作者:李言 来源:科学网微信公众号 发布时间:2024/3/16 20:33:46
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《自然》(20240314出版)一周论文导读

 

编译 | 李言

Nature, 14 March 2024, Volume 627 Issue 8003

《自然》2024年3月14日,第627卷,8003期

天文学Astronomy

A dynamical measure of the black hole mass in a quasar 11 billion years ago

110亿年前类星体中黑洞质量的动态测量

▲ 作者:R. Abuter, F. Allouche et al.

▲ 链接:

https://www.nature.com/articles/s41586-024-07053-4

▲ 摘要:

在此,我们通过空间解析宽线区域(BLR),报告了一个在红移为2的发光类星体中回顾了110亿年前的黑洞质量的动态测量。我们在Hα线的红色和蓝色的光圈之间检测出一个40微弧秒(0.31 pc)的空间偏移,它跟踪了旋转BLR的速度梯度。

在一个质量为3.2?×?108太阳质量的中心黑洞的影响范围内,一个厚实、适度倾斜的气体云盘再现了通量和微分相光谱。分子气体数据显示,宿主星系的动态质量为6?×?1011?太阳质量,显示一个质量不足的黑洞以超爱丁顿速率吸积。这表明有一个宿主星系比SMBH增长得更快,显示在某些系统中,星系和黑洞形成之间可能存在延迟。

▲ Abstract:

Here we report a dynamical measurement of the mass of the black hole in a luminous quasar at a redshift of 2, with a look back in time of 11?billion years, by spatially resolving the broad-line region (BLR). We detect a 40-μas (0.31-pc) spatial offset between the red and blue photocentres of the Hα line that traces the velocity gradient of a rotating BLR. The flux and differential phase spectra are well reproduced by a thick, moderately inclined disk of gas clouds within the sphere of influence of a central black hole with a mass of 3.2?×?108?solar masses. Molecular gas data reveal a dynamical mass for the host galaxy of 6?×?1011?solar masses, which indicates an undermassive black hole accreting at a super-Eddington rate. This suggests a host galaxy that grew faster than the SMBH, indicating a delay between galaxy and black hole formation for some systems.

Buoyant crystals halt the cooling of white dwarf stars

浮力晶体阻止了白矮星的冷却

▲ 作者:Antoine Bédard, Simon Blouin & Sihao Cheng  (程思浩)

▲ 链接:

https://www.nature.com/articles/s41586-024-07102-y

▲ 摘要:

在此,我们展示了蒸馏中断了数十亿年的冷却,并解释了不寻常的延迟星系族的所有观测特性。其亮度稳定超过了一些主序星,这些白矮星打破了传统的死亡恒星形象。

我们的研究结果强调了特殊合并残余的存在,并对使用白矮星以确定恒星族的年代具有深远影响。

▲ Abstract:

Here we show that distillation interrupts the cooling for billions of years and explains all the observational properties of the unusual delayed population. With a steady luminosity surpassing that of some main-sequence stars, these white dwarfs defy their conventional portrayal as dead stars. Our results highlight the existence of peculiar merger remnants and have profound implications for the use of white dwarfs in dating stellar populations.

生物学Biology

Genomic data in the All of Us Research Program

“我们所有人”研究项目的基因组数据

▲ 作者:The All of Us Research Program Genomics Investigators

▲ 链接:

https://www.nature.com/articles/s41586-023-06957-x

▲ 摘要:

这里,我们展示了245388个临床级基因组序列的项目基因组学数据发布。这一资源的多样性是独一无二的,因为77%的参与者来自历史上在生物医学研究中代表性不足的社区,46%的参与者来自代表性不足的种族和少数民族。

“我们所有人”项目确认了超过10亿个遗传变异,其中包括超过2.75亿个以前未报告的遗传变异,其中超过390万个具有编码结果。利用基因组数据和纵向电子健康记录之间的联系,我们评估了与117种疾病相关的3724种遗传变异,发现欧洲血统和非洲血统的参与者都有很高的复制率。

摘要级数据是公开的,个人级数据可以由研究人员通过All of Us Researcher Workbench访问,使用独特的数据护照模型,从最初的研究人员注册到数据访问的中位数时间为29小时。我们预计,这个多样化的数据集将为所有人推进基因组医学研究前景。

▲ Abstract:

Here we describe the programme’s genomics data release of 245,388 clinical-grade genome sequences. This resource is unique in its diversity as 77% of participants are from communities that are historically under-represented in biomedical research and 46% are individuals from under-represented racial and ethnic minorities. All of Us identified more than 1?billion genetic variants, including more than 275?million previously unreported genetic variants, more than 3.9?million of which had coding consequences. Leveraging linkage between genomic data and the longitudinal electronic health record, we evaluated 3,724 genetic variants associated with 117 diseases and found high replication rates across both participants of European ancestry and participants of African ancestry. Summary-level data are publicly available, and individual-level data can be accessed by researchers through the All of Us Researcher Workbench using a unique data passport model with a median time from initial researcher registration to data access of 29?hours. We anticipate that this diverse dataset will advance the promise of genomic medicine for all.

气候科学Climate Science

Drought triggers and sustains overnight fires in North America

干旱持续引发北美夜间火灾

▲ 作者:Kaiwei Luo, Xianli Wang, Mark de Jong & Mike Flannigan

▲ 链接:

https://www.nature.com/articles/s41586-024-07028-5

▲ 摘要:

在此,我们证明了干旱条件引发夜火,而这是形成大型活火的关键机制。我们利用地球静止卫星数据和地面火灾记录,研究了2017年—2020年北美23557起火灾的每小时昼夜周期,并确定了1095起彻夜燃烧事件(OBEs)。总共99%的OBEs与大面积火灾(大于1000公顷)有关,其中20%的大火中至少发现了一次OBEs。

起火后OBEs会较早发生,频率与火灾大小呈正相关。尽管气候变暖正在削弱夜间火灾的气候屏障,但我们发现,最近大型火灾中OBEs的主要驱动因素是燃料干燥和可用性的累积(即干旱条件),这往往会导致单次野火事件中连续数天甚至数周的OBEs。重要的是,我们表明白天干旱指标可以预测是否会在第二天晚上发生OBE,这可以促进夜间火灾的早期发现和管理。

▲ Abstract:

Here we demonstrate that drought conditions promote overnight burning, which is a key mechanism fostering large active fires. We examined the hourly diurnal cycle of 23,557 fires and identified 1,095 overnight burning events (OBEs, each defined as a night when a fire burned through the night) in North America during 2017–2020 using geostationary satellite data and terrestrial fire records. A total of 99% of OBEs were associated with large fires (>1,000?ha) and at least one OBE was identified in 20% of these large fires. OBEs were early onset after ignition and OBE frequency was positively correlated with fire size. Although warming is weakening the climatological barrier to night-time fires, we found that the main driver of recent OBEs in large fires was the accumulated fuel dryness and availability (that is, drought conditions), which tended to lead to consecutive OBEs in a single wildfire for several days and even weeks. Critically, we show that daytime drought indicators can predict whether an OBE will occur the following night, which could facilitate early detection and management of night-time fires. 

能源科学Energy Science

US oil and gas system emissions from nearly one million aerial site measurements

从近一百万个空中站点测量美国石油和天然气系统排放量

▲ 作者:Evan D. Sherwin, Jeffrey S. Rutherford et al.

▲ 链接:

https://www.nature.com/articles/s41586-024-07117-5

▲ 摘要:

我们将大约100万次空中现场测量数据整合到美国六个地区的区域排放清单中,这些地区包括了15次空中区域中52%的陆上石油和29%的天然气产量。我们为每一个构建完整的排放分布,采用经验为基础的模拟来估计少量排放情况。估计的总排放量范围从高产、富气地区天然气产量的0.75%(95% CI ?0.65%, 0.84%)到快速扩张、石油集中地区的9.63%(95% CI 9.04%, 10.39%)。

六个地区的加权平均值为2.95% (95% CI 2.79%, 3.14%),约为政府库存估计值的三倍。在15次调查中,只有的11次的调查中0.05%—1.66%的井场贡献了大部分井场排放量(50%—79%)。包括管道在内的附属中游设施贡献了估计区域排放量的18%—57%,同样集中在少数点源。这里量化的排放加起来,每年损失约10亿美元的商业天然气价值,每年造成93亿美元的社会成本。

▲ Abstract:

We integrate approximately one million aerial site measurements into regional emissions inventories for six regions in the USA, comprising 52% of onshore oil and 29% of gas production over 15?aerial campaigns. We construct complete emissions distributions for each, employing empirically grounded simulations to estimate small emissions. Total estimated emissions range from 0.75% (95% confidence interval (CI)?0.65%, 0.84%) of covered natural gas production in a high-productivity, gas-rich region to 9.63% (95% CI 9.04%, 10.39%) in a rapidly expanding, oil-focused region. The six-region weighted average is 2.95% (95% CI 2.79%, 3.14%), or roughly three times the national government inventory estimate. Only 0.05–1.66% of well sites contribute the majority (50–79%) of well site emissions in 11 out of 15?surveys. Ancillary midstream facilities, including pipelines, contribute 18–57% of estimated regional emissions, similarly concentrated in a small number of point sources. Together, the emissions quantified here represent an annual loss of roughly US$1?billion in commercial gas value and a US$9.3?billion annual social cost. 

地球科学Earth science

Mutualisms weaken the latitudinal diversity gradient among oceanic islands

互利共生削弱了海洋岛屿间的纬度多样性梯度

▲ 作者:Camille S. Delavaux, Thomas W. Crowther et al.

▲ 链接:

https://www.nature.com/articles/s41586-024-07110-y

▲ 摘要:

在此,我们使用一个独特的全球数据集来显示海洋岛屿上的维管植物表现出减弱的纬度多样性梯度(LDG),并探索这种影响的潜在机制。我们的研究结果表明,岛屿生物地理学的传统物理驱动因素——即面积和隔离——导致了特定纬度上岛屿和大陆多样性的差异(即岛屿物种赤字),因为更小更遥远的岛屿经历了较少的殖民化。

然而,具有共生关系的植物物种在岛屿上的代表性不足,我们发现这种植物共生过滤器比非生物因素更能解释岛屿物种赤字的变化。尤其是,需要动物授粉者或微生物共同主义者,如肝菌根真菌的植物物种,对赤道附近的岛屿物种逆差产生不成比例的贡献,这种影响随离赤道的距离增加而减少。

在大陆物种丰富度最高的低纬度地区,植物相互作用对物种丰富度的过滤作用特别强,削弱了海洋岛屿的LDG。

▲ Abstract:

Here we use a unique global dataset to show that vascular plants on oceanic islands exhibit a weakened LDG and explore potential mechanisms for this effect. Our results show that traditional physical drivers of island biogeography—namely area and isolation—contribute to the difference between island and mainland diversity at a given latitude (that is, the island species deficit), as smaller and more distant islands experience reduced colonization. However, plant species with mutualists are underrepresented on islands, and we find that this plant mutualism filter explains more variation in the island species deficit than abiotic factors. In particular, plant species that require animal pollinators or microbial mutualists such as arbuscular mycorrhizal fungi contribute disproportionately to the island species deficit near the Equator, with contributions decreasing with distance from the Equator. Plant mutualist filters on species richness are particularly strong at low absolute latitudes where mainland richness is highest, weakening the LDG of oceanic islands. 

 
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