def make_polmap(filename, title=None, figure=None, subplot=(1, 1, 1)):
hawc = fits.open(filename)
p = hawc['DEBIASED PERCENT POL'] # %
theta = hawc['ROTATED POL ANGLE'] # deg
stokes_i = hawc['STOKES I'] # I
error_i = hawc['ERROR I'] # error I
# 1. plot Stokes I
# convert from Jy/pix to Jy/sq. arcsec
pxscale = stokes_i.header['CDELT2'] * 3600 # map scale in arcsec/pix
stokes_i.data /= pxscale**2
error_i.data /= pxscale**2
fig = FITSFigure(stokes_i, figure=figure, subplot=subplot)
# 2. perform S/N cut on I/\sigma_I
err_lim = 100
mask = np.where(stokes_i.data / error_i.data < err_lim)
# 3. mask out low S/N vectors by setting masked indices to NaN
p.data[mask] = np.nan
# 4. plot vectors
scalevec = 0.4 # 1pix = scalevec * 1% pol # scale vectors to make it easier to see
fig.show_vectors(p, theta, scale=scalevec,
step=2) # step size = display every 'step' vectors
# step size of 2 is effectively Nyquist sampling
# --close to the beam size
# 5. plot contours
ncontours = 30
fig.show_contour(stokes_i,
cmap=cmap,
levels=ncontours,
filled=True,
smooth=1,
kernel='box')
fig.show_contour(stokes_i,
colors='gray',
levels=ncontours,
smooth=1,
kernel='box',
linewidths=0.3)
# Show image
fig.show_colorscale(cmap=cmap)
# If title, set it
if title:
fig.set_title(title)
# Add colorbar
fig.add_colorbar()
fig.colorbar.set_axis_label_text('Flux (Jy/arcsec$^2$)')
# Add beam indicator
fig.add_beam(facecolor='red',
edgecolor='black',
linewidth=2,
pad=1,
corner='bottom left')
fig.add_label(0.02,
0.02,
'Beam FWHM',
horizontalalignment='left',
weight='bold',
relative=True,
size='small')
# Add vector scale
# polarization vectors are displayed such that 'scalevec' * 1% pol is 1 pix long
# must translate pixel size to angular degrees since the 'add_scalebar' function assumes a physical scale
vectscale = scalevec * pxscale / 3600
fig.add_scalebar(5 * vectscale, "p = 5%", corner='top right', frame=True)
return stokes_i, p, mask, fig
#gc.show_contour(levels=levelsI,\
# filled=True,smooth=1,kernel='box',cmap='viridis')
#beam
gc.add_beam(color='red')
#title
gc.set_title(title, fontsize=title_size)
##Pol map
p = quality_cuts(stkI, stkIerr, p, perr, SNRp_cut, p_cut, SNRi_cut)
#2. polmap
gc.show_vectors(p,pa,scale=scalevec,\
step=2,color='black',linewidth=4.0)
gc.show_vectors(p,pa,scale=scalevec,\
step=2,color='grey',linewidth=2.0)
#show label
gc.add_label(0.1,0.95,'Total Flux',fontsize=label_fontsize,\
color='white',weight='bold',relative=True)
#legend vector
vecscale = scalevec * pxscale / 3600
gc.add_scalebar(vec_legend*vecscale,'P ='+np.str(vec_legend)+'%',\
corner='bottom right',frame=True,color='black',facecolor='blue')
#Figure parameters
gc.tick_labels.set_font(size=tick_labels)
gc.axis_labels.set_font(size=label_plot)
fig.savefig(figname, dpi=300)
os.system('open ' + figname)
