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VII/250       The 2dF Galaxy Redshift Survey  (2dFGRS)  (2dFGRS Team, 1998-2003)

The 2dF Galaxy Redshift Survey (2dFGRS) Colless M., Dalton G., Maddox S., Sutherland W., Norberg P., Cole S., Bland-Hawthorn J., Bridges T., Cannon R., Collins C., Couch W., Cross N., Deeley K., de Propris R., Driver S.P., Efstathiou G., Ellis R.S., Frenk C.S., Glazebrook K., Jackson C., Lahav O., Lewis I., Lumsden S., Madgwick D., Peacock J.A., Peterson B.A., Price I., Seaborne M., Taylor K. <Mon. Not. R. Astron. Soc. 328, 1039 (2001)> =2001MNRAS.328.1039C
ADC_Keywords: Surveys ; Galaxy catalogs ; Redshifts ; Galaxies, photometry Keywords: Surveys, galaxies: clusters: general ; Galaxies: distances and redshifts ; Cosmology: observations ; Large-scale structure of Universe Description: The 2dF Galaxy Redshift Survey (2dFGRS) is a major spectroscopic survey taking full advantage of the unique capabilities of the 2dF facility built by the Anglo-Australian Observatory. The 2dFGRS is integrated with the 2dF QSO survey (2QZ, Cat. VII/241). The 2dFGRS obtained spectra for 245591 objects, mainly galaxies, brighter than a nominal extinction-corrected magnitude limit of bJ=19.45. Reliable (quality≥3) redshifts were obtained for 221414 galaxies. The galaxies cover an area of approximately 1500 square degrees selected from the extended APM Galaxy Survey in three regions: a North Galactic Pole (NGP) strip, a South Galactic Pole (SGP) strip, and random fields scattered around the SGP strip. Redshifts are measured from spectra covering 3600-8000 Angstroms at a two-pixel resolution of 9.0 Angstrom and a median S/N of 13 per pixel. All redshift identifications are visually checked and assigned a quality parameter Q in the range 1-5; Q≥3 redshifts are 98.4% reliable and have an rms uncertainty of 85 km/s. The overall redshift completeness for Q≥3 redshifts is 91.8% but this varies with magnitude from 99% for the brightest galaxies to 90% for objects at the survey limit. The 2dFGRS data base is available on the World Wide Web at http://www.mso.anu.edu.au/2dFGRS/. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file 2dfgrs.dat 188 245591 Best observations of 2dFGRS spectra.dat 99 269937 Observed spectra parent.dat 142 407834 Details of source observations ngp.dat 209 135879 Photometric catalog in North Galactic Pole region sgp.dat 209 190824 Photometric catalog in South Galactic Pole region ran.dat 209 55620 Photometric catalog in random regions
See also: http://www.mso.anu.edu.au/2dFGRS/ : The 2dF Galaxy Redshift Survey Home Page VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004) Byte-by-byte Description of file: 2dfgrs.dat
Bytes Format Units Label Explanations
1- 6 I06 --- SeqNum 2dFGRS serial number (SEQNUM) 8 I1 --- o_SeqNum [1,6] Number of spectra obtained 10- 19 A10 --- Name 2dFGRS name (NAME) 21- 23 I03 --- UKST UKST plate number (IFIELD) 25- 26 I2 h RA1950.h Right ascension (B1950, hours) 28- 29 I2 min RA1950.m Right ascension (B1950, minutes) 31- 35 F5.2 s RA1950.s [0,60.] Right ascension (B1950, seconds) 37 A1 --- DE1950.- Declination sign (B1950) 38- 39 I2 deg DE1950.d Declination (B1950, degrees) 41- 42 I2 arcmin DE1950.m Declination (B1950, minutes) 44- 47 F4.1 arcsec DE1950.s [0,60.] Declination (B1950, seconds) 49- 50 I2 h RAh Right ascension (J2000, hours) 52- 53 I2 min RAm Right ascension (J2000, minutes) 55- 59 F5.2 s RAs [0,60.] Right ascension (J2000) 61 A1 --- DE- Declination sign (J2000, seconds) 62- 63 I2 deg DEd Declination (J2000, degrees) 65- 66 I2 arcmin DEm Declination (J2000, minutes) 68- 71 F4.1 arcsec DEs [0,60.] Declination (J2000, seconds) 73- 78 F6.3 mag Bjmag Final bj magnitude (BJG) (1) 80- 85 F6.3 mag Bjsel Final bj magnitude corrected from extinction (BJSEL) (G2) 87- 92 F6.3 mag Bjmag.o Original bj magnitude (BJG_OLD) (1) 94- 99 F6.3 mag Bjsel.o Original bj magnitude corrected from extinction (BJSELOLD) 102-106 F5.3 mag Gext Galactic extinction value (GALEXT) 108-113 F6.3 mag Bjmag.S ?=0 SuperCosmos bj magnitude (SB_BJ) (1) 115-120 F6.3 mag Rmag.S ?=0 SuperCosmos R magnitude (SR_R) (1) 122-128 F7.4 --- z.obs ?=-9 Best redshift (observed) (Z) (2) 130-136 F7.4 --- z ?=-9 Best redshift (heliocentric) (Z_HELIO) (2) 138-142 A5 --- ObsRun Observation run of best spectrum (OBSRUN) 144 I1 --- q_z [1,5] Redshift quality for best spectrum (reliable redshifts have quality≥3) (2) 146 I1 --- n_z Redshift type (abs=1, emi=2, man=3) (ABEMMA) 148-154 F7.4 --- z.abs ?=-9.999 Cross-correlation redshift (Z_ABS) (2) 156 I1 --- T Cross-correlation template (KBESTR) (2) 158-162 F5.2 --- Rx ?=-9.99 Cross-correlation R value (R_CRCOR) (2) 164-170 F7.4 --- z.em ?=-9.999 Emission redshift (Z_EMI) (2) 172 I1 --- o_z.em Number of emission lines for Z_EMI (NMBEST) (2) 175-179 F5.1 --- SNR Median signal to noise ratio per pixel (2) 181-188 F8.4 --- eta ?=-99.9 Eta spectral type parameter from best spectrum (ETA_TYPE) (G1)
Note (1): without extinction correction. Note (2): from best spectrum. When there is more than one 2dFGRS spectrum for a source, the best spectrum is the one with the highest redshift quality code; if there is more than one spectrum of this quality, then the spectrum with the latest date of observation is used. The other spectra are summarized in the file spectra.dat
Byte-by-byte Description of file: spectra.dat
Bytes Format Units Label Explanations
1- 6 I06 --- SeqNum Database serial number (SEQNUM) 8- 17 A10 --- Name 2dFGRS name (NAME) 19- 28 A10 "Y:M:D" ObsDate UT date of observation (UTDATE) 30- 34 A5 --- ObsRun Observation run (OBSRUN) 36- 42 F7.4 --- z.obs ?=-9.99 Redshift (observed) (Z) 44- 50 F7.4 --- z ?=-9.99 Redshift (heliocentric) (Z_HELIO) 52 I1 --- q_z [1,5] Redshift quality parameter (QUALITY) 54 I1 --- n_z Redshift type (abs=1, emi=2, man=3) (ABEMMA) 56- 62 F7.4 --- z.abs ?=-9.999 Cross-correlation redshift (Z_ABS) 64 I1 --- T Cross-correlation template (KBESTR) 66- 70 F5.2 --- Rx ?=-9.99 Cross-correlation R value (R_CRCOR) 71- 72 A2 --- --- [00] 74- 80 F7.4 --- z.em ?=-9.999 ?=-9.99 Emission redshift (Z_EMI) 82 I1 --- o_z.em Number of emission lines (NMBEST) 85- 89 F5.1 --- SNR Median signal to noise ratio per pixel (SNR) 91- 98 F8.4 --- eta ?=-99.9 spectral type parameter (G1) 99 A1 --- --- [0]
Byte-by-byte Description of file: parent.dat
Bytes Format Units Label Explanations
5- 10 I06 --- SeqNum Assigned sequence number to this object; determines the FITS filename (SEQNUM.fits) 13- 21 F9.6 rad RArad Right ascension (B1950), radians 23- 31 F9.6 rad DErad Declination (B1950), radians 33- 38 F6.3 mag Bjsel (BJSEL) Final bj magnitude (1) 40- 47 F8.5 --- z.obs ?=-9.99 Best redshift (observed) 49- 56 F8.5 --- z ?=-9.99 Best redshift (heliocentric) 58- 63 F6.3 mag bjlim ?=-1 2dFGRS bj magnitude limit of this area (2) 65- 67 I3 --- q_z [1,5]?=-99 Redshift quality parameter (reliable redshifts have quality≥3) 71- 76 F6.3 mag Bjmag Final bj without extinction correction (BJG) 78- 82 F5.2 mag Bj.ori Original bj magnitude with extinction correction (BJSELOLD) 84- 88 F5.2 mag Bj.old Original bj magnitude without extinction correction (BJG_OLD) 90- 92 I03 --- UKST UKST plate number (IFIELD) 94- 96 I3 --- obsfld ?=-99 Observed field number (OBSFLD(4:6)) 99-104 I6 "yyMMDD" GRSdate ?=000000 Observation date (GRSDATE) 107-114 F8.3 --- eta ?=-999 Spectral type parameter (ETA_TYPE) (G1) 117-119 I3 --- Plate [0,1]?=-99 2dF plate (0 or 1) (PLATE) 122-126 F5.3 --- e Eccentricity of the image (ECCENT) 129-131 I3 deg ora [0,180[ Orientation angle E-(N)-W (ORIENT) 134-135 I2 --- jon ?=-1 Eyeball classification (JON) (G3) 138-142 I5 pix area Isophotal area in pixels (AREA)
Note (1): Final bj magnitude with extinction correction (i.e. with corrections for isophote, field-effects and plate-matching, then calibrated to total mags with saturation correction, and then extinction corrected) Note (2): value -1.000 for sources not included in the survey sample
Byte-by-byte Description of file: ngp.dat sgp.dat ran.dat
Bytes Format Units Label Explanations
1- 6 I06 --- SeqNum Database serial number (SEQNUM) 9- 10 I2 h RAh Right Ascension B1950 (hours) 12- 13 I2 min RAm Right Ascension B1950 (minutes) 15- 19 F5.2 s RAs Right Ascension B1950 (seconds) 22 A1 --- DE- Declination B1950 (sign) 23- 24 I2 deg DEd Declination B1950 (degrees) 26- 27 I2 arcmin DEm Declination B1950 (minutes) 29- 32 F4.1 arcsec DEs Declination B1950 (seconds) 35- 40 F6.3 mag Bjsel Final bj magnitude with extinction correction (BJSEL) (G2) 43- 49 F7.1 --- psi psi classification parameter (PROB) (2) 51- 55 F5.3 --- k k classification parameter = k/k_star (PARK) 57- 61 F5.3 --- mu mu classification parameter = mu/mu_star (PARMU) 63- 64 I2 --- Cl [-4,2] Final classification (IGAL) (3) 66- 67 I2 --- jon [0,9]?=-1 Eyeball classification (JON) (G3) 69- 71 I3 deg ora [0,180[ Orientation angle E-(N)-W (ORIENT) 72- 73 A2 --- --- [.0] 75- 79 F5.3 --- e Eccentricity (ECCENT) 82- 86 I5 pix Area Isophotal area in pixels (AREA) 87 A1 --- --- [.] 89- 96 F8.1 pix Xpos Bj plate position in 8 micron pixels (X_BJ) 98-105 F8.1 pix Ypos Bj plate position in 8 micron pixels (Y_BJ) 108-110 I3 0.01pix dX ?=-99 Distortion difference (X(Bj)-X(R))*100 (DX) 111 A1 --- --- [.] 114-116 I3 0.01pix dY ?=-99 Distortion difference (Y(Bj)-Y(R))*100 (DY) 117 A1 --- --- [.] 120-125 F6.3 mag Bjmag Final bj magnitude (BJG) (1) 128-132 F5.2 mag Rmag Unmatched APM 'total' mag (RMAG) 135-139 F5.2 mag Pmag ?=0 Unmatched raw APM profile integrated magnitude (PMAG) 142-146 F5.2 mag Fmag ?=0 Unmatched raw APM 2" profile integrated magnitude (FMAG) 149-153 F5.2 mag Smag ?=0 Unmatched raw stellar mag from APMCAL (SMAG) 157-160 A4 --- --- [0.00] 162-164 I03 --- UKST UKST field number (IFIELD) 167-171 I5 --- Igal Galaxy number in UKST field (IGFIELD) 174-183 A10 --- Name 2dFGRS assigned name (4) 186-190 F5.2 mag Bjmag.o Original bj magnitude (BJG_OLD) (1) 192-196 F5.2 mag Bjsel.o Original bj magnitude with extinction correction (BJSELOLD) 199-203 F5.2 mag Bjmag.1 bj magnitude in 100k (VII/226) (100_BJG) (1) 205-209 F5.2 mag Bjsel.1 bj magnitude in 100k release (VII/226) with extinction correction (100BJSEL)
Note (1): without extinction correction. Note (2): psi parameter is defined as: -- for eyeballed galaxies: psi*1000 = (10000 + abs(jon) + psi*100) -- for eyeballed non-galaxies: psi*1000 = -(10000 + abs(jon) + psi*100) Note (3): the class is numbered as follows: -4 = noise -3 = star + star -2 = star + fuzz -1 = star 0 = galaxy + star merger 1 = galaxy 2 = galaxy + galaxy merger Note (4): name is blank if either (i) Bjsel.o is fainter than 19.45, or (ii) the object could not be allocated to a fibre by the configuration algorithm.
Global Notes: Note (G1): eta is a parameter derived from a Principal Component Analysis of the spectrum; it is negative for early-type galaxies, positive for later-type galaxies. See details in Madgwick et al., 2002MNRAS.333..133M Note (G2): bj magnitude with extinction correction means: corrections for isophote, field-effects and plate-matching, then calibrated to total mags with saturation correction, and then extinction corrected. Note (G3): Eyeball classification of galaxies is a positive value for galaxies brighter than about 18th mag, as follows: 0 = noise 1 = S0 2 = elliptical 3 = spiral 4 = irregular 5 = undetermined galaxy 6 = star 7 = star + star merger 8 = galaxy + star merger 9 = galaxy + galaxy merger Values between 11 and 19 may also be found.
History: From http://www.mso.anu.edu.au/2dFGRS/
(End) Francois Ochsenbein [CDS] 18-Dec-2007
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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