increasing towards the galactic centre */
cosb=cos(b2000);
galcart[1] = cos(l2000)*cosb;
galcart[2] = sin(l2000)*cosb;
galcart[3] = sin(b2000);
for (i=1;i<=3;i++)
galcart[i]=galcart[i]*dist;
/* Calculate the projected galactocentric distance to the source */
gcr=sqrt(pow(r0-galcart[1],2)+pow(galcart[2],2));
/* Calculate the proper motions in galactic coords */
matx2v(cel2gal,cel,gal);
/* Form the covarience matrix */
covmat[1][1] = pmraerr*pmraerr;
covmat[2][2] = pmdecerr*pmdecerr;
covmat[1][2] = covar*pmraerr*pmdecerr;
covmat[2][1] = covar*pmraerr*pmdecerr;
/* Postmultiply by the conversion matrix */
multiply(covmat,cel2gal,covmatgal);
/* Premultiply by the transpose of the conversion matrix */
ddtemp = cel2gal[1][2];
cel2gal[1][2] = cel2gal[2][1];
cel2gal[2][1]=ddtemp;
multiply(cel2gal,covmatgal,covmatgal);
pmlerr = sqrt(fabs(covmatgal[1][1]));
pmberr = sqrt(fabs(covmatgal[2][2]));
covargal = covmatgal[1][2]/fabs(pmlerr)/fabs(pmdecerr);
/* Calculate orthogonal vectors */
p[1] = -sin(l2000);
p[2] = cos(l2000);
p[3] = 0.0;
q[1] = -sin(b2000)*cos(l2000);
q[2] = -sin(b2000)*sin(l2000);
q[3] = cos(b2000);
r[1] = cos(b2000)*cos(l2000);
r[2] = cos(b2000)*sin(l2000);
r[3] = sin(b2000);
/* Form dot product with the sun's velocity vector */
vsl = -product(p,vsun)/dist/dang2vel;
vsb = -product(q,vsun)/dist/dang2vel;
/* Find the proper motions expected from galactic rotation using rotation */
/* curve model */
thetagal = atan2(galcart[2],r0-galcart[1]);
vrgal = v0gal; /* Use flat rotation curve */
vgal[1] = vrgal*sin(thetagal);
vgal[2] = vrgal*cos(thetagal)-v0gal;
vgal[3] = 0.0;
pmlrot=product(p,vgal)/dist/dang2vel;
pmbrot=product(q,vgal)/dist/dang2vel;
/* Take the galactiv rotation and solar motion off the galactic pm */
pmb = gal[2];
pml = gal[1];
pmb = pmb-pmbrot-vsb;
pml = pml-pmlrot-vsl;
*mul=pml;
*mulerr = pmlerr;
*mub = pmb;
*muberr = pmberr;
}
