THE X-RAY PROPERTIES OF TYPICAL HIGH-REDSHIFT RADIO-LOUD QUASARS

Journal Article · Thu Sep 01 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/738/1/53· OSTI ID:21582937

Saez, C; Brandt, W N ^[1]; Shemmer, O ^[2]; Chomiuk, L ^[3]; Lopez, L A ^[4]; Marshall, H L ^[5]; Miller, B P ^[6]; Vignali, C ^[7]

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1. Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)
2. Department of Physics, University of North Texas, Denton, TX 76203 (United States)
3. Jansky Fellow of the National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)
4. Department of Astronomy and Astrophysics, University of California Santa Cruz, 159 Interdisciplinary Sciences Building, 1156 High Street, Santa Cruz, CA 95064 (United States)
5. Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States)
6. Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)
7. Dipartimento di Astronomia, Universita degli Studi di Bologna, Via Ranzani 1, 40127 Bologna (Italy)

We report spectral, imaging, and variability results from four new XMM-Newton observations and two new Chandra observations of high-redshift (z {approx}> 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, ({Gamma}) = 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 K{alpha} emission lines or Compton-reflection continua. Our data also constrain intrinsic X-ray absorption in these RLQs. We find evidence for significant absorption (N{sub H} {approx} 1.7 x 10{sup 22}cm{sup -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 ({approx}14 kpc) X-ray emission that is most likely due to a jet; the X-ray luminosity of this putative jet is {approx}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.

• OSTI ID: 21582937
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 738; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
EMISSION
GALAXIES
IONIZING RADIATIONS
JETS
QUASARS
RADIATIONS
RED SHIFT
X RADIATION
X-RAY GALAXIES