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The Gemini Deep Deep Survey First Results Karl Glazebrook Johns Hopkins University

The Gemini Deep Deep Survey First Results Karl Glazebrook Johns Hopkins University.

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The Gemini Deep Deep Survey First Results Karl Glazebrook Johns Hopkins University

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  1. The Gemini Deep Deep Survey First Results Karl Glazebrook Johns Hopkins University GDDS Team: Karl Glazebrook (JHU), Bob Abraham (Toronto), Pat McCarthy (OCIW), Rick Murowinski (DAO), Ray Carlberg (Toronto), Ron Marzke SDSU), Sandra Savaglio (JHU), H-W Chen (OCIW), David Crampton (DAO), Isobel Hook (Oxford), Inger Jørgensen & Kathy Roth (Gemini)

  2. This talk • Current galaxy populations z<1 & z>2 • Evolution to z=1 of classical E/Sp • Lyman Break Galaxies (LBGs) at z>2 • The ‘redshift desert’ 1<z<2 • Why is it there? • What can we do about it? • Technical solution: ‘nod & shuffle’ • The Gemini Deep Deep Survey • Selection • Observations • Results

  3. The redshift desert n(z) Caltech FGRSCFRS R<24 LBGsR<25 Redshift What are these populations? ALL MAGSARE AB!`

  4. z<1 galaxies: SFR-z Measurements: Luminositydensities: Radio FIR Ha, Hb [OII] UV cuum (~2800Å) (1+z)3 (1+z)2 Slope allowed by local population synthesis‘cosmic spectrum’ 2dFGRS: Baldry et al. SDSS: Glazebrook et al. Orig. (1+z)4(Lilly et al. 1996)

  5. z<1 galaxies: morphology

  6. z<1 galaxies: morphological evolution z morphology Brinchmann et al. (1998,2000)

  7. z<1 galaxies: morphological evolution Brinchmann et al. 1998

  8. z<1 galaxies: morphological evolution ‘Stellar’Mass Massive galaxies in place at z=1Possible CDM contradictionWhat about z>1 ? Brinchmann et al. 2000

  9. z>2 galaxies: selection Populationappears R>23.5 Steidel et al.

  10. z>2 galaxies: morphology Opt. NIR Opt. NIR Irregular morphology (Dickinson et al.)When does Hubble Sequence form?

  11. z>2 galaxies: SFR-z • Data from low to high redshift: Lilly et al., Connoly et al., Madau et al., Steidel et al. • 1<z<2 filled in by photometric z’s • Dust corrections in z>2 Steidel et al. samples estimated from Hb/UV in a few galaxies. • Decline probably isn’t real. photo-z’s Steidel (1999)

  12. z>2 galaxies: masses Papovich, Dickinson, Ferguson (2001) K data at z=3 probes rest frame V - not ideal Optical + NIR photometry: best fit masses 109-1011M c.f. modern galaxies: 109-1012M ~ 10-20% of todays mass observed at z>2 ?

  13. Mass assembly SFR  Mass SFR  (1+z)3 z<1  (1+z)-1 z>1 = 0 z>5 17% SFR  (1+z)3 z<1 = const. 1 z>1 = 0 z>5 photo-z’s 27% Steidel (1999)

  14. The redshift desert Epoch of Mass assembly of galaxies? Formation of Hubble Sequence? n(z) Caltech FRSCFRSR<24 LBGsR<25 Redshift Cause ?

  15. Colors of current faint samples E/S0 Sbc SFR=const. Caltech FRS LBGs

  16. z=1.5 z=1 z=3 z=0 Why I: selection effect of redshift Galaxies especially elliptical galaxiesat z=1.5 are very faint! Very very hard to get good signal/noise spectra  detect weak absn lines  measure redshift Young stellar pop Old stellar pop

  17. z=0.5 z=1.5 z=1 Why II: sky background • Sky background is BRIGHT • NOISY Line emissionVARIES on 100s timescalesObjects are 100 fainterthan skySubtraction is very very hard Gemini Observatory Sky Spectrum 3500 4500 5500 6500 7500 8500 9500 10500 11500 Wavelength / Angstroms Optical + near-IR

  18. z~4 LBGs Steidel et al 1999I=24-25

  19. z=1.5 radio galaxies Model 53W091 R=24.8 I=23.5Keck/LRIS 20ksec ~3L* E. galaxy +53W069 Observed wavelength / Angstroms

  20. Simulated z=1.5 sub-L* elliptical Input Spectrum 53W069, + Poisson noise. 2800Å HK Simulated I=25 z=1.5early-type spectrum Exposure 100 ksecs(Gemini/GMOS) + 1% sky-subtraction error

  21. Technical solution: ‘nod & shuffle’ • Rapid nod of galaxy along slit (~60s) to give A/B images • Store B image adjacent to A, using CCD charge-shuffling - no readnoise penalty • History: • J.C. Cuillandre et al. 1994 ‘va et vient’ (NTT trials) • Sembach & Tonry 1996 (Dartmouth 2.4m) • Glazebrook & Bland-Hawthorn 1998 (AAT): • MOS mode (200 m-plex in HDF-S to R=23.4 • Demonstrate 10-4dsky/sky • 2001: Implemented on Gemini/GMOS

  22. A B A-B Sky cancellation: ‘nod and shuffle’ Storage of ‘sky’ image next to object image via ‘charge shuffling’Zero extra noise introduced, rapid switching (60s) Typically A=60s/15 cy: 1800s exposure10-3 subtraction

  23. Another example

  24. Gemini Deep Deep Survey GDDS Team: Karl Glazebrook (JHU), Bob Abraham (Toronto), Pat McCarthy (OCIW),Rick Murowinski (DAO), Ray Carlberg (Toronto), Ron Marzke (SDSU), Sandra Savaglio (JHU), H-W Chen (OCIW) David Crampton (DAO), Isobel Hook (Oxford), Inger Jørgensen & Kathy Roth (Gemini) Goal: Deep 100,000 sec MOS exposures on Las Campanas IR Survey fields to get redshifts of a complete K<22.4 I<25 sample covering 1<z<2

  25. Goals: • First Complete sample 1<z<2 • use photo-z’s to weed out low-z galaxies (BVRIzJHK) • Determine luminosity and mass functions • Can we see the assembly of mass? • Massive galaxies at z=2 would severely trouble CDM • Mass(z) more robust than SFR(z) • Relate to galaxy morphology (ACS) • Identify Ell/Sp/Irr over 1<z<2 • Track low-z behavior to high-z • E.g. can we see mass assembly of giant Ellipticals? • Can we track the dynamical evolution of spiral disks • Track SFH over 1<z<2: • Age of galaxies, metallicities of population

  26. GDDS history • Sep 2001: start of GDDS evil planning • Jan 2002: team approached Gemini observatory with nod & shuffle proposal • Feb 2002, obtained Gemini go-ahead. • Feb-May 2002. Implementation of N&S at DAO (~$10K cost) • May 2002: first N&S engineering observations on 8m • July 2002: N&S commissioned on sky • Aug 2002: First 4 nights of GDDS - Science Verification for N&S - success!! • Sep-Dec 2002: Band I queue time, 50 hrs

  27. Gemini + GMOS Gemini GMOS spectrograph Tel.+instr. efficiency GMOSLRISLDSS1 GMOS represents the best possible option for a red sensitive MOS. Ideal system for nod & shuffle

  28. Sky residuals SUMMED along long slit (1.8 arcmin) Cycle:A=60sB=60s + 25s o/head Raw Sky/20 Subtracted sky (i.e. ~10-3 level is enough for 200,000 sec pointed obs.)

  29. GDDS sample LCIRS4 fields BVRIzJHKs2626Limits:B<26.0 V<26.5R<26.8 I<25.8z<24.7 J<22.5H<22.5Ks<22.4 Use photo-z’s to weed out z<0.7 foreground I<25 typical model n(z):

  30. GDDS sample LCIRS K<20.3 sample + photo-z’s Red galaxies at high-z exist! Burstt=1t=2const. CNOC M* evol.

  31. GDDS mask 84 objects - 2 tiers with150 l/mm grating

  32. GDDS Spectra 77 objects 40,000 secs

  33. Example object: raw object+sky OH forest I=23.8

  34. Example object: N&S subtracted I=23.8 z=1.07 [OII] 3727at 7700Å

  35. GDDS: Oct 2002 snapshot • GDDS SV Aug 2002 + Band I Queue time (Sep/Oct 2002) Up to 100 ksec on first field (SA22) First 40 ksec now reduced and very preliminary redshifts • TO COME 2002-2003 (total time awarded 50 hrs in Band I): Complete 3 GDDS fields, secure 100 z>1 redshifts

  36. GDDS: ultra-super-preliminary results These are just the‘easy’ ones so far!~ 40 ksec Working on CCF Data on this field is still coming in. Full 100,000 secswill pound on z=1.5old red galaxies

  37. High Redshift Elliptical Galaxies? 53W091 at z=1.393V-I=2.2 I-K=2.94 Model: 4 Gyr old stellar populationat z=1.4, age of Universe = 4.5Gyrz(form) ≈10 Obj # 398 from GDDS SA22V-I=1.7 I-K=2.7 MgII fl FeII Rest-frame UV absorption line redshifts! Wavelength / Angstroms

  38. Accuracy of photo-z’s • First GDDS SA22field • Note: B data N/A for this one!! • Large scatter Not too bad z<0.7

  39. Colors of GDDS galaxies GDDS z=1.4 E/S0 template z=1.4 Sbc template HDF LBGs (Papovich et al. 2001)

  40. Color-z of GDDS galaxies E/S0 template At least halfway across the desert!! Again just the easy ones… Sbc template SFR=const. template

  41. GDDS: observed evolution? Ultra-super-duperpreliminary Large pinchof salt

  42. Determing IR luminosities: K correction Almost independent of spectral type for z<1.5, robust correction Old starburst SEDs

  43. IR luminosities of GDDS galaxies GDDS galaxies K<17.9 local sample(Glazebrook et al. 2003) M* z=0.1

  44. IR luminosities II GDDS galaxies z>1 K<17.9 local z<0.5 sample(Glazebrook et al. 2003) M* z=0.1 MK

  45. K<17.9 local z<0.5 sample(Glazebrook et al. 2003) K<17.9 local z<0.5 sample(Glazebrook et al. 2003) All GDDS galaxies Masses of GDDS galaxies

  46. Mass-Redshift relation K<17.9 local z<0.5 sample(Glazebrook et al. 2003) GDDS galaxies LBGs

  47. GDDS: summary • GDDS hits complete sample at z>1 • Photo-z selection z>1 ~works • Gets spectra via ‘nod & shuffle’ sky cancellation • Successfully commissioned July-Aug 2002, have data on first (half) field • Are we seeing a dearth of high mass galaxies at z>1 ? Possible epoch of mass assembly? • TO COME 2002-2003: Complete 3 GDDS fields, secure 100 redshifts Apply for HST/ACS imaging for morphologies Mass function vs Morphology vs z.

  48. z=1.4, I-K=2.7 GDDS: seeking old galaxies at z>1

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