ABSTRACT
We present improved results of the measurement of the correlation between galaxies and the intergalactic medium transmission at the end of reionization. We have gathered a sample of 13 ...spectroscopically confirmed Lyman-break galaxies (LBGs) and 21 Lyman-α emitters (LAEs) at angular separations 20 arcsec ≲ θ ≲ 10 arcmin (∼0.1–4 pMpc at z ∼ 6) from the sightlines to eight background z ≳ 6 quasars. We report for the first time the detection of an excess of Lyman-α transmission spikes at ∼10–60 cMpc from LAEs (3.2σ) and LBGs (1.9σ). We interpret the data with an improved model of the galaxy–Lyman-α transmission and two-point cross-correlations, which includes the enhanced photoionization due to clustered faint sources, enhanced gas densities around the central bright objects and spatial variations of the mean free path. The observed LAE(LBG)–Lyman-α transmission spike two-point cross-correlation function (2PCCF) constrains the luminosity-averaged escape fraction of all galaxies contributing to reionization to $\langle f_{\rm esc} \rangle _{M_{\rm UV}\lt -12} = 0.14_{-0.05}^{+0.28}\, (0.23_{-0.12}^{+0.46})$. We investigate if the 2PCCF measurement can determine whether bright or faint galaxies are the dominant contributors to reionization. Our results show that a contribution from faint galaxies ($M_{\rm UV} \gt -20 \, (2\sigma)$) is necessary to reproduce the observed 2PCCF and that reionization might be driven by different sub-populations around LBGs and LAEs at z ∼ 6.
ABSTRACT
We study the connection between morphology and dynamical state of the simulated galaxy clusters in z ∈ 0, 1.031 from The Three Hundred project. We quantify cluster dynamical state using a ...combination of dynamical indicators from theoretical measures and compare this combined parameter, χ, with the results from morphological classifications. The dynamical state of the cluster sample shows a continuous distribution from dynamically relaxed, more abundant at lower redshift, to hybrid and disturbed. The dynamical state presents a clear dependence on the radius, with internal regions more relaxed than outskirts. The morphology from multiwavelength mock observation of clusters in X-ray, optical, and Sunyaev–Zel’dovich (SZ) effect images is quantified by M – a combination of six parameters for X-ray and SZ maps and the offsets between the optical position of the brightest cluster galaxy (BCG) and the X-ray/SZ centroids. All the morphological parameters are highly correlated with each other, while they show a moderately strong correlation with the dynamical χ parameter. The X-ray or SZ peaks are less affected by the dynamical state than centroids, which results in reliable tracers of the cluster density peak. The principal source of contamination in the relaxed cluster fraction, inferred from morphological parameters, is due to dynamically hybrid clusters. Compared to individual parameters, which consider only one aspect of cluster property (e.g. only clumping or asymmetry), the combined morphological and dynamical parameters (M and χ) collect more information and provide a single and more accurate estimation of the cluster dynamical state.
Research has been conducted to enhance the hardness value of medium manganese steel through a heat treatment. Initially, this process begins with austenization at a temperature of 900°C, followed by ...tempering at 650°C and double tempering at 600°C, with each stage lasting 30 minutes. Subsequently, each stage concludes with a hot rolling process, after which air or water cools the material. As a result of these processes, the hardness tests revealed an increase in the hardness of medium manganese steel, reaching up to 389.70 BHN with a tensile strength of 827 MPa, which was notably achieved through air cooling. This significant increase in hardness is attributed to the emergence of the martensite phase and the presence of a large number of carbides, which are more evenly distributed after the double-tempering process. Additionally, small amounts of carbides were observed in the austenite matrix. Upon examination of the SEM fractography results, it was revealed that the fracture was mixed, with a cleavage area slightly larger than the dimple area. This observation suggests that despite its high hardness value, the sample retains good toughness.
The 'Note' shows that Agamben's book, The Man Without Content, raises the question of art criticism and in so doing also raises questions relating to the nature of art and the medium.
Two types of common mode voltage (CMV) exist in medium-voltage motor drive system based on modular multilevel converter (MMC) type topology, that are, arms CMV (ACMV) and system CMV (SCMV). The ...former will produce circulating current between phases, and the latter will do harm to the motor. This article proposes a suppression scheme of CMV with a dual dc bus MMC-based solid-state transformer (DBM 2 C-SST) based drive system. The horizontal submodules (SMs) of MMC are cascaded with a quadruple-active-bridge (QAB), then a low voltage is formed. Plus the original medium voltage bus, the system is characteristic as a dual dc bus. The primary triple-active-bridge of QAB which characterized by low-impedance and synchronous-switching helps to achieve the natural suppression of the fluctuating voltage of the MMC horizontal three SMs within the entire operating frequency range under the relevant modulation strategy, thus realizing the full suppression of ACMV and low-frequency components suppression of SCMV simultaneously, and with the additional minimum method of SCMV high-frequency components, the DBM 2 C-SST can achieve zero CMV. As the SMs fluctuating voltage and CMV are decreased, the values of SMs capacitance and arms inductance can be significantly reduced.
ABSTRACT We characterize the physical properties of the cool T ∼ 104 K circumgalactic medium (CGM) surrounding z ∼ 2-3 quasar host galaxies, which are predicted to evolve into present-day massive ...ellipticals. Using a statistical sample of 14 quasar pairs with projected separation <300 kpc and spectra of high dispersion and high signal-to-noise ratio, we find extreme kinematics with low metal ion lines typically spanning 500 km s−1, exceeding any previously studied galactic population. The CGM is significantly enriched, even beyond the virial radius, with a median metallicity M/H −0.6. The /Fe abundance ratio is enhanced, suggesting that halo gas is primarily enriched by core-collapse supernovae. The projected cool gas mass within the virial radius is estimated to be 1.9 × 1011 M (R /160 kpc)2, accounting for 1/3 of the baryonic budget of the galaxy halo. The ionization state of CGM gas increases with projected distance from the foreground quasars, contrary to expectation if the quasar dominates the ionizing radiation flux. However, we also found peculiarities not exhibited in the CGM of other galaxy populations. In one absorption system, we may be detecting unresolved fluorescent Ly emission, and another system shows strong N v lines. Taken together, these anomalies suggest that transverse sightlines are-at least in some cases-possibly illuminated. We also discovered a peculiar case where detection of the C ii fine-structure line implies an electron density >100 cm−3 and sub-parsec-scale gas clumps.
Single-phase CrCoNi medium-entropy alloys (MEA) are emerging recently as an interesting class of metallic materials, but the dynamic response of this MEA at high strain rates remains unknown. Here we ...have produced this MEA with various heterogeneous microstructures, using cold rolling followed by annealing at various temperatures. The high-strain-rate response of the MEAs was characterized using hat-shaped specimens in Hopkinson-bar experiments. A combination of high dynamic shear yield strength and large uniform dynamic shear strain was observed, exceeding all other metals and alloys reported so far. Even better dynamic shear properties was revealed when the experiments were conducted at cryogenic temperature. The strong strain hardening under dynamic shear loading can be attributed to the dynamic grain refinement and deformation twinning that accompany the homogeneous shear deformation. When compared to room temperature, the efficiency of grain refinement was found to be enhanced at cryogenic temperature, with a higher density of multiple twins, stacking faults, Lomer-Cottrell locks, and hcp phase via phase transformation inside the grains, which could be responsible for the better dynamic shear properties under cryogenic environment.
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We introduce the THE THREE HUNDRED project, an endeavour to model 324 large galaxy clusters with full-physics hydrodynamical re-simulations. Here we present the data set and study the differences to ...observations for fundamental galaxy cluster properties and scaling relations. We find that the modelled galaxy clusters are generally in reasonable agreement with observations with respect to baryonic fractions and gas scaling relations at redshift z = 0. However, there are still some (model-dependent) differences, such as central galaxies being too massive, and galaxy colours (g - r) being bluer (about 0.2 dex lower at the peak position) than in observations. The agreement in gas scaling relations down to 10^{13} h^{-1} M_{⊙} between the simulations indicates that particulars of the sub-grid modelling of the baryonic physics only has a weak influence on these relations. We also include - where appropriate - a comparison to three semi-analytical galaxy formation models as applied to the same underlying dark-matter-only simulation. All simulations and derived data products are publicly available.
Through a proprietary dataset of small and medium‐sized enterprises (SMEs) on China's National Equities Exchange and Quotations (NEEQ), we examine the impact of venture capital (VC) backup on access ...to bank loans by SMEs. We find that VC backup can help SMEs obtain more bank loans under better conditions and significantly relieve their financing constraint. This is especially meaningful for private SMEs, those in high‐tech, in regions of less‐developed banking industry, or with lower quality accounting information. This study may have policy implications as a pilot ‘combined debt‐equity financing’ discussion in the context of the largest bank‐based economy.
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