1998ApJS..119....1H


Query : 1998ApJS..119....1H

1998ApJS..119....1H - Astrophys. J., Suppl. Ser., 119, 1-23 (1998/November-0)

An optical near-infrared study of radio-loud quasar environments. I. Methods and z = 1-2 observations.

HALL P.B., GREEN R.F. and COHEN M.

Abstract (from CDS):

We have conducted an optical/near-infrared study of the environments of radio-loud quasars (RLQs) at redshifts z = 0.6-2.0. In this paper we discuss the sample selection and observations for the z = 1.0-2.0 subsample and the reduction and cataloging techniques used. We discuss technical issues at some length, since few detailed descriptions of near-IR data reduction and multicolor object cataloging are currently available in single literature references. Our sample of 33 RLQs contains comparable numbers of flat and steep radio spectrum sources and sources of various radio morphologies and spans a similar range of Mabs and Prad, which allows us to disentangle dependence of environment on optical or radio luminosity from redshift evolution. We use the standard ``shift-and-stare'' method of creating deep mosaicked images in which the exposure time (and thus the rms noise) at each pixel is not constant across the mosaic. An unusual feature of our reduction procedure is the creation of images with constant rms noise from such mosaics. We adopted this procedure to enable use of the FOCAS detection package over almost the entire mosaic instead of only in the area of deepest observation where the rms noise is constant, thereby roughly doubling our areal coverage. We correct the object counts in our fields for stellar contamination using the SKY model of Cohen and compare the galaxy counts to those in random fields. Even after accounting for possible systematic magnitude offsets, we find a significant excess of K ≳ 19 galaxies. Analysis and discussion of this excess population is presented by Hall & Green.

Abstract Copyright: ∼

Journal keyword(s): Galaxies: Clusters: General - Galaxies: Quasars: General - Radio Continuum: Galaxies - Surveys

Simbad objects: 33

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Number of rows : 33
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026
#notes
1 4C -00.01 QSO 00 06 22.6058589240 -00 04 24.453903468   20.14 19.35     ~ 196 1
2 3C 9 BLL 00 20 25.2231670656 +15 40 54.774271884   17.92 17.62     ~ 347 1
3 4C 09.01 QSO 00 36 23.7670329792 +10 07 58.463987088     17.5     ~ 41 1
4 QSO B0149+218 Bla 01 52 18.05904204 +22 07 07.6997943     18 18.89   ~ 201 1
5 4C -04.06 QSO 02 35 07.3418452008 -04 02 05.317096956   16.61 16.46 16.2   ~ 222 1
6 PB 6960 BLL 02 59 28.51615658 -00 19 59.9753897   17.74 17.58 17   ~ 146 1
7 4C 12.17 QSO 03 55 45.5995775184 +12 31 46.069953456     19.31     ~ 53 2
8 QSO B0736-063 QSO 07 38 57.1755700296 -06 26 58.057409076     18.5     ~ 74 1
9 7C 0808+2854 QSO 08 11 36.8956979880 +28 45 03.617834976   18.75 18.49     ~ 64 1
10 QSO J0834+0957 QSO 08 34 40.6150592856 +09 57 54.921119760   19.88 19.68     ~ 37 0
11 3C 205 Sy1 08 39 06.5324936736 +57 54 17.069000688   18.10 17.62     ~ 264 1
12 4C 11.32 QSO 09 28 43.3799586840 +11 34 24.628872288   19.18 19.06     ~ 43 2
13 QSO B0952+179 QSO 09 54 56.82361677 +17 43 31.2221518   17.31 17.23     ~ 222 1
14 Ton 1208 Bla 10 21 17.4744784608 +34 37 21.665888580   17.99 17.75 17.30   ~ 92 2
15 QSO J1129+0952 QSO 11 29 14.0977649040 +09 51 59.015628756   18.07 17.78     ~ 74 1
16 7C 1218+3359 QSO 12 20 33.8756544048 +33 43 12.026168040   18.80 18.61     ~ 271 1
17 QSO B1221+113 QSO 12 24 19.8147701040 +11 07 23.102165568   19.16 18.96     ~ 71 1
18 4C 40.32 QSO 13 00 33.3077988648 +40 09 07.675089480   19.31 19.44     ~ 162 1
19 7C 132816.2+252436 QSO 13 30 37.6960744824 +25 09 10.983105972   18.31 17.67     ~ 373 1
20 3C 298.0 Bla 14 19 08.1802187928 +06 28 34.802854680   17.12 16.79     ~ 422 1
21 LBQS 1430-0046 QSO 14 32 44.4416657448 -00 59 15.086271948   17.81 17.49     ~ 56 1
22 ICRF J143844.7+621154 Sy1 14 38 44.7834430248 +62 11 54.412540044   19.48 19.07     ~ 75 1
23 4C -05.64 Bla 15 10 53.59142427 -05 43 07.4175000   17.44 17.21     ~ 249 1
24 QSO B1556+335 Bla 15 58 55.1864381376 +33 23 18.608916984   18.22 17.79 17.6   ~ 115 1
25 4C 10.45 Bla 16 08 46.20318700 +10 29 07.7757424   18.5 18.70 18.03   ~ 409 1
26 QSO J1719+4804 Bla 17 19 38.2496454120 +48 04 12.247659408   15.33 14.60 14.25   ~ 186 1
27 4C 51.37 Bla 17 40 36.97784792 +52 11 43.4073694   18.16 18.70 16.73   ~ 441 1
28 QSO J2047-1639 Bla 20 47 19.6670792592 -16 39 05.842775556   17.55 17.36     ~ 107 1
29 QSO B2144+093 Bla 21 47 10.16296704 +09 29 46.6722487   18.72 18.54 16.51   ~ 225 1
30 4C 21.59 QSO 21 51 45.8862336840 +21 30 13.743231624     19     ~ 67 1
31 4C 11.69 Bla 22 32 36.40890093 +11 43 50.9040592   17.75 17.33     ~ 1205 2
32 4C 29.68 QSO 23 28 10.6609307784 +29 37 09.876341604   17.95 17.30     ~ 81 1
33 4C 06.76 QSO 23 48 31.7707716384 +06 24 59.781458520     17.5     ~ 65 1

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