121 research outputs found
The Sunyaev-Zel'dovich Effect at Five Arc-seconds: RXJ1347.5-1145 Imaged by ALMA
We present the first image of the thermal Sunyaev-Zel'dovich effect (SZE)
obtained by the Atacama Large Millimeter/submillimeter Array (ALMA). Combining
7-m and 12-m arrays in Band 3, we create an SZE map toward a galaxy cluster
RXJ1347.5-1145 with 5 arc-second resolution (corresponding to the physical size
of 20 kpc/h), the highest angular and physical spatial resolutions achieved to
date for imaging the SZE, while retaining extended signals out to 40
arc-seconds. The 1-sigma statistical sensitivity of the image is 0.017 mJy/beam
or 0.12 mK_CMB at the 5 arc-second full width at half maximum. The SZE image
shows a good agreement with an electron pressure map reconstructed
independently from the X-ray data and offers a new probe of the small-scale
structure of the intracluster medium. Our results demonstrate that ALMA is a
powerful instrument for imaging the SZE in compact galaxy clusters with
unprecedented angular resolution and sensitivity. As the first report on the
detection of the SZE by ALMA, we present detailed analysis procedures including
corrections for the missing flux, to provide guiding methods for analyzing and
interpreting future SZE images by ALMA.Comment: 20 pages, 13 figures. Accepted for publication in PAS
Cool core disturbed: Observational evidence for coexistence of sub-sonic sloshing gas and stripped shock-heated gas around the core of RX J1347.5-1145
RXJ1347.5-1145 (z = 0.451) is one of the most luminous X-ray galaxy clusters,
which hosts a prominent cool core and exhibits a signature of a major merger.
We present the first direct observational evidence for sub-sonic nature of
sloshing motion of the cool core. We find that a residual X-ray image from the
Chandra X-ray Observatory after removing the global emission shows a clear
dipolar pattern characteristic of gas sloshing, whereas we find no significant
residual in the Sunyaev-Zel'dovich effect (SZE) image from the Atacama Large
Millimeter/submillimeter Array (ALMA). We estimate the equation of state of
perturbations in the gas from the X-ray and SZE residual images. The inferred
velocity is 420 +310 -420 km s-1, which is much lower than the adiabatic sound
speed of the intracluster medium in the core. We thus conclude that the
perturbation is nearly isobaric, and gas sloshing motion is consistent with
being in pressure equilibrium. Next, we report evidence for gas stripping of an
infalling subcluster, which likely shock-heats gas to high temperature well in
excess of 20 keV. Using mass distribution inferred from strong lensing images
of the Hubble Space Telescope (HST), we find that the mass peak is located away
from the peak position of stripped gas with statistical significance of >
5{\sigma}. Unlike for the gas sloshing, the velocity inferred from the equation
of state of the excess hot gas is comparable to the adiabatic sound speed
expected for the 20 keV intracluster medium. All of the results support that
the southeast substructure is created by a merger. On the other hand, the
positional offset between the mass and the gas limits the self-interaction
cross section of dark matter to be less than 3.7 h-1 cm2 g-1 (95% CL).Comment: 18 pages, 10 figures, accepted for publication in Ap
Cross-Linguistic Influence on L2 before and after extreme reduction in input:The case of Japanese returnee children
This study investigates the choice of genitive forms (the woman’s book vs. the book of the woman) in the English of Japanese-English bilingual returnees (i.e., children who returned from a second language dominant environment to their first language environment). The specific aim was to examine whether change in language dominance/exposure influences choice of genitive form in the bilingual children; the more general question was the extent to which observed behavior can be explained by cross linguistic influence (CLI). First, we compared the choice of genitive form between monolingual English speakers and bilinguals who had recently returned to Japan from an English speaking environment. Second, we tracked changes in genitive preference within bilingual children, comparing their performances upon return to Japan to those of one year later. Results show that CLI alone is insufficient to explain the difference in genitive evaluation between bilinguals and monolinguals, as well as the intra-group bilingual variation over time. We suggest that both CLI and general processing considerations couple together to influence the changes in genitive preference
The glacial landforms and erosional features on the Easut Antarctic continental shelf and the related past subglacial environments during th last glaciation
第2回極域科学シンポジウム/第31回極域地学シンポジウム 11月16日(水) 国立国語研究
High-power laser experiment forming a supercritical collisionless shock in a magnetized uniform plasma at rest
We present a new experimental method to generate quasi-perpendicular supercritical magnetized collisionless shocks. In our experiment, ambient nitrogen (N) plasma is at rest and well-magnetized, and it has uniform mass density. The plasma is pushed by laser-driven ablation aluminum (Al) plasma. Streaked optical pyrometry and spatially resolved laser collective Thomson scattering clarify structures of plasma density and temperatures, which are compared with one-dimensional particle-in-cell simulations. It is indicated that just after the laser irradiation, the Al plasma is magnetized by a self-generated Biermann battery field, and the plasma slaps the incident N plasma. The compressed external field in the N plasma reflects N ions, leading to counter-streaming magnetized N flows. Namely we identify the edge of the reflected N ions. Such interacting plasmas form a magnetized collisionless shock
The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force
「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection
DOCK2 is involved in the host genetics and biology of severe COVID-19
「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target
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