1 / 56

A hot topic: the 21cm line III

A hot topic: the 21cm line III. Benedetta Ciardi. MPA. Some terminology & quantities. Differential brightness temperature Maps are difficult to obtain  statistical quantities Power spectrum: Angular power spectrum:. Some terminology & quantities. depends on e.g.:

munin
Download Presentation

A hot topic: the 21cm line III

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A hot topic: the 21cm line III Benedetta Ciardi MPA

  2. Some terminology & quantities • Differential brightness temperature • Maps are difficult to obtain  statistical quantities • Power spectrum: • Angular power spectrum:

  3. Some terminology & quantities

  4. depends on e.g.: - underlying density distribution - ionized fraction - Lyalpha distribution - … Some terminology & quantities • Differential brightness temperature • Maps are difficult to obtain  statistical quantities • Power spectrum: • Angular power spectrum:

  5. Absorption prior to reionization (Loeb & Zaldarriaga 2004) Absorption of CMB flux prior to structure formation  density structure Angular power spectrum (Loeb & Zaldarriaga 2004; Ali, Bharadwaj & Panday 2005; Barkana & Loeb 2005a; Pillepich, Porciani & Matarrese 2007; Lewis & Challinor 2007)

  6. Absorption prior to reionization Absorption of CMB flux prior to structure formation  density structure Angular power spectrum Pb. Observations at frequencies <50MHz are extremely challenging (Loeb & Zaldarriaga 2004)

  7. Atmospheric visibility Hubble Spitzer Chandra Compton GRO T. Wilson

  8. Absorption prior to reionization Absorption of CMB flux prior to structure formation  density structure Angular power spectrum Pb. Observations at frequencies <50MHz are extremely challenging (Loeb & Zaldarriaga 2004)

  9. Determination of cosmological parameters If density fluctuations dominate 21cm fluctuations  cosmological parameters Errors on cosmological parameter estimates at z=8 McQuinn et al. 2006

  10. Determination of cosmological parameters If density fluctuations dominate 21cm fluctuations  cosmological parameters Errors on cosmological parameter estimates at z=8 McQuinn et al. 2006

  11. Determination of cosmological parameters If density fluctuations dominate 21cm fluctuations  cosmological parameters Errors on cosmological parameter estimates at z=10, 12 McQuinn et al. 2006

  12. Linear power spectrum Pure CDM CMD + baryons Pure baryons Mao & Wu 2007 z=6 Baryonic Acoustic Oscillations • Cosmological perturbations excite sound waves  acoustic peaks in CMB • Imprints also on the power spectrum of non relativistic matter  BAO Eistenstein & Hu 1998 Cooray & Sheth 2002

  13. Linear power spectrum Pure CDM CMD + baryons Pure baryons Mao & Wu 2007 z=6 Baryonic Acoustic Oscillations • Cosmological perturbations excite sound waves  acoustic peaks in CMB • Imprints also on the power spectrum of non relativistic matter  BAO

  14. Baryonic Acoustic Oscillations • Cosmological perturbations excite sound waves  acoustic peaks in CMB • Imprints also on the power spectrum of non relativistic matter  BAO • BAO has been observed in large galaxy surveys as SDSS and 2dF

  15. BAO detection: galaxy surveys SDSS

  16. BAO detection: galaxy surveys SDSS Ωm h²=0.12 0.13 0.14 no baryons Eisentein et al. 2005 Cole et al. 2005

  17. BAO detection: galaxy surveys 2dF

  18. Baryonic Acoustic Oscillations • Cosmological perturbations excite sound waves  acoustic peaks in CMB • Imprints also on the power spectrum of non relativistic matter  BAO • BAO has been observed in large galaxy surveys as SDSS and 2dF • Measurements of BAO  information on cosmological parameters

  19. 21cmA LOFAR Mao & Wu 2007 BAO detection: 21cm observations • BAO signature on matter power spectrum  21cm power spectrum Mao & Wu 2007; Wyithe, Loeb & Geil 2007

  20. BAO detection: 21cm observations • BAO signature on matter power spectrum  21cm power spectrum • 21cm galaxy survey

  21. Gravitational lensing • Mass deflect light  multiple images, magnification, de-magnification, distortion

  22. Gravitational lensing • Mass deflect light  multiple images, magnification, de-magnification, distortion Turner 2002

  23. NASA Gravitational lensing • Mass deflect light  multiple images, magnification, de-magnification, distortion

  24. Gravitational lensing • Mass deflect light  multiple images, magnification, de-magnification, distortion • If distortions very small  statistical analysis • Measurement of distortion  reconstruction of the foreground mass

  25. Gravitational lensing • Mass deflect light  multiple images, magnification, de-magnification, distortion • If distortions very small  statistical analysis • Measurement of distortion  reconstruction of the foreground mass • Measurements of LSS weak lensing done with galaxies as background sources • Use NIRB, CMB or 21cm as background sources (Cooray 04; Pen 04; Zhan & Zaldarraiga 06; Lu & Pen 07) • Advantage of 21cm: many more sources, many more z

  26. Gravitational lensing Metcalf & White 2007

  27. Gravitational lensing Metcalf & White 2008

  28. Gravitational lensing HI sources at z=12 Spaced based gal. survey zmed=1.23 Redshifts and virial masses Hilbert, Metcalf & White 2007 20'

  29. HI sources Spaced based galaxy survey Ground based galaxy survey No noise Noise Hilbert, Metcalf & White 2007

  30. Redshift Evolution of HI density 0.015 z=18 z=16 z=14 z=13 0.0 (BC, Stoehr & White 2003) z=10.5 z=10 z=12 z=11.5 z=9 z=9.5 z=8.5 z=8

  31. Distribution of 12.8 12.0 13.5 (BC & Madau 2003) 11.3 10.6 9.9 9.3 8.7 8.1 Maps of brightness temperature K

  32. Simulated Synthetic -1.4 -1 -1.6 -2 -3 -1.8 -4 -2.0 z=10.6, ν=122 MHz -5 -2.2 -1 -1.6 -1.8 -2 -3 -2.0 -2.2 -4 z=9.89, ν=130 MHz -2.4 -5 -1.6 -1 -1.8 -2 -2.0 -2.2 -3 -2.4 -4 -2.6 z=9.26, ν=138 MHz -5 -2.8 Expected response • Instrument sampling • Instrument sensitivity • Convolution with a Gaussian • beam (s=3 arcmin) LOFAR-type telescope could be able to map the IGM reionization history & distinguish between reionization sources Valdes et al. 2006

  33. Observation of HII regions of high-z QSOs Additional tool to study the IGM at z~6; estimate of nHI Wyithe, Loeb & Barnes 2005 (Zaroubi & Silk 2005; Chen & Miralda-Escude' 2006; Cen 2006; Rhook & Haehnelt 2007; Liu et al. 2007)

  34. Early Late Early Late CMB/21cm line correlation • CMB anisotropies are produced by free electrons • 21cm line is emitted by neutral hydrogen

  35. Characteristic angular scale of the cross-correlation function Early Mpc/h Late CMB/21cm line correlation We find an anti-correlation below a characteristic angular scale, θ0, when the correlation function becomes < 0. The characteristic angular scale of the cross-correlation function gives an estimate of the typical dimension of the HII regions at redshift of the 21cm emission line. Also correlation with galaxies? (Salvaterra et al. 2005; Alvarez et al. 2006; Holder et al. 2006; Adshead & Furlanetto 2007)

  36. Late Early (BC & Madau 2003) Fluctuations of brightness temp. • Late/Early reionization show similar behaviour • The peak of the emission is ~10 mK • Early reion. peaks @ 90MHz, late reion. peaks @ 115MHz Planned radio telescopes should be able to detect such signal (Madau et al. 1997; Ciardi & Madau 2003; Furlanetto et al. 2004; Zaldarriaga et al. 2004; Mellema et al. 2006; Santos et al. 2007)

  37. Absorption features in high-z radio sources • Luminous radio source  21cm absorption features

  38. Absorption features in high-z radio sources • Luminous radio source  21cm absorption features • DLAs

  39. Absorption features in high-z radio sources DLAs

  40. Absorption features in high-z radio sources • Luminous radio source  21cm absorption features • DLAs

  41. Absorption features in high-z radio sources • Luminous radio source  21cm absorption features • DLAs • Proto-galactic disks and mini-halos

  42. Absorption features in high-z radio sources Proto-galactic disks & mini-halos Furlanetto & Loeb 2002

  43. Absorption features in high-z radio sources • Luminous radio source  21cm absorption features • DLAs • Proto-galactic disks and mini-halos

  44. Absorption features in high-z radio sources • Luminous radio source  21cm absorption features • DLAs • Proto-galactic disks and mini-halos • IGM  21cm forest

  45. Absorption features in high-z radio sources 21cm forest

  46. IGM absorption from high-z radio source (GRB's afterglow, Ioka & Meszaros 2004) Additional information HI in the IGM (Carilli, Gnedin & Owen 2002; Carilli et al. 2004)

  47. Absorption features in high-z radio sources • Luminous radio source  21cm absorption features • DLAs • Proto-galactic disks and mini-halos • IGM  21cm forest Pb. Are there bright enough sources of radio radiation at high-z?

  48. High-z radio sources

  49. spin temperature statistical weight Masers • Population inversion  masers

  50. Masers • Population inversion  masers • A maser can boost the 21cm signal by order of magnitudes I(r) grows exponentially with r !!!

More Related