Frontiers in Astronomy and Space Sciences最新文献

Measurement and calibration of non-linear shear terms in galaxy cluster fields 星系团场非线性剪切项的测量与校准

IF 2.6 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-08-09 DOI: 10.3389/fspas.2024.1411810

Binyang Liu, I. Dell’Antonio, Nicolas Chotard, D. Clowe

{"title":"Measurement and calibration of non-linear shear terms in galaxy cluster fields","authors":"Binyang Liu, I. Dell’Antonio, Nicolas Chotard, D. Clowe","doi":"10.3389/fspas.2024.1411810","DOIUrl":"https://doi.org/10.3389/fspas.2024.1411810","url":null,"abstract":"Galaxy cluster lensing is a powerful tool for measuring the mass of galaxy clusters, but accurate shear measurement and calibration are critical to obtaining reliable results. This study focuses on the measurement and calibration of weak lensing shears to improve mass estimates in cluster lensing. To deal with the problem, we first developed an image simulation pipeline, jedisim, which utilizes galaxy images extracted from the Hubble Space Telescope (HST) Ultra Deep Field (UDF) and the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS).The simulations represent realistic galaxy distributions and morphologies as input sources. The foreground halo with a Navarro–Frenk–White (NFW) profile is constructed such that the lensing signals of background galaxies can be measured by the Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST) Science Pipelines. By comparing the measured reduced shear gmeas and the true reduced shear gtrue, we observe non-linearity up to g≲0.6. We fit polynomials to the data with quadratic correction adequate to g≲0.4. Meanwhile, we conduct mass estimates using the pzmassfitter code on four different clusters.The mass estimate results are significantly improved after applying the shear calibration derived from the present work—from 4.954±0.504×1014M⊙ to 10.507±0.498×1014M⊙ after calibration for a simulated cluster with the mass of 10×1014M⊙. In multiple cases of validation, the estimated results are all consistent with true cluster mass.This study yields the first relationship between reality and shape measurement of the LSST Science Pipelines and serves as the first step toward the overall goal of mass calibration in cluster lensing. By addressing the challenges in shear measurement and calibration, we aim to enhance the accuracy and reliability of mass estimates in galaxy cluster lensing studies.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141924029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Practical actions towards equity in space physics 实现空间物理学公平的实际行动

IF 2.6 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-08-09 DOI: 10.3389/fspas.2024.1425500

M. Liemohn

引用次数: 0

On the correlation between the enantiomeric excess of L-isovaline and the level of aqueous alteration in carbonaceous meteorites 关于碳质陨石中 L-异戊烯对映体过量与水蚀程度之间的关系

IF 2.6 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-26 DOI: 10.3389/fspas.2024.1427260

David Avnir

{"title":"On the correlation between the enantiomeric excess of L-isovaline and the level of aqueous alteration in carbonaceous meteorites","authors":"David Avnir","doi":"10.3389/fspas.2024.1427260","DOIUrl":"https://doi.org/10.3389/fspas.2024.1427260","url":null,"abstract":"A positive correlation was observed between the enantiomeric excess (ee) of L-isovaline (L-iVal) and the degree of aqueous alteration (AqA) of carbonaceous meteorites. The origin of this remarkable phenomenon has remained enigmatic from two points of view: First, the correlation is between seemingly unrelated observables–nothing about AqA is of chiral characteristics; and second, following the accepted assumption that circularly polarized light (CPL) was the origin of the observed meteoritic ee of L-amino acids (AAs), it remined unclear why some of the observed levels of the ee of L-iVal in that correlation are significantly higher than those observed in laboratory simulations or those obtained from circular dichroism (CD) g-factor calculations. The current proposition accounting for this picture attributes late AqA conditions of the meteoritic parent bodies as providing the grounds for amplification of early initially CPL-generated low levels of L-ee. For reasons summarized below, this interpretation, which treats the CPL event and the AqA process as occurring in wide-time separated eras, is re-visited. An alternative interpretation of the observed correlation and of the high ee-values, is provided. It focuses on hydrophilic dust-aggregates clouds in wet star-forming regions in early pre-solar times, where both the CPL event and the grounds leading to the later AqA processes of the parent bodies, occurred. This mechanism removes the time separation between the initial ee formation and the AqA of the parent body, and replaces it with parallel processes, providing a scenario to the observation of high ee’s without total destruction, and to the apparent AqA/L-ee correlation. Although iVal is at the focus of this report, the steps of the development of the alternative mechanism and the conclusions that arise from it, are relevant and applicable to the general observations of L-ee’s of meteoritic AA’s.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141800216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Editorial: Star formation: numerical simulations and what they teach us 社论：恒星形成：数值模拟及其启示

IF 2.6 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-25 DOI: 10.3389/fspas.2024.1462935

James Wurster, P. Hennebelle, Kengo Tomida, Anna Rosen

引用次数: 0

Exploring the relationship between STEVE and SAID during three events observed by SuperDARN 在超级雷达网观测到的三个事件中探索 STEVE 和 SAID 之间的关系

IF 2.6 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-23 DOI: 10.3389/fspas.2024.1422164

E. P. Macho, W. Bristow, B. Gallardo-Lacourt, S. G. Shepherd, J. M. Ruohoniemi, E. Correia

引用次数: 0

Tracing field lines that are reconnecting, or expanding, or both 追踪正在重新连接或扩展的田间线路，或两者兼而有之

IF 2.6 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-22 DOI: 10.3389/fspas.2024.1401846

Jiong Qiu

引用次数: 0

To what degree does a high-energy aurora destroy F-region irregularities? 高能极光在多大程度上破坏了 F 区的不规则性？

IF 2.6 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-19 DOI: 10.3389/fspas.2024.1309136

M. Ivarsen, J.‐P St-Maurice, Yaqi Jin, Jaeheung Park, Lisa Buschmann, Lasse B. N. Clausen

{"title":"To what degree does a high-energy aurora destroy F-region irregularities?","authors":"M. Ivarsen, J.‐P St-Maurice, Yaqi Jin, Jaeheung Park, Lisa Buschmann, Lasse B. N. Clausen","doi":"10.3389/fspas.2024.1309136","DOIUrl":"https://doi.org/10.3389/fspas.2024.1309136","url":null,"abstract":"Using two separate databases of in situ ionospheric observations, we present case studies and perform a statistical investigation of the link between energetic precipitating particles during the polar night and high-latitude F-region steepening density spectra. Our study covers approximately 3 years of data obtained near the peak of the 24th solar cycle from four Defense Meteorological Satellite Program satellites and from the European Space Agency’s Swarm satellites. Focusing on the midnight sector of the auroral oval, we found that there is a near-perfect co-location between high-energy precipitating particles and occurrence of dissipating F-region plasma density spectra. This is because the precipitating energy flux strongly enhances the E-region Pedersen conductivity, allowing fast and efficient dissipation of kilometer-scale F-region irregularities. Spectra that are possibly non-dissipating are in turn co-located with the distribution of soft electron precipitation. Together, dissipating and non-dissipating density spectra constitute two distinct irregularity regimes. Surprisingly, we also found that efficient dissipation notwithstanding, high-energy precipitating particles cause a net increase in the F-region irregularity power, suggesting that growth and dissipation are interlinked and that some of the observed F-region irregularities may conceivably be generated in the E region. This work is expected to be beneficial for the classification of F-region in situ density spectra and suggests that such density spectra can be used to infer the presence of high-energy or low-energy precipitations based on spectral properties.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141821580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Magnetic fields and electric currents around the dayside magnetopause as inferred from data-constrained modeling 通过数据约束建模推断出的日侧磁层顶周围的磁场和电流

IF 2.6 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-18 DOI: 10.3389/fspas.2024.1425165

Z. Kaymaz, Zdenek Nemecek, N. Tsyganenko, V. S. Semenov, N. Erkaev, N. T. Gubaidulin

{"title":"Magnetic fields and electric currents around the dayside magnetopause as inferred from data-constrained modeling","authors":"Z. Kaymaz, Zdenek Nemecek, N. Tsyganenko, V. S. Semenov, N. Erkaev, N. T. Gubaidulin","doi":"10.3389/fspas.2024.1425165","DOIUrl":"https://doi.org/10.3389/fspas.2024.1425165","url":null,"abstract":"Based on a new mathematical framework and large multi-year multi-mission data sets, we reconstruct electric currents and magnetic fields around the dayside magnetopause and their dependence on the incoming solar wind, IMF, and geodipole tilt. The model architecture builds on previously developed mathematical frameworks and includes two separate blocks: for the magnetosheath and for the adjacent outer magnetosphere. Accordingly, the model is developed in two stages: 1) reconstruction of a best-fit magnetopause and underlying dayside magnetosphere, based on a simple shielded configuration, and 2) derivation of the magnetosheath magnetic field, represented by a sum of toroidal and poloidal terms, each expanded into spherical harmonic series of angular coordinates and powers of normal distance from the boundary. The spacecraft database covers the period from 1995 through 2022 and is composed of data from Geotail, Cluster, Themis, and MMS, with the total number of 1-min averages about 3 M. The modeling reveals orderly patterns of the IMF draping around the magnetosphere and of the magnetopause currents, controlled by the IMF orientation, solar wind pressure, and the Earth’s dipole tilt. The obtained results are discussed in terms of the magnetosheath flux pile-up and the dayside magnetosphere erosion during periods of northward or southward IMF, respectively.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141825088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Editorial: Editor’s challenge in space physics: solved and unsolved problems in space physics 社论：编辑的空间物理学挑战：已解决和未解决的空间物理学问题

IF 2.6 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-15 DOI: 10.3389/fspas.2024.1431804

Joseph E. Borovsky

引用次数: 0

Spatial profiles of magnetosheath parameters under different IMF orientations: THEMIS observations 不同 IMF 方向下磁鞘参数的空间分布：THEMIS 观测

IF 3 3区物理与天体物理

Frontiers in Astronomy and Space Sciences Pub Date : 2024-06-13 DOI: 10.3389/fspas.2024.1401078

G. Pi, Z. Němeček, J. Šafránková, K. Grygorov

{"title":"Spatial profiles of magnetosheath parameters under different IMF orientations: THEMIS observations","authors":"G. Pi, Z. Němeček, J. Šafránková, K. Grygorov","doi":"10.3389/fspas.2024.1401078","DOIUrl":"https://doi.org/10.3389/fspas.2024.1401078","url":null,"abstract":"Modification of the solar wind parameters at the bow shock (BS) and through the magnetosheath (MSH) is essential for the solar wind–magnetosphere interaction chain. The present study uses two approaches to determine the spatial profile of magnetic field strength and plasma parameters and their fluctuations along the Sun-Earth line under different interplanetary magnetic field (IMF) orientations with an emphasis on radial IMF conditions. The first method is based on the superposed epoch analysis of all the complete THEMIS MSH crossings between 2007 and 2010. The second approach uses the distance of the observing spacecraft from the model magnetopause (MP) expressed in units of an MSH thickness for all THEMIS observations. The results of both these analyses are consistent, and their comparison with simulations reveals the following features: 1) the sign of the IMF north-south component has a negligible effect on the spatial profile of the magnetic field strength or plasma parameters as well as on the level of fluctuations; 2) the ion temperature is enhanced for a radial MF and it is nearly isotropic throughout MSH; 3) the fluctuation level of plasma parameters just downstream BS is enhanced under a radial IMF, but it gradually decreases toward MP to a value typical for other IMF orientations; 4) magnetic field fluctuations are enhanced by a factor of 1.7 in the whole magnetosheath when IMF points radially.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141346746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0