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The First Billion Years of History - seeing Galaxies Close to the Dawn of Time

The First Billion Years of History - seeing Galaxies Close to the Dawn of Time Andrew Bunker, Anglo-Australian Observatory & University of Oxford KIAA/PKU Workshop.

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The First Billion Years of History - seeing Galaxies Close to the Dawn of Time

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  1. The First Billion Years of History - seeing Galaxies Close to the Dawn of Time Andrew Bunker, Anglo-Australian Observatory & University of Oxford KIAA/PKU Workshop

  2. "Lyman break technique" - sharp drop in flux at below Ly-. Steidel et al. have >1000 z~3 objects, "drop" in U-band.

  3. HUBBLE SPACE TELESCOPE

  4. "Lyman break technique" - sharp drop in flux at below Ly-. Steidel et al. have >1000 z~3 objects, "drop" in U-band. Pushing to higher redshift- Finding Lyman break galaxies at z~6 : using i-drops.

  5. Using HST/ACS GOODS data - CDFS & HDFN, 5 epochs B,v,i',z'

  6. By selecting on rest-frame UV, get inventory of ionizing photons from star formation. Stanway, Bunker & McMahon (2003 MNRAS) selected z-drops 5.6<z<7 - but large luminosity bias to lower z. Contamination by stars and low-z ellipticals.

  7. ESO VLTs 10-m Kecks 8-m Gemini

  8. The Star Formation History of the Univese Bunker, Stanway, z=5.8 Ellis, McMahon & McCarthy (2003) Keck/DEIMOS spectral follow-up & confirmation I-drops in the Chandra Deep Field South with HST/ACS Elizabeth Stanway, Andrew Bunker, Richard McMahon 2003 (MNRAS)

  9. GLARE I: Stanway, Glazebrook, Bunker et al. 2004 ApJ 604, L13

  10. GLARE II: Stanway, Bunker, Glazebrook et al. 2007 MNRAS 376, 272

  11. For I-drops (z~6) would only get ~1 per NIRSpec field bright enough for S/N~3-10 in continuum in 1000sec for abs line studies

  12. Looking at the UDF (going 10x deeper, z'=26 28.5 mag) Bunker, Stanway, Ellis &McMahon 2004

  13. Redshift z 1100 After era probed by CMBR the Universe enters the so-called “dark ages” prior to formation of first stars Hydrogen is then re-ionized by the newly-formed stars When did this happen? What did it? DARK AGES 10 5 2 0

  14. Implications for Reionization From Madau, Haardt & Rees (1999) -amountof star formation required to ionize Universe(C30 is a clumping factor).This assumes escape fraction=1 (i.e. all ionzing photons make it out of the galaxies)Our UDF data has star formation at z=6 which is 3x less than that required! AGN cannot do the job.We go down to 1M_sun/yr - but might be steep  (lots of low luminosity sources - forming globulars?)

  15. Ways out of the Puzzle - Cosmic variance- Star formation at even earlier epochs to reionize Universe (z>>6)?- Change the physics: different recipe for star formation (Initial mass function)?- Even fainter galaxies than we can reach with the UDF?

  16. Spitzer – IRAC (3.6-8.0 microns)

  17. - z=5.83 galaxy #1 from Stanway, Bunker & McMahon 2003 (spec conf from Stanway et al. 2004, Dickinson et al. 2004). Detected in GOODS IRAC 3-4m: Eyles, Bunker, Stanway et al.

  18. Other Population Synthesis Models Maraston vs. Bruzual & Charlot B&C =500Myr, 0.7Gyr, 2.4x1010Msun Maraston =500Myr, 0.6Gyr, 1.9x1010Msun

  19. 30Myr const SFR with E(B-V)=0.1 • No reddening • 0.2solar metallicity

  20. -Have shown that some z=6 I-drops have old stars and large masses (subsequently confirmed by H. Yan et al) -Hints that there may be z>6 galaxies similar (Egami lens). Mobasher source - z=6.5??? (probably lower-z) • Turn now to larger samples, to provide stellar mass density in first Gyr with Spitzer • - In Stark, Bunker, Ellis et al. (2006) we look at v-drops (z~5) in the GOODS-South • 21 have spectroscopic redshifts, 2/3rds unconfused at Spitzer resolution • - Also use 200 photometric redshifts (going fainter), >50 unconfused

  21. Eyles, Bunker, Ellis et al. astro-ph/0607306

  22. Eyles, Bunker, Ellis et al. astro-ph/0607306

  23. Eyles, Bunker, Ellis et al. astro-ph/0607306

  24. Eyles, Bunker, Ellis et al. astro-ph/0607306

  25. DAZLE - Dark Ages 'z' Lyman-alpha Explorer IoA - Richard McMahon, Ian Parry; AAO - Joss Bland-Hawthorne

  26. JAMES WEBB SPACE TELESCOPE – successor to Hubble (2013+)

  27. What is JWST? • 6.55 m deployable primary • Diffraction-limited at 2 µm • Wavelength range 0.6-28 µm • Passively cooled to <50 K • Zodiacal-limited below 10 µm • Sun-Earth L2 orbit • 4 instruments • 0.6-5 µm wide field camera (NIRCam) • 1-5 µm multiobject spectrometer (NIRSpec) • 5-28 µm camera/spectrometer (MIRI) • 0.8-5 µm guider camera (FGS/TF) • 5 year lifetime, 10 year goal • 2014 launch

  28. ESA Contributions to JWST • NIRSpec • ESA Provided • Detector & MEMS Arrays from NASA • MIRI Optics Module • ESA Member State Consortium • Detector & Cooler/Cryostat from NASA • Ariane V Launcher (ECA) (closely similar to HST model…)

  29. NIRSpec IST

  30. Absorption lines at z>5 - a single v. bright Lyman break z=5.5 galaxy, Dow-Hygelund et al (2005), AB=23-24, VLT spectrum (22 hours), R~3000; S/N=3-10 at R=1000,2700 in 1000sec NIRSpec

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