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The High-Redshift Universe

The High-Redshift Universe. Alberto Fernández-Soto Universitat de València. Plan of this talk. Definition and evolution of “high-redshift” “Objects” at high redshift Selection techniques for high-z objects Observations Towards galaxy evolution. How “high” is “high”?.

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The High-Redshift Universe

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  1. The High-Redshift Universe Alberto Fernández-Soto Universitat de València

  2. Plan of this talk • Definition and evolution of “high-redshift” • “Objects” at high redshift • Selection techniques for high-z objects • Observations • Towards galaxy evolution BJ60 - Valencia

  3. How “high” is “high”? • Start with the discovery and identification of QSOs in the 60s (3C273 z=0.16) • For 30 years “monsters” dominated (z ~ 4) • Radiogalaxies -- Quasars • Colour selection drove towards “normal” galaxies • LBGs @ z ~ 3 -- Dropouts @ z ~ 3 – 5 • QSOs again pushed in (SDSS z ~ 6) • GRBs stand a chance (GRB050904 @ z=6.29) • …but not as high as z=1000! BJ60 - Valencia

  4. BJ60 - Valencia

  5. Data compiled by X. Fan BJ60 - Valencia

  6. Search for high-z objects • Identification of “peculiar” objects • X-ray sources  AGNs  Clusters of galaxies  Peculiar stars (or…) • Radio sources  Radio-loud QSOs • Important selection effects • Plagued QSO catalogues for years • Non-detectability of normal galaxies • By definition! BJ60 - Valencia

  7. Colour selection Use of hydrogen-imprinted features Peebles 1967, Partridge (1974), BVR selection (Piskunov y Kupka 2001) BJ60 - Valencia

  8. Intergalactic Absorption quasar Charlton & Churchill (2000) z = 1.3 Charlton & Churchill (2000) z = 3.6 z = 6.3 Becker et al. (2001) BJ60 - Valencia

  9. “The perfect QSO spectrum” BJ60 - Valencia

  10. (Steidel 1999) BJ60 - Valencia

  11. NOAODWFS(Jannuzzi et al) BJ60 - Valencia

  12. The importance of it all… • Neutral hydrogen is ubiquitous… • The features imprinted by HI are the same, for all types of objects, at a given redshift  Possibility of unbiased selection BJ60 - Valencia

  13. Colour-selected normal galaxiesin the HDF (Lanzetta et al 1996) BJ60 - Valencia

  14. (Giavalisco 2001) BJ60 - Valencia

  15. Expected colors of high z Lyman break galaxies are well defined. (Steidel et al 1999) BJ60 - Valencia

  16. (Steidel et al 1999) BJ60 - Valencia

  17. BJ60 - Valencia (Le Fevre et al 2005)

  18. BJ60 - Valencia (Le Fevre et al 2005)

  19. Quasars re-enter the stage • Colour selection can also be applied to QSOs • High-redshift QSOs much more luminous than galaxies, but much more scarce • Need for photometric, large-area surveys: • SDSS  ugriz colour images  10 000 square degrees  selection of QSOs up to z > 6 BJ60 - Valencia

  20. 17,000 Quasars from the SDSS Data Release One 5 Ly a 3 2 CIV CIII 1 MgII OIII Ha 0 4000 A 9000 A BJ60 - Valencia

  21. The Highest Redshift Quasars Today(SDSS, Fan et al) • z>4: ~700 known • z>5: ~30 • z>6: 7 • SDSS i-dropout Survey: • By Spring 2004: 6000 deg2 at zAB<20 • Fourteen luminous quasars at z>5.7 • 20 – 40 at z~6 expected in the whole survey Total Discoveries SDSS Discoveries BJ60 - Valencia

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  23. Photometric redshifts • Originally in Baum (1963) • Koo (1985): “Poor man´s redshift machine” • Loh & Spillar (1986): Cosmology • Impulse with Hubble Deep Fields: • Deep, high quality, multi-colour images • High spatial resolution • Good spectral sample for calibration • Nowadays common tool of the trade BJ60 - Valencia

  24. Applications • “Poor man’s redshift machine” • Applications in (particularly): • Large volumes of data • Faint galaxy samples • Crowded fields • Proven accuracy: Dz/(1+z) ~ 0.05 (rms) • Catastrophic error rate < 5% • Already tested out to z ~ 6 BJ60 - Valencia

  25. Sbc z=0.66 BJ60 - Valencia

  26. Sbc z=1.29 BJ60 - Valencia

  27. Irr z=2.51 BJ60 - Valencia

  28. SB1 z=4.36 BJ60 - Valencia

  29. SB1 z=7.96 BJ60 - Valencia

  30. Z(phot) vs Z(spec) (Fernandez-Soto et al 2001) BJ60 - Valencia

  31. Colour selection + grism spectra z=5.83 Selected inside HUDF via BVizJH photometry (Malhotra et al 2005) BJ60 - Valencia

  32. Emission-line searches • Emission line searches for high redshift galaxies (tuned to Lyman-a) existed for many years, with very low success rates • Only over the last few years narrow-band searches tuned at z~6 have offered results • Particular mention to • LALA • Keck • Subaru BJ60 - Valencia

  33. Subaru emission-line searches • NB711 @ z=4.86 (Masami et al 2003) • NB816 @ z=5.75 (Ajiki et al 2003) • NB921 @ z=6.55 (Kodaira et al 2003) BJ60 - Valencia

  34. Subaru emission-line search Narrow-band filter tuned to Lyman a @ z=6.55 (Kodaira et al 2004) BJ60 - Valencia

  35. Keck emission-line survey(Hu et al 2005) BJ60 - Valencia

  36. The Large Area Lyman Alpha Survey BJ60 - Valencia

  37. Candidate z=6.5 LALA galaxies Ic(NDWFS) z’SDSSNB918 All data from NOAO 4m telescopes; NB918 stack is 24 hours’ integration. BJ60 - Valencia

  38. z’ 9180 A Gemini image of z=6.535 galaxy (Rhoads et al. 2004) BJ60 - Valencia

  39. LALA J142442.24+353400.2 @ z=6.535 Gemini spectrum shows asymmetric line, no continuum. (Rhoads et al. 2004) BJ60 - Valencia

  40. Observing the Distant Universe with clusters Gravitational Telescopes: Lensed Galaxies are much brighter Use a BIG telescope! 1021m primary with an 8m secondary! The Cosmic Telescope! NOTE: magnification x25  from z=6 to z=1.5  from z=10 to z=2.5 1021m (M~1014Mo) BJ60 - Valencia

  41. z=1.034 z=2.515 z=5.6 A2218 (zcl=0.17) A2218 3 spectroscopic confirmed multiply imaged systems. BJ60 - Valencia

  42. A z=10 galaxy (Pello et al 2004) BJ60 - Valencia

  43. Some large ongoing surveys BJ60 - Valencia

  44. DEEP2 • DEEP • Keck + LRIS • 1000 galaxies to I=24.5 • DEEP2 • Keck + Deimos, R=5000 • 50000 galaxies 0.7 < z < 1.4 (BRI selected) BJ60 - Valencia

  45. VVDS • VLT + VIMOS • Imaging with CFHT (BVRI), NTT (K), ESO2.2 (U) • Shallow: • 100 000 galaxies to AB(I)=22.5, R=250 • Subsample observed at R=2500 • Deep: • 50 000 galaxies to AB(I)=24 • Ultra-Deep: • 1000 galaxies to AB(I)=26 observed with IFU BJ60 - Valencia

  46. GOODS • 300 sq. arcmins., HDFN and CDFS • Spitzer (Dickinson) • Ultradeep IRAC, deep IRAC and MIPS • Hubble (Giavalisco) • BViz deep images • Extra data from • KP+CTIO (U), • VLT (NIR), • VLT+ Gemini+Keck (spectroscopy), • XMM+Chandra (X rays) BJ60 - Valencia

  47. ALHAMBRA • Aim: 8 x ½ square degree fields • Calar Alto 3.5m, LAICA + W2000 • AB(BVRI) = 25, AB(JHK) ~ 22 • Designed with photometric redshifts in mind: • Optical coverage from 3500 to 9500 A • 20 non-overlapping 300 A-wide filters • Redshift accuracy Dz / (1+z) ~ 0.02 • 800 000 galaxies to AB(I)=24 • ~2000 galaxies at z>5 BJ60 - Valencia

  48. Filter system and survey depth (Moles et al 2006) (Benitez et al 2006) BJ60 - Valencia

  49. BJ60 - Valencia

  50. What have we learned about the high-redshift universe? BJ60 - Valencia

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