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Quasars and Galaxies at the Highest Redshifts

Quasars and Galaxies at the Highest Redshifts. Richard McMahon Institute of Astronomy University of Cambridge, UK. Crafoord Symposium, Stockholm, Sep 2005. Some Background Information.

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Quasars and Galaxies at the Highest Redshifts

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  1. Quasars and Galaxies at the Highest Redshifts Richard McMahon Institute of Astronomy University of Cambridge, UK Crafoord Symposium, Stockholm, Sep 2005 Crafoord Symposium, Sept 2005

  2. Some Background Information • Main motivation is that objects at high redshift are ‘young’ due to the light travel time. e.g. we can ‘see’ objects that existed in the Universe before the Earth formed. • Quasars are the most luminous members of the Active Galactic Nuclei (AGN) family. • MB< -23 ; AGN light exceeds energy from host galaxy stellar light. • Quasars are intrinsically luminous bright beacons that are easier to observe that ‘normal’ galaxies like the Milky Way. Also ‘illuminate’ intervening material. i.e. IGM • Energy source is accretion of matter onto a super-massive black hole (107 to 109 Msol ) • Rees, 1984, ARA&A, 22, 471, ‘Black Hole Models for Active Galactic Nuclei’ • Recent observations have shown that most massive galaxies in the local Universe host super-massive black holes. The BH mass is correlated with the stellar bulge mass implies that the formation and evolution of BH and the stellar component in galaxies related (Magorrian et al, 1998; Ferrarese & Merrit, 2000; Gebhardt etal, 2000) • Rees, 1989, RvMA, 2, 1, ‘Is There a Massive Black Hole in Every Galaxy?’ • Radiative feedback from quasars may play a major role in formation and evolution of galaxies. Crafoord Symposium, Sept 2005

  3. Look Back Time matter, , H0 = 0.3, 0.7, 70 Formation of Solar System: ~5 Billion year ago (5Gyr) Crafoord Symposium, Sept 2005

  4. Highest Redshift History Quasars Galaxies Crafoord Symposium, Sept 2005

  5. Highest Redshift History “Gunn” Quasars Galaxies Crafoord Symposium, Sept 2005

  6. The Observational Challenges in surveys for surveys for high redshift objects • Experimentally difficult because: • Distant objects are very faint. • Rest frame UV radiation is red-shifted to regions of observed sky spectrum where night-time sky is bright. • Foreground objects are much more numerous so the experimental selection technique has to be very efficient. • May be undetectable, in a ‘reasonable’ amount of time using current technology; i.e. may need to wait or develop the technological solution. Crafoord Symposium, Sept 2005

  7. Basic observational principles in optical surveys for higher redshift quasars and galaxies • UV ‘drop-out’ due to: • Intrinsic or Intervening Neutral Hyrogen ‘Lyman limit’ at 912Å. • Intervening Lyman-a forest (<1216Å) • Emission line searches based on Lyman-(rest=1216Å) emission from ionized Hydrogen. Crafoord Symposium, Sept 2005

  8. 3C273 and z=3.62 comparison Crafoord Symposium, Sept 2005 Evolution of HI: 3C273 spectrum from HST/FOC z=0; z=3.6 QSO HIRES/Keck spectrum from M. Rauch

  9. z=4 Model Quasar +SDSS filter set Crafoord Symposium, Sept 2005

  10. Lyman- (rest=1216Å) Quasars at z 5 C,N,O,Si . Lyman- Forest z = 4.90, Schneider, Schmidt, Gunn, 1991, AJ, 98, 1951 z = 5.0, Fan with Guun, Lupton et al. 1999 (SDSS collaboration) Crafoord Symposium, Sept 2005

  11. z=5 quasar with SDSS filters Crafoord Symposium, Sept 2005

  12. z=6 quasar with SDSS filter set Crafoord Symposium, Sept 2005

  13. SDSS Surveys for z>5 Quasars Fan, et al. • Color selection of i-drop out quasars • At z>5.5, Lyα enters z-band  quasars have red i-z colour • Technical Challenges: • Rarest objects • One z~6 quasar every 500 deg2 • Key: contaminant elimination • Major contaminants are L and T type Brown Dwarfs  additional IR photometry Crafoord Symposium, Sept 2005

  14. SDSS compilation z>5.7 quasars Crafoord Symposium, Sept 2005

  15. ‘Edited’ Quasar compilation (pre-SDSS) Crafoord Symposium, Sept 2005

  16. Quasar compilation (now with SDSS) ? DR3QSO 50, 000 quasars Crafoord Symposium, Sept 2005

  17. Higher Redshift Quasar Surveys • Need to work in Infra-Red • Different detector technology • Sky ‘brightness’ problem • Two relevant projects • UK Infra Red Deep Sky Survey (UKIDSS) • WFCAM on UKIRT • Survey started in May 2005 • Pipeline Data processing centre(Cambridge+Edinburgh) • VISTA (will be an ESO telescope) (Surveys will start in early 2007?) Crafoord Symposium, Sept 2005

  18. The Night Sky Problem Broad band sky gets brighter as you go to redder wavelengths Crafoord Symposium, Sept 2005

  19. z=6 quasar (SDSS filter set) Crafoord Symposium, Sept 2005

  20. z=7 quasar (SDSS filter set) Crafoord Symposium, Sept 2005

  21. z=8 quasar (SDSS filter set) Crafoord Symposium, Sept 2005

  22. z=6 quasar (SDSS filter set + WFCAM) Crafoord Symposium, Sept 2005

  23. z=7 UKIDSS/VISTA Filters Crafoord Symposium, Sept 2005

  24. z=8 UKIDSS/VISTA Filters Crafoord Symposium, Sept 2005

  25. z=9 UKIDSS/VISTA Filters Crafoord Symposium, Sept 2005

  26. z=10 UKIDSS/VISTA Filters Crafoord Symposium, Sept 2005

  27. UK Infra Red Telescope (UKIRT) Wide Field Camera (WFCAM) • 3.6m telescope • Mauna Kea, Hawaii • 4x2048x2048 Hawaii II arrays • 0.4 arcsec pixels • 0.21 sq. degs / exposure • Not contiguous • Filters: • Z,Y,J,H,K,H2-S(1),Br-g Crafoord Symposium, Sept 2005

  28. Asembled WFCAM cryostat UKIRT Wide Field Cameraon Telescope Simulator WFCAM cryostat Crafoord Symposium, Sept 2005

  29. UKIDSS overview5 elements of UKIDSS(5-7 year duration) Crafoord Symposium, Sept 2005

  30. UKIDSS Science goals Cool Universe - Y brown dwarfs Obscured Universe - Galactic plane - reddened AGN, starbursts, EROs High-redshift Universe - 4000A break z>1; high redshift galaxy clusters - Quasars at z>6.5 Crafoord Symposium, Sept 2005

  31. Current Status of WFCAM+UKIDSS • Instrument started commissioning on-sky phase in Nov, 2004 • Science Verification started in April 2005 • UKIDSS Survey started in May, 2005 • Instrument taken off telecope in June, 2005 • As planned • Survey restarted end of Aug, 2005 • Should have 100deg2 of data by end of 2005 Crafoord Symposium, Sept 2005

  32. Visible and Infrared Survey Telescope for Astronomy • 4-m wide field survey telescope at European Southern Observatory (ESO) , Paranal near the VLT site. • Initially Infra Red camera only. (i.e. an IR SDSS) • 75% time for “large surveys”. (e.g. Southern SDSS) • UK project (consortium of 18 Universities; funded in 1999) • Principal Investigator Jim Emerson (QMUL, London) • Now part of UK ESO ‘late joining fee’. • Will become ESO facility on completion of construction and commissioning in late 2006. Crafoord Symposium, Sept 2005

  33. The ‘Heart of VISTA’; the IR focal plane: • 16 IR arrays, each 2048 x 2048; sparse filled mosaic; • 0.60 deg2 covered by detectors • 0.34 arcsec/pix. • 6 consecutive ‘offset’ pointings give a continuous region • 1.5deg by 1.0deg i.e. 1.5deg2 • every pixel covered by 2 pointings.

  34. Comparison of IR camera field sizes Moon! Crafoord Symposium, Sept 2005

  35. Dome – May 05 Crafoord Symposium, Sept 2005

  36. Summer 2005 Crafoord Symposium, Sept 2005

  37. Highest Redshift Galaxies Crafoord Symposium, Sept 2005

  38. Searches for higher redshift quasars and galaxies • UV ‘drop-out’ technique survey technique due to: • Intrinsic or Intervening ‘Lyman limit’ 912Å. • Intervening Lyman-a forest (<1216Å) • Emission line searches based on Lyman- emission from ionized Hydrogen. Crafoord Symposium, Sept 2005

  39. Highest Redshift History Quasars Galaxies Crafoord Symposium, Sept 2005

  40. High Redshift Lyman- emission lines surveys:Astrophysical principles for Success Partridge and Peebles, 1967, Are Young Galaxies visible? Minimum Flux limit • Previous surveysin the early 1990’s were based on the simple paradigm of a monolithic collapse. • expected star formation rates of 50-500 Msol yr-1 • i.e. the SCUBA/FIR Population? • Assume SFR detection limits more appropriate to a slowly forming disc or sub-galactic units in a halo • i.e. 1-3 Msol yr-1 • 1.0-2.0  10-17erg s-1 cm-2 at z=4 Minimum Volume • search a comoving volume within which you expect to find the progenitors of around 10 L* galaxies. (.i.e.~ Milky Way mass) • Local density 1.4±0.2  10-2 h50 Mpc-3 (e.g. Loveday etal, 1992) • minimum is 1000 Mpc3 Crafoord Symposium, Sept 2005

  41. Potential Narrow band filter locations 5.7 6.6 6.9 Crafoord Symposium, Sept 2005

  42. z=5.7 for Lyman- z=6.6 for Lyman- Crafoord Symposium, Sept 2005

  43. Basic experimental principle • Basic principle is to survey regions where the sky sky spectrum is darkest in between the intense airglow. • “Gaps in the OH airglow picket fence” • Lyman-alpha redshifts of gaps in “Optical-Silicon” CCD regime • 7400 Å; z=5.3 • 8120 Å; z=5.7; used extensively • 9200 Å; z=6.6; used extensively • 9600 Å; z=6.9; no results yet • CCDs have poor QE and sky relatively bright Crafoord Symposium, Sept 2005

  44. Summary of known spectroscopically confirmed z>6.0 galaxies Narrow Band Surveys • z>6.0; n=13 • from Hu et al. 2002(1), Kodeira et al. 2003(2), Rhoads et al 2004(1), Taniguchi et al. 2005(9) • z(max)=6.6 Other Surveys • 2 other z>6 emission line selected galaxies • Kurk et al, 2004(1); Stern etal, 2005(1) • Ellis etal, lensed search z=7 candidate (no line emission; photo-z) • i-drops Nagao et al, 2004(1); Stanway etal, 2004(1) • Quasars; SDSS n=5 (6.0< z<6.5) Crafoord Symposium, Sept 2005

  45. (observed; Lyman-)=9190Å (rest; Lyman-)=1216Å Redshift=6.558 Hu, etal, 2002 Crafoord Symposium, Sept 2005

  46. z=6.597 galaxy (Taniguchi et al, PASJ, 2005) • Survey: • Subaru 8.2m • Suprimecam 34’ x 27’; 0.2”/pixel • 132Å filter centred at 9196Å • Exposure time; 54,000 secs (15hrs) • Results • 58 candidates • 9 spectroscpoically confirmed with z=6.6 Crafoord Symposium, Sept 2005

  47. Composite spectrum of z=5.7 candidate galaxies z=0.6; unresolved and 4959 line [OIII]4959 [OIII](5007Å) z=1.2; note resolved doublet [OII](3727Å) z=5.7; note asymmetry n=18 galaxies Lyman-(1216Å) Hu, Cowie, Capak, McMahon, Hayashino, Komiyama, 2004, AJ, 127, 563 Crafoord Symposium, Sept 2005

  48. z~5.7 Lyman-(1216Å) emitters Observed wavelength (Angstroms) Crafoord Symposium, Sept 2005

  49. z~1.2 [OII]3727 doublet emitters Observed wavelength (Angstroms) Crafoord Symposium, Sept 2005

  50. The Night Sky Problem Broad band sky gets brighter as you go to redder wavelengths Crafoord Symposium, Sept 2005

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