Detectability of 21cm-signal during the Epoch of Reionization with - PowerPoint PPT Presentation

Detectability of 21cm-signal during the Epoch of Reionization with 21cm-LAE cross-correlation Kenji Hasegawa (Nagoya U.) Kenji Kubota (Kumamoto U.) Shintaro Yoshimura (Kumamoto U.) Akio K. Inoue (Osaka Sangyo U.) and others based on KH et al., 2016, arXiv: 1603.01961 ATERUI@NAOJ CfCA Kubota, KH, et al., 2018, arXiv: 1708.06291 Yoshiura, KH, et al., 2018 arXiv: 1709.04168 Inoue, KH et al. 2018, arXiv: 1801.00067 Sakura CLAW @ The Univ. of Tokyo, 26-30th March, 2018

first stars (First) galaxies Recombination First Star IGM is & AGN Formation almost ionized. z~1100 formation? z~10-30 z~f6 z<10 d e e s s z r e i n e g o v CMB photons A I i n k U r a D • HI 21cm line : tracer of neutral hydrogen during the Epoch of Reionization (EoR) => Provides us with fruitful information on the reionization process •Difficulty: Intense foreground emission ~K >> EoR signal ~mK

21cm observation … 21cm-galaxy cross-correlation cross-power spectrum … → We expect the detection of 21cm signal. FG in 21cm is non-correlated with galaxy survey. 21cm signal is correlated with galaxy distribution. galaxy survey … We perform both 21cm observation and galaxy survey. 21cm-LAE cross correlation Map of HI 21cm signal Distribution of LAEs 160 140 120 100 80 60 40 20 0 0 20 40 60 80 100 120 140 160 ◎ Why cross correlation? δ 21 = δ 21sig + δ 21noise + δ 21FG δ gal = δ gal sig + δ gal noise + h δ 21FG δ gal sig i + h δ 21FG δ gal noise i h δ 21 δ gal i = h δ 21sig δ gal sig i + ∼ 0 ∼ 0 • Estimate the detectability of 21cm - LAE cross power spectrum(CPS). • Modeling reionization process and LAEs.

Reionization Simulation Two-Step Approach: 1) High resolution cosmological Radiation Hydrodynamics (RHD) simulation (radiative transfer is consistently coupled with hydrodynamics) in a (20Mpc) 3 box. (e.g., KH & Semelin, 2013, KH et al. 2016) • Properties of galaxies (e.g., intrinsic ionizing photon emissivity, Ly α Luminosity, escape fraction of ionizing photons as a function of halo mass). • Small-scale clumping factor in the IGM 2) Large-scale Radiative Transfer simulation (160Mpc) with the models of galaxies and clumping factor. (e.g., Kubota et al. 2018, Yoshimura et al. 2018) • Representative reionization history • Spatial Distributions of HI.

4096 3 particles for N -body (M h,min =2.5 × 10 7 M sun ) 256 3 grids for RT (dx=0.6Mpc)

Comparison : Simulations vs Observations Constraint by QSO spectra Thomson Opt. Depth Emissivity/1.5 Fiducial Emissivity × 1.5 Fan et al. 2006 Planck et al. 2016 • Our simulation well reproduces the observations. • ~factor 2 uncertainty in the ionizing photon emissivity is allowed to reproduce the observations. What about LAEs?

Distribution of Observable Ly α Emitting Galaxies From RHD simulation � M h � 1 . 1 L α , int ≈ 10 42 � [erg / s] , 10 10 M �

Distribution of Observable Ly α Emitting Galaxies From RHD simulation Ly α escape fraction : Parameter � M h � 1 . 1 L α , int ≈ 10 42 � L α , obs = f esc , α T α , IGM L α , int . [erg / s] , 10 10 M � Ray-tracing through the IGM (Yajima, Sugimura, KH+, 2018)

Modelling Ly α Emitting Galaxies Collaboration with a Subaru HSC project (SILVERRUSH) Inoue, KH, et al. 2018 • To reproduce observed Angular Correlation Function and Luminosity function, M halo -dependent escape fraction Ly α LF ( < τ > ∝ M halo1/3 ) with a large scatter is favored. • Ly α RT simulations (e.g., Yajima et al. 2014) show the similar trend. ACF (Obs data (red circles) from Ouchi et al. 2018) Transparrent IGM N HI = 10 20 cm -2

Preparation for estimating the detectability of the CPS HI 21cm signal estimated from our simulation SKA HSC FoV: ~25 [deg 2 ] Deep: 670 antennae within 1000m Total survey Area : 27 [deg 2 ] ~ 0.5 1000hrs observing time h -3 Gpc 3, Limiting Luminosity : 4.1 × 10 42 erg/s @z=6.6, redshift error =0.0007 w/ PFS =0.1 w/o PFS

detection limit σ g σ N sample variance Errors on the cross-power spectrum based on Furlanetto&Lidz(2007) µ =cos θ : angle between LOS and k Error on 21cm observation T 2 D 2 ∆ D � λ 2 � 2 , sys sample variance + thermal noise δ P 21 ( k , µ ) = P 21 ( k , µ ) + Bt int n ( k ⊥ ) A e Error on LAE survey δ P gal ( k , µ ) = P gal ( k , µ ) + n − 1 gal exp( k 2 ∥ σ 2 sample variance + shot noise*z error r ) , Error on the spherically averaged cross-power spectrum 2[ δ P 2 21 , gal ( k , µ )] = P 2 21 , gal ( k , µ ) + δ P 21 ( k , µ ) δ P gal ( k , µ ) . ∆ µ � k 3 V sur 1 1 � , = δ P 2 4 π 2 δ P 2 21 , gal ( k ) 21 , gal ( k , µ ) µ δ P 21,gal ( k ) = � P 2 σ A ( k ) ∝ 21 , gal + P 21 P gal + P 21 σ g + σ N P gal + σ N σ g .

z=6.6 red: simulated cross-power spectrum black: sensitivity SKA1 (1000h) ×HSC Detectability of 21cm-LAE CPS w/o FG � P 2 σ A ( k ) ∝ 21 , gal + P 21 P gal + P 21 σ g + σ N P gal + σ N σ g . variance = shaded detection limit = curve Expected errors on cross power spectrum(z=6.6) 10 3 10 2 10 1 21,gal |(mK) 10 0 | ∆ 2 10 -1 10 -2 signal(z=6.6,f HI =0.44) error(SKA-Deep+PFS) error(SKA-Deep) 10 -3 0.1 1 large scale<= =>Small scale k[Mpc -1 ] ・ SKA × HSC Deep is expected to detect the signal at large scales (k<0.5 Mpc -1 )

red: simulated cross-power spectrum blue: sensitivity w/ PFS black: sensitivity w/o PFS SKA1 (1000h) ×HSC z=6.6 Detectability of 21cm-LAE CPS w/o FG � P 2 σ A ( k ) ∝ 21 , gal + P 21 P gal + P 21 σ g + σ N P gal + σ N σ g . variance = shaded detection limit = curve Expected errors on cross power spectrum(z=6.6) 10 3 10 2 10 1 21,gal |(mK) 10 0 | ∆ 2 10 -1 10 -2 signal(z=6.6,f HI =0.44) error(SKA-Deep+PFS) error(SKA-Deep) 10 -3 0.1 1 large scale<= =>Small scale k[Mpc -1 ] ・ SKA × HSC Deep is expected to detect the signal at large scales (k<0.5 Mpc -1 ) ・ Spectroscopy by PFS enhances the detectability at small scales.

red: simulated cross-power spectrum blue: sensitivity w/ PFS black: sensitivity w/o PFS SKA1 (1000h) ×HSC z=6.6 Detectability of 21cm-LAE CPS w/o FG � P 2 σ A ( k ) ∝ 21 , gal + P 21 P gal + P 21 σ g + σ N P gal + σ N σ g . variance = shaded detecting limit = curves Expected errors on cross power spectrum(z=6.6) 10 3 10 2 10 1 21,gal |(mK) 10 0 | ∆ 2 10 -1 10 -2 signal(z=6.6,f HI =0.44) error(SKA-Deep+PFS) error(SKA-Deep) 10 -3 0.1 1 large scale<= =>Small scale k[Mpc -1 ] ・ SKA × HSC Deep is expected to detect the signal at large scales (k<0.5 Mpc -1 ) ・ Spectroscopy by PFS enhances the detectability at small scales ・ Behavior of the CPS at small scales is sensitive to the ionizing photon emissivities of LAEs (Kaneuji, KH; preliminary)

Diffuse emission Point sources Impact of Foreground Emission late model, no FG removal 10 5 MWA GLEAM catalogue Signal (Hurley-Walker+2017) Detection limit Total noise 10 4 Point source Modeled by J. Line Diffuse 21,gal [mK] 10 3 10 2 2 orders of ∆ 2 A parametric model of diffuse magnitude emission from our Galaxy 10 1 (Jelic et al 2008, Trott et al 2016) 10 0 1 k[ h Mpc -1 ] ・ The contribution from foreground does not vanish. ・ Foreground removal is still required for detecting the EoR 21cm signal, even in the case of CC analysis.

Summary • A two-step approach (RHD + large-scale post-processing radiative transfer) to simulate the large-scale cosmic reionization process • Modelling LAEs (Inoue, KH et al. 2018) M h -dependent Lya escape fraction is favored • PFS enhances the detectability of the 21cm-LAE CPS at low scales. (Kubota, KH et al. 2018) • Many efforts for foreground removal is required even in the case of the CPS measurement. (Yoshiura, KH et al. 2018)