Regions in ds9 serve multiple purposes. Some are purely decorative such as the Text and Compass. Some are functional such as Projection, and some represent multiple analysis regions such as Annulus and Panda
Panda=PieANDAnnulus
In this section we demonstrate a few of these
This data has been heavily processed to remove the point sources embedded in the extended emission. The basic steps replicate the An image of Diffuse Emission thread.
The processing starts with cluster Abell401, OBS_ID 14024
download_chandra_obsid 14024
chandra_repro 14024 out=repro
fluximage "14024/repro/acisf14024_repro_evt2.fits[ccd_id=0:3]" out=a401 bin=1 \
band="0.500:3.000:1.4" psfecf=0.9
wavdetect infile='a401_0.500-3.000_thresh.img' outfile='wav.out' \
scellfile='wav.cell' imagefile='wav.recon' defnbkgfile='wav.nbkg' \
expfile='a401_0.500-3.000_thresh.expmap' \
psffile='a401_0.500-3.000_thresh.psfmap' \
scales='1.4 2 4 8 12 16'
roi infile=wav.out outsrcfile="srcfill/srcs_%04d.fits" group=indi \
radiusmode=mul bkgradius=3 bkgfactor=2 bkgfunction=add targetbkg=target
splitroi @srcfill/srcs.lis points
dmfilth a401_0.500-3.000_thresh.img a401.img method="POISSON" \
srclist="@points.src.reg" bkglist="@points.bg.reg"
aconvolve a401.img a401_sm.img lib:'gaus(2,5,1,2,2)' meth=slide clob+
aconvolve a401_0.500-3.000_thresh.expmap a401_sm.exp lib:'gaus(2,5,1,2,2)' \
meth=slide clob+
dmimgcalc a401_sm.img a401_sm.exp a401_sm.flux div clob+
dmimgthresh a401_sm.flux a401_sm_thresh.flux cut=5% \
exp=a401_0.500-3.000_thresh.expmap value=0 clob+
cd RegionDecoration;
ds9 a401_sm_thresh.flux -block 4 -scale linear -pan to 4205.73 4357.09 physical &
xpaset -p ds9 region load ds9.reg
import -window "SAOImage ds9" -resize 50% ds9_04_regions_02.png
display < ds9_04_regions_02.png
grep 'fill=1' ds9.reg
grep 'darkgreen' --after-context=12 ds9.reg
grep 'width=.$' ds9.reg
grep 'tag=' ds9.reg
xpaset -p ds9 regions group "{Outter Edge}" color magenta
# Open Region -> Groups ...
sleep 3
import -window "Groups" ds9_04_regions_03.png
display < ds9_04_regions_03.png
xpaset -p ds9 quit