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HDF(N)

Example script for HDF(N) illustrated with screenshots (cut at will!)

stats_on_plot Nic this one should come up first followed by the one you have already - stats_on_plot has positive binned flux at I<25, the other one stats_off_plot is just noise.

Fornax, moon and ISAAC fields

Science summary

HDF(N)

• The Hubble Space Telescope observed the Hubble Deep Field (N) and Flanking fields using WFPC2 in 1995. About 3000 galaxies have been catalogued in the HDF(N), covering 4.7 square arcmin. Since then, the region has been surveyed at all wavelengths from radio to x-ray, by instruments including:
  • The CFHT and other ground-based optical telescopes with wider fields and/or better wavelength coverage;
  • The Very Large Array, MERLIN and other radiotelescopes - EVN, WSRT. A total of about 100 radio galaxies brighter than 40 microJy are found in a 10 arcmin^2 region, mostly over 1-2 arcsec in size.
  • The CHANDRA X-ray sattelite, which made over 300 detections;
  • The SCUBA submillimetre bolometer array, which found six enigmatic sources;
  • The ISO IR sattelite, which found 100 firm or probable sources.
  as well as more focussed observations of individual objects.

  In 6 yrs since the first data were released, although over 100 papers have been published, the images have not been fully analysed. The sheer volume of data and the many different formats and conventions have made multi-wavelength comparison very tedious, abeit neccessary to classify faint objects. The counterparts to, for example, x-ray sources, may be too faint to be catalogued independently but still be statistically significant. If we can count the proportions of galaxies which contain starburst regions, AGN, both or neither, as a function of distance, this will reveal the association and evolution of these phenomena.

  Example science projects for Demo:

  1. High-resolution comparison of radio and optical data at positions of SCUBA sources Serjeant et al. 2003 . The identification of these sources has been controversial as they have no or very reddened optical counterparts and may be dust-enshrouded starbursts at redshifts around 3.
  2. Comparison of radio, optical and x-ray data in regions between 2' and 5' radius from the central fields. The radio data in these regions are fully imaged for the first time. In the inner few arcmin, radio sources brighter than 100 uJy are mostly AGN, mostly nearby but at least one at z>4. However 70% of the fainter classified sources are starbursts. Many of these have x-ray counterparts. Is all this emission of starburst origin? The x-ray correlation is independent of radio brightness and we can now test the suggestion that the emission has distinct origins within the same galaxy - an embedded AGN? This suggests much of the faint x-ray emission may come from radio-quiet AGN. However this is based on a few tens of sources or each type; these data allow us to search a fivefold larger region.

  3. 85% of radio detections are associated with optical galaxies of magnitude I<25, at 0.3 < z < 1.3. This trend continues down to statistical detections of 15 - 25 uJy sources. The remaining optically faint sources (including some of the brighter radio objects) are mostly at higher redshifts (where these have been measured). It has been suggested that these are dusty starbursts with embedded AGN (confirmed in at least one case by a VLBI detection of a compact radio core at z=4.4.) In the inner fields there is also a statistical excess of faint radio emission associated with ISO sources. We can now investigate radio emission at the position of objects at known redshift in the larger region.

  The data available include all catalogues currently in Vizier. Those coveringmost or all of the 8'.5 field include the optical multi-waveband catalogue Vanden Berk+, 2000 J/AJ/119/2571, the redshift catalogue Cohen+ 2000 J/ApJ/538/29 and the Chandra CDF(N) catalogue Brandt+ 2001 J/AJ/122/2810, and in addition the first electronic publication of the full list of ISO sources based on Aussell+ 1999 B/avo.iso and of the radio sources >40 uJy based on Muxlow et al. 2003 B/avo.hdf (table lightweight figs; note that these last two are not publically released yet in this form and the authors should be contacted if you wish to use these data outside the Demo).

  Image data includes the HDF/HFF and the MERLIN+VLA data at close to full resolution (0.0625 arcsec pixels), and these data plus the CHANDRA and ISO data, all regridded to the resolution of the CHANDRA data, see sky coverage of image data used for AVO Demo. The data are astrometrically aligned and in physical photometric units although care should be taken interpreting data which have been regridded very differently from their native resolution, see [[http://wiki.astrogrid.org/bin/view/Astrogrid/HDFNorthAstrometry][notes on data preparation]].

  1. Optically faint sources - load full-resolution field 36 radio and optical, make colour composition (rg), contour radio to show faint extended source close to position of SCUBA 850.1 (SCUBA position 12:36:52.32+62:12:26.3, errors (0.1, 0.7) arcsec; IRAM position 12:36:51.98+62:12:25.7, error 0.3 arcsec)
  2. Radio-x-ray comparison:
     1. load radio, optical, x-ray at CHANDRA resolution. Make rgb. Load catalogues... Look at region around 12:37:02.75+62:15:43.8: three x-ray sources, one with optical counterpart, all 3 with faint radio counterparts..... Plot SEDs of interesting sources.
     2. (if ACE working) measure CHANDRA fluxes in physical units and feed back to add to SED.
     3. (if ACE working in dual-image mode) use mask maps to measure radio flux at on- and off-source positions of CHANDRA sources.
  3. Redshift distribution of radio sources - plot circles proportional to z and look at radio and x-ray flux as a function thereof.

(topic created by AnitaRichards 24.05.2012@04:25:41)