Virtual Observatory Software for Astronomers

HDF Radio Images (MERLIN+VLA) Cutout Service

The data

18 days of MERLIN data and 42h of A-array VLA data at 1.4 GHz (21 cm) have been combined to image a 10-arcmin field centred on the Hubble Deep Field (HDF). This area also includes the Hubble Flanking Fields (HFF). The 7-sigma confidence limit is ~27 microJy over most of this field. Muxlow et al. (2005) decribe the data and the source catalogue in Vizier is also available via VOExplorer as Radio sources in HDF and HFF (Short Name J/MNRAS/358/1159).

Cut-out service

What's available

The AstroGrid Cut-out service for MERLIN+VLA HDF Radio Images provides images within the following ranges:

  • Resolution 0.2, 0.3, 0.4 or 0.5 arcsec (restoring beam; all pixels are 0.0625 arcsec)
  • Image size between 8 and 128 arcsec on a side (square images)
  • Centre RA must be in range (12:36:12.701 to 12:37:25.917) = (189.052920 to 189.357991); Dec must in in range (+62:08:41.70 to +62:17:13.63) = (+62.144916 to +62.287119). HDF names like J123613.97+620852.6 are also recognised.

If you enter values outside these ranges, the service will attempt to produce an image with the nearest compatible parameters (e.g. it will be truncated if it overlaps the edge of the available field of view).

Usage

Use the VOExplorer to select the Cut out HDF(N) (GOODS) MERLIN+VLA radio images and click on Execute Task. This gives you the Task Runner interface.

Click on Execute (top right) to send the query. Once complete, you can start Aladin and send the output file as a table.

Data product

A VOTable containing the URL of your image is returned to cache or to the chosen file store. If you send it to Aladin, you can display the image and some information, or you can view the VOTable in TopCat to copy the URL and download the image. See Helper Applications? for more information on tools which link directly to AstroGrid. You can also dowload the VOTable itself. Any errors or warnings will be given in the VOTable INFO field.

Acknowledgements

This service makes use of ParselTongue python wrapper developed by RadioNet, MERLIN and the VLA which should be credited as well as acknowledging AstroGrid and Muxlow et al. (2005).

Attachments

Acknowledging AstroGrid. If you make use of the AstroGrid system or tools, we would be grateful if you could acknowledge this use in any resulting publications. You could use these words: 'This research has made use of data obtained using, or software provided by, the UK's AstroGrid Virtual Observatory Project, which is funded by the Science and Technology Facilities Council and through the EU's Framework 6 programme.' Use of any data discovered or accessed through AstroGrid should of course be mentioned as noted by the data providers.

Licensing and Copyright. AstroGrid software is released under the Academic Free License.. The copyright on the text used in these web pages is owned by the contributing authors. Copyright on images used are assumed to be with the indicated or implied source as appropriate.