NEWS :
- 27-Aug-2003 - In order to facilitate spectroscopic follow-ups from
the ground, we are planning to pre-release (goal is on October
30th) the coordinates of sources selected on the basis of a
pre-defined i-z color cut. The expected depth of the data used
for selecting these objects is about 30 per cent of the final depth.
- 7-May-2003 - UDF pointing changed by 30 arcsec in order
to improve GS availability
- 26-Feb-2003 - UDF pointing is finalized.
- 12-Feb-2003 - Selected the following exposure times: 55
orbits each in F435W and F606W, 150 orbits each in F775W and
F850LP. Selected a pointing in the GOODS CDFS area including both a
confirmed z=5.8 galaxy and a type II QSO.
- 6-Feb-2003 - The filter subcommittee opted for using the 4 GOODS
filters
The ACS Ultra Deep Field (UDF) is a survey
carried out using the Advanced Camera for Surveys on HST and taking
advantage of the Director's Discretionary time. The data will be made
public.
The UDF will consist of a single ultra-deep field
(about 400 orbits in total) within the CDF-S GOODS area.
- Filters.
The survey will use four filters: F435W (55 orbits), F606W (55 orbits),
F775W (150 orbits), and F850LP (150 orbits). The F435W (B) and F606W
(V) exposures will be one magnitude deeper than the equivalent HDF
filters. The F775W (I) exposure will be 1.5 magnitude deeper than the
equivalent HDF exposure. The depth in F775W and F850LP is optimized for
searching very red objects at the detection limit of the F850LP
image.
- Pointing.
The
pointing
will be RA(J2000)=3 32 39.0 and Decl.(J2000)=-27 47 29.1
These
coordinates have been changed slightly in May 2003 due to guide star availability and
implementation issues.
We have attempted to include in the field both
a spectroscopically confirmed z=5.8 galaxy and a spectroscopically confirmed
type Ia SN at z=1.3. The pointing
avoids the gaps with the lowest effective
exposure on the Chandra ACIS image of CDFS.
- Phase II and Execution.
The phase II is accessible on the web as DD proposal
9978 .
Data taking will begin on September 24th and continue through January 16th (click here
for more details).
We plan to release the reduced ACS data and catalogs by February 7th.
This basic structure of
the survey represents a consensus recommendation of a Scientific Advisory
Committee to the STScI Director Steven Beckwith.
A local
Working Group
is looking in detail at the implementation
of the survey.
Reports
-
Field Selection Criteria for the ACS Ultra Deep Field
New Version with improved zodiacal background discussion and changes to
the radio selection criteria available in pdf
and in postscript . The old version is still available in both pdf
and postscript .
-
Planning of the ACS Ultra Deep Field
Available in pdf
and in postscript
-
Radio and Sub-mm Considerations for the ACS Ultra Deep Field (Revised 15 Jan 2003)
Available in pdf
and in postscript
-
Alma worksheet (from SVWB)
Available in bitmap , gif
or jpg .
UDF Poster
-
Click here for a pdf copy of the poster to advertise the UDF at the January 2003 AAS (large file).
Figures
-
Schlegel's E(B-V) North Galactic cap map
Available in gif
-
Schlegel's E(B-V) South Galactic cap map
Available in gif
-
Summary plot of best verified fields
Available in pdf
and in postscript
Additional Material
- Rogier Windhorst has contributed plots of the
median photometric redshift vs B mag and
of the
median photometric redshift vs I mag . Both plots are
derived for the HDF.
- Rogier has also contributed a draft paper on the natural
confusion limit. This is available in gzipped
postscript and
PDF .
- Finally, this is a postscript of fig 3 of Driver et al.
(1998, ApJL 496, L93) showing N(z) vs (-mag for the HDF. The 4 panels indicate the total sample and the early-, mid- and late-type galaxies.
Last updated 27 August 2003
