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Probing the Hi-z Universe with ELTs

Probing the Hi-z Universe with ELTs. Jean-Paul Kneib LAM. Motivating Science Case First Galaxies in the Universe. - Description of first galaxy physics and dynamics: how different from lower-z? - When and for how long PopIII stars shined (6<z<30)? How and when the Universe reionized?

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Probing the Hi-z Universe with ELTs

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  1. Probing the Hi-z Universe with ELTs Jean-Paul Kneib LAM

  2. Motivating Science CaseFirst Galaxies in the Universe - Description of first galaxy physics and dynamics: how different from lower-z? - When and for how long PopIII stars shined (6<z<30)? • How and when the Universe reionized? • By which objects? Light DM

  3. Millenium simulation: Springel et al 2005 High-redshift structures are much less massive than local one Jenkins et al 2001

  4. POP III POP II High-z Galaxy CountsTheoretical PredictionsStiavelli et al 2004 Down to JWST sensitivity in imaging a few to hundreds galaxies per sq arcmin (more if only POP II)

  5. Population III galaxy E. LinesSchaerer 2003 HeII lines should reveals PopIII stars, but HeII is quickly fading with time

  6. Today state of the Art: UDF-NICMOSBouwens et al 2005, 2006

  7. Luminosity evolution of the LF z=3 z=6 L* galaxy at z~6 have AB~26 with density of 1 per sq.armin Bouwens et al (2006) suggest a luminosity evolution of the LF - drop of counts in the 3 < z < 6 essentially due to luminous objects Is star formation dominated by low-luminosity objects at z>6?

  8. Similar luminosity evolution for Lya in 5.7<z<6.6 Kashikawa et al 2006

  9. Today state of the Art:Cluster lensesEllis et al 2001, Kneib et al 2004, Egami et al 2004Stark et al 2006Richard et al 2007 Z~6.8 lensed galaxy

  10. High redshift galaxy SEDEgami et al 2005 HST+Spitzer Old stars already exist at z~7 zform~9-11 Similar results On the z~6 field objects

  11. High Redshift Galaxy Morphology as Seen through a Cosmic Lens • Lots of structure as small as 10 mas!!! • Strong interest of an integral field

  12. High redshift galaxy SB and sizeBouwens et al 2005 At higher redshift z>7 => typical size down to 0.10” 0.18”

  13. Low luminosity Lya emitter at z~8-10 : Critical Line Mapping with Keck/NIRSPEC Previous work similar in optical LAE @ z~5 (LRIS) A2218 Santos, et al. 2004 Line mapping of 9 clusters with NIRSPEC in the J-band probing Ly between 8.5 < z < 10.4 Sensitive to sources down to 0.1 M yr-1 over 50 Mpc3 (comobile) Stark, et al. 2007 Long slit spectroscopy in Highly magnified region In massive clusters

  14. Example: Abell 2390 Line flux sensitivity Critical line zS > 7 10-17 cgs NIRSPEC Slits • 9 cluster-lenses well constraints with deep ACS/WFPC images • Sensitivity ~ 3-9.10-18 cgs; magnification > 15-20 • Area on sky observed: 0.3 arcmin2; V(comobile) ~ 50 Mpc3 • 6 candidates (> 5 ) • 8.6 < z < 10.1 L ~ 2 - 10. 1041 cgs SFR ~ 0.2 -1 M an-1

  15. Candidates Lya Emitters Very difficult to prove that these candidates are genuine

  16. Different possibility for the nature of the emission line Removal of Contaminants Raie • Deep optical spectrocopy can remove possible contaminant(Santos et al 2004) à 4000-9500 Å : H, [O III] and [O II] • No [OIII] usually remove the possibility of H • can check with spectroscopy in H-band & with Spitzer/IRS (in progress)

  17. Are z~10 galaxies responsible for reionization? assumptions: fc ~ 0.1-0.5 t ~ 250-575 Myr Stark et al (2007) all are real 2 are real Even if only1-3 of our 6 candidates are real, low luminosity galaxies may play an important role on reionization none is real

  18. 8 well-constrained clusters with ACS/F850LP + IRAC imaging • 11 NICMOS pointings in 6 lensing clusters (4 orbits F110W, 5 orbits F160W) • K-band ground based imaging with Keck/NIRC + Subaru/MOIRCS Lensed dropout with ACS/NICMOS Richard et al 2007

  19. z~7-8 and z~10 candidates Z~7-8 • 10 candidate z-drops with H ~ 26 - 26.8 • Implied SFR ~ 0.1 - 2 M yr-1 (unlensed) • spectroscopic follow-up with NIRSPEC • z~2 LRGs expected to be main contaminants Richard et al 2007 2 good candidate J-drops (J-H>1.8) each with HAB~25.5 - 25.7 SFR ~ 0.1 - 1 M yr-1 (unlensed) Z~10

  20. Strong lensing permits us to probe z-band dropouts ~1-1.5 magnitudes deeper than the UDF in a field of ~2.5 arcmin2 Deeper than UDF - impact on reionization Richard et al 2007 HST-LENS Bouwens et al Lensed candidates HUDF F850LP - F110W # of sources required for reionization F110W • High surface density of z/J-drops (contamination to be checked) • suggests significant contribution to reionization from low luminosity galaxies • lensing survey valuably extends constraints set by UDF

  21. Prospects with ELTs

  22. Comparison JWST/ELT sensitivities Almost 10-100 more efficient than JWST spectroscopy ELT spectro 10 and 100 ksec

  23. Redshifts, Metallicityand Photometric Bands Y J H K Need of multi-band spectroscopy !

  24. Redshift: no problems if done in 2 bands except may be for 13<z<14 (more difficult in K-band) Metal/ISM enrichment study: impossible for z~9 and 11<z<13, difficult above z>13 NIR Spectral signatures of Hi-z galaxies Y J H K

  25. High-z galaxy (LBG) counts extrapolating current detections No-evolution – reference z~6 Evolution – from z~6

  26. High-z galaxy (LAE) counts extrapolating current detections Semi-analytic simulation prediction fitted to z~6 LAEs Devriendt et al 2006 Kashikawa et al 2006

  27. Feeding the ELT with Hi-z targets Deep Hubble observations: UDF-like (blank fields and clusters) + future WFPC3 data [now & 2009-2013] UltraVista deep imaging [2011]intrinsicallyluminous objects JWST imaging [2013]intrinsicallyfaint objects Wide field imager in space[2016?] intrinsicallyluminous objects ELT images [2016?] intrinsicallyfaint objects transient objects GRBs/SNs

  28. technical requirements from hi-z galaxy studies • Infrared from Y to K band (highest redshift), • High spatial Resolution (AO) ~50 mas or better (sensitivity/objects are small), • “wide” Field of View >~5x5 sq.arcmin (low density of objects), • Multi-objects spectrograph >30 objects (statistics), • IFU ~1 sq.arcsec FoV (blind search/largest {lensed} objects), • Spectral resolution R~4000 (OH suppression, dynamics), • possibly two photometric bands in parallel (line diagnostic, Ly-alpha+HeII)

  29. Spectrum Simulator -PSF Y band, Y=27, 2 different scales Need to achieve PSF with adequate sampling that match the object size

  30. Spectrum Simulator -Depth J band, J=27-28, (R=4000 about 80% of clean sky) R=4000 is sufficient to subtract sky lines, and give ~10km/s resolution at z>8 which allow dynamical mass estimates of these early systems

  31. Metallic Absorption lines and MetallicityRix et al 2004 Best Fit Probe ISM enrichment as a function of redshift

  32. Other Science Prospects • Tomography of 1<z<3 galaxies: physics and dynamics. • The center of our Galaxy • The AGN engines, feeding and demography of black holes • Minor objects in the Solar systems

  33. Galaxy Morphological Transformation in Clusters Amongst ~12 z~0.2 HST clusters we caught 2 cluster galaxies being stripped (ram pressure+tidal stripping), nicknamed “Comet Galaxies” Abell 2667 Covonne et al 2006, Cortese et al 2007

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