We study the effects of galaxy formation physics on the magnetization of the intergalactic medium (IGM) using the IllustrisTNG simulations. We demonstrate that large-scale regions affected by the outflows from galaxies and clusters contain magnetic fields that are several orders of magnitude stronger than in unaffected regions with the same electron density. Moreover, like magnetic fields amplified inside galaxies, these magnetic fields do not depend on the primordial seed, i.e. the adopted initial conditions for magnetic field strength. We study the volume filling fraction of these strong field regions and their occurrence in random lines of sight. As a first application, we use these results to put bounds on the photon-axion conversion from spectral distortion of the CMB. As photon-axion coupling grows with energy, stronger constraints could potentially be obtained using data on the propagation of gamma-ray photons through the IGM. Finally, we also briefly discuss potential applications of our results to the Faraday Rotation measurements.
Previously derived Faraday rotation constraints on the volume-filling intergalactic magnetic field (IGMF) have used analytic models that made a range of simplifying assumptions about magnetic field evolution in the intergalactic medium and did not consider the effect of baryonic feedback on large-scale structures. In this work we revise existing Faraday rotation constraints on the IGMF using a numerical model of the intergalactic medium from the IllustrisTNG cosmological simulation that includes a sophisticated model of the baryonic feedback. We use the IllustrisTNG model to calculate the rota…
Fast radio bursts (FRBs) are millisecond-duration radio transients and can be used as a cosmological probe. However, the dispersion measure (DM) contributed by intergalactic medium (IGM) is hard to be distinguished from other components. In this paper, we use the IllustrisTNG simulation to realistically estimate the $DM_{\rm IGM}$ up to $z\sim 9$. We find $DM_{\rm IGM} = 892^{+721}_{-270}$ pc cm$^{-3}$ at $z=1$. The probability distribution of $DM_{\rm IGM}$ can be well fitted by a quasi-Gaussian function with a long tail. The tail is caused by the structures along the line of sight in IGM. Su…
We study the generation of intergalactic magnetic fields in two models for first-order phase transitions in the early Universe that have been studied previously in connection with the generation of gravitational waves (GWs): the Standard Model supplemented by an $|H|^6$ operator (SM+$H^6$) and a classically scale-invariant model with an extra gauged U(1) $B - L$ symmetry (SM$_{B-L}$). We consider contributions to magnetic fields generated by bubble collisions and by turbulence in the primordial plasma, and we consider the hypotheses that helicity is seeded in the gauge field or kinetically. We…
Galactic outflows driven by star formation and active galactic nuclei blow bubbles into their local environments, causing galactic magnetic fields to be carried into intergalactic space. We explore the redshift-dependent effect of these magnetized bubbles on the Faraday Rotation Measure (RM) of extragalactic radio sources. Using the IllustrisTNG cosmological simulations, we separate the contribution from magnetic bubbles from that of the volume-filling magnetic component expected to be due to the seed field originating in the Early Universe. We use this separation to extract the redshift depen…
The Square Kilometer Array is expected to provide the first tomographic observations of the neutral intergalactic medium at redshifts z>6 and pinpoint the locations of individual ionized bubbles during early stages of cosmic reionization. In scenarios where star-forming galaxies provide most of the ionizing photons required for cosmic reionization, one expects the first ionized bubbles to be centered on overdensities of such galaxies. Here, we model the properties of galaxy populations within isolated, ionized bubbles that SKA-1 should be able to resolve at z=7-10, and explore the prospects fo…
Intergalactic magnetic fields in the voids of the large-scale structure can be probed via measurements of secondary gamma-ray emission from gamma-ray interactions with extragalactic background light. Lower bounds on the magnetic field in the voids were derived from the non-detection of this emission. It is not clear a priori what kind of magnetic field is responsible for the suppression of the secondary gamma-ray flux: a cosmological magnetic field that might be filling the voids or the field spread by galactic winds driven by star formation and active galactic nuclei. We used IllustrisTNG cos…
Known as the "Missing Baryon Problem", about one-third of baryons in the local universe remain unaccounted for. The missing baryons are thought to reside in the warm-hot intergalactic medium (WHIM) of the cosmic web filaments, which are challenging to detect. Recent Chandra X-ray observations used a novel stacking analysis and detected an OVII absorption line toward the sightline of a luminous quasar, hinting that the missing baryons may reside in the WHIM. To explore how the properties of the OVII absorption line depend on feedback physics, we compare the observational results with prediction…
Turbulent Transport of Galactic Magnetic Fields into Cosmic Voids: Insights from IllustrisTNG
Graduate School of Science, Nagoya University（名古屋大学大学院理学研究科）；Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University（名古屋大学小林-益川粒子宇宙起源研究所）；Institute for Advanced Research, Nagoya University（名古屋大学高等研究院）
The missing baryon problem is one of the major unsolved problems in astronomy. Fast radio bursts (FRBs) are bright millisecond pulses with unknown origins. The dispersion measure of FRBs is defined as the electron column density along the line of sight, and accounts for every ionized baryon. Here we measure the baryon content of the Universe using 22 localized FRBs. Unlike previous works that fixed the value of dispersion measure of FRB host galaxies and ignored the inhomogeneities of the intergalactic medium (IGM), we use the probability distributions of dispersion measures contributed by hos…
We study supernova-driven galactic outflows as a mechanism for injecting turbulence in the intergalactic medium (IGM) far from galaxies. To this aim we follow the evolution of a 10^13 Msun galaxy along its merger tree, with carefully calibrated prescriptions for star formation and wind efficiencies. At z~3 the majority of the bubbles around galaxies are old (ages >1Gyr), i.e. they contain metals expelled by their progenitors at earlier times; their filling factor increases with time reaching about 10% at z<2. The energy deposited by these expanding shocks in the IGM is predominantly in kinetic…
We explore the use of Deep Learning to infer the temperature of the intergalactic medium from the transmitted flux in the high redshift Lyman-alpha forest. We train Neural Networks on sets of simulated spectra from redshift z=2-3 outputs of cosmological hydrodynamic simulations, including high temperature regions added in post-processing to approximate bubbles heated by Helium-II reionization. We evaluate how well the trained networks are able to reconstruct the temperature from the effect of Doppler broadening in the simulated input Lyman-alpha forest absorption spectra. We find that for spec…
Using the CoDa II simulation, we study the Ly$α$ transmissivity of the intergalactic medium (IGM) during reionization. At $z>6$, a typical galaxy without an active galactic nucleus fails to form a proximity zone around itself due to the overdensity of the surrounding IGM. The gravitational infall motion in the IGM makes the resonance absorption extend to the red side of Ly$α$, suppressing the transmission up to roughly the circular velocity of the galaxy. In some sight lines, an optically thin blob generated by a supernova in a neighboring galaxy results in a peak feature, which can be mistake…
Lyman-$α$ (Ly$α$) spectra provide insights into the small-scale structure and kinematics of neutral hydrogen (HI) within galaxies as well as the ionization state of the intergalactic medium (IGM). The former defines the intrinsic spectrum of a galaxy, which is modified by the latter. These two effects are degenerate. Using the IllustrisTNG100 simulation, we study the impact of the IGM on Ly$α$ spectral shapes between $z\sim 0$ and $5$. We compute the distribution of the expected Ly$α$ peaks and of the peak asymmetry for different intrinsic spectra, redshifts and large-scale environments. We fi…
The dispersion measure (DM)--redshift relation of fast radio bursts (FRBs) has been proposed as a potential new tool for probing intergalactic medium (IGM) and for studying cosmology. However, the poor knowledge of the baryon fraction in the IGM ($f_{\mathrm{IGM}}$) and its degeneracy with cosmological parameters impose restrictions on the cosmological applications of FRBs. Furthermore, DMs contributed by the IGM ($\mathrm{DM_{IGM}}$) and host galaxy ($\mathrm{DM_{host}}$), important cosmological quantities, cannot be exactly extracted from observations, which would bring uncontrolled systemat…
We present a comprehensive study of the distribution of matter around different populations of large-scale cosmic filaments, using the IllustrisTNG simulation at z=0. We computed the dark matter (DM), gas, and stellar radial density profiles of filaments, and we characterise the distribution of the baryon fraction in these structures. We find that baryons exactly follow the underlying DM distribution only down to r~7 Mpc to the filament spines. At shorter distances (r<7 Mpc), the baryon fraction profile of filaments departs from the cosmic value $Ω_\mathrm{b} / Ω_\mathrm{m}$. While in the r~0.…
X-ray emission in IllustrisTNG circum-cluster environments. II -- Possible origins of the soft X-ray excess emission
Sorbonne Université（索邦大学）；Institut d’Astrophysique de Paris（巴黎天体物理学研究所）；Max-Planck Institute for Astrophysics（马克斯·普朗克天体物理学研究所）；Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学 Kavli宇宙粒子与宇宙学研究所（IPMU））；University of Alabama in Huntsville（阿拉巴马大学亨茨维尔分校）；Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas (CSIC)（安达卢西亚天体物理研究所，西班牙高等科学研究委员会）；New York City College of Technology, City University of New York（纽约城市学院技术分校，纽约市立大学）；Université Paris-Saclay（巴黎萨克雷大学）；Institut d’Astrophysique Spatiale（天体物理研究所）；Laboratoire de Physique de l’Ecole Normale Supérieure（巴黎高等师范学院物理实验室）
A stochastic forward model for the intergalactic dispersion-measure distribution of Fast Radio Bursts
University of Cape Town（开普敦大学）；African Institute for Mathematical Sciences（非洲数学科学研究所）；National Institute for Theoretical and Computational Sciences (NITheCS)（国家理论与计算科学研究所）；Universidade Federal de Ouro Preto（欧罗普雷图联邦大学）；INAF – Osservatorio Astronomico di 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）；Universidade Federal do Espírito Santo（圣埃斯皮里图联邦大学）
Magnetogenesis by galactic processes: impact on circumgalactic and intergalactic fields
Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学 Kavli 宇宙物理数学研究所）；Center for Data-Driven Discovery, Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学 数据驱动发现中心）；Kavli Institute for Particle Astrophysics & Cosmology (KIPAC), Stanford University（斯坦福大学 Kavli 粒子天体物理与宇宙学研究所）
Traditional excursion set based models of H II bubble growth during the epoch of reionization are known to violate photon number conservation, in the sense that the mass fraction in ionized bubbles in these models does not equal the ratio of the number of ionizing photons produced by sources and the number of hydrogen atoms in the intergalactic medium. E.g., for a Planck13 cosmology with electron scattering optical depth $τ\simeq0.066$, the discrepancy is $\sim15$ per cent for $x_{\rm HII}=0.1$ and $\sim5$ per cent for $x_{\rm HII}=0.5$. We demonstrate that this problem arises from a fundament…
Learning the Universe with the 2nd Generation of CAMELS: Varying 35 parameters of the IllustrisTNG model in (50Mpc/h)^3 boxes
Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理学中心）；Columbia Astrophysics Laboratory, Columbia University（哥伦比亚大学天体物理实验室，哥伦比亚大学）；NSF-Simons AI Institute for the Sky (SkAI)（NSF-西蒙斯天空人工智能研究所（SkAI））；School of Physics, Korea Institute for Advanced Study（韩国高等科学研究院物理学院）；Department of Physics, University of Connecticut（康涅狄格大学物理系）；Department of Physics and Astronomy, Rutgers University（罗格斯大学物理与天文系）；Department of Astronomy, Columbia University（哥伦比亚大学天文系）；Department of Astrophysical Sciences, Princeton University（普林斯顿大学天体物理科学系）；TransferLab, appliedAI Institute for Europe（欧洲应用人工智能研究所 TransferLab）；Kavli Institute for Cosmology, Madingley Road, Cambridge CB3 0HA, UK（剑桥大学卡弗里宇宙学研究所）；Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK（剑桥大学天文学研究所）
Direct detection of regions of ionized hydrogen (HII) has been suggested as a promising probe of cosmic reionization. Observing the redshifted 21-cm signal of hydrogen from the epoch of reionization (EoR) is a key scientific driver behind new-generation, low-frequency radio interferometers. We investigate the feasibility of combining low-frequency observations with the Square Kilometre Array and near infra-red survey data of the Wide-Field Infrared Survey Telescope to detect cosmic reionization by imaging HII bubbles surrounding massive galaxies during the cosmic dawn. While individual bubbles…
The THESAN project: Lyman-alpha emitters as probes of ionized bubble sizes
Massachusetts Institute of Technology（麻省理工学院）；The University of Texas at Dallas（德克萨斯大学达拉斯分校）；Universidad ECCI（ECCI大学）；York University（约克大学）；The University of Tokyo（东京大学）；University of Edinburgh（爱丁堡大学）
The visibility of LyA emitting galaxies during the Epoch of Reionization is controlled by both diffuse HI patches in large-scale bubble morphology and small-scale absorbers. To investigate the impact on LyA photons, we apply a novel combination of analytic and numerical calculations to three scenarios: (i) the `bubble' model, where only diffuse HI outside ionized bubbles is present; (ii) the `web' model, where HI exists only in overdense self-shielded gas; and (iii) the more realistic 'web-bubble' model, which contains both. Our analysis confirms that there is a degeneracy between the ionizati…
The cosmic web's Lyman-$α$ glow at $z \approx 2.5$; hydrodynamic models, dust, and wide-field, narrow-band detection
Main Astronomical Observatory of the National Academy of Sciences of Ukraine（乌克兰国家科学院主天文台）；Astronomical Observatory, Taras Shevchenko National University of Kyiv（基辅塔拉斯舍甫琴科国立大学天文台）；University of Aberdeen（阿伯丁大学）；Beijing Normal University（北京师范大学）；Institute of Astronomy, University of Cambridge（剑桥大学天体物理研究所）；Big Questions Institute（重大问题研究所）；Stony Brook University（石溪大学）；American Museum of Natural History（美国自然历史博物馆）；Amazon Web Services（亚马逊云服务）；The University of Nottingham（诺丁汉大学）
The CAMELS-CROCODILE Simulation Suite: A New Cosmology--Astrophysics Playground for Machine Learning
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）；Nevada Center for Astrophysics（内华达天体物理中心）；Nagoya University（名古屋大学）；Princeton University（普林斯顿大学）；Flatiron Institute（平顿研究所）
本文介绍 CAMELS-CROCODILE 模拟套件，扩展 CAMELS 框架以独立实现重子物理，并验证其与 IllustrisTNG 的差异，同时展示图神经网络跨模型推断的局限性，强调跨物理模型训练和测试 ML 的必要性。
The first stars and quasars are known sources of hard ionizing radiation in the first billion years of the Universe. We examine the joint effects of X-rays and hard UV radiation from such first-light sources on the hydrogen and helium reionization of the intergalactic medium (IGM) at early times, and the associated heating. We study the growth and evolution of individual HII, HeII and HeIII regions around early galaxies with first stars and/or QSO populations. We find that in the presence of helium-ionizing radiation, X-rays may not dominate the ionization and thermal history of the IGM at red…
Upper limits from the current generation of interferometers targeting the 21-cm signal from high redshifts have recently begun to rule out physically realistic, though still extreme, models of the Epoch of Reionization (EoR). While inferring the detailed properties of the first galaxies is one of the most important motivations for measuring the high-$z$ 21-cm signal, they can also provide useful constraints on the properties of the intergalactic medium (IGM). Motivated by this, we build a simple, phenomenological model for the 21-cm power spectrum that works directly in terms of IGM properties…
Impact of anisotropic photon emission from sources during the epoch of reionisation
University of Sussex（萨塞克斯大学）；The Open University of Israel（以色列开放大学）；Stockholm University（斯德哥尔摩大学）；KTH Royal Institute of Technology（瑞典皇家理工学院）；University of Groningen（格罗宁根大学）
Ly$α$ visibility from z = 4.5 to 11 in the UDS field: Evidence for a high neutral hydrogen fraction and small ionized bubbles at z $\sim$ 7
INAF – Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Dipartimento di Fisica, Università di Roma Sapienza（罗马大学物理系）；NSF’s National Optical-Infrared Astronomy Research Laboratory（美国国家光学-红外天文研究实验室）；Astrophysics Science Division, NASA Goddard Space Flight Center（NASA戈达德太空飞行中心天体物理学部）；Department of Astronomy, The University of Texas at Austin（德克萨斯大学奥斯汀分校天文学系）；Max Planck Institut für Astrophysik（马克斯·普朗克天体物理学研究所）；Institute for Astronomy, University of Edinburgh（爱丁堡大学天文学研究所）
We introduce the THESAN project, a suite of large volume (L = 95.5 cMpc) radiation-magnetohydrodynamic simulations that simultaneously model the large-scale statistical properties of the IGM during reionization and the resolved characteristics of the galaxies responsible for it. The flagship simulation has dark matter (DM) and baryonic mass resolutions of $3.1 \times 10^6$ $M_\odot$ and $5.8 \times 10^5 $ $M_\odot$, respectively. The gravitational forces are softened on scales of 2.2 ckpc with the smallest cell sizes reaching 10 pc at z=5.5, enabling predictions down to the atomic cooling limi…
We use spatially resolved long-slit spectroscopy from Magellan to investigate the extent, kinematics, and ionization structure in the narrow-line regions of 15 luminous, obscured quasars with z<0.5. Increasing the dynamic range in luminosity by an order of magnitude, as well as improving the depth of existing observations by a similar factor, we revisit relations between narrow-line region size and the luminosity and linewidth of the narrow emission lines. We find a slope of 0.22 +/- 0.04 for the power-law relationship between size and luminosity, suggesting that the nebulae are limited by ava…
