1. A high z (z~6.3) GRB-- GRB050904 Reported by Bubu 2006 Mar.17

2. Oh, Nature X-ray: Nature Vol 440,p164 (9 March 2006) At 01:51:44 Universal Time (UT) on 4 September 2005, Swift’s Burst Alert Telescope (BAT) detected GRB 050904 and 81 seconds later a 4’ -radius localization was distributed to observers on the ground. Swift’s X-Ray Telescope (XRT) automatically slewed to the BAT localization and 76 minutes after the burst a 6’’ -radius XRT localization was distributed. NIR/Optical: Nature 440,181 Observe the XRT localization at both near-infrared (NIR) and visible wavelengths over the next few hours. Optical: Nature 440,184 Observe the field of GRB 050904 with the Faint Object Camera And Spectrograph (FOCAS) on the 8.2-m Subaru Telescope on top of Mauna Kea, Hawaii, after 3.4 days of the burst.

3. X-ray light curve Long burst: duration T 90 =225s How to see it from this figure??

4. NIR and optical image Image of the afterglow: 3.2days after burst The photometric redshift of the burst is determined from the Measurements of the NIR afterglow and the failure to detect the optical after glow

5. Optical spectrum Z~(8900-1216)/1216 ~ 6.3 The first detection of significant neutral hydrogen absorption at Z>6 It is found in mental-enriched regions even at such an early phase of the Universe

6. High z GRB Impulse (Previous record: GRB000131, z=4.5) To study the metal free population III stars, since they are viable GRB progenitors for long term GRBs To explore the distribution of neutral hydrogen in the vicinity of a GRB, in the host galaxy and/or in intergalactic space (IGM) at high z Provide the information for the reionization history of the Universe ( z reionazation era ~6)

7. Interesting …..

8. Reference and source of pictures Nature Vol 440,p164 Nature 440,181 Nature 440,184