ADC/CDS Standard Document for Catalog:/journal_tables/ApJ/455/60/
ADC/CDS Standard Document for Catalog:| 1. Use the ADC Data Viewer Suite to visualize the data. |
|
| 2. Get the data files via anonymous FTP. (See Note.) |
|
J/ApJ/455/60 CFRS II: 0000-00 and 1000+25 fields (Le Fevre+ 1995)
================================================================================
The Canada-France Redshift Survey: II. Spectroscopic program :
data for the 0000-00 and 1000+25 fields
Le Fevre O., Crampton D., Lilly S.J., Hammer F., Tresse L.
<Astrophys. J. 455, 60 (1995)>
=1995ApJ...455...60L (SIMBAD/NED BibCode)
================================================================================
ADC_Keywords: Galaxies, photometry ; Galaxies, spectra ; Redshifts
Keywords: galaxies: distances and redshifts - techniques: spectroscopic
Abstract:
This paper describes the methods used to obtain the spectroscopic data
and construct redshift catalogs for the Canada-France Deep Redshift
Survey (CFRS). The full data set consists of more than 1000 spectra,
of objects with 17.5=<I_AB_=<22.5, obtained from deep multislit data
with the MARLIN and MOS-SIS spectrographs at the Canada-France-Hawaii
Telescope (CFHT). The final spectroscopic catalog contains 200 stars,
591 galaxies with secure redshifts in the range 0=<z=<1.3, six QSOs,
and 146 objects with very uncertain or unknown redshifts, leading to
an overall success rate of identification of 85%. In addition, 67
objects affected by observational problems have been placed in a
supplemental list. We describe here the instrumental setup and the
observing procedures used to gather this large data set efficiently.
New optimal ways of packing spectra on the detector to increase
significantly the multiplexing gain offered by multislit spectroscopy
are described. Dedicated data reduction procedures have been developed
under the IRAF environment to allow for fast and accurate processing.
Very strict procedures have been followed to establish a reliable list
of final spectroscopic measurements. Fully independent processing of
the data has been carried out by three members of the team for each
data set associated with a multislit mask, and final redshifts were
assigned only after the careful comparison of the three independent
measurements. A confidence class scheme was established. We strongly
emphasize the benefits of such procedures. Finally, we present the
spectroscopic data obtained for 303 objects in the 0000-00 and 1000+25
fields. The success rate in spectroscopic identification is 83% for
the 0000-00 field and 84% for the 1000+25 field.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 97 90 Spectroscopic catalog in the 0000-00 field
table3.dat 97 210 Spectroscopic catalog in the 1000+25 field
--------------------------------------------------------------------------------
See also:
J/ApJ/455/75 : CFRS III: 1415+52 and 2215+00 fields (Lilly+ 1995)
J/ApJ/455/88 : CFRS IV: 0300+00 field (Hammer+ 1995)
J/ApJ/464/79 : CFRS XI: High-redshift field galaxies morphology (Schade+ 1996)
J/ApJ/481/49 : CFRS XIV. Field galaxies up to z=1 (Hammer+ 1997)
Byte-by-byte Description of file: table2.dat table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.4 --- CFRS Canada-France Redshift Survey designation
9- 10 I2 h RAh Right ascension (J2000)
12- 13 I2 min RAm Right ascension (J2000)
15- 19 F5.2 s RAs Right ascension (J2000)
21 A1 --- DE- Declination sign
22- 23 I2 deg DEd Declination (J2000)
25- 26 I2 arcmin DEm Declination (J2000)
28- 29 I2 arcsec DEs [00/60] Declination (J2000)
31- 35 F5.2 mag Imag I_AB_ magnitude (1)
37- 41 F5.2 mag V-I (V-I)_AB_ colour index (2)
43- 47 F5.2 --- Q ? Compactness parameter;
see CFRS I. (1995ApJ...455...50L)
49- 54 F6.4 --- z ? Redshift
56- 57 I2 --- C Confidence class of spectroscopic
identification (3)
58 A1 --- Note [*] *: did correl z=0.3
59- 62 I4 0.1nm Lam1 ? Spectroscopic feature (4)
63 I1 --- Cont1 [2]? Spectroscopic feature (4)
64- 67 I4 0.1nm Lam2 ? Spectroscopic feature (4)
68 A1 --- Cont2 [1C]? Spectroscopic feature (4)
69- 72 I4 0.1nm Lam3 ? Spectroscopic feature (4)
73 I1 --- Cont3 [1]? Spectroscopic feature (4)
74- 77 I4 0.1nm Lam4 ? Spectroscopic feature (4)
78 I1 --- Cont4 [1]? Spectroscopic feature (4)
79- 82 I4 0.1nm Lam5 ? Spectroscopic feature (4)
83 I1 --- Cont5 [1]? Spectroscopic feature (4)
84- 87 I4 0.1nm Lam6 ? Spectroscopic feature (4)
89- 92 I4 0.1nm Lam7 ? Spectroscopic feature (4)
94- 97 I4 0.1nm Lam8 ? Spectroscopic feature (4)
--------------------------------------------------------------------------------
Note (1): Measured in isophotal aperture; see CFRS I. (1995ApJ...455...50L)
Note (2): Measured in a 3" aperture; see CFRS I. (1995ApJ...455...50L)
Note (3): Each object identification was assigned a confidence class.
This scheme is somewhat different from a pure "quality" scheme, and
the confidence class reflects the consensus probability that a
redshift measurement is correct and represents the confidence in the
measurement one gets from a combination of S/N, the number and
agreement of features, and the continuum shape.
The notation was set to classes 0-4, 8, 9 12-14, 92-94 as follow:
0-4: 0: when no redshift could be assigned
1: probability of 50% that the measurement was correct
2: probability of more than 75% that the measurement was correct
3: measurement at least 95% secure
4: unquestionably correct identification
8-9: 8: object for which the algorithm indicates that the emission
line is [O II]{lambda}3727
9: object for which the redshift ambiguity still could not be
resolved
12-14: QSO are identified with the same quality notation 1-4 as
galaxies, but a 1 is placed in front, e.g.,
14 is a very secure QSO.
92-94: Objects which do not belong to the main catalog, either because
they have I_AB_=22.5 or I_AB_<17.5, because of instrumental
problems but have a redshift determination, or whose photometry
was adjusted fainter than I_AB_=22.5 after the spectroscopic
observation, are kept in a supplemental catalog and are
identified by a 9 in front of the confidence class, e.g., 93.
The objects in this supplemental catalog may thus have biases
that will not be present in the statistically complete sample.
In any use of these data, attention should be paid to the confident
class that has been assigned to each spectroscopic identification.
Identifications with C=<1 are not used in the CFRS scientific analyses
described elsewhere. See the text for more information.
Note (4): Features noted in the spectra. These are largely self-explanatory,
except that a 1 indicates that the continuum shape supported the
identification in cases in which the number of distinct features
was small and a 2 indicates the multiple features of an M star.
C indicates continuum
--------------------------------------------------------------------------------
History: Prepared via OCR at CDS.
References:
Lilly S.J. et al., Paper I. =1995ApJ...455...50L
Lilly S.J. et al., Paper III. =1995ApJ...455...75L, Cat. <J/ApJ/455/75>
Hammer F. et al., Paper IV. =1995ApJ...455...88H, Cat. <J/ApJ/455/88>
Crampton D. et al., Paper V. =1995ApJ...455...96C
Lilly S. J. et al., Paper VI. =1995ApJ...455..108L
Hammer F. et al., Paper VII. =1995MNRAS.276.1085H
Le Fevre O. et al., Paper VIII. =1996ApJ...461..534L
Schade D. et al., Paper IX. =1995ApJ...451L...1S
Schade D. et al., Paper X. =1996MNRAS.278...95S
Schade D. et al., Paper XI. =1996ApJ...464...79S, Cat. <J/ApJ/464/79>
Tresse L. et al., Paper XII. =1996MNRAS.281..847T
Le Fevre et al., Paper XIII. =1996BCFHT..34...10L
Hammer et al., Paper XIV. =1997ApJ...481...49H, Cat. <J/ApJ/481/49>
================================================================================
(End) James Marcout, Patricia Bauer [CDS] 27-Mar-1997