2000ApJS..130...67S


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.20CET02:14:07

2000ApJS..130...67S - Astrophys. J., Suppl. Ser., 130, 67-89 (2000/September-0)

A uniform analysis of the Lyα forest at z=0-5. II. Measuring the mean intensity of the extragalactic ionizing background using the proximity effect.

SCOTT J., BECHTOLD J., DOBRZYCKI A. and KULKARNI V.P.

Abstract (from CDS):

Moderate-resolution data for 40 quasi-stellar objects (QSOs) at z~2 were combined with spectra of comparable resolution of 59 QSOs with redshifts greater than 1.7 found in the literature to form a large, homogeneous sample of moderate-resolution (∼1 Å) QSO spectra. These spectra were presented and the statistics of the Lyα forest were discussed in Paper I. In this analysis, we demonstrate that a proximity effect is present in the data; i.e., there exists a significant (5.5 σ) deficit of lines at zabs~zem. Within 1.5 h–1 Mpc of the QSO emission redshift, the significance does depend on QSO luminosity, in accordance with the theory that this effect is caused by enhanced ionization of hydrogen in the vicinity of the QSO from UV photons from the QSO itself. The photoionization model of Bajtlik, Duncan, & Ostriker permits an estimate of the mean intensity of the extragalactic background radiation at the Lyman limit. We compare the results of this standard analysis with those obtained using a maximum likelihood technique. If the spectrum of the background is assumed to be identical to that of each individual QSO, and if this background is assumed to be constant over the redshift range 1.7<z<3.8, then the best-fit value for J(ν0) is found to be 1.4+1.1–0.5x10–21 ergs.s–1.cm–2.Hz–1.sr–1, using QSO redshifts based on the Lyα emission line. Systemic QSO redshifts based on the [O III] λ5007 emission line for 19 objects in our sample show an average redshift of ∼400 km.s–1 with respect to Lyα emission. Using redshifts based on [O III] or Mg II for the 35 objects for which they are measured and adding 400 km.s–1 to the remaining QSO Lyα redshifts gives a lower value of J(ν0), 7.0+3.4–4.4x10–22 ergs.s–1.cm–2.Hz–1.sr–1. This value is in reasonable agreement with the predictions of various models of the ionizing background based on the integrated quasar luminosity function. Allowing for the fact that individual QSOs have different spectral indices that may also be different from that of the background, we use the standard methods to solve for the H I photoionization rate, Γ, and the parameters describing its evolution with redshift. The best-fit value for the H I ionization rate we derive is 1.9+1.2–1.0x10–12 s–1, in good agreement with models of the background that incorporate QSOs only. Finally, we use simulated Lyα forest spectra including the proximity effect to investigate curve-of-growth effects in the photoionization model used in the analysis. We find that the presence of lines on the saturated part of the curve of growth could cause our estimates of the background intensity to be overestimated by a factor of 2-3. This large absorption-line sample and these techniques for measuring the background and understanding the systematics involved allow us to place what we believe are the firmest limits on the background at these redshifts.

Abstract Copyright:

Journal keyword(s): Cosmology: Diffuse Radiation - Galaxies: Intergalactic Medium - Galaxies: Quasars: Absorption Lines

CDS comments: T.5: 2 QSO not identified, created as EQ 0027+014 and EQ 0952+335

Simbad objects: 103

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Number of rows : 103

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 QSO J0003-2603 QSO 00 03 22.9530051057 -26 03 18.306624161   18 17.53     ~ 272 0
2 QSO B0001+087 QSO 00 03 42.6 +08 59 40   19.3 19.3     ~ 26 0
3 QSO B0002-422 QSO 00 04 48.2718823544 -41 57 28.150311306   17.44 17.21     ~ 154 0
4 QSO B0002+0507 QSO 00 05 20.2154590 +05 24 10.802383   16.56 16.21 16.26   ~ 169 1
5 LBQS 0006+0200 QSO 00 09 31.4294197202 +02 17 07.302632948   17.96 17.60     ~ 20 0
6 6C 001403+811827 QSO 00 17 08.4748554 +81 35 08.136591   17.60 16.52 15.95   ~ 356 1
7 LBQS 0027+0149 QSO 00 29 52.1114709914 +02 06 06.196390391   17 18.9     ~ 41 0
8 EQ 0027+014 ? 00 30 +01.7           ~ 1 0
9 QSO B0029+073 QSO 00 32 18.3632841201 +07 38 32.570529037     18.4     ~ 35 0
10 QSO B0037-018 QSO 00 40 18.2487280865 -01 37 24.288634544     18     ~ 17 0
11 QSO B0043+0354 Sy1 00 45 47.2230875166 +04 10 23.385233220   15.88 16.00     ~ 151 0
12 PHL 868 QSO 00 52 02.4058732462 +01 01 29.273279329   17.87 17.67     ~ 92 0
13 LBQS 0058+0155 QSO 01 00 54.1201344020 +02 11 36.334277171   17.48 17.16     ~ 157 0
14 PHL 957 QSO 01 03 11.2740814277 +13 16 17.810502093   16.97 16.57     ~ 325 0
15 QSO B0114-0857 QSO 01 17 23.3717382582 -08 41 32.342636462   17.4 17.7     ~ 59 0
16 4C -04.04 QSO 01 22 27.8854454120 -04 21 27.174885117   17.34 16.88     ~ 170 1
17 4C 25.05 QSO 01 26 42.792640150 +25 59 01.30015820     17.50 17.86   ~ 144 1
18 QSO B0142-100 QSO 01 45 16.5955770048 -09 45 17.269954127   17.23 16.95     ~ 222 1
19 QSO B0150-202 QSO 01 52 27.3265166930 -20 01 07.045135067     17.4     ~ 87 0
20 QSO B0153+744 QSO 01 57 34.9662542558 +74 42 43.219635727   16 16.0 16.7   ~ 194 1
21 4C -03.07 QSO 02 28 53.2112655818 -03 37 37.125617755   17.03 16.96 16.8   ~ 139 1
22 QSO B0237-2322 QSO 02 40 08.1742481040 -23 09 15.727160394   16.78 16.63     ~ 469 0
23 LBQS 0256-0000 QSO 02 59 05.6356418535 +00 11 21.961950181   18.50 18.11     ~ 120 0
24 LBQS 0301-0035 QSO 03 03 41.0490260705 -00 23 21.909853081   18.26 17.93 17.6   ~ 101 0
25 LBQS 0302-0019 QSO 03 04 49.8591748182 -00 08 13.537401746   18.08 17.80 17.5   ~ 231 0
26 QSO J0336-2019 QSO 03 36 26.9931728258 -20 19 40.069193022     18.2     ~ 40 1
27 QSO B0348+061 QSO 03 51 16.5649131749 +06 19 14.314532863     17.6     ~ 47 0
28 QSO B0400+258 QSO 04 03 05.58606763 +26 00 01.5028075     18 19.00   ~ 178 1
29 QSO B0421+019 QSO 04 24 08.5619980 +02 04 24.964522   17.18 17.04     ~ 137 1
30 QSO J0427-1302 QSO 04 27 07.3052521536 -13 02 53.708892234     17.50     ~ 148 1
31 QSO J0455-4216 QSO 04 55 23.0623318803 -42 16 17.398158654   17.77 17.06     ~ 133 0
32 QSO B0636+68 QSO 06 42 04.2571549110 +67 58 35.621670643     16.46 16.01   ~ 200 1
33 QSO B0731+653 QSO 07 36 21.2979100309 +65 13 12.006365459   19.10 18.5     ~ 45 1
34 QSO B0747+611 QSO 07 52 22.63 +60 57 52.6   17.52 17.22     ~ 25 0
35 QSO B0831+128 QSO 08 34 08.6354159987 +12 38 36.538570211     17.8     ~ 40 0
36 QSO B0837+109 QSO 08 40 17.8827247841 +10 34 28.948941990   18.77 18.48     ~ 36 1
37 4C 71.07 QSO 08 41 24.36526906 +70 53 42.1730054     16.5 16.8   ~ 686 1
38 LB 8755 QSO 08 50 51.8064086080 +15 22 15.118719975   18.02 17.93     ~ 86 1
39 LB 8775 QSO 08 51 41.7700385121 +16 12 21.959037123   16.70       ~ 83 0
40 QSO B0905+1507 QSO 09 08 23.9000444110 +14 55 16.604628602   19.27 19.03     ~ 23 0
41 QSO B0913+0715 QSO 09 16 13.9617253427 +07 02 24.488538434     17.1     ~ 92 0
42 QSO B0936+3653 QSO 09 39 35.1200567136 +36 40 00.929295808   18.54 18.32     ~ 31 0
43 QSO B0938+1159 QSO 09 41 13.5598141517 +11 45 32.319621196   19.84 19.63     ~ 89 1
44 EQ 0952+335 ? 09 55 +33.3           ~ 1 0
45 QSO B0955+4717 QSO 09 58 45.4278739390 +47 03 24.435007786   18.01 17.87     ~ 26 0
46 QSO J0958+1202 QSO 09 58 52.1995469763 +12 02 45.039648267   18.24 17.91     ~ 99 0
47 CSO 38 QSO 10 11 55.5949036516 +29 41 41.594419393   16.28 16.05     ~ 97 0
48 Ton 34 QSO 10 19 56.5978371667 +27 44 01.737988341   16.06 15.69     ~ 101 0
49 QSO B1033+1342 QSO 10 36 26.8848891069 +13 26 51.752372510   18.62 18.31     ~ 42 1
50 QSO B1115+080A QSO 11 18 16.951 +07 45 58.23   16.61 16.44     ~ 608 2
51 QSO B1159+123 QSO 12 01 47.9113685833 +12 06 30.254501010   18.85 18.16     ~ 83 0
52 QSO B1206+1155 QSO 12 09 17.9388252679 +11 38 30.373315694   18.15 17.89     ~ 55 0
53 QSO B1207+399 QSO 12 10 10.2202190384 +39 39 36.097710837   17.59 17.37     ~ 33 0
54 QSO B1208+101 QSO 12 10 57.0378198925 +09 54 27.078644555     17.5     ~ 110 1
55 LBQS 1210+1731 QSO 12 13 03.0132688253 +17 14 23.238685675   18.21 18.03     ~ 73 0
56 QSO J1217+3305 QSO 12 17 32.5426358433 +33 05 38.031844984     17.5 17.7   ~ 108 1
57 QSO B1225-017 QSO 12 27 59.1904234312 -02 03 03.645312831   18.25 18.02     ~ 15 0
58 Ton 618 QSO 12 28 24.9659944 +31 28 37.629250   16.15 15.87 15.35   ~ 247 1
59 Ton 621 QSO 12 33 55.5211038431 +29 07 49.048963020   17.19 16.92     ~ 31 0
60 LB 19 QSO 12 50 05.726 +26 31 07.51   16.12 15.92     ~ 184 0
61 QSO J1318+4706 QSO 13 18 01.8758008474 +47 06 27.792523843   18.74 18.52     ~ 29 0
62 QSO B1323-1042 QSO 13 26 00.0665597801 -10 57 05.646042765     17.0     ~ 11 0
63 QSO J1331+4101 QSO 13 31 41.1395073171 +41 01 58.777289024   17.52 17.41     ~ 101 0
64 LBQS 1334-0033 QSO 13 36 47.1443113848 -00 48 57.079268552   17.65 17.56     ~ 56 0
65 QSO B1337+285 QSO 13 40 04.9509815608 +28 16 53.237469530   17.45 17.15     ~ 13 0
66 QSO B1346-036 QSO 13 48 44.0080978009 -03 53 24.505425349   17.33 17.27     ~ 56 0
67 QSO B1358+1134 QSO 14 00 39.0049797858 +11 20 22.406182442   17.6 17.6     ~ 29 0
68 QSO B1400+1126 QSO 14 02 37.2666655210 +11 12 27.295170875     18.9     ~ 18 0
69 QSO B1402+044 QSO 14 05 01.11981424 +04 15 35.8189966   19.86 19.53 19.22   ~ 164 1
70 QSO B1406+492 QSO 14 08 28.5429186921 +49 02 22.126933649   18.27 18.05     ~ 26 0
71 QSO B1408+009 QSO 14 11 23.5100304276 +00 42 53.006767574   18.41 18.26     ~ 38 1
72 QSO B1410+0936 QSO 14 13 21.0607048196 +09 22 04.851990161     17.8     ~ 27 0
73 QSO B1421+331 QSO 14 23 26.0579478241 +32 52 20.360753583   16.99 16.70     ~ 102 0
74 QSO B1422+2309 QSO 14 24 38.09400 +22 56 00.5900   16.77 15.84 14.79   ~ 409 1
75 [PBW92] 1422+231 gLS 14 24 38.09400 +22 56 00.5900   16.77 15.84 14.79   ~ 354 0
76 8C 1435+638 QSO 14 36 45.8021364767 +63 36 37.865982148   17.06 16.86 16.23   ~ 183 1
77 QSO B1445+101 QSO 14 45 16.46524525 +09 58 36.0728255   18.58 17.78     ~ 349 1
78 QSO B1451+123 QSO 14 54 18.5816006547 +12 10 53.905442682     18.6     ~ 73 0
79 QSO B1511+091 QSO 15 13 52.5260150813 +08 55 55.726621813   18.22 17.92     ~ 52 1
80 QSO B1512+1316 QSO 15 14 26.3775603029 +13 05 52.536045974     19.5     ~ 16 0
81 QSO B1548+093 QSO 15 51 03.3925649152 +09 08 49.191994854   18.29 18.07     ~ 75 1
82 QSO B1601+182 QSO 16 03 18.7506067285 +18 09 04.924893528   19.68 19.28     ~ 20 0
83 QSO B1603+3820 QSO 16 04 55.4000146242 +38 12 01.628038791   16.37 15.99     ~ 44 0
84 QSO J1605+1745 QSO 16 05 01.3234758724 +17 45 16.059728521   20.05 19.75     ~ 28 0
85 QSO B1604+290 QSO 16 06 55.9496649751 +28 55 19.139382398     17.0     ~ 26 0
86 QSO B1607+1819 QSO 16 10 05.2857490387 +18 11 43.416238738     18.5     ~ 41 1
87 QSO B1614+051 QSO 16 16 37.55681502 +04 59 32.7367495   19.60 19.17 19.49   ~ 173 2
88 QSO B1623+269B QSO 16 25 28.871 +26 47 44.57     21.0     ~ 10 1
89 HS 1700+6416 QSO 17 01 00.6195618802 +64 12 09.118927057   16.39 16.17     ~ 334 0
90 QSO J1716+5328 QSO 17 16 35.5678393946 +53 28 15.827636771   16.30 16.48     ~ 68 0
91 7C 173832.79+350219.00 QSO 17 40 20.2522851968 +35 00 47.790857899     20.8     ~ 22 1
92 QSO B1946+770 QSO 19 44 54.8535021452 +77 05 52.674235091     15.8     ~ 138 0
93 QSO B2126-15 QSO 21 29 12.17589777 -15 38 41.0413097   17.61 17.3 17.3   ~ 459 1
94 QSO B2134+0028 QSO 21 36 38.5862648232 +00 41 54.210724774   17.30 17.08 17.02   ~ 517 2
95 QSO J2236+1326 QSO 22 36 19.1927104940 +13 26 20.313308644   19.15 18.69     ~ 102 0
96 QSO B2233+136 QSO 22 36 27.0815393491 +13 57 14.017410008   19.04 18.73     ~ 63 0
97 4C 24.61 QSO 22 54 09.34189749 +24 45 23.4226569     17.8     ~ 132 1
98 PB 5194 Sy1 22 57 09.6143906565 +02 25 32.055508697   17 16.72     ~ 10 0
99 QSO J2257+0243 QSO 22 57 17.56309815 +02 43 17.5117291   18.04 17.96 18.45   ~ 143 1
100 QSO B2310+385 QSO 23 12 58.7938580 +38 47 42.658552     17.5     ~ 36 0
101 QSO B2311-036 QSO 23 14 07.2240316408 -03 25 27.644540471   19.9 19.9     ~ 31 0
102 QSO B2320+079 QSO 23 22 36.0902085468 +08 12 01.594650867   17.6   18.2   ~ 69 1
103 QSO B2329-0204 QSO 23 31 36.3392717302 -01 48 07.044010902   17.5 17.0     ~ 22 0

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2020.02.20-02:14:07

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