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 similar to 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.
Variability of the extreme z=4.72 blazar, GB 1428+4217 / Fabian, A. C.; Celotti, Anna Lisa; Pooley, G.; Iwasawa, K.; Brandt, W. N.. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 308:1(1999), pp. L6-L10. [10.1046/j.1365-8711.1999.02910.x]
Variability of the extreme z=4.72 blazar, GB 1428+4217
Celotti, Anna Lisa;
1999-01-01
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 similar to 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
