Variability of the extreme z=4.72 blazar, GB 1428+4217

Abstract

We report X-ray and radio variability of GB 1428+4217 which confirm its blazar nature. IR observations reveal a powerful optical-UV component, not obscured by dust, which is suggestive of the presence of a billion solar mass black hole, already formed by z ~ 5. A detailed comparison of the broad band spectral properties of GB 1428+4217 with those of nearby blazars shows it to be extreme, but nevertheless consistent with the trend found for nearby sources.

MNRAS, in press - 5 pages, 5 figures

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• Chandra Observations of Radio-Loud Quasars at z > 4: X-rays from the Radio Beacons of the Early Universe
• The X-ray Properties of z>4 Quasars
• XMM-Newton observations of GB B1428+4217: confirmation of intrinsic soft X-ray absorption
• The blazar GB1428+4217: a warm absorber at z=4.72?
• Broadband Observations of High Redshift Blazars
• Evidence of thick obscuring matter revealed in the X-ray spectrum of the Z=4.28 quasar RXJ1028.6-0844
• Discovery of a Kiloparsec Scale X-ray/Radio Jet in the z=4.72 Quasar GB 1428+4217
• XMM-Newton observations of four high-z quasars
• The first XMM-Newton spectrum of a high redshift quasar - PKS 0537-286
• Physical parameters of a relativistic jet at very high redshift: the case of the blazar J1430+4204
• MM-Newton Observations of two high redshift quasars: RX J1028-0844 and BR 0351-1034
• Fast jet proper motion discovered in a blazar at z = 4.72
• Two Candidate High-Redshift X-ray Jets Without Coincident Radio Jets
• Radio and X-ray observations of an exceptional radio flare in the extreme z=4.72 blazar GB B1428+4217
• $Fermi$-LAT detection of a transient $\gamma$-ray source in the direction of a distant blazar B3 1428+422 at $z=4.72$
• X-rays from the First Massive Black Holes
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