The radio-loud quasar SDSS J102623.61+254259.5, at a redshift z = 5.3, is one of the most distant radio-loud objects. Since its radio flux exceeds 100 mJy at a few GHz, it is also one of the most powerful radio-loud sources. We propose that this source is a blazar, i.e. we are seeing its jet at a small viewing angle. This claim is based on the spectral energy distribution of this source, and especially on its strong and hard X-ray spectrum, as seen by Swift, very typical of powerful blazars. Observations by the Gamma-Ray Burst Optical/Near-Infrared Detector (GROND) and by the Wide-field Infrared Survey Explorer (WISE) allow us to establish the thermal nature of the emission in the near-IR-optical band. Assuming that this is produced by a standard accretion disc, we derive that it emits a luminosity of Ld≃ 9 × 10^46 erg s-1 and that the black hole has a mass between 2 and 5 billion solar masses. This poses interesting constraints on the mass function of heavy (>10^9 Msun) black holes at high redshifts
Sbarrato, T., Ghisellini, G., Nardini, M., Tagliaferri, G., Foschini, L., Ghirlanda, G., et al. (2012). SDSS J102623.61+254259.5: The second most distant blazar at z = 5.3. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. LETTERS, 426(1), L91-L95 [10.1111/j.1745-3933.2012.01332.x].
SDSS J102623.61+254259.5: The second most distant blazar at z = 5.3
SBARRATO, TULLIA;NARDINI, MARCO;Ghirlanda, G;
2012
Abstract
The radio-loud quasar SDSS J102623.61+254259.5, at a redshift z = 5.3, is one of the most distant radio-loud objects. Since its radio flux exceeds 100 mJy at a few GHz, it is also one of the most powerful radio-loud sources. We propose that this source is a blazar, i.e. we are seeing its jet at a small viewing angle. This claim is based on the spectral energy distribution of this source, and especially on its strong and hard X-ray spectrum, as seen by Swift, very typical of powerful blazars. Observations by the Gamma-Ray Burst Optical/Near-Infrared Detector (GROND) and by the Wide-field Infrared Survey Explorer (WISE) allow us to establish the thermal nature of the emission in the near-IR-optical band. Assuming that this is produced by a standard accretion disc, we derive that it emits a luminosity of Ld≃ 9 × 10^46 erg s-1 and that the black hole has a mass between 2 and 5 billion solar masses. This poses interesting constraints on the mass function of heavy (>10^9 Msun) black holes at high redshifts
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