J/A+A/418/885 The FORS Deep Field Spectroscopic Survey (Noll+, 2004)
The FORS Deep Field Spectroscopic Survey
Noll S., Mehlert D., Appenzeller I., Bender R., Boehm A., Gabasch A.,
Heidt J., Hopp U., Jaeger K., Seitz S., Stahl O., Tapken C., Ziegler B.L.
<Astron. Astrophys. 418, 885 (2004)>
=2004A&A...418..885N 2004A&A...418..885N
ADC_Keywords: Galaxies, spectra ; Redshifts
Keywords: galaxies: high-redshift - galaxies: starburst -
galaxies: fundamental parameters - galaxies: evolution
Description:
We present a catalogue and atlas of low-resolution spectra of a sample
of 341 objects with reliable redshifts in the FORS Deep Field (FDF).
The sample contains 42 stars, 8 QSOs, and 291 galaxies up to z=5.98
objects are at z>2. For z>1 most objects were selected using
photometric redshifts. The limiting I magnitude has been I=24.5 for
2<z<4.
All spectra were obtained using the FORS instruments at the ESO VLT
and cover the wavelength range 3300-10000Å. The grism 150I with a
1" slit width was used, resulting in a spectral resolution element of
our spectra of 18-24Å, depending on the light distribution in the
slit. Most objects were observed several times. Typical exposure times
were about 10h for our z>2 objects. The individual spectra were
S/N-optimised co-added. The final spectra were flux calibrated,
smoothed to the resolution element, and corrected for atmospheric
extinction. Moreover, the spectra were corrected for the atmospheric A
and B bands.
Redshifts and rough object types were derived by cross-correlation of
the galaxy spectra with six template spectra, which had been created
from high-quality FDF spectroscopic data by an iterative procedure.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 105 341 Data of FDF objects with spectroscopic redshift
fdfss/* . 331 Sub-directory: FDF spectra
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See also:
J/A+A/398/49 : UBgRIJKs photometry in the FORS Deep Field (Heidt+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- FDF Identification number in the FDF (1)
6- 7 I2 h RAh Right ascension (J2000) (1)
9- 10 I2 min RAm Right ascension (J2000) (1)
12- 15 F4.1 s RAs Right ascension (J2000) (1)
17 A1 --- DE- Declination sign (1)
18- 19 I2 deg DEd Declination (J2000) (1)
21- 22 I2 arcmin DEm Declination (J2000) (1)
24- 25 I2 arcsec DEs Declination (J2000) (1)
27- 30 F4.1 mag BTmag ?=99.9 Total Bessel B magnitude (1)
32- 35 F4.1 mag ITmag ?=99.9 Total Bessel I magnitude (1)
37- 40 I4 min Texp Total exposure time
42- 44 I3 % f/f0 Slit throughput (2)
46- 50 F5.1 --- S/N S/N per resolution element (3)
52 A1 --- n_S/N [BgRI] Filter band for S/N measurement (3)
54 I1 --- Qs ? Quality of the spectrum (4)
56 I1 --- Type [1/8] Object type (5)
58- 63 F6.4 --- z Spectroscopic redshift
65- 70 F6.4 --- e_z ? Mean error of redshift
72- 74 I3 % e_Type ? Uncertainty of Type (6)
76 I1 --- q_z Quality of redshift (7)
78- 97 A20 --- Notes ? Notes (8)
99-105 A7 --- File ? File name in sub-directory fdfss/ (9)
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Note (1): Taken from Heidt et al., 2003, Cat. J/A+A/398/49, if FDF<9000
Note (2): Effective ratio between the flux which passed through the slit
and the actual object flux in %. Low f/f0 usually correspond to large
object extensions. Typical values for point-like objects are around
0.7. Large values (>0.8) can be caused by systematic spectral errors
and/or inaccurate photometry due to very low fluxes or object crowding.
Note (3): S/N is the average signal-to-noise ratio per resolution element
in the filter band given in n_S/N (B, g, R, I). In each case the band
with the highest S/N was selected. The S/N as a function of wavelength
was calculated by dividing the object spectrum by its error function.
Note (4): Flag indicating systematic errors in the spectrum.
Qs=1 refers to distorted spectra, Qs=2 to local defects.
Note (5): Object type:
The classes 1 to 6 represent galaxies, 7 indicates QSOs, and 8 refers
to stars.
For the galaxy types the ratio of the UV to the optical flux in the
rest frame increases from 1 to 5/6 corresponding to a sequence from
early-type to extreme starburst galaxies. Special class 6 represents
starburst galaxies with strong Lyα emission. In case the
continuum could be measured suitably, it turned out that the class 6
galaxies also belong to type 5.
Note (6): Relative rms deviation between spectrum and the optimal template
in % of the average spectral flux.
Note (7): q_z=1 indicates objects with secure redshifts and qz=2 with
probable redshifts (90% confidence level). The presented catalogue
does not contain objects with uncertain redshifts.
Note (8): Further information on the object.
For stars a rough spectral type is given. Quasars and strong Lyα
emission galaxies are indicated by the entries "QSO" and "LAB"
(Lyα bright, i.e. Lyα emission EW≥20Å), respectively.
"600R" indicates galaxies whose redshift and object type were verified
by means of the medium resolution spectra of Ziegler et al.
(2002ApJ...564L..69Z 2002ApJ...564L..69Z).
Note (9): Blanks indicate that the spectrum has not been made available
due to strong systematic errors or very low S/N.
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Byte-by-byte Description of files: fdfss/*
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Bytes Format Units Label Explanations
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1- 4 I4 0.1nm lambda [3500,9300] Wavelength in Å (1)
6- 14 F9.4 10-20W/m2/nm flux Calibrated flux in 10-21W/m2/Å
16- 22 F7.4 10-20W/m2/nm noise Noise level in 10-21W/m2/Å (2)
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Note (1): Wavelength in air (~ wavelength in vacuum/1.000277)
Note (2): Statistical error per resolution element (~ 0.5 * error per
pixel)
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Acknowledgements: Stefan Noll
(End) Patricia Bauer [CDS] 27-Apr-2004