ROSAT observations of z>3 quasars

T. E. Pickering, Christopher D Impey, C. B. Foltz

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Successful pointed observations using the ROSAT PSPC were made of seven z>3 optically selected quasars from the Large Bright Quasar Survey (LBQS). Four detections and three 3σ upper limits resulted. Combining these data with the heterogeneous sample of Avni & Tananbaum [ApJ, 305, 83 (1986)] confirms their conclusion that the ratio of x-ray to optical luminosity is correlated with optical luminosity and probably not correlated with redshift. This suggests that x-ray luminosity evolves more slowly than optical luminosity. These results are then used in conjunction with the LBQS database to estimate the contribution to the 2 keV x-ray background of bright, optically selected quasars with mBJ < 18.85; the result is about 5%.

Original languageEnglish (US)
Pages (from-to)1542-1547
Number of pages6
JournalAstronomical Journal
Volume108
Issue number5
StatePublished - Nov 1994

Fingerprint

quasars
luminosity
x rays
estimates

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Pickering, T. E., Impey, C. D., & Foltz, C. B. (1994). ROSAT observations of z>3 quasars. Astronomical Journal, 108(5), 1542-1547.

ROSAT observations of z>3 quasars. / Pickering, T. E.; Impey, Christopher D; Foltz, C. B.

In: Astronomical Journal, Vol. 108, No. 5, 11.1994, p. 1542-1547.

Research output: Contribution to journalArticle

Pickering, TE, Impey, CD & Foltz, CB 1994, 'ROSAT observations of z>3 quasars', Astronomical Journal, vol. 108, no. 5, pp. 1542-1547.
Pickering TE, Impey CD, Foltz CB. ROSAT observations of z>3 quasars. Astronomical Journal. 1994 Nov;108(5):1542-1547.
Pickering, T. E. ; Impey, Christopher D ; Foltz, C. B. / ROSAT observations of z>3 quasars. In: Astronomical Journal. 1994 ; Vol. 108, No. 5. pp. 1542-1547.
@article{46aa357658e047fe8700531d8eaa1ae0,
title = "ROSAT observations of z>3 quasars",
abstract = "Successful pointed observations using the ROSAT PSPC were made of seven z>3 optically selected quasars from the Large Bright Quasar Survey (LBQS). Four detections and three 3σ upper limits resulted. Combining these data with the heterogeneous sample of Avni & Tananbaum [ApJ, 305, 83 (1986)] confirms their conclusion that the ratio of x-ray to optical luminosity is correlated with optical luminosity and probably not correlated with redshift. This suggests that x-ray luminosity evolves more slowly than optical luminosity. These results are then used in conjunction with the LBQS database to estimate the contribution to the 2 keV x-ray background of bright, optically selected quasars with mBJ < 18.85; the result is about 5{\%}.",
author = "Pickering, {T. E.} and Impey, {Christopher D} and Foltz, {C. B.}",
year = "1994",
month = "11",
language = "English (US)",
volume = "108",
pages = "1542--1547",
journal = "Astronomical Journal",
issn = "0004-6256",
publisher = "IOP Publishing Ltd.",
number = "5",

}

TY - JOUR

T1 - ROSAT observations of z>3 quasars

AU - Pickering, T. E.

AU - Impey, Christopher D

AU - Foltz, C. B.

PY - 1994/11

Y1 - 1994/11

N2 - Successful pointed observations using the ROSAT PSPC were made of seven z>3 optically selected quasars from the Large Bright Quasar Survey (LBQS). Four detections and three 3σ upper limits resulted. Combining these data with the heterogeneous sample of Avni & Tananbaum [ApJ, 305, 83 (1986)] confirms their conclusion that the ratio of x-ray to optical luminosity is correlated with optical luminosity and probably not correlated with redshift. This suggests that x-ray luminosity evolves more slowly than optical luminosity. These results are then used in conjunction with the LBQS database to estimate the contribution to the 2 keV x-ray background of bright, optically selected quasars with mBJ < 18.85; the result is about 5%.

AB - Successful pointed observations using the ROSAT PSPC were made of seven z>3 optically selected quasars from the Large Bright Quasar Survey (LBQS). Four detections and three 3σ upper limits resulted. Combining these data with the heterogeneous sample of Avni & Tananbaum [ApJ, 305, 83 (1986)] confirms their conclusion that the ratio of x-ray to optical luminosity is correlated with optical luminosity and probably not correlated with redshift. This suggests that x-ray luminosity evolves more slowly than optical luminosity. These results are then used in conjunction with the LBQS database to estimate the contribution to the 2 keV x-ray background of bright, optically selected quasars with mBJ < 18.85; the result is about 5%.

UR - http://www.scopus.com/inward/record.url?scp=0039539277&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0039539277&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0039539277

VL - 108

SP - 1542

EP - 1547

JO - Astronomical Journal

JF - Astronomical Journal

SN - 0004-6256

IS - 5

ER -