The ASCA spectrum of the z = 4.72 blazer GB 1428+4217

A. C. Fabian, K. Iwasawa, A. Celotti, W. N. Brandt, R. G. McMahon, I. M. Hook

Research output: Contribution to journalArticle

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Abstract

The X-ray-luminous quasar GB 1428+4217 at redshift 4.72 has been observed with ASCA. The observed 0.5-10 keV flux is 3.2 × 10-12 erg cm-2 s-1. We report here on the intrinsic 4 - 57 keV X-ray spectrum, which is very flat (photon index 1.29). We find no evidence for flux variability within the ASCA data set or between it and ROSAT data. We show that the overall spectral energy distribution of GB 1428+4217 is similar to that of lower redshift MeV blazars, and present models that fit the available data. The Doppler beaming factor is likely to be at least 8. We speculate on the number density of such high-redshift blazars, which must contain rapidly formed massive black holes.

Original languageEnglish (US)
Pages (from-to)L25-L28
JournalMonthly Notices of the Royal Astronomical Society
Volume295
Issue number1
StatePublished - Mar 21 1998

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blazars
spectral energy distribution
erg
quasars
x rays
photons
energy
index
distribution

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Fabian, A. C., Iwasawa, K., Celotti, A., Brandt, W. N., McMahon, R. G., & Hook, I. M. (1998). The ASCA spectrum of the z = 4.72 blazer GB 1428+4217. Monthly Notices of the Royal Astronomical Society, 295(1), L25-L28.
Fabian, A. C. ; Iwasawa, K. ; Celotti, A. ; Brandt, W. N. ; McMahon, R. G. ; Hook, I. M. / The ASCA spectrum of the z = 4.72 blazer GB 1428+4217. In: Monthly Notices of the Royal Astronomical Society. 1998 ; Vol. 295, No. 1. pp. L25-L28.
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abstract = "The X-ray-luminous quasar GB 1428+4217 at redshift 4.72 has been observed with ASCA. The observed 0.5-10 keV flux is 3.2 × 10-12 erg cm-2 s-1. We report here on the intrinsic 4 - 57 keV X-ray spectrum, which is very flat (photon index 1.29). We find no evidence for flux variability within the ASCA data set or between it and ROSAT data. We show that the overall spectral energy distribution of GB 1428+4217 is similar to that of lower redshift MeV blazars, and present models that fit the available data. The Doppler beaming factor is likely to be at least 8. We speculate on the number density of such high-redshift blazars, which must contain rapidly formed massive black holes.",
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Fabian, AC, Iwasawa, K, Celotti, A, Brandt, WN, McMahon, RG & Hook, IM 1998, 'The ASCA spectrum of the z = 4.72 blazer GB 1428+4217', Monthly Notices of the Royal Astronomical Society, vol. 295, no. 1, pp. L25-L28.

The ASCA spectrum of the z = 4.72 blazer GB 1428+4217. / Fabian, A. C.; Iwasawa, K.; Celotti, A.; Brandt, W. N.; McMahon, R. G.; Hook, I. M.

In: Monthly Notices of the Royal Astronomical Society, Vol. 295, No. 1, 21.03.1998, p. L25-L28.

Research output: Contribution to journalArticle

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AU - Fabian, A. C.

AU - Iwasawa, K.

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AU - Brandt, W. N.

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AU - Hook, I. M.

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AB - The X-ray-luminous quasar GB 1428+4217 at redshift 4.72 has been observed with ASCA. The observed 0.5-10 keV flux is 3.2 × 10-12 erg cm-2 s-1. We report here on the intrinsic 4 - 57 keV X-ray spectrum, which is very flat (photon index 1.29). We find no evidence for flux variability within the ASCA data set or between it and ROSAT data. We show that the overall spectral energy distribution of GB 1428+4217 is similar to that of lower redshift MeV blazars, and present models that fit the available data. The Doppler beaming factor is likely to be at least 8. We speculate on the number density of such high-redshift blazars, which must contain rapidly formed massive black holes.

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Fabian AC, Iwasawa K, Celotti A, Brandt WN, McMahon RG, Hook IM. The ASCA spectrum of the z = 4.72 blazer GB 1428+4217. Monthly Notices of the Royal Astronomical Society. 1998 Mar 21;295(1):L25-L28.