J/A+A/398/49 UBgRIJKs photometry in the FORS Deep Field (Heidt+, 2003)
The FORS Deep Field:
Field selection, photometric observations and photometric catalog
Heidt J., Appenzeller I., Gabasch A., Jaeger K., Seitz S., Bender R.,
Boehm A., Snigula J., Fricke K.J., Hopp U., Kuemmel M., Moellenhoff C.,
Szeifert T., Ziegler B., Drory N., Mehlert D., Moorwood A.F.M.,
Nicklas H., Noll S., Saglia R.P., Seifert W., Stahl O., Sutorius E.,
Wagner S.J.
<Astron. Astrophys. 398, 49 (2003)>
=2003A&A...398...49H 2003A&A...398...49H
ADC_Keywords: Galaxies, optical ; Galaxies, photometry ; Morphology ;
Photometry, CCD
Keywords: methods: data analysis - catalogs - galaxies: general -
galaxies: fundamental parameters - galaxies: photometry
Abstract:
The FORS Deep Field project is a multi-colour, multi-object
spectroscopic investigation of a 7' times 7' region near the south
galactic pole based mostly on observations carried out with the FORS
instruments attached to the VLT telescopes. It includes the
QSO Q0103-260 (z=3.36). The goal of this study is to improve our
understanding of the formation and evolution of galaxies in the young
Universe. In this paper the field selection, the photometric
observations, and the data reduction are described. The source
detection and photometry of objects in the FORS Deep Field is
discussed in detail. A combined B and I selected UBgRIJKs photometric
catalog of 8753 objects in the FDF is presented and its properties are
briefly discussed. The formal 50% completeness limits for point
sources, derived from the coadded images, are 25.64, 27.69, 26.86,
26.68, 26.37, 23.60 and 21.57 in U, B, g, R, I, J and Ks
(Vega-system), respectively. A comparison of the number counts in the
FORS Deep Field to those derived in other deep field surveys shows
very good agreement.
Description:
Photometric and morphological parameters for 8753 objects (mostly
galaxies) in the FORS Deep Field are presented. For each object we
report the coordinates, total B and I magnitudes, aperture photometry
within 2" in UBgRIJKs and morphological parameters (FWHM, elongation,
PA and star-galaxy classification parameter from SExtractor). 3 flags
are given, which give information on blending of the objects (from
SExtractor), if an object was detected on the B or I frame only and a
preliminary classification of 35 point-like objects. Finally, weights
for the determination of the total B and I magnitudes are given.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 197 8753 Photometrical and morphological parameters
for 8753 objects in the FORS Deep Field
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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6- 9 I4 --- FDF Identification number in FORS Deep Field
11- 11 I1 h RAh Right ascension (J2000)
14- 14 I1 min RAm Right ascension (J2000)
16- 20 F5.2 s RAs Right ascension (J2000)
22 A1 --- DE- Declination sign
23- 24 I2 deg DEd Declination (J2000)
26- 27 I2 arcmin DEm Declination (J2000)
29- 32 F4.1 arcsec DEs [0/60] Declination (J2000)
34- 38 F5.2 mag BTmag ? Total Bessel B-magnitude
41- 44 F4.2 mag e_BTmag ? Error for BTmag
46- 50 F5.2 mag ITmag ? Total Bessel I-magnitude
53- 56 F4.2 mag e_ITmag ? Error for ITmag
58- 62 F5.2 mag Umag2s ? Aperture-mag in Bessel U within 2"
65- 68 F4.2 mag e_Umag2s ? Error for Umag2s
70- 74 F5.2 mag Bmag2s ? Aperture-mag in Bessel B within 2"
77- 80 F4.2 mag e_Bmag2s ? Error for Bmag2s
82- 86 F5.2 mag gmag2s ? Aperture-mag in Gunn g within 2"
89- 92 F4.2 mag e_gmag2s ? Error for gmag2s
94- 98 F5.2 mag Rmag2s ? Aperture-mag in Bessel R within 2"
101-104 F4.2 mag e_Rmag2s ? Error for Rmag2s
106-110 F5.2 mag Imag2s ? Aperture-mag in Bessel I within 2"
113-116 F4.2 mag e_Imag2s ? Error for Imag2s
118-122 F5.2 mag Jmag2s ? Aperture-mag in J within 2"
125-128 F4.2 mag e_Jmag2s ? Error for Jmag2s
130-134 F5.2 mag Ksmag2s ? Aperture-mag in Ks within 2"
137-140 F4.2 mag e_Ksmag2s ? Error for Ksmag2s
143-147 F5.2 arcsec FWHM ? FWHM of objects
150-153 F4.2 --- Elong ? Elongation of objects (1)
155-159 F5.1 deg PA ? Position angle of major axis
161-164 F4.2 --- S/G ? Star-galaxy classification parameter
(1: star, 0: galaxy)
167-168 I2 --- Flag1 Sextractor flag (2)
170-174 A5 --- Flag2 Detection flag (3)
176-183 A8 --- Flag3 Classification flag (4)
186-190 F5.3 --- w_BTmag ? Weight for BTmag
193-197 F5.3 --- w_ITmag ? Weight for ITmag
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Note (1): The elongation is defined as a/b, where a and b are given
by the 2nd order moment of the light distribution along the major
and minor axis, respectively (is also 1/(1-e) if e=ellipticity)
Note (2): Sextractor flag:
1: Object has neigbours which may significantly bias BTmag or ITmag
2: Object is blended with another one
3: Sum of 1 + 2
4: At least one pixel is saturated or close to saturation
7: Sum of 1 + 2 + 4
8: Object is truncated (e.g. too close to image boundary)
16: Object aperture data are incomplete or corrupted
17: Sum of 1 + 16
18: Sum of 2 + 16
19: Sum of 1 + 2 + 16
24: Sum of 8 + 16
Note (3): Detection flags:
Bonly: Object was only detected in B-band
Ionly: Object was only detected in I-band
Note (4): Classification flags:
QSO or star (G, M, K, L)
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Acknowledgements: Jochen Heidt
References:
Heidt, Appenzeller, Bender et al., the FORS Deep Field,
Reviews in Modern Astronomy 14 : Dynamic Stability and Instabilities in
the Universe, edited by Reinhard E. Schielicke. Hamburg, Germany :
Astronomische Gesellschaft, 2001., p.209
(End) Jochen Heidt [LSW Heidelberg, Germany] 12-Dec-2002