Abstract

We report on a search for X-ray emission from quasars with redshifts greater than 4 using the ROSAT public database. Our search has doubled the number of z > 4 quasars detected in X-rays from six to 12. Most of those known prior to this work were radio-loud and X-ray-selected sources; our study increases the number of X-ray-detected, optically selected z > 4 quasars from one to seven. We present their basic X-ray properties and compare these with those of lower redshift quasars. We do not find any evidence for strong broadband spectral differences between optically selected z > 4 quasars and those at lower redshifts.

Original languageEnglish (US)
Pages (from-to)2031-2037
Number of pages7
JournalAstronomical Journal
Volume119
Issue number5
DOIs
StatePublished - May 2000

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quasars
x rays
radio
broadband

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

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title = "The X-ray properties of z > 4 quasars",
abstract = "We report on a search for X-ray emission from quasars with redshifts greater than 4 using the ROSAT public database. Our search has doubled the number of z > 4 quasars detected in X-rays from six to 12. Most of those known prior to this work were radio-loud and X-ray-selected sources; our study increases the number of X-ray-detected, optically selected z > 4 quasars from one to seven. We present their basic X-ray properties and compare these with those of lower redshift quasars. We do not find any evidence for strong broadband spectral differences between optically selected z > 4 quasars and those at lower redshifts.",
author = "Shai Kaspi and Brandt, {W. N.} and Schneider, {Donald P.}",
year = "2000",
month = "5",
doi = "10.1086/301362",
language = "English (US)",
volume = "119",
pages = "2031--2037",
journal = "Astronomical Journal",
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}

The X-ray properties of z > 4 quasars. / Kaspi, Shai; Brandt, W. N.; Schneider, Donald P.

In: Astronomical Journal, Vol. 119, No. 5, 05.2000, p. 2031-2037.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The X-ray properties of z > 4 quasars

AU - Kaspi, Shai

AU - Brandt, W. N.

AU - Schneider, Donald P.

PY - 2000/5

Y1 - 2000/5

N2 - We report on a search for X-ray emission from quasars with redshifts greater than 4 using the ROSAT public database. Our search has doubled the number of z > 4 quasars detected in X-rays from six to 12. Most of those known prior to this work were radio-loud and X-ray-selected sources; our study increases the number of X-ray-detected, optically selected z > 4 quasars from one to seven. We present their basic X-ray properties and compare these with those of lower redshift quasars. We do not find any evidence for strong broadband spectral differences between optically selected z > 4 quasars and those at lower redshifts.

AB - We report on a search for X-ray emission from quasars with redshifts greater than 4 using the ROSAT public database. Our search has doubled the number of z > 4 quasars detected in X-rays from six to 12. Most of those known prior to this work were radio-loud and X-ray-selected sources; our study increases the number of X-ray-detected, optically selected z > 4 quasars from one to seven. We present their basic X-ray properties and compare these with those of lower redshift quasars. We do not find any evidence for strong broadband spectral differences between optically selected z > 4 quasars and those at lower redshifts.

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