II/258 Hubble Ultra Deep Field Catalog (UDF) (STScI, 2004)
The Hubble Ultra Deep Field Catalog
Beckwith S.V.W.
<Space Telescope Science Institute (2004)>
ADC_Keywords: Photometry, HST ; Surveys ; Galaxy catalogs
Mission_Name: HST
Description:
The Hubble Ultra Deep Field (PI: Steven V. W. Beckwith) is a 400-orbit
Cycle 12 program to image a single field of the Wide Field Camera
(WFC) of the Advanced Camera for Surveys (ACS) in four filters: F435W
(B), F606W (V), F775W (i), and F850LP (z). The observations took place
over 4 months from September 2003 to January 2004 under two program
IDs: 9978 and 10086.
The observations consist of half-orbit exposures, cycling through each
of the filters in a 4-point dither pattern to provide sub-pixel
sampling, as well as a larger-scale 3-point line pattern to cover the
2 second of arc gap between the two ACS/WFC chips. The total exposure
times are summarized below, with typical exposure times of 1200s for
individual images. The AB magnitude zero-points for ACS are current as
of March 2004.
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Number of Number of Total Exp. AB mag.
Orbits Exposures Time (s) zero-point
---------------------------------------------------------------
B (F435W): 56 112 134880 25.673
V (F606W): 56 112 135320 26.486
i (F775W): 144 288 347110 25.654
z (F850LP): 144 288 346620 24.862
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More details are found in the "intro.txt" file, or from the
UDF home page.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
intro.txt 68 419 Introduction
udf-i.dat 213 10179 The Ultra-Deep Field Catalog from F775W image
udf-z.dat 213 7016 The Ultra-Deep Field Catalog from F850LP image
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See also:
II/253 : Chandra Deep Field South: multi-colour data (Wolf+, 2004)
http://cadcwww.hia.nrc.ca/udf/ : Ultra Deep Field High-Level Science Products
http://www.stsci.edu/hst/udf : Ultra Deep Field Home Page
Byte-by-byte Description of file: udf-i.dat udf-z.dat
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Bytes Format Units Label Explanations
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3- 7 I5 --- UDF Running number (G1)
11- 17 F7.2 pix Xpos Position of the source (toward East)
20- 26 F7.2 pix Ypos Position of the source (toward North)
29- 39 F11.7 deg RAdeg Right Ascension (J2000)
42- 52 F11.7 deg DEdeg Declination (J2000)
56- 60 F5.1 deg Theta [-90,+90] source orientation "Theta"
(counterclockwise from the X-axis = PA-90)
64- 68 F5.3 --- ell Ellipticity (1-b/a)
74- 80 F7.2 pix R50 Half-light radius
83- 88 F6.2 pix FWHM FWHM of a Gaussian fit to each source
93- 96 F4.2 --- Sty Stellarity (1 for point sources,
0 for fully resolved sources)
105-111 F7.4 mag Bmag ?=99.00 AB magnitude in F435W filter (2)
113-119 F7.4 mag e_Bmag ?=99.00 Formal error on Bmag
122-127 F6.1 --- Bs/n Signal to Noise ratio in F435W filter
132-138 F7.4 mag Vmag ?=99.00 AB magnitude in F606W filter (2)
140-146 F7.4 mag e_Vmag ?=99.00 Formal error on Vmag
149-154 F6.1 --- Vs/n Signal to Noise ratio in F606W filter
159-165 F7.4 mag imag ?=99.00 AB magnitude in F775W filter (2)
167-173 F7.4 mag e_imag ?=99.00 Formal error on imag
176-181 F6.1 --- is/n Signal to Noise ratio in F775W filter
186-192 F7.4 mag zmag ?=99.00 AB magnitude in F850LP filter (2)
194-200 F7.4 mag e_zmag ?=99.00 Formal error on zmag
203-208 F6.1 --- zs/n Signal to Noise ratio in F850LP filter
212-213 I2 --- Flags SExtractor flags (1)
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Note (1): combination of binary flags with the following meaning:
1 = The object has neighbors, bright and close enough to
significantly bias the photometry, or bad pixels
2 = The object was originally blended with another one.
4 = At least one pixel of the object is saturated (or very close to).
8 = The object is truncated (too close to an image boundary).
16 = Object's aperture data are incomplete or corrupted.
Note (2): magnitude isophotally matched.
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Global Notes:
Note (G1): Nomenclature note:
Objects in udf-i.dat file are identified as UDF NNNNN in Simbad.
Objects in udf-z.dat file are identified as UDF 3NNNN in Simbad,
(i.e, in udf-z.dat file, "Seq = 1" is "UDF 30001" in Simbad).
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History:
From http://cadcwww.hia.nrc.ca/udf/acs-wfc/
(End) Francois Ochsenbein [CDS] 07-May-2005