20050922 Crafoord Symposium

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Information about 20050922 Crafoord Symposium
Science-Technology

Published on August 29, 2007

Author: Mahugani

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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:  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. MBandlt; -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, ARAandamp;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 andamp; 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. Look Back Time:  Formation of Solar System: ~5 Billion year ago (5Gyr) Look Back Time matter, , H0 = 0.3, 0.7, 70 Highest Redshift History:  Highest Redshift History Galaxies Quasars Highest Redshift History:  Highest Redshift History Galaxies Quasars 'Gunn' The Observational Challenges in surveys for surveys for high redshift objects:  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. Basic observational principles in optical surveys for higher redshift quasars and galaxies:  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 (andlt;1216Å) Emission line searches based on Lyman-(rest=1216Å) emission from ionized Hydrogen. 3C273 and z=3.62 comparison:  3C273 and z=3.62 comparison Evolution of HI: 3C273 spectrum from HST/FOC z=0; z=3.6 QSO HIRES/Keck spectrum from M. Rauch z=4 Model Quasar +SDSS filter set:  z=4 Model Quasar +SDSS filter set Multi-colour Selection and discovery of z>4 Quasars (pre-SDSS):  Multi-colour Selection and discovery of zandgt;4 Quasars (pre-SDSS) Cambridge-APM Surveys See Storrie-Lombardi, Irwin, McMahon and Hook, 2001. n=49; zandgt;4 quasars 15, 000 deg2 Only two wavebands are needed. In practice this results in some(50%) contamination by M-stars Slide11:  z = 4.90, Schneider, Schmidt, Gunn, 1991, AJ, 98, 1951 z = 5.0, Fan with Guun, Lupton et al. 1999 (SDSS collaboration) Quasars at z  5 Lyman- Forest C,N,O,Si . Lyman- (rest=1216Å) z=5 quasar with SDSS filters :  z=5 quasar with SDSS filters z=6 quasar with SDSS filter set:  z=6 quasar with SDSS filter set SDSS Surveys for z>5 Quasars:  SDSS Surveys for zandgt;5 Quasars Color selection of i-drop out quasars At zandgt;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 Fan, et al. z>5.7 quasars:  zandgt;5.7 quasars Separating z~6 quasars and Brown Dwarfs Follow-up IR photometry quasar: z-J ~ 1 L to T dwarf stars z-J andgt; 2 Fan, Narayanan, Lutpon, Strauss et al. Zandgt;5.7 quasar SDSS compilation z>5.7 quasars:  SDSS compilation zandgt;5.7 quasars ‘Edited’ Quasar compilation (pre-SDSS):  ‘Edited’ Quasar compilation (pre-SDSS) Quasar compilation (now with SDSS):  ? Quasar compilation (now with SDSS) DR3QSO 50, 000 quasars Higher Redshift Quasar Surveys:  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?) The Night Sky Problem:  The Night Sky Problem Broad band sky gets brighter as you go to redder wavelengths z=6 quasar (SDSS filter set):  z=6 quasar (SDSS filter set) z=7 quasar (SDSS filter set):  z=7 quasar (SDSS filter set) z=8 quasar (SDSS filter set):  z=8 quasar (SDSS filter set) z=6 quasar (SDSS filter set + WFCAM) :  z=6 quasar (SDSS filter set + WFCAM) z=7 UKIDSS/VISTA Filters :  z=7 UKIDSS/VISTA Filters z=8 UKIDSS/VISTA Filters:  z=8 UKIDSS/VISTA Filters z=9 UKIDSS/VISTA Filters:  z=9 UKIDSS/VISTA Filters z=10 UKIDSS/VISTA Filters:  z=10 UKIDSS/VISTA Filters UK Infra Red Telescope (UKIRT) Wide Field Camera (WFCAM) :  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 UKIRT Wide Field Cameraon Telescope Simulator:  UKIRT Wide Field Camera on Telescope Simulator WFCAM cryostat UKIDSS overview5 elements of UKIDSS(5-7 year duration):  UKIDSS overview 5 elements of UKIDSS(5-7 year duration) UKIDSS Science goals:  UKIDSS Science goals Cool Universe - Y brown dwarfs Obscured Universe - Galactic plane - reddened AGN, starbursts, EROs High-redshift Universe - 4000A break zandgt;1; high redshift galaxy clusters - Quasars at zandgt;6.5 Current Status of WFCAM+UKIDSS:  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 Visible and Infrared Survey Telescope for Astronomy:  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. The ‘Heart of VISTA’; the IR focal plane::  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. Comparison of IR camera field sizes:  Comparison of IR camera field sizes Moon! Dome – May 05:  Dome – May 05 Summer 2005:  Summer 2005 Slide39:  Design Reference Programme (epoch 2001; ~ 400 clear nights) used for Project Planning ESO Survey Call for Proposal is being planned Z filter now included Highest Redshift Galaxies:  Highest Redshift Galaxies Searches for higher redshift quasars and galaxies:  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 (andlt;1216Å) Emission line searches based on Lyman- emission from ionized Hydrogen. Highest Redshift History:  Highest Redshift History Galaxies Quasars High Redshift Lyman- emission lines surveys:Astrophysical principles for Success:  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 Slide44:  Potential Narrow band filter locations 5.7 6.6 6.9 Slide45:  z=5.7 for Lyman- z=6.6 for Lyman- Basic experimental principle:  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 Summary of known spectroscopically confirmed z>6.0 galaxies:  Summary of known spectroscopically confirmed zandgt;6.0 galaxies Narrow Band Surveys zandgt;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 zandgt;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 (6.0andlt; zandlt;6.5) Slide48:  (observed; Lyman-)=9190Å (rest; Lyman-)=1216Å Redshift=6.558 Hu, etal, 2002 z=6.597 galaxy (Taniguchi et al, PASJ, 2005):  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 Composite spectrum of z=5.7 candidate galaxies:  Composite spectrum of z=5.7 candidate galaxies z=5.7; note asymmetry z=1.2; note resolved doublet z=0.6; unresolved and 4959 line [OIII]4959 Lyman-(1216Å) [OII](3727Å) [OIII](5007Å) n=18 galaxies Hu, Cowie, Capak, McMahon, Hayashino, Komiyama, 2004, AJ, 127, 563 z~5.7 Lyman-(1216Å) emitters:  z~5.7 Lyman-(1216Å) emitters Observed wavelength (Angstroms) z~1.2 [OII]3727 doublet emitters:  z~1.2 [OII]3727 doublet emitters Observed wavelength (Angstroms) The Night Sky Problem:  The Night Sky Problem Broad band sky gets brighter as you go to redder wavelengths Narrow band searches in the near Infrared :  Narrow band searches in the near Infrared OH lines contribute 95% of sky background in 1.0-1.7m range; i.e. 20 times the continuum emission. Filters need to have widths of 10Å or 0.1% to avoid OH lines. c.f. 100Å in the optical NB. Narrower band means you solve a smaller redshift range i.e. volume so wide field is needed. Some of the technical issues Filter design and manufacture Field angle shift of central wavelength Out of band blocking; Infrared OH Sky Observations: Mahaira etal, 1993, PASP:  Infrared OH Sky Observations: Mahaira etal, 1993, PASP GOOD NEWS The 1.0 to 1.8 micron IR sky is very dark between the OH lines which contain 95% of broad band background. THE NOT SO GOOD NEWS The narrowest gaps are narrower than in the optical; filter widths of 0.1 per cent are needed compared with 1% filters in optical. THIS IS A TECHNICAL CHALLENGE WE HAVE SOLVED; see Ian Parry’s talk Slide56:  Sky emission and absorption spectrum around 1.06 and 1.33 microns showing DAZLE filter pairs for Lyman  at z=7.7, 9.9; other gaps are at 8.8, 9.2 DAZLE – Dark Age Z Lyman Explorer McMahon, Parry, Bland-Hawthorn(AAO), Horton et al IR narrow band imager with OH discrimination at R=1000 i.e. 0.1% filter FOV 6.9  6.9 arcmin 2048 Rockwell Hawaii-II 0.2'/pixel Sensitivity: 2. 10-18 erg cm-2 sec-1(5), 10hrs on VLT i.e. ~1 M yr-1 at z=8; DAZLE: Digital state:  DAZLE: Digital state 3D CAD drawing of DAZLE Final Design on VLT UT3(Melipal) Visitor Focus Nasmyth Platform. UT3 optical axis is 2.5m above the platform floor grey shading shows the DAZLE cold room(-40C)which is 2.5m(l) x 1.75m(w) x 3m(h). Blue Dewar at top contains the 2048 x 2048 pixel IR detector Dazle in Cambridge Laboratory(Aug 2005):  Dazle in Cambridge Laboratory(Aug 2005) Refridgeration ‘Box’ Highest Redshift History:  Highest Redshift History Galaxies Quasars Quasar compilation (now with SDSS):  ? Quasar compilation (now with SDSS) DR3QSO 50, 000 quasars Some Future ground based surveys for higher redshift Galaxies and Quasars:  Some Future ground based surveys for higher redshift Galaxies and Quasars zandgt;7 galaxies Dark Ages ‘Z’ Lyman- Explorer (DAZLE) on the VLT (to start Jan 2006) zandgt;7 quasars UKIDSS: UK Intra-Red Deep Sky Survey (started May 2005; 5 year survey project) UKIRT (Hawaii) + WFCAM ESO members; Public Access from late 2005); Worldwide +18month VISTA Surveys (to start early 2007) FINAL SLIDE:  FINAL SLIDE

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