2004AJ....128..523B


C.D.S. - SIMBAD4 rel 1.7 - 2020.02.18CET05:49:18

2004AJ....128..523B - Astron. J., 128, 523-533 (2004/August-0)

Chandra observations of radio-loud quasars at z>4: x-rays from the radio beacons of the early universe.

BASSETT L.C., BRANDT W.N., SCHNEIDER D.P., VIGNALI C., CHARTAS G. and GARMIRE G.P.

Abstract (from CDS):

We present the results of Chandra observations of six radio-loud quasars (RLQs) and one optically bright radio-quiet quasar (RQQ) at z~4.1-4.4. These observations cover a representative sample of RLQs with moderate radio loudness (R~40-400), filling the X-ray observational gap between optically selected RQQs (predominantly R≲2-10) and the five known blazars at z>4 (R~800-27,000), where R=f5GHz/f4400Å(rest frame). We study the relationship between X-ray luminosity and radio loudness for quasars at high redshift and constrain RLQ X-ray continuum emission and absorption. From a joint spectral fit of nine moderate-R RLQs observed by Chandra, we find tentative evidence for absorption above the Galactic NH, with a best-fit neutral intrinsic column density of NH=2.4+2.0–1.8x1022/cm2, consistent with earlier claims of increased absorption toward high-redshift RLQs. We also search for evidence of an enhanced jet-linked component in the X-ray emission due to the increased energy density of the cosmic microwave background at high redshift, but we find neither spatial detections of X-ray jets nor a significant enhancement in the X-ray emission relative to comparable RLQs at low to moderate redshifts. Overall, the z~4-5 RLQs have basic X-ray properties consistent with comparable RLQs in the local universe, suggesting that the accretion/jet mechanisms of these objects are similar as well.

Abstract Copyright:

Journal keyword(s): Galaxies: Active - Galaxies: High-Redshift - Galaxies: Jets - Galaxies: Nuclei - Galaxies: Quasars: General

Simbad objects: 19

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Number of rows : 19

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 J0121+0347 QSO 01 21 26.1465867043 +03 47 06.754828139     17.90     ~ 25 0
2 QSO J0210-0018 QSO 02 10 43.1610494689 -00 18 18.482961149   23.49 21.97     ~ 54 0
3 QSO J0525-3343 QSO 05 25 06.1754530726 -33 43 05.643316632     18.50 18.5   ~ 47 1
4 QSO J0635-7516 QSO 06 35 46.5080299 -75 16 16.815501   15.96 15.75 15.82   ~ 504 1
5 4C 41.17 rG 06 50 52.098 +41 30 30.53           ~ 315 1
6 [VV2006] J072518.3+370517 QSO 07 25 18.21 +37 05 19.3   24.32 21.09 19.5 18.7 ~ 10 0
7 QSO J0747+2739 QSO 07 47 11.1475926883 +27 39 03.365274417     17.20     ~ 48 0
8 [VV2006] J083946.1+511203 QSO 08 39 46.2165638609 +51 12 02.815203752   22.29 20.66 18.9 18.3 ~ 54 1
9 QSO J0913+5919 QSO 09 13 16.551 +59 19 21.68   24.96 23.32 24.948   ~ 47 0
10 [VV2006] J091824.4+063654 QSO 09 18 24.3798479393 +06 36 53.441403312   22.23 21.02 19.5 18.6 ~ 41 1
11 QSO B1026-084 QSO 10 28 38.7978854994 -08 44 38.519229195     21.00 19.6   ~ 65 1
12 3C 273 BLL 12 29 06.6996828061 +02 03 08.598846466   13.05 14.830 14.11   ~ 5275 1
13 [VV2006] J130940.6+573309 QSO 13 09 40.6903939855 +57 33 09.960910681   21.94 20.68 19.5   ~ 30 0
14 [VV2006] J132512.5+112330 QSO 13 25 12.4930213164 +11 23 29.842170302   22.66 20.95     ~ 45 0
15 [VV2006] J142308.0+224219 QSO 14 23 08.2370035677 +22 41 58.088996906       19.9 20.1 ~ 10 1
16 7C 142826.80+421756.00 QSO 14 30 23.74163330 +42 04 36.4911889   24.43 22.04 20.2   ~ 110 1
17 QSO B1508+572 QSO 15 10 02.92236464 +57 02 43.3759071   22.73 21.38 19.23   ~ 150 0
18 QSO B1713+218 QSO 17 15 21.253 +21 45 31.84     21.00     ~ 16 1
19 QSO J1759+6638 QSO 17 59 28.0962874459 +66 38 52.600237844     21.9 20.220   ~ 31 0

    Equat.    Gal    SGal    Ecl

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2020.02.18-05:49:18

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