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Radio astronomical probes of Cosmic Reionization and the 1 st luminous objects

Radio astronomical probes of Cosmic Reionization and the 1 st luminous objects Chris Carilli, NRL, April 2008. Brief introduction to cosmic reionization

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Radio astronomical probes of Cosmic Reionization and the 1 st luminous objects

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  1. Radio astronomical probes of Cosmic Reionization and the 1st luminous objects Chris Carilli, NRL, April 2008 • Brief introduction to cosmic reionization • Objects within reionization – recent observations of molecular gas, dust, and star formation, in the host galaxies of the most distant QSOs: early massive galaxy and SMBH formation • Neutral Intergalactic Medium (IGM) – HI 21cm telescopes, signals, and challenges USA – Carilli, Wang, Wagg, Fan, Strauss Euro – Walter, Bertoldi, Cox, Menten, Neri, Omont

  2. Ionized Neutral Reionized

  3. Chris Carilli (NRAO) Berlin June 29, 2005 WMAP – structure from the big bang

  4. Hubble Space Telescope Realm of the Galaxies

  5. Dark Ages • Last phase of cosmic evolution to be tested • Bench-mark in cosmic structure formation indicating the first luminous structures Cosmic Reionization

  6. Constraint I: Gunn-Peterson Effect z Barkana and Loeb 2001

  7. Constraint I: Gunn-Peterson Effect • End of reionization? • f(HI) <1e-4 at z= 5.7 • f(HI) >1e-3 at z= 6.3 Fan et al 2006

  8. Constraint II: CMB large scale polarization -- Thomson scattering during reionization • Scattering CMB local quadrapole => polarized • Large scale: horizon scale at reioniz ~ 10’s deg • Signal is weak: • TE ~ 10% TT • EE ~ 1% TT Hinshaw et al 2008 e = 0.084 +/- 0.016 ~ l/mfp ~l nee(1+z)^2

  9. Constraint II: CMB large scale polarization -- Thomson scattering during reionization • Rules-out high ionization fraction at z> 15 • Allows for finite (~0.2) ionization to high z • Most action occurs at z ~ 8 to 14 Dunkley et al. 2008

  10. Fan, Carilli, Keating ARAA 06 GP => First light occurs in ‘twilight zone’, opaque for obs <0.9 m • GP => pushing into near-edge of reionization at z ~ 6 • CMB pol => substantial ionization fraction persists to z ~ 11

  11. Radio observations of z ~ 6 QSO host galaxies • IRAM 30m + MAMBO: sub-mJy sens at 250 GHz + wide fields  dust • IRAM PdBI: sub-mJy sens at 90 and 230 GHz +arcsec resol. mol. Gas, C+ • VLA: uJy sens at 1.4 GHz  star formation • VLA: < 0.1 mJy sens at 20-50 GHz + 0.2” resol.  mol. gas (low order)

  12. Why QSOs? • Spectroscopic redshifts • Extreme (massive) systems MB < -26 => Lbol> 1e14 Lo MBH > 1e9 Mo • Rapidly increasing samples: z>4: > 1000 known z>5: > 100 z>6: 20 Fan 05

  13. Magorrian, Tremaine, Gebhardt, Merritt… QSO host galaxies – MBH -- Mbulge relation • Most (all?) low z spheroidal galaxies have SMBH: MBH=0.002 Mbulge • ‘Causal connection between SMBH and spheroidal galaxy formation’ • Luminous high z QSOs have massive host galaxies (1e12 Mo)

  14. MAMBO surveys of z>2 QSOs 2.4mJy • 1/3 of luminous QSOs have S250 > 2 mJy, independent of redshift from z=1.5 to 6.4 • LFIR ~ 1e13 Lo ~ 0.1 x Lbol Dust heating by starburst or AGN?

  15. Dust => Gas: LFIR vs L’(CO) z ~ 6 QSO hosts ~ Star formation 1e3 Mo/yr Index=1.5 1e11 Mo ~ Gas Mass • non-linear => increasing SF eff (SFR/Gas mass) with increasing SFR • FIR-luminous high z QSO hosts have massive gas reservoirs (>1e10 Mo) = fuel for star formation

  16. Pushing into reionization: QSO 1148+52 at z=6.4 • Highest redshift SDSS QSO (tuniv = 0.87Gyr) • Lbol = 1e14 Lo • Black hole: ~3 x 109 Mo (Willot etal.) • Gunn Peterson trough (Fan etal.)

  17. 1148+52 z=6.42: Dust detection MAMBO 250 GHz 3’ S250 = 5.0 +/- 0.6 mJy LFIR = 1.2e13 Lo Mdust =7e8 Mo Dust formation? • AGB Winds ≥ 1.4e9yr > tuniv = 0.87e9yr => dust formation associated with high mass star formation:Silicate gains (vs. eg. Graphite) formed in core collapse SNe (Maiolino 07)?

  18. 1148+5251 Radio to near-IR SED TD = 50 K Elvis SED Radio-FIR correlation • FIR excess = 50K dust • Radio-FIR SED follows star forming galaxy • SFR ~ 3000 Mo/yr

  19. 1148+52 z=6.42: Gas detection 46.6149 GHz CO 3-2 Off channels Rms=60uJy VLA IRAM • FWHM = 305 km/s • z = 6.419 +/- 0.001 • M(H2) ~ 2e10 Mo • Mgas/Mdust ~ 30 (~ starburst galaxies) VLA

  20. CO excitation ladder 2 NGC253 Dense, warm gas: CO excitation similar to starburst nucleus Tkin > 80 K nH2 ~ 1e5 cm^-3 MW

  21. J1148+52: VLA imaging of CO3-2 0.4”res rms=50uJy at 47GHz 1” 0.15” res • Separation = 0.3” = 1.7 kpc • TB = 35K => Typical of starburst nuclei, but scale is 10x larger CO extended to NW by 1” (=5.5 kpc)

  22. [CII] 158um fine structure line: dominant ISM gas cooling line [CII] traces PDRs associated with star formation

  23. [CII] 158um at z=6.4 • z>4 => FS lines redshift to mm band • L[CII] = 4x109 Lo (L[NII] < 0.1 L[CII]) • [CII] similar extension as molecular gas ~ 6kpc => distributed star formation • SFR ~ 6.5e-6 L[CII] ~ 3000 Mo/yr IRAM 30m [CII] [NII] 1” [CII] PdBI Walter et al. [CII] + CO 3-2

  24. Gas dynamics: Potential for testing MBH - Mbulge relation at high z -- mm lines are only direct probe of host galaxies Mdyn~ 4e10Mo Mgas~ 2e10 Mo Mbh ~ 3e9 Mo => Mbulge ~1e12 Mo (predicted) 1148+5251 z=6.42 z<0.5

  25. FIR - Lbol in QSO hosts Z~6 Low z IR QSOs: major mergers AGN+starburst? Low z Optical QSOs: early-type hosts Wang + 08, Hao 07 FIR luminous z ~ 6 QSO hosts follow relation establish by IR-selected QSOs at low z => (very) active star forming host galaxies?

  26. Downsizing: Building a giant elliptical galaxy + SMBH at tuniv < 1Gyr z=10 10.5 Li, Hernquist, Roberston.. • Multi-scale simulation isolating most massive halo in 3Gpc^3 (co-mov) • Stellar mass ~ 1e12 Mo forms in series (7) of major, gas rich mergers from z~14, with SFR ~ 1e3 - 1e4 Mo/yr • SMBH of ~ 2e9 Mo forms via Eddington-limited accretion + mergers • Evolves into giant elliptical galaxy in massive cluster (3e15 Mo) by z=0 8.1 6.5 • Rapid enrichment of metals, dust, molecules • Rare, extreme mass objects: ~ 100 SDSS z~6 QSOs on entire sky • Integration times of hours to days to detect HyLIGRs

  27. SMA The need for collecting area: lines cm telescopes: low order molecular transitions -- total gas mass, dense gas tracers , GBT (sub)mm: high order molecular lines. fine structure lines -- ISM physics, dynamics • FS lines will be workhorse lines in the study of the first galaxies with ALMA. • Study of molecular gas in first galaxies will be done primarily with cm telescopes ALMA will detect dust, molecular and FS lines in ~ 1 hr in ‘normal’ galaxies (SFR ~ 10 Mo/yr = LBGs, LAEs) at z ~ 6, and derive z directly from mm lines.

  28. The need for collecting area: continuum A Panchromatic view of galaxy formation Arp 220 vs z SMA cm: Star formation, AGN (sub)mm Dust, molecular gas Near-IR: Stars, ionized gas, AGN

  29. Cosmic Stromgren Sphere • Accurate host redshiftfrom CO: z=6.419+/0.001 Ly a, high ioniz lines: inaccurate redshifts (z > 0.03) • Proximity effect:photons leaking from 6.32<z<6.419 White et al. 2003 z=6.32 • ‘time bounded’ Stromgren sphere: R = 4.7 Mpc tqso = 1e5 R^3 f(HI)~ 1e7yrs or f(HI) ~ 1 (tqso/1e7 yr)

  30. Loeb & Rybicki 2000

  31. CSS: Constraints on neutral fraction at z~6 • Nine z~6 QSOs with CO or MgII redshifts:<R> = 4.4 Mpc • GP => f(HI) > 0.001 • If f(HI) ~ 0.001, then <tqso> ~ 1e4 yrs – implausibly short given QSO fiducial lifetimes (~1e7 years)? • Probability arguments + size evolution suggest: f(HI) > 0.05 Wyithe et al. 2005 Fan et al 2006 P(>xHI) 90% probability x(HI) > curve =tqso/4e7 yrs

  32. OI Fan, Carilli, Keating ARAA 2006 • Not ‘event’ but complex process, large variance: zreion ~ 14 to 6 • Good evidence for qualitative change in nature of IGM at z~6 ESO

  33. 3, integral measure? Geometry, pre-reionization? Local ionization? OI Abundance? Saturates, HI distribution function, pre-ionization? Local ioniz.? • Current probes are all fundamentally limited in diagnostic power • Need more direct probe of process of reionization ESO

  34. Studying the pristine neutral IGM using redshifted HI 21cm observations (100 – 200 MHz) 1e13 Mo • Large scale structure • cosmic density,  • neutral fraction, f(HI) • Temp: TK, TCMB, Tspin 1e9 Mo

  35. Experiments under-way: pathfinders 1% to 10% SKA LOFAR (NL) MWA (MIT/CfA/ANU) SKA 21CMA (China)

  36. Signal I: HI 21cm Tomography of IGM Furlanetto, Zaldarriaga + 2004 z=12 9 • TB(2’) = 10’s mK • SKA rms(100hr) = 4mK • LOFAR rms (1000hr) = 80mK 7.6

  37. Signal II: 3D Power spectrum analysis only LOFAR  + f(HI) SKA McQuinn + 06

  38. Signal III: Cosmic Web after reionization Ly alpha forest at z=3.6 ( < 10) Womble 96 • N(HI) = 1e13 – 1e15 cm^-2, f(HI/HII) = 1e-5 -- 1e-6 => before reionization N(HI) =1e18 – 1e21 cm^-2 • Lya ~ 1e7 21cm => neutral IGM opaque to Lya, but translucent to 21cm

  39. Signal III: Cosmic web before reionization: HI 21Forest 19mJy z=12 z=8 130MHz 159MHz • Perhaps easiest to detect • Only probe of small scale structure • Requires radio sources: expect 0.05 to 0.5 deg^-2 at z> 6 with S151 > 6 mJy? • radio G-P (=1%) • 21 Forest (10%) • mini-halos (10%) • primordial disks (100%)

  40. Signal IV: Cosmic Stromgren spheres around z > 6 QSOs • LOFAR ‘observation’: • 20xf(HI)mK, 15’,1000km/s • => 0.5 x f(HI) mJy • Pathfinders: Set first hard limits on f(HI) at end of cosmic reionization 5Mpc Wyithe et al. 2006 Prediction: first detection of HI 21cm signal from reionization will be via imaging rare, largest CSS, or absorption toward radio galaxy. 0.5 mJy

  41. Challenge I: Low frequency foreground – hot, confused sky Eberg 408 MHz Image (Haslam + 1982) Coldest regions: T ~ 100 (/200 MHz)^-2.6 K Highly ‘confused’: 1 source/deg^2 with S140 > 1 Jy

  42. Solution: spectral decomposition (eg. Morales, Gnedin…) • Foreground = non-thermal = featureless over ~ 100’s MHz • Signal = fine scale structure on scales ~ few MHz Signal/Sky ~ 2e-5 10’ FoV; SKA 1000hrs Cygnus A 500MHz 5000MHz • Simply remove low order polynomial or other smooth function • Xcorr/power spectral analysis in 3D – different symmetries in freq

  43. Challenge II: Ionospheric phase errors – varying e- content • TIDs – ‘fuzz-out’ sources • ‘Isoplanatic patch’ = few deg = few km • Phase variation proportional to ^2 • Solution: • Reionization requires only short baselines (< 1km) • Wide field ‘rubber screen’ phase self-calibration 15’ Virgo A VLA 74 MHz Lane + 02

  44. Challenge III: Interference 100 MHz z=13 200 MHz z=6 • Solutions -- RFI Mitigation (Ellingson06) • Digital filtering • Beam nulling • Real-time ‘reference beam’ • LOCATION!

  45. VLA-VHF: 180 – 200 MHz Prime focus X-dipole Greenhill, Blundell (SAO); Carilli, Perley (NRAO) Leverage: existing telescopes, IF, correlator, operations • $110K D+D/construction (CfA) • First light: Feb 16, 05 • Four element interferometry: May 05 • First limits: Winter 06/07

  46. Project abandoned: Digital TV KNMD Ch 9 150W at 100km

  47. RFI mitigation: location, location location… 100 people km^-2 1 km^-2 0.01 km^-2 Chippendale & Beresford 2007

  48. C.Carilli, A. Datta (NRAO/SOC), J. Aguirre (U.Penn) • Focus: Reionization (power spec,CSS,abs) • Very wide field: 30deg • Correlator: FPGA-based from Berkeley wireless lab • Staged engineering approach: GB05 8 stations  Boolardy08 32 stations

  49. PAPER: Staged Engineering • Broad band sleeve dipole + flaps • 8 dipole test array in GB (06/07) => 32 station array in WA (2008) to 256 (2009) • FPGA-based ‘pocket correlator’ from Berkeley wireless lab • S/W Imaging, calibration, PS analysis: AIPY + Miriad/AIPS => Python + CASA, including ionospheric ‘peeling’ calibration 100MHz 200MHz BEE2: 5 FPGAs, 500 Gops/s

  50. PAPER/WA -- 4 Ant, July 2007 RMS ~ 1Jy; DNR ~ 1e4 1e4Jy Parsons et al. 2008 CygA 1e4Jy

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