The hyperfine transition of $^3$He$^+$ at 3.5cm has been thought as a probe of the high-z IGM since it offers a unique insight into the evolution of the helium component of the gas, as well as potentially give an independent constraint on the 21cm signal from neutral hydrogen. In this paper, we use radiative transfer simulations of reionization driven by sources such as stars, X-ray binaries, accreting black holes and shock heated interstellar medium, and simulations of a high-z quasar to characterize the signal and analyze its prospects of detection. We find that the peak of the signal lies in the range 1-50 $μ$K for both environments, but while around the quasar it is always in emission, in the case of cosmic reionization a brief period of absorption is expected. As the evolution of HeII is determined by stars, we find that it is not possible to distinguish reionization histories driven by more energetic sources. On the other hand, while a bright QSO produces a signal in 21cm that is very similar to the one from a large collection of galaxies, its signature in 3.5cm is very peculiar and could be a powerful probe to identify the presence of the QSO. We analyze the prospects of the signal's detectability using SKA1-mid as our reference telescope. We find that the noise power spectrum dominates over the power spectrum of the signal, although a modest S/N ratio can be obtained when the wavenumber bin width and the survey volume are sufficiently large.
We investigate the fraction of baryon mass in intergalactic medium ($f_\mathrm{IGM}$), using 18 well-localized FRBs in the redshift range $z\in (0.0039,0.66)$. We construct a five-parameter Bayesian inference model, with the probability distributions of dispersion measures (DM) of IGM and host galaxy properly taken into account. To check the possible redshift evolution, we parameterize $f_\mathrm{IGM}$ as a mildly evolving function of redshift, $f_\mathrm{IGM}=f_\mathrm{IGM,0}[1+αz/(1+z)]$. By simultaneously constraining five parameters, we get $f_\mathrm{IGM,0} = 0.92^{+0.06}_{-0.12}$ and $α=…
Arguably the best hope of understanding the tail end of the reionization of the intergalactic medium (IGM) at redshift z > 6 is through the detection and characterization of the Gunn-Peterson (GP) damping wing absorption of the IGM in bright quasar spectra. However, the use of quasar spectra to measure the IGM damping wing requires a model of the quasar's intrinsic Lyman-alpha emission line. Here we quantify the uncertainties in the intrinsic line shapes, and how those uncertainties affect the determination of the IGM neutral fraction. We have assembled a catalog of high-resolution HST spectra…
We continue our series of papers on intergalactic medium (IGM) tracers using quasi-stellar objects (QSOs), having examined gamma-ray bursts (GRBs) and blazars in earlier studies. We have estimated the IGM properties of hydrogen column density (Nhxigm), temperature and metallicity using XMM-Newton QSO spectra over a large redshift range, with a collisional ionisation equilibrium (CIE) model for the ionised plasma. The Nhxigm parameter results were robust with respect to intrinsic power laws, spectral counts, reflection hump and soft excess features. There is scope for a luminosity bias given bo…
Because the same massive stars that reionized the intergalactic medium (IGM) inevitably exploded as supernovae that polluted the Universe with metals, the history of cosmic reionization and enrichment are intimately intertwined. While the overly sensitive Ly-alpha transition completely saturates in a neutral IGM, strong low-ionization metal lines like the MgII 2796,2804 doublet will give rise to a detectable `metal-line forest' if the metals produced during reionization (Z ~ 10^{-3}Z_sol) permeate the neutral IGM. We simulate the MgII forest for the first time by combining a large hydrodynamic…
We study 21cm and Ly$\mathrmα$ fluctuations, as well as H$\mathrmα$, while distinguishing between Ly$\mathrmα$ emission of galactic, diffuse, and scattered intergalactic medium (IGM) origin. Cross-correlation information about the state of the IGM is obtained, testing neutral versus ionized medium cases with different tracers in a seminumerical simulation setup. In order to pave the way toward constraints on reionization history and modeling beyond power spectrum information, we explore parameter dependencies of the cross-power signal between 21$\,$cm and Ly$\mathrmα$, which displays a charact…
We present a study of the cosmological Ly$α$ emission signal at $z > 4$. Our goal is to predict the power spectrum of the spatial fluctuations that could be observed by an intensity mapping survey. The model uses the latest data from the HST legacy fields and the abundance matching technique to associate UV emission and dust properties with the halos, computing the emission from the interstellar medium (ISM) of galaxies and the intergalactic medium (IGM), including the effects of reionization, self-consistently. The Ly$α$ intensity from the diffuse IGM emission is 1.3 (2.0) times more intense …
We publish the survey for galaxies in 20 fields containing ultraviolet bright quasars (with z_em 0.1 to 0.5) that can be used to study the association between galaxies and absorption systems from the low-z intergalactic medium (IGM). The survey is magnitude limited (R~19.5 mag) and highly complete out to 10' from the quasar in each field. It was designed to detect dwarf galaxies (L ~ 0.1 L*) at an impact parameter rho 1Mpc (z=0.1) from a quasar. The complete sample (all 20 fields) includes R-band photometry for 84718 sources and confirmed redshifts for 2800 sources. This includes 1198 galaxies…
The epoch of first star formation and the state of the intergalactic medium (IGM) at that time are not directly observable with current telescopes. The radiation from those early sources is now part of the Cosmic Infrared Background (CIB) and, as these sources ionize the gas around them, the IGM plasma would produce faint temperature anisotropies in the Cosmic Microwave Background (CMB) via the thermal Sunyaev-Zeldovich (TSZ) effect. While these TSZ anisotropies are too faint to be detected, we show that the cross-correlation of maps of source-subtracted CIB fluctuations from {\it Euclid}, wit…
Using hydrodynamical simulations coupled to a radiative transfer code, we study the additional heating effects in the intergalactic medium (IGM) produced by $z\sim 6$ quasars in their near-zones. If helium is predominantly in HeII to begin with, both normalization ($T_0$) and slope ($γ$) of the IGM effective equation-of-state get modified by the excess ionization from the quasars. Using the available constraints on $T_0$ at $z\sim6$, we discuss implications for the nature and epoch of HI and HeII reionization. We study the extent of the HeIII region as a function of quasar age and show, for a …
We analyze the association of galaxies to Lya and OVI absorption, the most commonly detected transitions in the low-z intergalactic medium (IGM), in the fields of 14 quasars with z_em = 0.06-0.57. Confirming previous studies, we observe a high covering fraction for Lya absorption to impact parameter rho = 300kpc: 33/37 of our L>0.01L* galaxies show Lya equivalent width W_Lya>50mA. Galaxies of all luminosity L>0.01L* and spectral type are surrounded by a diffuse and ionized circumgalactic medium (CGM), whose baryonic mass is estimated at ~10^(10.5 +/- 0.3) Msun for a constant N_H. The virialize…
Probing Large-scale Structure and the Multi-Phase IGM at the Cosmic Noon -- Insights from a Joint Survey with Euclid, CSST, JPCam, and JUST
Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；Observatório Nacional（国家天文台）；University of Michigan（密歇根大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；School of Astronomy and Space Science, University of Chinese Academy of Sciences(UCAS)（中国科学院大学天文与空间科学学院）；Department of Astronomy, Tsinghua University（清华大学天文系）；Department of Physics, University of Milano-Bicocca（米兰比可卡大学物理系）；Shanghai Jiao Tong University（上海交通大学）
(Abridged) We present an imaging and spectroscopic survey of galaxies in fields around QSOs HE0226-4110, PKS0405-123, and PG1216+069. The fields are selected to have ultraviolet echelle spectra available, which uncover 195 Lya absorbers and 13 OVI absorbers along the three sightlines. We obtain robust redshifts for 1104 galaxies of rest-frame absolute magnitude M_R-5log h <~ -16 and at projected physical distances rho <~ 4 h^{-1} Mpc from the QSOs. HST/WFPC2 images of the fields around PKS0405-123 and PG1216+069 are available for studying the optical morphologies of absorbing galaxies. Combini…
We consider the possibility of the detection of $^3$HeII hyperfine line (rest frequency, $8.67 \, \rm GHz$) emission from ionized zones around accreting black holes (BHs) formed at high redshifts, $z=15\hbox{--}30$. We show that the brightness temperature in 8.67GHz line increases and reaches a peak value after the accretion onto the BH exhausts and HeIII recombines into HeII. This period of brightening last up to 40~million years. We find that during this period the maximum brightness temperature reaches $\simeq 0.2\hbox{--}0.5 μ$K, depending on the epoch when such a black hole starts growing…
QSO near-zones are an important probe of the the ionization state of the IGM at z ~ 6-7, at the end of reionization. We present here high-resolution cosmological 3D radiative transfer simulations of QSO environments for a wide range of host halo masses, 10$^{10-12.5}$ M_sun. Our simulated near-zones reproduce both the overall decrease of observed near-zone sizes at 6 < z < 7 and their scatter. The observable near-zone properties in our simulations depend only very weakly on the mass of the host halo. The size of the H II region expanding into the IGM is generally limited by (super-)Lyman Limit…
We present new absorption-line analysis and new galaxy survey data obtained for the field around PKS0405-123 at z=0.57. Combining previously known OVI absorbers with new identifications in the higher S/N UV spectra obtained with COS, we have established a sample of 7 OVI absorbers and 12 individual components at z=0.0918-0.495 along the sightline toward PKS0405-123. We complement the available UV absorption spectra with galaxy survey data that reach 100% completeness at projected distances rho<200 kpc of the quasar sightline for galaxies as faint as 0.1L* (0.2L*) out to redshifts of z=0.35 (z=…
Probing Direct Contributions of Galaxies and AGN to Cosmic Reionization in a Quasar Field J0226+0302 with JWST NIRCam and NIRSpec
University of Michigan（密歇根大学）；Steward Observatory, University of Arizona（亚利桑那大学斯图尔德天文台）；Cosmic Dawn Center (DAWN), Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所黎明中心）；Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学宇宙起源研究核心理论研究中心）；Center for Data-Driven Discovery, Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学宇宙起源研究核心理论中心数据驱动发现中心）；Department of Physics & Astronomy, University of California, Riverside（加州大学河滨分校物理与天文学系）
Extragalactic dispersion measures (DMs) obtained from observations of fast radio bursts (FRBs) are an excellent tool for probing intergalactic medium (IGM) and for conducting cosmography. However, the DM contribution from the IGM (${\rm DM_{IGM}}$) depends on the fraction of baryon mass in the IGM, $f_{\rm IGM}$, which is not properly constrained. As $f_{\rm IGM}(z)$ is geometrically related to the Hubble parameter $H(z)$ and ${\rm DM_{IGM}}(z)$, here we propose that combining two independent measurements of FRBs and $H(z)$ in similar redshift ranges provides a novel and cosmology-free method …
We explore the observability of the neutral hydrogen (HI) and the singly-ionized isotope helium-3 ($^3$HeII) in the intergalactic medium (IGM) from the Epoch of Reionization down to the local Universe. The hyperfine transition of $^3$HeII, which is not as well known as the HI transition, has energy splitting corresponding to 8 cm. It also has a larger spontaneous decay rate than that of neutral hydrogen, whereas its primordial abundance is much smaller. Although both species are mostly ionized in the IGM, the balance between ionization and recombination in moderately high density regions rende…
The recently discovered fast radio bursts (FRBs), presumably of extra-galactic origin, have the potential to become a powerful probe of the intergalactic medium (IGM). We point out a few such potential applications. We provide expressions for the dispersion measure and rotation measure as a function of redshift, and we discuss the sensitivity of these measures to the HeII reionization and the IGM magnetic field. Finally we calculate the microlensing effect from an isolate, extragalctic stellar-mass compact object on the FRB spectrum. The time delays between the two lensing images will induce c…
The ionization and thermal state of the intergalactic medium (IGM) during the epoch of reionization has been of interest in recent times because of their close connection to the first stars. We present in this paper a semi-numerical code which computes the large-scale temperature and ionized hydrogen fields in a cosmologically representative volume accounting for the patchiness in these quantities arising from reionization. The code is an extension to a previously developed version for studying the growth of ionized regions, namely, Semi Numerical Code for ReionIzation with PhoTon Conservation…
The unprecedentedly bright optical afterglow of GRB 130606A located by Swift at a redshift close to the reionization era (z = 5.913) provides a new opportunity to probe the ionization status of intergalactic medium (IGM). Here we present an analysis of the red Ly alpha damping wing of the afterglow spectrum taken by Subaru/FOCAS during 10.4-13.2 hr after the burst. We find that the minimal model including only the baseline power-law and HI absorption in the host galaxy does not give a good fit, leaving residuals showing concave curvature in 8400-8900 A with an amplitude of about 0.6% of the fl…
We use Swift blazar spectra to estimate the key intergalactic medium (IGM) properties of hydrogen column density(Nhxigm), metallicity and temperature over a redshift range of 0.03 leq z leq 4.7, using a collisional ionisation equilibrium(CIE) model for the ionised plasma. We adopted a conservative approach to the blazar continuum model given its intrinsic variability and use a range of power law models. We subjected our results to a number of tests and found that the Nhxigm parameter was robust with respect to individual exposure data and co-added spectra for each source, and between Swift and…
Probing the Cosmic Baryon Distribution and the Impact of Active Galactic Nuclei Feedback with Fast Radio Bursts in CROCODILE Simulation
The University of Osaka（大阪大学）；The University of Tokyo（东京大学）；University of Nevada, Las Vegas（内华达大学拉斯维加斯分校）；Zhejiang University（浙江大学）；Seoul National University（首尔大学）
Probing Reionization up to the Mark: The Marked Power Spectrum to unveil the HI 21-cm signal from the EoR
Indian Institute of Technology Indore（印度技术学院印多尔分校）；McGill University（麦吉尔大学）；INAF–Astronomical Observatory of Trieste（意大利国家天体物理研究所的里雅斯特天文台）；IFPU–Institute for Fundamental Physics of the Universe（宇宙基础物理研究所）
Probing Helium Reionization Through the $^{3}\mathrm{He}^{+}$ Hyperfine Transition Line
Ludwig-Maximilians-Universität München (LMU)（慕尼黑路德维希-马克西米利安大学）；Univ Lyon, Univ Lyon1, Ens de Lyon, CNRS, CRAL UMR5574（里昂大学）；Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学）
We compare a sample of five high-resolution, high S/N Ly$α$ forest spectra of bright $6<z \lesssim 6.5$ QSOs aimed at spectrally resolving the last remaining transmission spikes at $z>5$ with those obtained from mock absorption spectra from the Sherwood and Sherwood-Relics suites of hydrodynamical simulations of the intergalactic medium (IGM). We use a profile fitting procedure for the inverted transmitted flux, $1-F$, similar to the widely used Voigt profile fitting of the transmitted flux $F$ at lower redshifts, to characterise the transmission spikes that probe predominately underdense regi…
We present models of low- and high-ionization metal-line absorbers (O I, C II, C IV and Mg II) during the end of the reionization epoch, at z ~ 6. Using four cosmological hydrodynamical simulations with different feedback schemes (including the Illustris and Sherwood simulations) and two different choices of hydro-solver, we investigate how the overall incidence rate and equivalent width distribution of metal-line absorbers varies with the galactic wind prescription. We find that the O I and C II absorbers are reasonably insensitive to the feedback scheme. All models, however, struggle to repr…
We present constraints on both the kinetic temperature of the intergalactic medium (IGM) at z=8.4, and on models for heating the IGM at high-redshift with X-ray emission from the first collapsed objects. These constraints are derived using a semi-analytic method to explore the new measurements of the 21 cm power spectrum from the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER), which were presented in a companion paper, Ali et al. (2015). Twenty-one cm power spectra with amplitudes of hundreds of mK^2 can be generically produced if the kinetic temperature of the …
We consider cosmological implications of the formation of first stellar size black holes (BHs) in the universe. Such BHs form and grow by accretion in minihaloes of masses $\simeq 10^5-10^7~M_\odot$, and emit non-thermal radiation which impact the ionization and thermal state of the IGM. We compute the implications of this process. We show that the influence regions for hydrogen increase to 10kpc (physical length) for non-growing BHs to more than 0.3--1Mpc for accreting BHs, the influence regions are ten times smaller for singly ionized helium. We consider three possible observables from the i…
There are few data available with which to constrain the thermal history of the intergalactic medium (IGM) following global recombination. Thus far, most constraints flow from analyses of the Cosmic Microwave Background and optical spectroscopy along a few lines of sight. However, direct study of the IGM in emission or absorption against the CMB via the 1S hyperfine transition of Hydrogen would enable broad characterization thermal history and source populations. New generations of radio arrays are in development to measure this line signature. Bright foreground emission and the complexity of …
The discovery of fast radio bursts (FRBs) about a decade ago opened up new possibilities for probing the ionization history of the Intergalactic Medium (IGM). In this paper we study the use of FRBs for tracing the epoch of HeII reionization, using simulations of their dispersion measures. We model dispersion measure contributions from the Milky Way, the IGM (homogeneous and inhomogeneous) and a possible host galaxy as a function of redshift and star formation rate. We estimate the number of FRBs required to distinguish between a model of the Universe in which helium reionization occurred at z …
We explore high-redshift gamma-ray bursts (GRBs) as promising tools to probe pre-galactic metal enrichment. We utilize the bright afterglow of a Pop III GRB exploding in a primordial dwarf galaxy as a luminous background source, and calculate the strength of metal absorption lines that are imprinted by the first heavy elements in the intergalactic medium (IGM). To derive the GRB absorption line diagnostics, we use an existing highly-resolved simulation of the formation of a first galaxy which is characterized by the onset of atomic hydrogen cooling in a halo with virial temperature >10^4 K. We…
The inhomogeneous cosmological reionization process leaves tangible imprints in the intergalactic medium down to z=4-5. The Lyman-alpha forest flux power spectrum provides a potentially powerful probe of the epoch of reionization. With the existing SDSS I/II quasar sample we show that two cosmological reionization scenarios, one completing reionization at z=6 and the other at z=9, can be distinguished at ~7 sigma level by utilizing Lyman alpha forest absorption spectra at z=4.5+-0.5, in the absence of other physical processes that may also affect the Lyman alpha flux power spectrum. The redshi…
We present new constraints on the 21cm Epoch of Reionization (EoR) power spectrum derived from 3 months of observing with a 32-antenna, dual-polarization deployment of the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) in South Africa. In this paper, we demonstrate the efficacy of the delay-spectrum approach to avoiding foregrounds, achieving over 8 orders of magnitude of foreground suppression (in $\textrm{mK}^2$). Combining this approach with a procedure for removing off-diagonal covariances arising from instrumental systematics, we achieve a best 2-sigma uppe…
The redshifted 21-cm radiation from the atomic hydrogen (HI) provides an excellent direct probe to study the evolution of HI in IGM and thus reveal the nature of the first luminous objects, their evolution and role during Cosmic Dawn (CD) and Epoch of Reionization (EoR), and formation and evolution of the structures thereafter. Direct mapping of the HI density during the CD-EoR is rather difficult with the current and future instruments due to large foreground and other observational contamination. The first detection of this redshifted HI signal is planned through statistical estimators. Give…
We measure the intergalactic medium (IGM) opacity in the Ly$α$ as well as in the Ly$β$ forest along $19$ quasar sightlines between $5.5\lesssim z_{\rm abs}\lesssim 6.1$, probing the end stages of the reionization epoch. Owing to its lower oscillator strength the Ly$β$ transition is sensitive to different gas temperatures and densities than Ly$α$, providing additional constraints on the ionization and thermal state of the IGM. A comparison of our measurements to different inhomogeneous reionization models, derived from post-processing the Nyx cosmological hydrodynamical simulation to include sp…
Probing ionized bubbles around luminous sources during reionization with SKA 21-cm observations
Jadavpur University（贾达普大学）；Indian Institute of Technology Indore（印度印多尔理工学院）；The Open University of Israel（以色列开放大学）；Indian Institute of Technology Madras（印度马德拉斯理工学院）
The Epoch of Reionization (EoR) is the epoch in which hydrogen in the Universe reionize after the "Dark Ages". This is the second of two major phase transitions that hydrogen in the Universe underwent, the first phase being the recombination era in which hydrogen became neutral at redshift about 1100. The EoR, occurs around z of 10 and is probably caused by the first radiation emitting astrophysical sources, hence it is crucial to our understanding of when and how the Universe "decided" to start forming astrophysical objects and how that influenced subsequent structure formation in the Univers…
We propose a method of measuring extremely weak magnetic fields in the intergalactic medium prior to and during the epoch of cosmic reionization. The method utilizes the Larmor precession of spin-polarized neutral hydrogen in the triplet state of the hyperfine transition. This precession leads to a systematic change in the brightness temperature fluctuations of the 21-cm line from the high-redshift universe, and thus the statistics of these fluctuations encode information about the magnetic field the atoms are immersed in. The method is most suited to probing fields that are coherent on large …
We have detected narrow HI 21cm and CI absorption at $z \sim 1.4 - 1.6$ towards Q0458$-$020 and Q2337$-$011, and use these lines to test for possible changes in the fine structure constant $α$, the proton-electron mass ratio $μ$, and the proton gyromagnetic ratio $g_p$. A comparison between the HI 21cm and CI line redshifts yields $ΔX/X = [+6.8 \pm 1.0] \times 10^{-6}$ over $0 < <z> \le 1.46$, where $X = g_p α^2/μ$, and the errors are purely statistical, from the gaussian fits. The simple line profiles and the high sensitivity of the spectra imply that statistical errors in this comparison are…
One of the major science goals of the Square Kilometre Array (SKA) is to understand the role played by atomic hydrogen (HI) gas in the evolution of galaxies throughout cosmic time. The hyperfine transition line of the hydrogen atom at 21-cm is one of the best tools to detect and study the properties of HI gas associated with galaxies. In this article, we review our current understanding of HI gas and its relationship with galaxies through observations of the 21-cm line both in emission and absorption. In addition, we provide an overview of the HI science that will be possible with SKA and its …
We model the 21-cm signal and LAE population evolution during the epoch of reionization in order to predict the 21cm-LAE cross-power spectrum. We employ high-dynamic-range simulations of the IGM to create models that are consistent with constraints from the CMB, Lyman-$α$ forest and LAE population statistics. Using these models we consider the evolution of the cross-power spectrum for a selection of realistic reionization histories and predict the sensitivity of current and upcoming surveys to measuring this signal. We find that the imprint of a delayed-end to reionization can be observed by f…
Detecting the signature of helium reionization through 3HeII 3.46cm line-intensity mapping
Heidelberg University（海德堡大学）；Universität Bonn, Argelander-Institut für Astronomie（波恩大学阿根兰德天文学研究所）；SISSA, International School for Advanced Studies（国际高等研究院）；Università di Trieste（的里雅斯特大学）；IFPU, Institute for Fundamental Physics of the Universe（宇宙基础物理研究所）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学 Kavli 宇宙粒子与天体物理学研究所）；Aix Marseille Univ, CNRS, CNES, LAM（艾克斯-马赛大学）；INAF – Astronomical Observatory of Trieste（意大利国家天体物理研究所的里雅斯特天文台）
We examine the statistics of the low-redshift Ly-alpha forest in an adaptive mesh refinement hydrodynamic cosmological simulation of sufficient volume to include distinct large-scale environments. We compare our HI column density distribution of absorbers both with recent work and between two highly-refined regions of our simulation: a large-scale overdensity and a large-scale underdensity (on scales of approximately 20 Mpc). We recover the average results presented in Kollmeier et al. (2014) using different simulation methods. We further break down these results as a function of environment t…
In the most distant reaches of the Universe, the 21-cm hyperfine transition in neutral hydrogen provides one of the only available tracers of large-scale structure. A number of instruments have been working and planned to measure the 21-cm line signals, and in particular, Experiment to Detect the Global EoR Signature (EDGES) recently has reported the first detection of an absorption signal, which corresponds to the 21-cm line global signal at the epoch of reionization (EoR). The future large radio telescope, Square Kilometre Array (SKA) will be able to deliver the high-precision measurement of…
We present composite spectra constructed from a sample of 242,150 Lyman-alpha (Lya) forest absorbers at redshifts 2.4<z<3.1 identified in quasar spectra from the Baryon Oscillation Spectroscopic Survey (BOSS) as part of Data Release 9 of the Sloan Digital Sky Survey III. We select forest absorbers by their flux in bins 138 km/s wide (approximately the size of the BOSS resolution element). We split these absorbers into five samples spanning the range of flux -0.05 < F<0.45. Tests on a smaller sample of high-resolution spectra show that our three strongest absorption bins would probe circumgalac…
Due to their long mean free paths, X-rays are expected to have many significant impacts globally on the properties of the intergalactic medium (IGM) by their heating and ionizing processes on large scales. At high redshifts, X-rays from Population (Pop) III binaries might have important effects on cosmic reionization and the Lyman alpha forest. As a continuation of our previous work on Pop III binary X-rays (Xu et al. 2014), we use the Pop III distribution and evolution from the Renaissance Simulations, a suite of self-consistent cosmological radiation hydrodynamics simulations of the formatio…
