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Resolving the CIB: I) Methods to identify the sources responsible for the CIB

Resolving the CIB: I) Methods to identify the sources responsible for the CIB . Deciphering the CIB Banyuls 08/10/2012. Matthieu Béthermin CEA Saclay. The extragalactic background light (EBL). SED of the extragalactic background light ( from Dole & Béthermin, in prep .).

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Resolving the CIB: I) Methods to identify the sources responsible for the CIB

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  1. Resolving the CIB:I) Methods to identify the sources responsible for the CIB Deciphering the CIB Banyuls 08/10/2012 Matthieu BétherminCEA Saclay

  2. The extragalactic background light (EBL) SED of the extragalactic background light (from Dole & Béthermin, in prep.)

  3. Absolutemeasurements:need an absolutephotometry and an accurateremoving of the foregrounds. Upperlimits:derivedfrom the absorptions of TeV photons from the blazars by the COB/CIB. Lowerlimits:from the numbercounts and statistical analyses (stacking, P(D)). Measurements of the cosmic infrared background (CIB) level Total extrapolated contribution Direct counts Stacking Measurements of the cosmicinfrared background (from Béthermin+11, CRF proceeding)

  4. SUMMARY • ABSOLUTE MESUREMENTS OF THE CIB • UPPER LIMITS FROM OPACITY OF THE UNIVERSE TO TEV PHOTONS • LOWER LIMITS FROM DEEP SURVEY (AND SOME TECHNICAL STUFFS ABOUT SOURCE EXTRACTION AND COUNTS) • MORE STRINGENT LOWER LIMITS BY STACKING ANALYSIS • GO DEEPER WITH P(D) ANALYSIS

  5. ABSOLUTE MEASUREMENTS

  6. ABSOLUTE MEASUREMENTS OF THE CIB: The challenge of FOREGROUND SUBTRACTION

  7. ABSOLUTE MEASUREMENTS OF THE CIB: The challenge of FOREGROUND SUBTRACTION Spectral energy distribution of the background light (Matsuura+11).

  8. MODELS OF ZODIACAL EMISSION Sun Sun Earth Earth Sun Sun Earth Earth Model of zodiacal emission in the solar system (Kelsall+98)

  9. MODELS OF ZODIACAL EMISSION Model of zodiacal emission in the solar system (Kelsall+98)

  10. ABSOLUTE MEASUREMENTS OF THE CIB: The challenge of FOREGROUND SUBTRACTION

  11. SUBTRACTION OF THE GALACTIC CIRRUS EMISSIONS Correlation between HI column density and intensity at 100 microns in IRAS data (Lagache+00)

  12. SUBTRACTION OF THE GALACTIC CIRRUS EMISSIONS Decomposition of the HI emissivity into 3 components (Penin+12b, see also Miville-Deschênes+05)

  13. SUBTRACTION OF THE GALACTIC CIRRUS EMISSIONS Intermediate velocity cloud Local High velocity cloud Spatial distribution of HI clouds in ELAIS-N1 field (Pénin+12) From Miville-Deschênes+05

  14. SUBTRACTION OF THE GALACTIC CIRRUS EMISSIONS 100 microns IRAS map around ELAIS-N1: all component (left), model of cirrus (center), cirrus removed (right) (Pénin+12)

  15. UPPER LIMITS FROM HIGH ENERGY PHOTONS

  16. PHOTON-PHOTON SCATTERING TeV photon from blazar e- IR EBL photon e+ Cross section of the photon-photon interaction: Minimal energy of the IR photon for interaction: 2 (mec2)2/EΥ = 0.5 MeV2 /EΥ or λIR (microns) ≈ 0.6 EΥ (TeV) Details and references in e.g. Béthermin+11

  17. ABSORPTION OF BLAZAR TEV PHOTONS BY THE EBL 100 TeV 100 GeV 10 TeV 1TeV Spectral energy distribution of the extragalactic background light (Dole+06)

  18. Absorption of TEV PHOTONS ALONG A LINE OF SIGHT From Hess collaboration

  19. EFFECT ON BLAZAR SPECTRUMS Intrinsic Observed Observed and intrinsic TeV spectrum of a distant blazar (Aharaonian+06) Compilation of blazar spectra (Kneise&Dole 10)

  20. UPPER LIMITS ON EBL SED From Meyer+12

  21. LOWER LIMITS FROM DEEP SURVEYS

  22. Resolving the CIB Spitzer 24 microns

  23. Resolving the CIB Galaxy number counts at 24 microns (Béthermin+10a) Spitzer 24 microns

  24. Resolving the CIB Cumulative contribution of the IR galaxies to the CIB as a function of the flux cut (Béthermin+10a) Spitzer 24 microns

  25. SOURCE EXTRACTION: IN A VERY SIMPLIFIED CASE Let’s discuss this (over-?)simplified case: • The PSF is a Dirac (i.e. the flux of a source lies only in one pixel). • The source density is small (i.e. less than one source per pixel). • Constant Gaussian instrumental noise. The PDF of the signal (Smes) in pixel hosting a source with a flux Si is: The probability to detect a source for a threshold Sd is: The mean flux of the detected sources with an initial flux Si is:

  26. SOURCE EXTRACTION IN A VERY SIMPLIFIED CASE The mean flux of the detected sources with an initial flux Si is: The probability to detect a source for a threshold Sd is: Completeness for a 5sigma threshold Flux boosting (5 sigma threshold) Smes ≈ Si Smes ≈ Sd

  27. EMPIRICAL ESTIMATION OF COMPLETENESS AND FLUX BOOSTING IN A COMPLEXE CASE Step 1: inject few artificial sources in the real map Step 2: Rerun the extraction tool Step 3: compute the completeness from the fraction of recovered sources (and the flux boosting from their mean flux). Principle of source injection (from Morgan Cousin)

  28. Resolving the CIB: THE PROBLEM OF THE CONFUSION Spitzer 24 microns CIB 80% résolved (Béthermin+10a)

  29. Resolving the CIB: THE PROBLEM OF THE CONFUSION Spitzer 160 microns CIB 15% résolved (Béthermin+10a)

  30. Resolving the CIB: THE PROBLEM OF THE CONFUSION Herschel 160 microns CIB 70% résolved (Berta+10)

  31. Resolving the CIB: THE PROBLEM OF THE CONFUSION Herschel 500 microns CIB 6% résolved (Oliver+10)

  32. CONFUSION LIMIT 2 regimes Source density limited Fluctuation limited In general, when source density reaches 20 beams/sources Fluctuation due to faint sources:

  33. CONFUSION NOISE AND CONFUSION LIMIT 1-σ confusion noise (top) and confusion limit (bottom) as a function of wavelength for various diameters of telescopes (Béthermin+11)

  34. Using the 24 micron observations as a prior 24 microns Spitzer 250 microns Herschel

  35. Using the 24 micron observations as a prior 24 microns Spitzer 250 microns Herschel

  36. Using the 24 micron observations as a prior 24 microns Spitzer 250 microns Herschel

  37. Using the 24 micron observations as a prior 24 microns Spitzer 250 microns Herschel Principle of the PSF-fitting photometry using a prior on positions. Model fitted to the data This task can be performed with several codes: DAOPHOT, Starfinder, GALFIT, FASTPHOT…

  38. MORE STRINGENT LOWER LIMIT BY STACKING

  39. Using the 24 micron observations as a prior 24 microns Spitzer 250 microns Herschel

  40. Using the 24 micron observations as a prior 24 microns Spitzer 250 microns Herschel

  41. Using the 24 micron observations as a prior 24 microns Spitzer 250 microns Herschel

  42. STACKING: THE MOVIE Directed by Hervé Dole

  43. LOWER LIMIT OF THE CIB BY STACKING Spectral energy distribution of the CIB (Dole+06)

  44. LOWER LIMIT OF THE CIB BY STACKING Spectral energy distribution of the CIB (Dole+06)

  45. LOWER LIMIT OF THE CIB BY STACKING Lower limits to the CIB in the sub-mm derived by stacking in the BLAST data (Marsden+09)

  46. Counting the faintinfrared sources by stacking COUNTS AT 160 MICRONS Extragalactic number counts at 160 microns measured with Spitzer (Béthermin+10a)

  47. Counting the faintinfrared sources by stacking stacking COUNTS AT 160 MICRONS Extragalactic number counts at 160 microns measured with Spitzer (Béthermin+10a)

  48. CONTRIBUTION OF THE UNRESOLVED SOURCES TO THE CIB Cumulative contribution of the 160 microns sources to the CIB (Béthermin+10a)

  49. The clustering of the 24 microns sources biases the stacking results. This bias can be >20% with Spitzer at 160 microns and with BLAST Biases due to the clustering Simulation including the Simulation with clustering Effect of the clustering on the stacking(from Bavouzet's thesis)

  50. Correlation function and stacking - Results of a stacking with IAS method (see Nicolas Bavouzet thesis or the annexe B of Béthermin et al. 2010b) Biases due to clustering Auto-correlation of the stacked population Cross-correlation with other populations Radial profile of the results of a SPIRE stacking (Béthermin+12b)

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