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

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 journal › Article › peer-review

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 language	English (US)
Pages (from-to)	L25-L28
Journal	Monthly Notices of the Royal Astronomical Society
Volume	295
Issue number	1
State	Published - Mar 21 1998

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Cite this

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

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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T1 - The ASCA spectrum of the z = 4.72 blazer GB 1428+4217

AU - Fabian, A. C.

AU - Iwasawa, K.

AU - Celotti, A.

AU - Brandt, W. N.

AU - McMahon, R. G.

AU - Hook, I. M.

PY - 1998/3/21

Y1 - 1998/3/21

N2 - 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.

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

Abstract

All Science Journal Classification (ASJC) codes

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