[ITAL]Chandra[/ITAL] Detection of Highest Redshift ([CLC][ITAL]z[/ITAL][/CLC] ∼ 6) Quasars in X-Rays

We report on Chandra observations of three quasars SDSSP J083643+005453,SDSSP J103027+052455, and SDSSP J130608+035626 at redshifts 5.82, 6.28 and 5.99respectively. All the three sources are clearly detected in the X-ray band, upto rest frame energies of ~55 keV. These observations demonstrate theunprecedented sensitivity of Chandra to detect faint sources in relativelyshort exposure times (5.7--8.2 ksec). The broad band X-ray properties of thesehighest redshift quasars do not appear to be any different from their lowerredshift cousins. Spectra of the sources could not be determined with only fewcounts detected. Observations with XMM-Newton will be able to constrain thespectral shapes, if they are simple. Determination of complex spectra in areasonable amount of time, however, will have to await next generation of X-raymissions.Comment: Submitted to ApJ Letter