J/MNRAS/328/150 KX redshift survey (Croom+, 2001)
A small-area faint KX redshift survey for QSOs in the ESO Imaging Survey Chandra Deep Field South. Croom S.M., Warren S.J., Glazebrook K. <Mon. Not. R. Astron. Soc. 328, 150 (2001)> =2001MNRAS.328..150C
ADC_Keywords: X-ray sources ; Redshifts ; QSOs ; Galaxies, IR ; Galaxies, photometry Keywords: surveys - galaxies: active - quasars: general - infrared: galaxies Abstract: In this paper we present preliminary spectroscopic results from a small-area faint K-excess (KX) survey, and compare KX selection against UVX selection. The aim of the KX method is to produce complete samples of QSOs that are flux-limited in the K band, in order to minimize any selection bias in samples of QSOs from the effects of reddening and extinction. Using the photometric catalogue of the ESO Imaging Survey Chandra Deep Field South (48arcmin2) we have identified compact objects with J-K colours redder than the stellar sequence that are brighter than K=19.5. We have obtained spectra of 33 candidates, using the LDSS++ spectrograph on the Anglo-Australian Telescope (AAT). Amongst the 11 bluer candidates, with V-J<3, three are confirmed as QSOs. Identification of the 22 redder candidates with V-J≥3 is substantially incomplete, but so far no reddened QSOs have been found. Near-infrared spectroscopy will be more effective in identifying some of these targets. Only two UVX (U-B←0.2) sources brighter than K=19.5 are found that are not also KX selected. These are both identified as galactic stars. Thus KX selection appears to select all UVX QSOs. The surface density of QSOs in the blue subsample (V-J<3) at K≤19.5 is 325+136-177°-2. Because identification of the red subsample (V-J≥3) is substantially incomplete, the 2σ upper limit on the density of reddened QSOs is large, <1150°-2. As anticipated, at these faint magnitudes the KX sample includes several compact galaxies. Of the 14 with measured redshifts, there are roughly equal numbers of early- and late-type objects. Nearly all the early-type galaxies are found in a single structure at z=0.66. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 131 13 KX-selected objects and spectroscopic identifications for the blue subsample, V-J≤3.0 table2.dat 131 41 KX-selected objects and spectroscopic identifications for the red subsample, V-J>3.0 table3.dat 131 2 The two UVX non-KX sources with K≤19.5 in our survey area table4.dat 131 16 K≤19 galaxies observed in addition to our KX survey
See also: J/A+A/379/740 : ESO Imaging Survey (Arnouts+, 2001) J/A+A/377/442 : Chandra Deep Field South: R-band photometry (Wolf+, 2001) J/A+A/375/1 : IR obs. of Chandra Deep Field + HDF-South (Saracco+, 2001) J/AJ/122/2810 : Chandra Deep Field North Survey. V. (Brandt+, 2001) J/ApJ/554/742 : Chandra Deep Survey of the HDF-N (Hornschemeier+, 2001) Byte-by-byte Description of file: table?.dat
Bytes Format Units Label Explanations
1- 4 A4 --- [CWG2001] Designation (1) 6 I1 h RAh Right ascension (J2000.0) 8- 9 I2 min RAm Right ascension (J2000.0) 11- 15 F5.2 s RAs Right ascension (J2000.0) 17 A1 --- DE- Declination sign (J2000.0) 18- 19 I2 deg DEd Declination (J2000.0) 21- 22 I2 arcmin DEm Declination (J2000.0) 24- 27 F4.1 arcsec DEs Declination (J2000.0) 29- 33 F5.2 mag Umag ? Bessel U magnitude 35- 39 F5.2 mag Bmag ? Bessel B magnitude 41- 45 F5.2 mag Vmag ? Bessel V magnitude 47- 51 F5.2 mag Rmag ? Bessel R magnitude 53- 57 F5.2 mag Jmag J magnitude 59- 63 F5.2 mag Kmag K magnitude 65- 68 F4.2 --- S/GK K-band SExtractor stellarity parameter (star=1, galaxy=0) 70- 74 F5.3 --- z ? Redshift 76- 81 A6 --- Type Type of object (Gal or QSO) (2) 83-131 A49 --- Lines Spectral features, both absorption and emission
Note (1): Designations: KX NN for tables 1 and 2 UVXN for table 3 KG NN for table 4 Note (2): An (e) or (a) after gal denotes emission- or absorption- dominated spectra respectively; an "?" indicates that the type could not be identified from the spectra.
History: Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 31-Jan-2002
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