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Suman Majumdar Department of Astronomy and Oskar Klein Centre Stockholm University Redshift Space Anisotropies in the EoR 21-cm Signal: what do they tell us about the sources of reionization?
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Collaborators o Hannes Jensen, Kai Yan Lee, Garrelt Mellema (Stockholm University, Sweden) o Kanan K. Datta (Presidency University, India) o Ilian T. Iliev (University of Sussex, UK) o Emma Chapman, Filipe Abdalla (University College London, UK) ……………………
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90
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Robertson et al., 2013, ApJ, 768, 1Mitra et al., 2012, MNRAS, 419, 2 Present constraints From WMAP, SPT, QSO, LAE/LBG,.....
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90 WHO? WHEN? HOW? !!A Murder Mystery!!
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90 HI 21-cm Radiation !!Time Travel!!
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GMRT MWA LOFAR SKA
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Direct Probe of Reionization Timing and duration of EoR Properties of EoR Sources IGM Properties Large scale distribution of HI Physical Processes involved 90 HI 21-cm Radiation !!Time Travel!!
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Probable first detection would be via --- “Variance” “Spherically Averaged Power Spectrum” Patil et al., 2014, MNRAS, 443, 2Pober et al., 2014, ApJ, 782, 2
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Redshift Space Distortion Line of Sight
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Redshift Space Distortion Line of Sight Real Space Redshift Space
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Redshift Space Distortion Line of Sight Real Space Redshift Space
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Power Spectrum in Redshift Space Observed power spectrum will be “anisotropic” (or LoS dependent). LoS θ k
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Power Spectrum in Redshift Space Effect of this anisotropy on the 21-cm power spectrum will be significant. LoS θ k o Bharadwaj and Ali, 2004, MNRAS, 352, 142 o Bharadwaj and Ali, 2005, MNRAS, 356, 4 o Barkana and Loeb, 2005, ApJL, 624, L65
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Power Spectrum in Redshift Space Considering the model with quasi-linear approximations ---- Mao et al., 2013, MNRAS, 2012, 422, 2
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Power Spectrum in Redshift Space Considering the model with quasi-linear approximations ---- Mao et al., 2013, MNRAS, 2012, 422, 2 Power Spectrum of Matter Density Field
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Power Spectrum in Redshift Space Considering the model with quasi-linear approximations ---- Mao et al., 2013, MNRAS, 2012, 422, 2 Power Spectrum of HI Density Field
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Power Spectrum in Redshift Space Considering the model with quasi-linear approximations ---- Mao et al., 2013, MNRAS, 2012, 422, 2 Cross-Power Spectrum of HI and Matter Density Field
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Power Spectrum in Redshift Space Jensen et al., 2013, MNRAS, 435, 1
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Power spectrum in Redshift Space Kaiser, N., 1987, MNRAS, 227, 1 Hamilton, A. J. S., 1992, APJL, 385, L5
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Legendre Polynomial Power spectrum in Redshift Space Kaiser, N., 1987, MNRAS, 227, 1 Hamilton, A. J. S., 1992, APJL, 385, L5
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Angular Multipoles Power spectrum in Redshift Space Kaiser, N., 1987, MNRAS, 227, 1 Hamilton, A. J. S., 1992, APJL, 385, L5
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Angular Multipoles Power spectrum in Redshift Space Kaiser, N., 1987, MNRAS, 227, 1 Hamilton, A. J. S., 1992, APJL, 385, L5
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Majumdar, Bhardwaj & Choudhury, 2013, MNRAS, 434, 3 Majumdar et al., 2014, MNRAS, 443, 4 Model with Quasi-linear Approximations
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Blessing in disguise!!! Redshift Space Distortions Barkana and Loeb, 2005, ApJL, 624, L65
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Monopole (l=0) and Quadrupole (l=2) Majumdar, Bhardwaj & Choudhury, 2013, MNRAS, 434, 3 Majumdar et al., 2014, MNRAS, 443, 4
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Monopole (l=0) and Quadrupole (l=2) Majumdar, Bhardwaj & Choudhury, 2013, MNRAS, 434, 3 Majumdar et al., 2014, MNRAS, 443, 4
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Monopole (l=0) and Quadrupole (l=2) Majumdar, Bhardwaj & Choudhury, 2013, MNRAS, 434, 3 Majumdar et al., 2014, MNRAS, 443, 4 Will these observables behave differently for different source models?
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Simulation o DM distribution: P 3 M N-body simulation o Box size: (714.28 Mpc) 3 o Minimum halo mass used: 2.02x10 9 M sun o 21-cm brightness temperature fields: Excursion set based semi-numerical formalism (on a 600 3 grid) o Assumption: T S >> T γ o All source models are tuned to have same reionization history (i.e. x HI vs z)
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Source Models o Fiducial: 100% UV (Global inside-out) o Clumping: Fiducial with approx. self shielding criteria o Hard X-ray dominated : x% UV + y% H o Soft X-ray dominated: x% UV + y% S o Hard+Soft X-ray: x% UV + y% H + z% S o Sources with power law response: No. of photons ∝ (halo mass) n o Sources of a limited halo mass range
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21-cm Maps in Redshift Space mK LoS FiducialClumpingUV 20%, H 80% UV 20%, S 80%UV 50%, S 40%, H 10% Pl = 3
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Monopole or Spherically avg. Power spectrum
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Quadrupole (l=2)
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Quadrupole (l=2)/ Monopole(l=0)
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P 2 -P 0 Phase Space Diagram
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Conclusions: o Even with the exactly same reionization history (x HI vs z) different source models will trace different trajectories in the phase space of P 2 – P 0. o However, the differences between the different trajectories (for some of the source models) compared to that of the fiducial model could be very small. o A significant contribution (≤50%) from a uniform ionizing background will be difficult to rule out from these measurements due to this degeneracy. o A huge (~80%) contribution from a uniform ionizing background should be easy to rule out. o Reionization driven by extremely massive sources will trace a uniquely different trajectory in this phase space than the fiducial model.
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감사합니다
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Reionization History
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Power Spectrum of the Signal P(k) = |A(k)| 2 k = 2Π/L
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Signal (in image plane)
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21-cm Line pe p e 21 cm 1420 MHz ν o = 1420 MHz/(1+z) λ o = 21 (1+z) cm
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90 HI 21-cm Radiation !!Time Travel!!
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Radio Interferometry “Visibility” = FT of Sky Brightness Temp.
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Radio Interferometry “Visibility” Signal NoiseForegrounds
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21-cm Brightness Tempereture Underlying Matter Density Field + State of the Hydrogen
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Underlying Matter Density Field + State of the Hydrogen Cosmology 21-cm Brightness Tempereture
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Underlying Matter Density Field + State of the Hydrogen Cosmology Astrophysics 21-cm Brightness Tempereture
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Underlying Matter Density Field + State of the Hydrogen Cosmology Astrophysics 21-cm Power Spectrum 21-cm Brightness Tempereture
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Comparison Cross-correlation with C 2 - RAY :- (in real space)
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