Source code for galfitools.sky.GalfitSky

#!/usr/bin/env python3

import os
import os.path
import subprocess as sp

import numpy as np
from astropy.io import fits
from galfitools.galin.std import GetAxis
from galfitools.galin.MakeMask import ds9satbox
from galfitools.mge.mge2galfit import PrintHeader
from galfitools.mge.mge2galfit import PrintSky




def galfitSky(imgname, maskfile, mgzpt, scale, X, Y, sky) -> None:
    """Computes the sky using GALFIT

    It uses the FITS image and a mask to compute the
    to make an initial parameter file to compute sky background
    by GALFIT

    Parameters
    ----------
    imgname : str
            name of the FITS image

    maskfile : str
            name of the mask image
    mgzpt: float
            magnitud zeropoint
    scale : float
            plate scale
    X, Y : float, float x,y position of center
    sky : float
        initial parameter of sky

    Notes
    -----
    The function returns a GALFIT initial parameter file
    named sky.txt. The user must run GALFIT with this file
    to obtain the sky background


    """
    flagpos = False

    (NCol, NRow) = GetAxis(imgname)

    convbox = 100

    #    sky=0.55
    fit = 1
    Z = 0

    #    scale = 0.0455  # arcsec/pixel

    ###################################################
    #  Create GALFIT input file header to compute sky #
    ###################################################

    #    imgname = "ngc4342.fits"
    root_ext = os.path.splitext(imgname)
    TNAM = root_ext[0]

    ##################
    #################

    # Here we use an accurate four gaussians MGE PSF for
    # the HST/WFPC2/F814W filter, taken from Table 3 of
    # Cappellari et al. (2002, ApJ, 578, 787)

    #    sigmapsf = [0.494, 1.44, 4.71, 13.4]      # In PC1 pixels
    #    normpsf = [0.294, 0.559, 0.0813, 0.0657]  # total(normpsf)=1

    parfile = "sky.txt"
    outname = TNAM

    rmsname = "none"
    psfname = "none"

    consfile = "none"

    T1 = "{}".format(imgname)
    T2 = outname + "-sky.fits"
    T3 = "{}".format(rmsname)

    if flagpos is False:  # pragma: no cover
        xlo = 1
        ylo = 1
        (xhi, yhi) = GetAxis(imgname)

    plate = 1

    fout1 = open(parfile, "w")

    PrintHeader(
        fout1,
        T1,
        T2,
        T3,
        psfname,
        1,
        maskfile,
        consfile,
        xlo,
        xhi,
        ylo,
        yhi,
        convbox,
        convbox,
        mgzpt,
        plate,
        plate,
        "regular",
        0,
        0,
    )

    index = 0

    index += 1

    PrintSky(fout1, index, sky, Z, fit)

    fout1.close()

    print("To compute sky run: galfit sky.txt")