ORIENTI, MonicaMonicaORIENTID'AMMANDO, FILIPPOFILIPPOD'AMMANDOGIROLETTI, MARCELLOMARCELLOGIROLETTIFinke, JustinJustinFinkeDallacasa, DanieleDanieleDallacasa2020-06-112020-06-1120162075-4434http://hdl.handle.net/20.500.12386/26012High redshift blazars are among the most powerful objects in the Universe. Although they represent a significant fraction of the extragalactic hard X-ray sky, they are not commonly detected in γ-rays. High redshift ( <mml:math display="inline"> <mml:mrow> <mml:mi>z</mml:mi> <mml:mo>></mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:math>) objects represent <mml:math display="inline"> <mml:mrow> <mml:mo><</mml:mo> <mml:mn>10</mml:mn> </mml:mrow> </mml:math> per cent of the active galactic nuclei (AGN) population observed by Fermi so far, and γ-ray flaring activity from these sources is even more uncommon. The characterization of the radio-to-γ-ray properties of high redshift blazars represents a powerful tool for the study of the energetics of such extreme objects and the Extragalactic Background Light. This contribution will present results of multi-band campaigns, from radio to γ-rays, on PKS 0836+710, PKS 2149-306, and TXS 0536+145. The latter is the highest redshift detection of a flaring γ-ray blazar so far. At the peaks of their respective flares these sources reached an apparent isotropic gamma-ray luminosity of about 10 <mml:math display="inline"> <mml:msup> <mml:mrow></mml:mrow> <mml:mn>50</mml:mn> </mml:msup> </mml:math> erg·s <mml:math display="inline"> <mml:msup> <mml:mrow></mml:mrow> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math>, which is comparable with the luminosity observed from the most powerful blazars. The physical properties derived from the multi-wavelength observations of these sources are then compared with those shown by the high redshift population.STAMPAenArticle10.3390/galaxies40300262-s2.0-85054253164000385480600019https://www.mdpi.com/2075-4434/4/3/262016Galax...4...26OFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation