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Science with ELTs from Galaxies to the Origins of the Universe Isobel Hook University of Oxford

Science with ELTs from Galaxies to the Origins of the Universe Isobel Hook University of Oxford. Or Why cosmology is not a waste of time. Science with ELTS. THE UNEXPECTED. Near-IR Diffraction limits. 0.5”. W M W L 0.3 0.7 0.0 0.0. Starburst region. JWST. Giant HII region.

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Science with ELTs from Galaxies to the Origins of the Universe Isobel Hook University of Oxford

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  1. Science with ELTsfrom Galaxies to the Origins of the UniverseIsobel HookUniversity of Oxford Or Why cosmology is not a waste of time

  2. Science with ELTS THE UNEXPECTED

  3. Near-IR Diffraction limits 0.5” WM WL 0.3 0.7 0.0 0.0 Starburst region JWST Giant HII region Compact HII region Globular cluster + dramatic improvement in point-source sensitivity

  4. Depth gains over 8m with 0.5” images(point sources, background limited case)

  5. Science Cases 50-100m ELT 30m – GSMT 20m – GMT Technical Requirements

  6. Black Holes • Only a few black holes have accurate mass measurements • How common are they? • Why do their masses relate to the mass of their host galaxy bulges? • GMT 20m: wide-field YJHKs survey with 0.2” images could discover AGN at high-z (up to 10?) Artist’s conception of an AGN (GLAST/NASA)

  7. ELT can resolve sphere of influence at large distances E.g. a 100m telescope at diffraction limit can resolve 104 Mo BH out to 10 Mpc from us Supermassive 109 Mo BH at all redshifts (where they exist!) Black Holes • FOV: 5” • Few mas resolution • ~1mm or optical • R ~ few x 1000 • Ideally suited to IFU M. Hughes et al

  8. Structure Formation • Models predict build-up of structure under gravity • Sophisticated simulations of Dark Matter clustering Millenium simulation, Springel et al

  9. Millennium simulation (Springel et al) Dark Matter Galaxies • Relation to luminous matter must be determined empirically • Need to model feedback – AGN, SNe, winds… • Are the models correct?

  10. Goal: to understand formation of galaxies & feedback processes (SNe, AGN) Want to spatially resolve on kpc scales: Star formation history Stellar mass Extinction Metallicity Ionisation state Line shapes (> winds) Internal dynamics (dynamical masses) Relate this to build-up of dark matter in galaxy haloes Evolution of galaxies:Physics of galaxies 1 < z < 5 Velocity fields of distant galaxies from GIRAFFE Integral-field Unit observations (Flores et al 2004)

  11. Map evolution dark matter from 1<z<5 Understand effects of merging and feedback processes Want to measure: kinematics within large galaxies kinematics of satellites lensing of background objects (halo masses) Evolution of Galaxies:Assembly of galaxy haloes Evolution of dark matter in a galaxy halo- Abadi et al 2003

  12. Gravitational lensing • Distorted background images give mass estimate: amount & distribution of Dark Matter • Also allows discovery of boosted distant objects • GMT: Contiguous 1’x1’ IFU • Or multiple IFUs A2218 WFPC2/HST image A. Fruchter

  13. Evolution of galaxies: Requirements FALCON concept (Hammer et al) • Galaxies & haloes comb. • Multiple IFUs • Different types • R ~ 5000-10000 • 0.7 (or 0.3) to 2.5mm • AO system for resolved studies (0.01-0.05”) • Patrol FOV > 2’ (10’) • ~ 1 night per field with a 100m • 30m (GSMT) : to z~3 • Dynamical masses • Integrated properties: • - metalicity, ages, winds

  14. GSMT 30m case assumes point sources: star clusters and QSOs Then reach AB~31 with a 30m The First Galaxies • z~ 6-7 galaxies have been found • Higher-z must exist • Old populations seen at z~6 • z ~ 6 QSOs imply massive galaxies at earlier epochs • Universe is ionised by something! • Find by imaging • JWST will find candidates? • Need ELT for continuum spectroscopy Bremer & Lehnert (2005) • 60m could reach ABH~29 in 100hrs at low R (depending on source size) • Spectroscopy at z>10 hard even for 100m. z >13 even harder!

  15. SCUBA-2 (JCMT) : 850m SCOWL (OWL) : 850m Sub-mm on an ELT • Sub-mm camera on an ELT would have mapping speed far superior to ALMA

  16. High-z Galaxies: Requirements • Large FOV: 5-10’ sq. • z >10 galaxies very rare • need multiplex for efficiency • Image sizes 0.1-0.2” • z >10 : probably integrated properties only • AO for contrast? • R~ 300-10000 • z >10 : redshifts only • 5 < z <10 : stellar masses etc • Wavelength range 1-2.4mm • Up to z~13 can be done in H z=5.74 z=5.65 z=6.58 z=6.17 Lehnert & Bremer (2005); Cuby et al (2003)

  17. Becker et al. 2001 z = 5.99 The re-ionisation history of the Universe • When was the Universe ionised? By what? • Need to probe reionisation of IGM to very high z • Look along line–of-sight to distant sources • Possible point sources at z>10 QSOs / AGN GRBs SNe (Pop III?) z = 6.28 • R: 1000 –10,000 • Single sources • IR (JHK) • > 30m needed for R=104 at z>10 for all except brightest GRBs

  18. Tomography of the IGM • At lower z can study multiple sightlines • QSOs / AGN • Compact galaxies • Measure evolution of IGM • Enrichment • Ionisation state • E.g. GMT 20m : 2 < z < 3.5 • 0.2 / sq arcmin at R~24 • R ~ 10,000 MOS

  19. Cosmology and Fundamental parameters • What drives the acceleration of the Universe? • What is the Dark Energy?

  20. M = 0 Open M < 1 M = 1 Closed M > 1 fainter - 14 - 9 - 7 today billion years Mean distance between galaxies Time From B. Leibundgut

  21. The Fate of the Universe Can’t currently distinguish these but SNLS, WFMOS, SNAP.. • The equation of state of the universe: w = < p/r > • w =-1 : cosmol. Const • w > -1 : quintessence.. • If -1 < w < -1/3 (e.g. L) • Universe accelerates faster than horizon • Galaxies drop out of view • Currently-bound structures (MW) unaffected • If w < -1 “Phantom energy” • (r+p < 0) • Even bound structures ripped apart • “Big Rip” • Caldwell, Kamionkowski & Weinberg (2003): • for w=-3/2 trip = 35 Gyr t-1Gyr Erase galaxy clusters t-60Myr Milky Way destroyed t-3mo Solar System unbound t-30mins Earth explodes t-10-19s Atoms dissociate

  22. Measuring the Expansion History • Primary distance indicators e.g. Cepheids to z~0.1 • Type Ia SNe to z~4 • Type II SNe to z~10 • Gamma-Ray Bursts • QSO absorption lines Limits for a 100m telescope

  23. High-z Supernovae Type Ia and Type II Simulated Hubble diagram for supernovae Spectroscopy of SNe Ia to z~4 (100m) [or z > 1.2 with GMT] Lidman et al 2005 • Finding: MCAO-fed IR imager • 2’x2’ FOV • Spectroscopy: R~ 2000 in JHK • One at a time or MOS over 5’ Della Valle & Gilmozzi

  24. The Cosmic Star formation rate • SNe also trace star formation • Sensitive to stars of all masses • Can measure the rate from now to z~10 or even higher

  25. GRBs potentially detectable to z15-20 ELT could measure jet break time at high-z Allows determination of opening angle > collimation-corrected Energy > peak energy Needs more data in the meantime.. Gamma Ray Bursts as Distance indicators • Single targets • R= 8000-10000 • 0.8-2.4mm

  26. Cosmic Differential Expansion (CODEX) • Direct measurement of the expansion of the universe from shifting of absorption lines • Effect is a few cm/s/yr (Sandage 1962) • Would need to measure ~100 QSOs (Loeb 1998) • Twice over ~10 yr baseline at 0.1m/s accuracy • Current instruments (e.g. HARPS) stable to ~1m/s over years • CODEX Study underway • Single objects • R >100,000 to 400,000 • 0.4-0.7mm

  27. Fundamental constants:Variation of the fine structure constant? • Variations may imply • Extra spatial dimensions? • Scalar field acting late in the Universe? • QSO absn lines give two conflicting results on Da • Need to resolve even the sharpest lines ~1km/s wide. • Need 1cm/s precision • R~300,000 (fibre-fed) • 60-100m ELT 2 orders of mag improvement Chand et al – VLT/UVES (2004) Murphy et al – Keck/HIRES- (2003, 2004)

  28. Conclusions ELTS will measure: • Physical processes in galaxies up to z ~ 6 • Black Holes across the Universe • Star formation history to z > 10 (?) • Properties of new “galaxies” z > 10 ? • Ionisation history to z > 10 - 20 • Expansion history to z > 4 • Fundamental constants & nature of Dark Energy • Who knows what else…

  29. http:www.saao.ac.za/IAUS232/

  30. The END

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