THE X-RAY PROPERTIES OF TYPICAL HIGH-REDSHIFT RADIO-LOUD QUASARS
Author(s)Saez, C.; Brandt, W. N.; Shemmer, O.; Chomiuk, L.; Lopez, Laura A.; Miller, B. P.; Vignali, C.; Marshall, Herman Lee; ... Show more Show less
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We report spectral, imaging, and variability results from four new XMM-Newton observations and two new Chandra observations of high-redshift (z ≳4) radio-loud quasars (RLQs). Our targets span lower, and more representative, values of radio loudness than those of past samples of high-redshift RLQs studied in the X-ray regime. Our spectral analyses show power-law X-ray continua with a mean photon index,[ Γ] = 1.74 ± 0.11, that is consistent with measurements of lower redshift RLQs. These continua are likely dominated by jet-linked X-ray emission, and they follow the expected anticorrelation between photon index and radio loudness. We find no evidence of iron Kα emission lines or Compton-reflection continua. Our data also constrain intrinsic X-ray absorption in these RLQs. We find evidence for significant absorption (N[subscript H] ≈ 1.7×10[superscript 22]cm[superscript −2]) in one RLQ of our sample (SDSS J0011+1446); the incidence of X-ray absorption in our sample appears plausibly consistent with that for high-redshift RLQs that have higher values of radio loudness. In the Chandra observation of PMN J2219−2719 we detect apparent extended (∼14 kpc) X-ray emission that is most likely due to a jet; the X-ray luminosity of this putative jet is ≈2% that of the core. The analysis of a 4.9 GHz Very Large Array image of PMN J2219−2719 reveals a structure that matches the X-ray extension found in this source. We also find evidence for long-term (450–460 days) X-ray variability by 80%–100% in two of our targets.
DepartmentKavli Institute for Astrophysics and Space Research
Saez, C., W. N. Brandt, O. Shemmer, L. Chomiuk, L. A. Lopez, H. L. Marshall, B. P. Miller, and C. Vignali. “THE X-RAY PROPERTIES OF TYPICAL HIGH-REDSHIFT RADIO-LOUD QUASARS.” The Astrophysical Journal 738, no. 1 (August 11, 2011): 53. © 2011 The American Astronomical Society
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