2015MNRAS.449.2818T

Query : 2015MNRAS.449.2818T

2015MNRAS.449.2818T - Mon. Not. R. Astron. Soc., 449, 2818-2836 (2015/May-3)

Neural-network selection of high-redshift radio quasars, and the luminosity function at z ∼ 4.

TUCCILLO D., GONZALEZ-SERRANO J.I. and BENN C.R.

Abstract (from CDS):

We obtain a sample of 87 radio-loud quasi-stellar objects (QSOs) in the redshift range 3.6 ≤ z ≤ 4.4 by cross-correlating sources in the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) radio survey (S1.4GHz > 1 mJy) with star-like objects having r < 20.2 in Sloan Digital Sky Survey (SDSS) Data Release 7. Of these 87 QSOs, 80 are spectroscopically classified in previous work (mainly SDSS), and form the training set for a search for additional such sources. We apply our selection to 2916 FIRST-DR7 pairs and find 15 likely candidates. Seven of these are confirmed as high-redshift quasars, bringing the total to 87. The candidates were selected using a neural-network, which yields 97 percent completeness (fraction of actual high-z QSOs selected as such) and an efficiency (fraction of candidates which are high-z QSOs) in the range of 47-60 percent. We use this sample to estimate the binned optical luminosity function (LF) of radio-loud QSOs at z ∼ 4, and also the LF of the total QSO population and its comoving density. Our results suggest that the radio-loud fraction at high z is similar to that at low z and that other authors may be underestimating the fraction at high z. Finally, we determine the slope of the optical LF and obtain results consistent with previous studies of radio-loud QSOs and of the whole population of QSOs. The evolution of the LF with redshift was for many years interpreted as a flattening of the bright-end slope, but has recently been re-interpreted as strong evolution of the break luminosity for high-z QSOs, and our results, for the radio-loud population, are consistent with this.

Abstract Copyright: © 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society (2015)

Journal keyword(s): surveys - galaxies: active - galaxies: high-redshift - galaxies: luminosity function, mass function - quasars: general - cosmology: observations

VizieR on-line data: <Available at CDS (J/MNRAS/449/2818): table4.dat table5.dat>

Simbad objects: 104

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Number of rows : 104
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 QSO B0151-00 QSO 01 53 39.6078379368 -00 11 04.929367704   21.73 20.12     ~ 72 0
2 [VV2006] J030025.2+003223 QSO 03 00 25.2255914544 +00 32 24.236608308   22.52 21.17     ~ 36 0
3 [VV2006] J072518.3+370517 QSO 07 25 18.21 +37 05 19.3   24.32 21.09 19.5 18.7 ~ 11 0
4 QSO J0747+2739 QSO 07 47 11.1466907592 +27 39 03.365989812     17.20     ~ 74 0
5 FIRST J074738.4+133747 QSO 07 47 38.4886619064 +13 37 47.329123584   22.73 20.81     ~ 4 0
6 [VV2006] J075113.1+312038 QSO 07 51 13.0540750896 +31 20 38.013372204   21.52 20.61     ~ 35 0
7 [VV2006] J075122.4+452334 QSO 07 51 22.3642577184 +45 23 34.227215088   22.10 21.22     ~ 24 0
8 SDSS J075757.87+095607.5 QSO 07 57 57.8733376248 +09 56 07.520119188           ~ 7 0
9 SDSS J080710.74+131739.4 QSO 08 07 10.7466779952 +13 17 39.460529724   21.61 20.85     ~ 25 1
10 [VV2006] J081009.9+384756 Bla 08 10 09.9573700608 +38 47 57.082826868   21.24 20.38 19.8   ~ 51 0
11 SDSS J081555.01+465321.4 QSO 08 15 55.0173020496 +46 53 21.411131928           ~ 7 0
12 SDSS J082323.32+155206.8 QSO 08 23 23.3292574824 +15 52 06.813066396   21.52 20.44     ~ 26 1
13 SDSS J083316.91+292228.0 QSO 08 33 16.9173992400 +29 22 28.000443720           ~ 11 0
14 QSO J0833+0959 QSO 08 33 22.4989675248 +09 59 41.202402252   20.33 19.59     ~ 47 1
15 [VV2006] J083808.4+534810 QSO 08 38 08.4506504664 +53 48 09.894689100   21.94 20.88     ~ 29 0
16 [VV2006] J083946.1+511203 QSO 08 39 46.2164854008 +51 12 02.827270296   22.29 20.66 18.9 18.3 ~ 72 1
17 [VV2006] J084044.2+341101 QSO 08 40 44.1900360912 +34 11 01.651788420   21.90 20.76     ~ 32 0
18 SDSS J084818.88+393806.0 QSO 08 48 18.8846380632 +39 38 06.001894464           ~ 6 0
19 SDSS J085257.12+243103.1 QSO 08 52 57.1213050144 +24 31 03.182860416   21.02 20.28     ~ 39 1
20 SDSS J085501.81+182437.7 QSO 08 55 01.8175537752 +18 24 37.754845884   21.74 20.87     ~ 17 0
21 SDSS J085724.32+110549.1 QSO 08 57 24.3281197704 +11 05 49.143913368           ~ 9 0
22 2MASS J08594404+2125108 QSO 08 59 44.0736978552 +21 25 11.137135368   20.80 19.78     ~ 19 0
23 SDSS J090254.16+413506.5 QSO 09 02 54.1724585496 +41 35 06.512220780   21.56 20.69     ~ 12 0
24 6C 090629+480201 QSO 09 09 53.8426606872 +47 49 43.037158584   20.5 19.8     ~ 16 1
25 7C 091107.79+505115.00 QSO 09 14 36.2226538656 +50 38 48.537761388           ~ 14 1
26 [VV2006] J091824.4+063654 QSO 09 18 24.3794748888 +06 36 53.419791528   22.23 21.02 19.5 18.6 ~ 56 1
27 SDSS J092640.28-023041.4 QSO 09 26 40.2859851600 -02 30 41.432667696           ~ 11 0
28 2MASS J09283287+1848242 QSO 09 28 32.8753026312 +18 48 24.418644012   19.18 18.41     ~ 20 0
29 QSO J0937+0828 QSO 09 37 14.4853902864 +08 28 58.543420404   20.50 19.61     ~ 43 0
30 [VV2006] J094003.0+511602 QSO 09 40 03.0245808072 +51 16 02.719730532   20.44 19.68 18.47   ~ 35 0
31 [VV2006] J100012.3+102152 QSO 10 00 12.2659420848 +10 21 51.836790420   21.12 20.41     ~ 29 0
32 SDSS J101403.75+451053.2 * 10 14 03.7610096208 +45 10 53.367450096           ~ 2 0
33 SDSS J101747.76+342737.8 QSO 10 17 47.7593349864 +34 27 37.848286116   21.50 20.79     ~ 25 0
34 SDSS J102940.93+100410.9 QSO 10 29 40.9316655504 +10 04 10.900296408           ~ 9 0
35 7C 102757.70+433620.00 QSO 10 30 55.9539269304 +43 20 37.725922824   21.48 20.68     ~ 33 1
36 SDSS J103420.43+414937.5 QSO 10 34 20.4349348920 +41 49 37.543128636           ~ 14 0
37 QSO J1034+1102 QSO 10 34 46.5347918856 +11 02 14.587007532   21.08 20.01     ~ 37 0
38 SDSS J103717.72+182303.0 QSO 10 37 17.7301065552 +18 23 03.089060844   22.25 21.04     ~ 15 0
39 [VV2006] J105121.3+612038 QSO 10 51 21.3820735440 +61 20 38.065288164   20.60 19.71     ~ 32 0
40 QSO J1057+4555 QSO 10 57 56.2610108784 +45 55 53.070401748   20.19 18.80 17.2 16.8 ~ 118 0
41 SDSS J105807.46+033059.6 QSO 10 58 07.4689951872 +03 30 59.629775256           ~ 13 0
42 [VV2006] J110147.9+001039 QSO 11 01 47.8912568880 +00 10 39.489976344   22.12 21.21     ~ 34 1
43 SDSS J110543.86+255343.1 QSO 11 05 43.8704520456 +25 53 43.062901404   22.29 21.21     ~ 15 0
44 SDSS J110946.44+190257.6 QSO 11 09 46.4464717824 +19 02 57.607027116   22.81 21.40     ~ 16 0
45 [VV2006] J111055.2+430509 QSO 11 10 55.2174702288 +43 05 10.172491368   21.04 19.79 18.08   ~ 31 0
46 QSO J1117+1311 QSO 11 17 01.8984156408 +13 11 15.581756256   19.50 18.77     ~ 42 0
47 [VV2006] J111736.4+445655 QSO 11 17 36.3432155064 +44 56 55.727941092   21.95 21.01     ~ 27 0
48 SDSS J112339.59+291710.7 QSO 11 23 39.5980480920 +29 17 10.661836956   21.20 20.36     ~ 19 0
49 [VV2006] J112530.5+575723 QSO 11 25 30.5043006792 +57 57 22.694864148   20.78 20.19     ~ 30 0
50 SDSS J112742.74+363429.5 QSO 11 27 42.7475581824 +36 34 29.477777412           ~ 8 0
51 [VV2006] J112749.5+051140 QSO 11 27 49.4552870736 +05 11 40.581971340   20.82 19.93     ~ 32 0
52 [VV2006] J112938.7+131232 QSO 11 29 38.7351490536 +13 12 32.215262364   20.56 19.72     ~ 26 0
53 SDSS J113300.71-041158.4 Q? 11 33 00.7181357976 -04 11 58.543280376           ~ 1 0
54 SDSS J113330.91+380638.1 QSO 11 33 30.9066848808 +38 06 38.180473056   21.71 20.74     ~ 24 0
55 SDSS J113729.42+375224.2 QSO 11 37 29.4270664848 +37 52 24.229331796   22.43 21.30     ~ 25 0
56 [VV2006] J115045.6+424000 QSO 11 50 45.6122068896 +42 40 01.129696716   21.61 20.76     ~ 26 0
57 SDSS J115107.42+501558.5 QSO 11 51 07.4309792640 +50 15 58.612121244           ~ 9 0
58 SDSS J115449.36+180204.3 QSO 11 54 49.3503727800 +18 02 04.350355440   21.62 20.66     ~ 20 0
59 SDSS J120407.84+484548.0 QSO 12 04 07.8475276800 +48 45 48.091000500           ~ 11 0
60 2MASS J12044715+3309384 QSO 12 04 47.1499698000 +33 09 38.745290664   21.82 20.49     ~ 37 0
61 SDSS J120531.73+290149.2 QSO 12 05 31.7343635016 +29 01 49.075423608           ~ 7 0
62 NVSS J121329-032725 Rad 12 13 29.4408115608 -03 27 25.909814628           ~ 2 0
63 [VV2006] J122027.9+261904 QSO 12 20 27.9578921016 +26 19 03.507369204   20.12 19.16     ~ 29 0
64 SDSS J122819.96+474030.4 QSO 12 28 19.9714961376 +47 40 30.419454936           ~ 10 0
65 SDSS J123128.23+184714.3 QSO 12 31 28.2298717920 +18 47 14.336540628   20.61 20.07     ~ 18 0
66 SDSS J123142.17+381658.9 QSO 12 31 42.1733201928 +38 16 59.050272720   22.18 21.20     ~ 33 1
67 [VV2006] J124054.9+543651 QSO 12 40 54.9134346096 +54 36 52.191730548   22.03 20.77 19.74   ~ 30 0
68 6C 123945+373654 QSO 12 42 09.81238457 +37 20 05.6921765   20.60 19.82     ~ 82 1
69 SDSS J124323.16+235842.2 QSO 12 43 23.1675230712 +23 58 42.230217792   21.54 20.72     ~ 21 1
70 SDSS J124443.06+060934.6 QSO 12 44 43.0704748656 +06 09 34.589059596           ~ 11 0
71 SDSS J124658.82+120854.7 QSO 12 46 58.8323266176 +12 08 54.724998876   23.29 21.58     ~ 24 0
72 [VV2006] J124943.7+152706 QSO 12 49 43.6659645192 +15 27 07.124285160   21.59 20.48     ~ 28 0
73 [VV2000] J130348.9+002010 QSO 13 03 48.9439829880 +00 20 10.472010216   21.33 20.00     ~ 46 0
74 [VV2006] J130738.9+150752 QSO 13 07 38.8348573800 +15 07 52.124589696   21.60 20.71     ~ 28 0
75 SDSS J131242.86+084105.0 QSO 13 12 42.8679333912 +08 41 05.098313040   20.27 19.42     ~ 35 0
76 [VV2006] J131536.6+485629 QSO 13 15 36.5795773968 +48 56 29.124570300   21.36 20.60     ~ 31 0
77 [VV2006] J132512.5+112330 QSO 13 25 12.4927366824 +11 23 29.838681816   22.66 20.95     ~ 60 0
78 SDSS J134854.37+171149.6 QSO 13 48 54.3716989968 +17 11 49.618512024   21.14 19.95     ~ 18 0
79 QSO B1351-018 Bla 13 54 06.89532721 -02 06 03.1904962   20.62 19.91 19.277   ~ 177 1
80 [VV2006] J135554.6+450421 QSO 13 55 54.5543010504 +45 04 21.058175928   22.02 20.66     ~ 24 0
81 FIRST J140635.6+622543 QSO 14 06 35.6707612200 +62 25 43.334203260   21.05 20.25     ~ 4 0
82 QSO J1408+0205 QSO 14 08 50.9138577456 +02 05 22.680293784   20.55 19.75     ~ 37 0
83 [VV2006] J142209.7+465932 QSO 14 22 09.7036625736 +46 59 32.554792968   22.01 20.83     ~ 34 1
84 [VV2006] J142326.5+391226 QSO 14 23 26.4847501584 +39 12 26.270468280   22.38 21.23     ~ 26 0
85 SDSS J143413.05+162852.7 QSO 14 34 13.0555554936 +16 28 52.716936900   21.91 20.71     ~ 18 0
86 6C 143400+544902 QSO 14 35 33.7785 +54 35 59.308   21.67 20.87     ~ 46 1
87 [VV2006] J144542.8+490248 QSO 14 45 42.7640313984 +49 02 48.936331824   19.41 18.31     ~ 48 0
88 [VV2006] J144643.3+602714 QSO 14 46 43.3687820112 +60 27 14.296193028   21.53 20.57     ~ 27 0
89 FIRST J145329.0+481725 QSO 14 53 29.0171608848 +48 17 24.930618864   22.44 21.08     ~ 4 0
90 QSO J1503+0419 QSO 15 03 28.8873529680 +04 19 48.993415428   19.86 18.89     ~ 72 1
91 [VV2006] J150643.8+533133 QSO 15 06 43.8069787992 +53 31 34.459949964   20.66 19.82 17.89   ~ 34 0
92 SDSS J151146.99+252424.3 QSO 15 11 46.9891569288 +25 24 24.281091252   23.31 21.62     ~ 15 0
93 SDSS J152028.14+183556.1 QSO 15 20 28.1413587912 +18 35 56.154478488   21.78 20.68     ~ 19 0
94 SDSS J153336.13+054356.5 QSO 15 33 36.1382602224 +05 43 56.517139848   21.58 20.58     ~ 19 0
95 SDSS J154336.58+165621.8 Q? 15 43 36.5838500544 +16 56 21.753607236           ~ 2 0
96 SDSS J161716.49+250208.1 QSO 16 17 16.4916688896 +25 02 08.182583376   22.75 21.41     ~ 24 0
97 [VV2006] J161933.7+302115 QSO 16 19 33.6547423584 +30 21 15.057452988   21.66 20.64 18.70   ~ 31 0
98 FIRST J163708.2+091424 QSO 16 37 08.2977857712 +09 14 24.545294844   21.33 20.36     ~ 5 0
99 [VV2006] J163950.5+434004 QSO 16 39 50.5194357432 +43 40 03.701223408   19.59 18.67 17.8 17.4 ~ 45 1
100 [VV2006] J164326.2+410343 QSO 16 43 26.2370447184 +41 03 43.441300332 23.11 21.79 20.81     ~ 34 1
101 2MASS J22275812+0037055 BLL 22 27 58.1313623424 +00 37 05.426018868   18.00 17.46 18.5   ~ 35 2
102 FIRST J222814.3-085525 QSO 22 28 14.4159068616 -08 55 25.779956016   21.75 20.85     ~ 3 0
103 SDSS J223535.59+003602.0 QSO 22 35 35.5907261352 +00 36 02.005563204   22.17 21.07 20.4   ~ 26 0
104 SDSS J235022.40-095144.3 QSO 23 50 22.3979799480 -09 51 44.460538020   20.97 20.21     ~ 10 0

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