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 1

• 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. – M B < -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 (10 7 to 10 9 M sol ) –

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.

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Look Back Time  matter ,   , H 0 = 0.3, 0.7, 70 Formation of Solar System: ~5 Billion year ago (5Gyr) 0 0.5

1.0

3.0

6.0

8.0

10

30 100 1000 Redshift Look back Time (Gyr) 0.0

5.0

7.7

11.4

12.5

12.8

13.0

13.4

13.45

13.46

Age of Universe 13.5 Gyr 8.5

5.7 Gyr 2.1 Gyr

915 Myr 630 Myr 460Myr

97 Myr 16 Myr 0.42 Myr Crafoord Symposium, Sept 2005 3

Highest Redshift History Quasars Galaxies Crafoord Symposium, Sept 2005 4

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

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 6

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.

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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 8

z=4 Model Quasar +SDSS filter set

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Lyman  (  rest =1216Å) Quasars at Lyman  Forest C,N,O,Si .

z

 5 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

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z=6 quasar with SDSS filter set

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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 deg 2 • Key:

contaminant elimination

– Major contaminants are L and T type

Brown Dwarfs



additional IR photometry

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SDSS compilation z>5.7 quasars

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‘Edited’ Quasar compilation (pre-SDSS)

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Quasar compilation (now with SDSS)

DR3QSO 50, 000 quasars Crafoord Symposium, Sept 2005 ?

18

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 19

The Night Sky Problem 4400 5500 6000 7500

8900 10,300

12,500 16,500 22,000 Crafoord Symposium, Sept 2005 22.1

21.3

20.4

19.0

18.0

17.0

16.0

14.0

13.0

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z=6 quasar (SDSS filter set) Crafoord Symposium, Sept 2005 21

z=7 quasar (SDSS filter set)

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z=8 quasar (SDSS filter set)

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z=6 quasar (SDSS filter set + WFCAM)

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z=7 UKIDSS/VISTA Filters

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z=8 UKIDSS/VISTA Filters

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z=9 UKIDSS/VISTA Filters

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z=10 UKIDSS/VISTA Filters

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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,H 2 -S(1),Br-g

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UKIRT Wide Field Camera on Telescope Simulator

Asembled WFCAM cryostat

WFCAM cryostat

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UKIDSS overview

5 elements of UKIDSS(5-7 year duration)

Sub-Survey Large Area Survey LAS Bands YJHK Limit (K) 18.4

Area deg 2 4000 night s 262 Deep Extragalactic Survey Ultra Deep Survey Galactic Plane Survey Galactic Clusters Survey DXS JK UDS JHK GPS JHK GCS JHK 21.0

23.0

19.0

18.7

35 0.77

1800 1600 118 296 186 84

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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

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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 100deg 2 of data by end of 2005 Crafoord Symposium, Sept 2005 33

V isible and I nfrared S urvey T elescope for A stronomy

• 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.

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The ‘Heart of VISTA’; the IR focal plane:

• 16 IR arrays, each 2048 x 2048; sparse filled mosaic; • 0.60 deg 2 covered by detectors • 0.34 arcsec/pix. - 6 consecutive ‘offset’ pointings give a continuous region - 1.5deg by 1.0deg i.e. 1.5deg

2 - every pixel covered by 2 pointings.

Comparison of IR camera field sizes Moon!

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Dome – May 05 Crafoord Symposium, Sept 2005 37

Summer 2005

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Highest Redshift Galaxies

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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.

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Highest Redshift History Quasars Galaxies Crafoord Symposium, Sept 2005 42

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 M – i.e. the SCUBA/FIR Population?

sol yr -1 Assume SFR detection limits more appropriate to a slowly forming disc or sub-galactic units in a halo – i.e. 1-3 M  sol yr -1

1.0-2.0



10 -17 erg 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

h

50 Mpc -3

minimum is 1000 Mpc 3

(e.g. Loveday etal, 1992) Crafoord Symposium, Sept 2005 43

Potential Narrow band filter locations 5.7

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6.6 6.9

44

z=5.7 for Lyman  Crafoord Symposium, Sept 2005 z=6.6 for Lyman  45

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 46

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 47

 (observed; Lyman  )=9190 Å  (rest; Lyman  )=1216 Å Redshift=6.558

Hu, etal, 2002 Crafoord Symposium, Sept 2005 48

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 redshift z AB i-z 9235Ang 6.597

26.49

>1.72

49

Composite spectrum of z=5.7 candidate galaxies [OIII]4959 n=18 galaxies z=0.6; unresolved and 4959 line [OIII](5007 Å) z=1.2; note resolved doublet [OII](3727 Å) z=5.7; note asymmetry Lyman  (1216 Å) Hu, Cowie, Capak, McMahon, Hayashino, Komiyama, 2004, AJ, 127, 563 Crafoord Symposium, Sept 2005 50

z~5.7 Lyman  (1216Å) emitters 51

z~1.2 [OII]3727 doublet emitters 52

The Night Sky Problem Broad band sky gets brighter as you go to redder wavelengths Waveband B V R I Z J H K Central Wavelength (Angstroms) 4400 5500 6000 7500 9000 12,500 16,500 21,000 ‘Dark’ Sky Brightness 22.1

21.3

20.4

19.0

18.0

16.0

14.0

13.0

Crafoord Symposium, Sept 2005 Redshift Lyman  (1216Å) 2.6

3.5

3.9

5.2

6.4

9.3

12.6

16.3

53

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; Crafoord Symposium, Sept 2005 54

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 Crafoord Symposium, Sept 2005 55

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 10hrs on VLT i.e. ~1 M  -2 sec -1 (5  ), yr -1 at z=8; 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 56

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 Crafoord Symposium, Sept 2005 57

Dazle in Cambridge Laboratory(Aug 2005) Refridgeration ‘Box’ Crafoord Symposium, Sept 2005 58

Highest Redshift History Quasars Galaxies Crafoord Symposium, Sept 2005 59

Quasar compilation (now with SDSS)

DR3QSO 50, 000 quasars Crafoord Symposium, Sept 2005 ?

60

Some Future ground based surveys for higher redshift Galaxies and Quasars

z>7 galaxies

• Dark Ages ‘Z’ Lyman  2006) Explorer (DAZLE) on the VLT (to start Jan

z>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) Crafoord Symposium, Sept 2005 61

FINAL SLIDE

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