skip to main content

Title: Patchy Kinetic Sunyaev–Zel’dovich Effect with Controlled Reionization History and Morphology

Using the novel semi-numerical code for reionization AMBER, we model the patchy kinetic Sunyaev–Zel’dovich (kSZ) effect by directly specifying the reionization history with the redshift midpointzmid, duration Δz, and asymmetryAz. We further control the ionizing sources and radiation through the minimum halo massMhand the radiation mean free pathλmfp. AMBER reproduces the free-electron number density and the patchy kSZ power spectrum of radiation–hydrodynamic simulations at the target resolution (1 Mpch−1) with matched reionization parameters. With a suite of (2 Gpc/h)3simulations using AMBER, we first constrain the redshift midpoint 6.0 <zmid< 8.9 using the Planck 2018 Thomson optical depth result (95% CL). Then, assumingzmid= 8, we find that the amplitude ofD=3000pkSZscales linearly with the duration of reionization Δzand is consistent with the 1σupper limit from South Pole Telescope (SPT) results up to Δz< 5.1 (Δzencloses 5%–95% ionization). Moreover, a shorterλmfpcan lead to a ∼10% lowerD=3000pkSZand a flatter slope in theD=3000pkSZΔzscaling relation, thereby affecting the constraints on Δzat= 3000. Allowingzmidandλmfpto vary simultaneously, we get spectra consistent with the SPT result (95% CL) up to Δz= 12.8 (butAz> 8 is needed to ensure the end of reionization beforez= 5.5). We show that constraints on the asymmetry require ∼0.1μk2measurement accuracy at multipoles other than= 3000. Finally, we find that the amplitude and shape of the kSZ spectrum are only weakly sensitive toMhunder a fixed reionization history and radiation mean free path.

more » « less
Award ID(s):
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
Date Published:
Journal Name:
The Astrophysical Journal
Page Range / eLocation ID:
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    The Abundance Matching Box for the Epoch of Reionization (AMBER) is a semi-numerical code for modeling the cosmic dawn. The new algorithm is not based on the excursion set formalism for reionization, but takes the novel approach of calculating the reionization-redshift fieldzre(x)assuming that hydrogen gas encountering higher radiation intensity are photoionized earlier. Redshift values are assigned while matching the abundance of ionized mass according to a given mass-weighted ionization fractionx¯i(z). The code has the unique advantage of allowing users to directly specify the reionization history through the redshift midpointzmid, duration Δz, and asymmetryAzinput parameters. The reionization process is further controlled through the minimum halo massMminfor galaxy formation and the radiation mean free pathlmfpfor radiative transfer. We implement improved methods for constructing density, velocity, halo, and radiation fields, which are essential components for modeling reionization observables. We compare AMBER with two other semi-numerical methods and find that our code more accurately reproduces the results from radiation-hydrodynamic simulations. The parallelized code is over four orders of magnitude faster than radiative transfer simulations and will efficiently enable large-volume models, full-sky mock observations, and parameter-space studies. AMBER will be made publicly available to facilitate and transform studies of the Epoch of Reionization.

    more » « less
  2. Abstract

    The mean free path of ionizing photons,λmfp, is a critical parameter for modeling the intergalactic medium (IGM) both during and after reionization. We present direct measurements ofλmfpfrom QSO spectra over the redshift range 5 <z< 6, including the first measurements atz≃ 5.3 and 5.6. Our sample includes data from the XQR-30 VLT large program, as well as new Keck/ESI observations of QSOs nearz∼ 5.5, for which we also acquire new [Cii] 158μm redshifts with ALMA. By measuring the Lyman continuum transmission profile in stacked QSO spectra, we findλmfp=9.331.80+2.06,5.401.40+1.47,3.311.34+2.74, and0.810.48+0.73pMpc atz= 5.08, 5.31, 5.65, and 5.93, respectively. Our results demonstrate thatλmfpincreases steadily and rapidly with time over 5 <z< 6. Notably, we find thatλmfpdeviates significantly from predictions based on a fully ionized and relaxed IGM as late asz= 5.3. By comparing our results to model predictions and indirectλmfpconstraints based on IGM Lyαopacity, we find that the evolution ofλmfpis consistent with scenarios wherein the IGM is still undergoing reionization and/or retains large fluctuations in the ionizing UV background well below redshift 6.

    more » « less
  3. Abstract

    We present thez≈ 6 type-1 quasar luminosity function (QLF), based on the Pan-STARRS1 (PS1) quasar survey. The PS1 sample includes 125 quasars atz≈ 5.7–6.2, with −28 ≲M1450≲ −25. With the addition of 48 fainter quasars from the SHELLQs survey, we evaluate thez≈ 6 QLF over −28 ≲M1450≲ −22. Adopting a double power law with an exponential evolution of the quasar density (Φ(z) ∝ 10k(z−6);k= −0.7), we use a maximum likelihood method to model our data. We find a break magnitude ofM*=26.380.60+0.79mag, a faint-end slope ofα=1.700.19+0.29, and a steep bright-end slope ofβ=3.841.21+0.63. Based on our new QLF model, we determine the quasar comoving spatial density atz≈ 6 to ben(M1450<26)=1.160.12+0.13cGpc3. In comparison with the literature, we find the quasar density to evolve with a constant value ofk≈ −0.7, fromz≈ 7 toz≈ 4. Additionally, we derive an ionizing emissivity ofϵ912(z=6)=7.231.02+1.65×1022ergs1Hz1cMpc3, based on the QLF measurement. Given standard assumptions, and the recent measurement of the mean free path by Becker et al. atz≈ 6, we calculate an Hiphotoionizing rate of ΓH I(z= 6) ≈ 6 × 10−16s−1, strongly disfavoring a dominant role of quasars in hydrogen reionization.

    more » « less
  4. Abstract

    Measurement of the largest angular scale (< 30) features of the cosmic microwave background (CMB) polarization is a powerful way to constrain the optical depth to reionization and search for the signature of inflation through the detection of primordialB-modes. We present an analysis of maps covering 73.6% of the sky made from the 40 GHz channel of the Cosmology Large Angular Scale Surveyor (CLASS) from 2016 August to 2022 May. Taking advantage of the measurement stability enabled by front-end polarization modulation and excellent conditions from the Atacama Desert, we show this channel achieves higher sensitivity than the analogous frequencies from satellite measurements in the range 10 << 100. Simulations show the CLASS linear (circular) polarization maps have a white noise level of125(130)μKarcmin. We measure the Galaxy-maskedEEandBBspectra of diffuse synchrotron radiation and compare to space-based measurements at similar frequencies. In combination with external data, we expand measurements of the spatial variations of the synchrotron spectral energy density (SED) to include new sky regions and measure the diffuse SED in the harmonic domain. We place a new upper limit on a background of circular polarization in the range 5 << 125 with the first bin showingD< 0.023μKCMB2at 95% confidence. These results establish a new standard for recovery of the largest-scale CMB polarization from the ground and signal exciting possibilities when the higher sensitivity and higher-frequency CLASS channels are included in the analysis.

    more » « less
  5. Abstract

    Strong lensing offers a precious opportunity for studying the formation and early evolution of super star clusters that are rare in our cosmic backyard. The Sunburst Arc, a lensed Cosmic Noon galaxy, hosts a young super star cluster with escaping Lyman continuum radiation. Analyzing archival Hubble Space Telescope images and emission line data from Very Large Telescope/MUSE and X-shooter, we construct a physical model for the cluster and its surrounding photoionized nebula. We confirm that the cluster is ≲4 Myr old, is extremely massiveM∼ 107M, and yet has a central component as compact as several parsecs, and we find a gas-phase metallicityZ= (0.22 ± 0.03)Z. The cluster is surrounded by ≳105Mof dense clouds that have been pressurized toP∼ 109K cm−3by perhaps stellar radiation at within 10 pc. These should have large neutral columnsNHI> 1022.8cm−2to survive rapid ejection by radiation pressure. The clouds are likely dusty as they show gas-phase depletion of silicon, and may be conducive to secondary star formation ifNHI> 1024cm−2or if they sink farther toward the cluster center. Detecting strong [Niii]λλ1750,1752, we infer heavy nitrogen enrichmentlog(N/O)=0.210.11+0.10. This requires efficiently retaining ≳500Mof nitrogen in the high-pressure clouds from massive stars heavier than 60Mup to 4 Myr. We suggest a physical origin of the high-pressure clouds from partial or complete condensation of slow massive star ejecta, which may have an important implication for the puzzle of multiple stellar populations in globular clusters.

    more » « less