1. Deciphering the Ancient Universe with Gamma-Ray Bursts Nobuyuki Kawai (Tokyo Tech) http://www-tap.scphys.kyoto-u.ac.jp/GRB2010/

2. 2 Cosmic Time Neutral opaque Universe Ionized transparent Universe GRB as a probe for high-z Universe GRB as a luminous light source GRB as a mark for a death of a massive star

3. 3 Imprints in GRB spectra Molecular Cloud H II Region WR Wind Shell SN ejecta galaxy ISM IGM EjectaCSM SFR ISMIGM

4. 4 Ly  break S II Si II* OIOI C II Si II GRB 050904 at t=3.4 d Subaru FOCAS 4.0 hrs,  Kawai et al. (2006) Totani et al. (2006) [S/H]=-1.3 Log N HI =21.6  z IGM,u = z DLA = 6.295  best fit x HI = 0.00  x HI < 0.17 (68 % C.L.) 0.60 (95% C.L.)

5. History of the Universe 5 Reinization Chemical evolution Star formation rate IGM Neutral Fraction Metallicity Cosmic star formation rate

6. “Tanvir Plot” Tanvir 2009 GRBs Galaxies Quasars

7. 7 960 970 980 wavelength [nm] 2 1 0 Flux density Ly  700 800 900 1000 wavelength [nm] 1010 Ly  S + Si + O C + 800 900 1000 wavelength [nm] 30 20 10 0 Ly  optical/NIR spectra of highest-z objects Galaxy z = 6.96 Quasar z = 6.4 GRB z = 6.3 Lyman alpha emitter can be found with systematic wide-field narrow band survey + spectroscopy little information in spectra (e.g. metal?) luminosity selected very rare: only 10 at z>6 in SDSS steadily bright complicated spectra: difficult to interpret proximity effect luminosity-selected rare: ~ 6 ? bright at early phase simple intrinsic spectra: abundant information no proximity effect sampling normal star- forming glaxy

8. Agenda  What do we know about GRBs?  What do we know about the ancient Universe?  How can we use GRBs to understand the history of the Universe?  What are the future prospects? 8

9. Poster Competition  Eligible if you are not giving a talk  Indicate your entry by the color sticker  Entry closed at Monday afternoon  Anonymous Judges choose three winners  Winners give 10 min talk on Friday  Young participants (students, postdocs) are particularly encouraged 9

10. Cosmic Chemical Evolution 10 Fynbo et al. 2006 Prochaska et al. 2003 Sollerman et al. 2005 Savaglio, et al. 2009 GRB 050904 Kawai et al. 2006

11. Reionization 11

12. Star Formation Rate 12