The Hubble Deep Field: latest news

Hawaii Hubble Deep Field North (Subaru images).

The Hubble Deep Fields at the Rome Observatory.

European VLBI Network observations of the HDF-N.

Westerbork Synthesis Radio Telescope 1.4 GHz observations.

First x-ray results from Chandra HDF Observations are now available.

The VLA survey of the HDF and flanking fields now has its own web site.

Hawaii Flanking Field Catalog. Includes astrometry, photometry, redshifts, and H&K band infrared images.

A New Catalog of Photometric Redshifts in the HDF (Fernandez-Soto, Lanzetta, and Yahil 1998, ApJ submitted).

The link to the HDF South page has been added.

The ISO HDF web page has been updated to include copies of the accepted papers (I-V), active catalogs, tests of the reliability of sources, and other items of interest.

Hubble Deep Field Academy -- Educational Resource for Middle School students

The topic of the 1997 STScI May Symposium will be the Hubble Deep Field.

Data and Preprints of the ISO HDF observations are now available.

A search of the STScI library STEPsheet reveals the following HDF Preprints and Publications. If yours is not listed here, please send a copy to the STScI Librarian (Librarian, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218).

Infrared followup obervations using the KPNO IRIM camera are now available.

A new set of WFPC-2 mosaics are available courtesy of Mark Dickinson and Richard Hook. The World Coordinate System (WCS) keywords in the mosaics and in the IRIM data have been updated to match the system defined in Williams et al (1996, AJ, 112, 1335) based on radio interferometric positions for several HDF sources. An iraf script hdf_wcs_fix.cl is available to updated the header information in the version 2 drizzled images.

To make room for the mosaics, we have deleted the version-1 HST WFPC images from the archive disk. The v2 images (still available) should be better for most purposes. If (for some peculiar reason) you want the v1 images, you may request a tape from ferguson@stsci.edu.

The Hawaii Active Catalog provides a cursor-driven interface to information on individual HDF galaxies.

Plans are underway for a southern HDF. There is no specific date or field yet for the observations. Fields under consideration are being searched for a suitable QSO for absorption line studies.

The topic for the 1997 STScI May Symposium will be the Hubble Deep Field. Dates are still to be determined. Further details will be announced here, through mailings, and on the STScI meetings web page.

Preprints from the VLA survey are available: abstract; postscript ; figure 1; figure 2.

Redshifts from the DEEP project survey with Keck are now available.

There is now a web page for the ISO HDF followup observations.

The Drizzle algorithm used to reduce the HDF is now publicly available in a beta release version.

The Version 2 catalogs have finally been put on the web. Details of the STScI & ST-ECF data reduction, source detection, and photometry are described in Williams et al. (AJ, in press).

SUNY Stony Brook now has an HDF Web page.

The Berkeley HDF group now has a web page, listing, among other things redshifts for about 30 galaxies in the HDF and flanking fields.

Redshifts from the Caltech and Hawaii Keck runs have been added to the Caltech web page.

Astrometry of the HDF flanking fields has been carried out by the DEEP collaboration.

HDF version 3 has slowed considerably, mostly because it is not a high priority given the modest expected gains in resolution and S/N. The new target date is the end of the summer

A cautionary note on photometry. The zeropoints listed for the HDF do not include a correction for contamination, which progressively adds attenuation between monthly decontaminations (warmups) of WFPC-2. As the HDF was taken shortly after a DECON, this effect is less than 0.05 mag for F300W, and significantly less for the redder filters. The F300W correction will be posted here once it is computed.

A more serious concern is that the F300W exposures, which have low backgrounds and low source count rates, are in a regime where charge-transfer effects (CTE) could be significant. Measured magnitudes of faint sources in the F300W band could be up to 0.2 mag fainter than true magnitudes, with the size of the effect depending on row number. The effect is probably only a few hundredths of a mag for the optical filters because of their higher backgrounds. Laboratory tests and observations in Cycle 6 are being planned to try to arrive at a calibration of CTE as a function of row number, source count rate, background level, the number of counts in the previous image, and the time elapsed between images. Details of recent investigations of the CTE and (and a similar, probably related photometric dependence on exposure time) are posted on the WFPC-2 advisory page.

A TIFF format image of the HDF + flanking fields, overlaid on a KPNO 4-m image has been added, for use a finder chart. CAUTION -- the frames in this image were aligned by eye. Has anyone in the greater HDF community yet done a precise registration of the HDF and flanking fields?

Added an update on J, H, and K band observations from the KPNO 4-m telescope.

New links to HDF followup at Cambridge and Lick Observatory have been added to the clearinghouse.

Our new target date for version 3 of the data reduction is now the end of May.

Well, the superdarks & superbiases are almost done...version 3 is probably still several weeks down the road, as there are quite a few other issues that have to be addressed in this final reduction.

Sky levels for the individual chips are now posted.

It is now clear that we will miss the April 1 target date for the version 3 release of the HDF data. We are in the midst of remaking superdarks and superbiases, correcting at the same time for the MgF faceplate glow. We are shooting for April 15.

Information on VLA observations has been added to the HDF clearinghouse.

There is a problem in the World Coordinate System (WCS) in the version 2 images. The v2 image headers have had a lot of stuff stripped out of them that was in the v1 edition. 99% of that information was useless, but two keywords pertaining to the WCS were not. The parameters CTYPE1 and CTYPE2 should be set to 'RA---TAN' and 'DEC--TAN', respectively (note the number of dashes in each entry!). Currently, they are incorrectly set to 'PIXEL'.

The weight images in Version 2 give the inverse variance of the images in counts per second per INPUT (WF- or PC-sized) pixel. However, when you measure the noise in the drizzled images, you will be measuring it in counts per second per OUTPUT pixel. The ratio of areas (and therefore counts) between the input and output pixels is 6.25 in the WF and 1.31 in the PC. As a result the standard deviation estimated from 1./sqrt(weight) must be divided by the ratio of areas before comparison with the noise measured in the images.

A list of frames not used version 2 has been added.

Version 2 of the HDF data is now available. The additional processing has resulted in roughly a 10% improvement in S/N for the F450, F606, and F814W filters.

Information on image registration and combination and on the drizzle algortihm have been updated in preparation for the expected release of Version 2 on 29 Feb 1996 (what would we have done were it not a leap year?).

Proposals are now being solicited for ISO observations of the Hubble Deep Field. Up-to-date information about the ISO mission and instruments can be found on the ISO Homepage. Detailed information about the HDF proposal opportunity is on the same HomePage under the heading "ISO and the Hubble Deep Field".

Version 2 is just about ready. Really. The final scattered light subtraction is being done today.

Added a link to the University of Hawaii HDF web page provided by Len Cowie.

Flanking Field images. 1 & 2 orbit exposures of 8 adjacent fields have been installed on the ftp site.

Version 2 of the data is running a bit behind. We had hoped to have it ready Feb. 1, but it now looks like Feb. 8 is a better bet. The masking of moving targets is almost complete. Then the frames will be restacked, redrizzled, and will have scattered light subtracted.

The ESO/ECF HDF group now has a link in the HDF clearinghouse.

A link to the call for HDF archival proposals has been added. The deadline is March 15, 1996.

The catalogs released on January 15 had an error in the x,y and RA, DEC coordinates. They have been corrected and re-released January 16. The new versions will be stored as FITS tables (*.fits) rather than stsdas tables (*.tab), but may not propagate to the ftp site until mid-day on January 16.

HDF web pages are installed, but many are incomplete and will remain so until January 20th or so. If you have questions, contact the undersigned.