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J/AJ/127/2455       Gemini Deep Deep Survey (GDDS)           (Abraham+, 2004)

The Gemini Deep Deep Survey. I. Introduction to the survey, catalogs, and composite spectra. Abraham R.G., Glazebrook K., Mccarthy P.J., Crampton D., Murowinski R., Jorgensen I., Roth K., Hook I.M., Savaglio S., Chen H.-W., Marzke R.O., Carlberg R.G. <Astron. J., 127, 2455-2483 (2004)> =2004AJ....127.2455A
ADC_Keywords: Galaxies, photometry ; Redshifts ; Photometry, infrared Keywords: galaxies: evolution Abstract: The Gemini Deep Deep Survey (GDDS) is an ultradeep (K<20.6mag, I<24.5mag) redshift survey targeting galaxies in the "redshift desert" between z=1 and z=2. The primary goal of the survey is to constrain the space density at high redshift of evolved high-mass galaxies. We obtained 309 spectra in four widely separated 30-arcmin2 fields using the Gemini North telescope and the Gemini Multi-Object Spectrograph (GMOS). The spectra define a one-in-two sparse sample of the reddest and most luminous galaxies near the I-K versus I color-magnitude track mapped out by passively evolving galaxies in the redshift interval 0.8<z<1.8. This sample is augmented by a one-in-seven sparse sample of the remaining high-redshift galaxy population. The GMOS spectrograph was operating in a nod-and-shuffle mode, which enabled us to remove sky contamination with high precision, even for typical exposures times of 20-30hr per field. The resulting spectra are the deepest ever obtained. In this paper we present our sample of 309 spectra, along with redshifts, identifications of spectral features, and photometry. This makes the GDDS the largest and most complete infrared-selected survey probing the redshift desert. The seven-band (VRIz'JHKs) photometry is taken from the Las Campanas Infrared Survey (Cat. VII/228). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table4.dat 140 309 Master data table table5.dat 49 273 Spectral Features and Classifications
See also: VII/228 : Las Campanas Infrared Survey (Chen+, 2001-2002) Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 2 A2 --- --- [SA] 3- 9 A7 --- GDDS GDDS object identification (HH-NNNN) 11- 16 F6.4 --- z ? Redshift 18- 19 I2 h RAh Hour of right ascension (J2000) 21- 22 I2 min RAm Minute of right ascension (J2000) 24- 28 F5.2 s RAs Second of right ascension (J2000) 30 A1 --- DE- Sign of the declination (J2000) 31- 32 I2 deg DEd Degree of declination (J2000) 34- 35 I2 arcmin DEm Arcminute of declination (J2000) 37- 41 F5.2 arcsec DEs Arcsecond of declination (J2000) 43- 44 I2 --- Conf Redshift confidence (G1) 46- 48 A3 --- Ovlap Slit geometry/collision class (1) 50- 56 F7.5 --- Weight Sampling weight (2) 58- 62 F5.2 mag Bmag ? B-band magnitude (3) 63 A1 --- n_Bmag [s] s for 2σ detection limit in Bmag 64- 68 F5.2 mag e_Bmag ? Uncertainty in Bmag (3) 70- 74 F5.2 mag Vmag V-band magnitude (3) 75 A1 --- n_Vmag [s] s for 2σ detection limit in Vmag 76- 80 F5.2 mag e_Vmag ? Uncertainty in Vmag (3) 82- 86 F5.2 mag Rmag ? Cousins R-band magnitude (3) 87 A1 --- n_Rmag [s] s for 2σ detection limit in Rmag 88- 92 F5.2 mag e_Rmag ? Uncertainty in Rmag (3) 94- 98 F5.2 mag Icmag Cousins I-band magnitude (3) 99 A1 --- n_Icmag [s] s for 2σ detection limit in Icmag 100-103 F4.2 mag e_Icmag Uncertainty in Icmag (3) 105-109 F5.2 mag z'mag z'-band magnitude (3) 110 A1 --- n_z'mag [s] s for 2σ detection limit in z'mag 111-115 F5.2 mag e_z'mag ? Uncertainty in z'mag (3) 117-121 F5.2 mag Hmag ? H-band magnitude (3) 122 A1 --- n_Hmag [s] s for 2σ detection limit in Hmag 123-127 F5.2 mag e_Hmag ? Uncertainty in Hmag (3) 129-133 F5.2 mag Ksmag Ks-band magnitude (3) 134 A1 --- n_Ksmag [s] s for 2σ detection limit in Ksmag 135-139 F5.2 mag e_Ksmag ? Uncertainty in Ksmag (3)
Note (1): Classification of spectrum overlaps take the following numbers: 0 = Both A and B channels uncontaminated (at most very minor masking needed). 1 = Single channel overlap. Offending channel not used (at most very minor masking needed). 2 = A contaminating zeroth-order line has been masked. Remaining continuum is trustworthy. 3 = Two channel collision. Major masking used in extraction. Continuum in blue should not be trusted. 4 = Two channel collision. Major masking used in extraction. Continuum in red should not be trusted. 5 = Extreme measures needed to try to recover a spectrum. Continuum should not be trusted. Note (2): The practical upshot of our general mask design strategy is graphically summarized in the bottom left panel of Figure 6. This panel is a two-dimensional histogram showing the number of independent slits assigned each cell of color-magnitude space. For the reasons just described heavy emphasis is given to the (22<I<24.5, 3<I-Ks<5) region of color-magnitude space. The relative number of slits as a function of the average population in each cell expected in a wide-area survey can be computed by dividing the bottom left panel of the figure by the top left panel. The values computed using this procedure are shown in the bottom right panel and correspond to sampling weights. These weights will prove important in the computation of the luminosity and mass functions in future papers in this series. Note (3): Non-detections have been placed at the formal 2σ detection limit of the filter and magnitude error set to blank.
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 2 A2 --- --- [SA] 3- 9 A7 --- GDDS GDDS object identification (HH-NNNN) 11 I1 --- AGN [0/1] Indicative of AGN activity (1) 13 I1 --- [OII] [0/2] Is [O II] (3727 Å) present? (1) 15 I1 --- [OIII] [0/2] Is [O III] (5007 Å) present? (1) 17 I1 --- HiBal [0/2] Are Balmer lines bluer than Hβ present? (1) 19 I1 --- LoBal [0/2] Is Hα and/or Hβ present? (1) 21 I1 --- Fe2375 [0/2] Is Fe II (2375 Å) present? (1) 23 I1 --- Fe2600 [0/2] Is Fe II (2600 Å) present? (1) 25 I1 --- Mg2800 [0/2] Is Mg II (2800 Å) present? (1) 27 I1 --- Mg2852 [0/2] Is Mg II (2852 Å) present? (1) 29 I1 --- HandK [0/2] Are Ca II H & K lines present? (1) 31 I1 --- Balmer [0/2] Is the Balmer decrement present? (1) 33 I1 --- D4000 [0/2] Is the D4000 feature present? (1) 35 I1 --- Temp Redshift template code (2) 37- 39 I3 --- Class Spectral class (3) 41- 42 I2 --- Conf Confidence code (G1) 44- 48 F5.3 --- z Redshift
Note (1): Flag is: 0=No, 1=Yes 2=Feature did not fall within the wavelength range of our spectra Note (2): Redshift template code as follows: 1 = Comparison against a reference template was used to obtain the redshift 2 = No template needed to obtain the redshift Note (3): Classes use the following numbers: 001 = Objects showing pure, or nearly pure, signatures of an evolved stellar population (e.g., D4000, H&K, or template matches) 100 = Objects that are dominated by the flat-UV continuum and strong emission-lines characteristic of star- forming systems 010 = those showing signatures of intermediate ages (e.g., strong Balmer absorption). Many objects show characteristics of more than one type and so are assigned classes that are the sum of old (001), intermediates (010), and young (100) populations. Example: Objects listed as "101" may show strong H&K absorption and 4000Å breaks and yet have a flat-UV continuum tail indicative of a low level of ongoing star formation.
Global notes: Note (G1): Redshift confidence classes as follows: 0 = Failures. No redshift determined. If a redshift is given in table4.dat it should be taken as an educated guess. 1 = Failures. Confidence <50%. Very insecure 2 = Redshift Inferred from Multiple Features. Confidence >75%. Reasonably secure. Two or more matching lines/features. 3 = Redshift Inferred from Multiple Features. Confidence = 95%. Secure. Two or more matching lines/features + supporting continuum. 4 = Redshift Inferred from Multiple Features. Confidence: Certain. Unquestionably correct. 8 = Single-Line Redshift. Single emission line. Continuum suggests line is [O II] λ3727. 9 = Single-Line Redshift. Single emission line. 14 = AGN Redshift. Class 4 as above, but with AGN characteristics.
History: From electronic version of the journal References: Savaglio et al., Paper II 2004ApJ...602...51S Glazebrook et al., Paper III 2004Natur.430..181G McCarthy et al., Paper IV 2004ApJ...614L...9M
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 08-Jul-2004
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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