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Start Aladin < hdfn3.ajs
This loads two high-res (radio and optical) cut-out images and makes
an RG plot,
Then loads the three 8'.5 images (radio, optical, x-ray) and makes an
RGB of them. In both RGB's radio=red, optical=green, x-ray=blue.
Then it loads catalogues:
Then plots circles proportional to redshift (spectro- or photo-metric,
in catalogues loaded).
This gives 16 planes:
MERLIN+VLA 0".0625 pixels cutout 36
HST 0".0625 pixels cutout 36
RG of above two planes
MERLIN+VLA 0".492 (CHANDRA) pixels
HST as above
CHANDRA as above
RGB of above 3 planes
B/avo.rad/catalog from Muxlow+ 2003 MERLIN+VLA catalogue
B/avo.iso/15um from Aussel+ 1999 ISO 15 um
B/avo.iso/7um from Aussel+ 1999 ISO 7 um
J/AJ/119/2571 Vanden Berk+ 2000 UBVRI photometry of HDF (& HFF)
J/ApJ/538/29 Cohen+ 2000 HDF-N (& HFF) Caltech faint galaxy redshifts
J/AJ/122/2810 Brandt+ 2001 Chandra catalogue
Redshift plot
Radio flux density
x-ray counts
Cutout 36 is the field covering the SCUBA source 850.1, at
12:36:52.22+62:12:26.5 (error 0.1, 0.7 arcsec) thought to be
identified with the IRAM source at 12:36:51.98+62:12:25.7 (0.3 arcsec)
Select plane 1 and the hist button and set to approx. 190 223 255
Zoom in on 12:36:52.22+62:12:26.5 (use bright galaxies to SW as
finder) to x4
Tag this position and also the IRAM position above
Plot contours: select 'current zoom' and move levels to range 199 -
223 (the bottom end is important, you can tweak later though).
Go to RG image (plane 3) and use hist button to set
radio (red) 183 208 255 approx
optical (green) 16 37 255 approx
Zoom in on the position above (use tags to guide you) and then click
on the contour plane (top of stack) and properties button, to change
colours and levels if necessary. (NB do not apply more than once there
is a bug).
You can see there is a trace of radio emission with a tiny bright core
close to the IRAM position (westerly tag). This is thought to be
associated with a faint red Scd galaxy 3-593.1 at z=1.7 or more, in
the wings of the bright elliptical. You can also just see this in the
optical image plane 2 if you zoom and set the histogram to 39 47 255.
(it helps to turn the contours on and off)
- - - - - - - -
Select the full RGB image plane 7
Turn off planes 1-3 (high-res), the catalogues and the contours and
the tag planes at the top of the stack. Fix the histogram -
Something like
Red (radio) 168 175 200
Green (optical) 39 77 255
Blue (x-ray) 28 128 255
Note that the brightest sources in each regime are not usually
coincident. Turn on radio and x-ray catalogues (first and last in
catalogue series, red and gold planes) In particular if the Chandra
sources coincide with anything it is often radio - use the magnifying
glass.
Zoom in on the FR1 123644+621133 (maybe tweak the histogram again)
- bright core at all freqs, radio-only jets
Turn on the rest of the catalogues
Compare starburst 123659+621449 and AGN 123652+621444 spectra (with
CHANDRA cata if we can feed it back in): Zoom x2 around
12:36:58+62:15:14 and select these two sources (can just be done
without any other marked sources - however it may be easier to follow
the SED if you create 123652+621444 first and then add the other).
Each time you make an SED plot, click on x-axis log/linear till it
gives a log scale.
AGN 123652+621444 is bright in the radio and has a steep optical
spectrum but no IR. (labelled, blue points in screen shot - note this
has had the SED colours and symbols tweaked). Using the magnifying
glass on the image shows it is also x-ray bright.
starburst 123659+621449 is bright in the IR only, detected but faint
at other optical and radio, but is x-ray faint.
Turn off everything except the catalogues; zoom out to x1 and then
turn on the top two radio and x-ray filters. Radio sources <100 uJy
are in red and brigher in orange; x-ray sources <80 counts are in dark
blue and brighter in cyan.
Although the sources coincide quite a lot the brightness is not well
correlated. At the radio-brighter end most of the radio sources are
AGN. At the fainter end 70% are starbursts, but the lack close
correlation with x-ray brightness (and the slight position offsets
despite the very good astrometry of both catalogues) suggests that the
x-ray emission can come from different processes in the same galaxy
(?embedded AGN?). There are relatively few such sources with good
classifications and redshifts in the inner 3' so the extension to the
whole field will test this suggestion on a better sample.
Turn on the HST (plane 5) and hunt around in the HFF -
e.g. 123641+620948 - what is it?
for high-res, local load
http://www.merlin.ac.uk/avodemo/HDFHSTCUTOUT53.FITS
Turn on all the catalogues and look around 12:36:46+62:14:42
This is a pair of radio sources (unresolved in the VLA-only image)
which do not have a good classification.
Note that although both sources have optical
counterparts, neither have catalogued red-shifts. The nearest optical
object with a red-shift is too far away to be likely to be related;
however the fainter radio source could just be associated with an ISO
source given the latter's greater position uncertainty.
The labelled object is radio-brighter and has a faint x-ray counterpart
(more westerly in the image). The sources are probably unrelated -
but what are they? Neither has a red-shift nor an optical
classification.
Local load http://www.merlin.ac.uk/avodemo/HDFM+VCUTOUT21.FITS
and zoom in.
- - - - - - -
Turn on radio map plane 4 and all the catalogues and then turn on the
radio flux filter and the redshift filter (fix the radio histogram if
necessary). Zoom in and roam around, note that the brighter (gold
circle) radio sources are often associated with higher z
(e.g. 123642+621331 at z=4.4) or have no optical counterpart bright
enough to give a redshift (e.g. the previous example); conversely many
relatively nearby radio sources are faint. (Don't mess around, the
circle size goes haywire!) In the field shown (123642+621331 at NW
corner) the faint radio sources have a range of redshifts between 0.4
and 2.8 (where measured). This extends down to below the catalogue
7sigma confidence limit; thre is a statistical excess of radio sources
15 - 25 uJy associated with optical sources but only at I<25,
0.3<z<1.3 e.g. in zoom in
(topic created by AnitaRichards 24.05.2012@04:26:05)
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