convsyn.py

#!/usr/bin/python3
# 2-CLAUSE BSD LICENCE
#Copyright 2015-2021 Hugo Tabernero, Jonay Gonzalez Hernandez, Emilio Marfil, and David Montes
#Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
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from astropy.convolution import convolve
from astropy.modeling.functional_models import Voigt1D
from scipy import interpolate, special, mean
import scipy.signal as ss
import numpy as np
import matplotlib.pyplot as plt

def vlambda(inlamb,vstep):

    vlight=2.99792458e5
    xw2=max(inlamb)-0.1
    xw1=min(inlamb)+0.1
    iw1=np.where(inlamb > xw1)
    iw2=np.where(inlamb > xw2)
    iw1=iw1[0]
    iw2=iw2[0]
    w1=inlamb[iw1[0]+1]
    w2=inlamb[iw2[0]-1]

    npix=np.long((iw2[0]-1)-(iw1[0]+1)*vstep)
    wmid=np.sqrt(w1*w2)
    vave=vlight*(10.**(np.log10(w2/w1)/(npix-1.))-1.)
    dwave=(np.log10(w2)-np.log10(w1))/(npix-1.)

    vwavel=np.log10(wmid)-(dwave*np.arange(np.long(npix/2.)))
    vwaveu=np.log10(wmid)+(dwave*np.arange(np.long(npix/2.)))
    vwavel=10.**vwavel[1:len(vwavel)-1]
    vwavel=np.sort(vwavel)
    vwaveu=10.**vwaveu[1:len(vwaveu)-1]
    vwave=np.concatenate((vwavel,[wmid],vwaveu))

    return vwave

#Warning: The public version of convsyn does not include the CARMENES LSF
def conkern(inlamb, influx, vbroad, ldc, kop, channel=None):
    # You must provide vbroad in km/s.
    # Alternatively, you can also give the resolution.
    if vbroad >= 0.: 
        vstep=1
        vlight=2.99792458e5
        vwave=vlambda(inlamb,vstep)
        xw2=max(inlamb)-0.1
        xw1=min(inlamb)+0.1
        iw1=np.where(inlamb > xw1)
        iw2=np.where(inlamb > xw2)
        iw1=iw1[0]
        iw2=iw2[0]
        w1=inlamb[iw1[0]+1]
        w2=inlamb[iw2[0]-1]
        tck=interpolate.splrep(inlamb,influx,k=3, s=0)
        vflux=interpolate.splev(vwave,tck,der=0)
        npix=np.long((iw2[0]-1)-(iw1[0]+1)*vstep)
        wmid=np.sqrt(w1*w2)
        vave=vlight*(10.**(np.log10(w2/w1)/(npix-1.))-1.)
	
        x1=vwave
        y1=vflux
        if kop == 'g': 
            if vbroad > 1000. and kop == 'g':
                vibr=(vlight/vbroad)/(2.*np.sqrt(2.*np.log(2.)))
            else:
                vibr=vbroad#(2.*np.sqrt(2.*np.log(2.)))
            sigma=vibr*wmid/vlight
            nx1=len(x1)
            dx1=(x1[nx1-1]-x1[0])/float(nx1-1)
            xk = (np.arange(nx1)-nx1/2)*dx1
            a1=0.
            a2=sigma
            zk=(xk-a1)/a2
            a0=1./np.sqrt(2.*np.pi)/sigma
            yk=a0*np.exp(-(zk**2.)/2.)
            #ii = np.where(yk > 0.0)

        elif kop == 'r':
            vrot=vbroad
            xi=vrot/vlight*wmid
            d  = 1.0/(np.pi*(1.0-ldc/3.0))
            c1 = 2.0*(1.0-ldc)*d
            c2 = 0.5*np.pi*ldc*d
            nx1 = len(x1)
            dx1 = (x1[nx1-1]-x1[0])/float(nx1-1)
            xk = (np.arange(nx1)-nx1/2)*dx1
            d2 = 1.0-(xk/xi)**2
            ii = np.where(d2 <= 0.0)
            #xk = xk[ii]
            d2[ii] = 0
            yk = c1*np.sqrt(d2)+c2*d2
 
        elif kop == 'm':
            vmac = vbroad
            xi = vmac/vlight*wmid
            nx1 = len(x1)
            dx1 = (x1[nx1 - 1] - x1[0])/float(nx1 - 1)
            xk = (np.arange(nx1) - nx1/2) * dx1
            xk = (xk/xi)
            spi = np.sqrt(np.pi)
            A = 2./(spi*vmac)
            yk = A*(np.exp(-xk**2)-(spi*abs(xk)*special.erfc(abs(xk))))
        nfact = np.sum(yk)
        if nfact > 0.:
            outflux = convolve(y1, yk/nfact, boundary='fill',fill_value=1.)  
        else:
            outflux = y1
        tck2 = interpolate.splrep(vwave,outflux,k=3, s=0)
        bflux = interpolate.splev(inlamb, tck2, der=0)

    else:
        bflux = influx

    return bflux