Pub Date : 2024-07-09DOI: 10.3847/1538-4365/ad4a5c
N. H. Bian, Gang Li
Lagrangian perspectives on the small-scale structure of anisotropic Alfvénic turbulence are adopted. We are interested in relating the statistical properties of the Eulerian field increments evaluated along the fluid particle trajectories, in the direction perpendicular to the guiding magnetic field and along the magnetic field lines. We establish the basis for a unified multifractal phenomenology of Eulerian and Lagrangian Alfvénic turbulence. The critical balance condition is generalized to structure functions of an order different than 2. A Lagrangian perspective is not only useful for investigating the small-scale structure of Alfvénic turbulence, it is also tailored to the modeling of large-scale turbulent transport. Therefore, we develop Lagrangian stochastic models for the dispersion of fluid particles and magnetic field lines in the solar wind. The transport models are based on the integrated Ornstein–Uhlenbeck process that is not Markov, yielding smooth stochastic fluid particle trajectories and magnetic field lines. Brownian diffusion is recovered by tending the integral scale parameter to zero while keeping the diffusivity finite.
{"title":"Lagrangian Perspectives on the Small-scale Structure of Alfvénic Turbulence and Stochastic Models for the Dispersion of Fluid Particles and Magnetic Field Lines in the Solar Wind","authors":"N. H. Bian, Gang Li","doi":"10.3847/1538-4365/ad4a5c","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4a5c","url":null,"abstract":"Lagrangian perspectives on the small-scale structure of anisotropic Alfvénic turbulence are adopted. We are interested in relating the statistical properties of the Eulerian field increments evaluated along the fluid particle trajectories, in the direction perpendicular to the guiding magnetic field and along the magnetic field lines. We establish the basis for a unified multifractal phenomenology of Eulerian and Lagrangian Alfvénic turbulence. The critical balance condition is generalized to structure functions of an order different than 2. A Lagrangian perspective is not only useful for investigating the small-scale structure of Alfvénic turbulence, it is also tailored to the modeling of large-scale turbulent transport. Therefore, we develop Lagrangian stochastic models for the dispersion of fluid particles and magnetic field lines in the solar wind. The transport models are based on the integrated Ornstein–Uhlenbeck process that is not Markov, yielding smooth stochastic fluid particle trajectories and magnetic field lines. Brownian diffusion is recovered by tending the integral scale parameter to zero while keeping the diffusivity finite.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141566709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-08DOI: 10.3847/1538-4365/ad4a6f
Jihye Hong, Timothy C. Beers, Young Sun Lee, Yang Huang, Yutaka Hirai, Jonathan Cabrera Garcia, Derek Shank, Shuai Xu, Haibo Yuan, Mohammad K. Mardini, Thomas Catapano, Gang Zhao, Zhou Fan, Jie Zheng, Wei Wang, Kefeng Tan, Jingkun Zhao, Chun Li
Photometric stellar surveys now cover a large fraction of the sky, probe to fainter magnitudes than large-scale spectroscopic surveys, and are relatively free from the target selection biases often associated with such studies. Photometric-metallicity estimates that include narrow/medium-band filters can achieve comparable accuracy and precision to existing low-resolution spectroscopic surveys such as Sloan Digital Sky Survey/SEGUE and LAMOST. Here we report on an effort to identify likely members of the Galactic disk system among the very metal-poor (VMP; [Fe/H] ≤ −2) and extremely metal-poor (EMP; [Fe/H] ≤ −3) stars. Our analysis is based on an initial sample of ∼11.5 million stars with full space motions selected from the SkyMapper Southern Survey (SMSS) and Stellar Abundance and Galactic Evolution Survey (SAGES). After applying a number of quality cuts to obtain the best available metallicity and dynamical estimates, we analyze a total of ∼5.86 million stars in the combined SMSS/SAGES sample. We employ two techniques that, depending on the method, identify between 876 and 1476 VMP stars (6.9%−11.7% of all VMP stars) and between 40 and 59 EMP stars (12.4%−18.3% of all EMP stars) that appear to be members of the Galactic disk system on highly prograde orbits (vϕ > 150 km s−1). The total number of candidate VMP/EMP disklike stars is 1496, the majority of which have low orbital eccentricities, ecc ≤ 0.4; many have ecc ≤ 0.2. The large fractions of VMP/EMP stars associated with the Milky Way disk system strongly suggest the presence of an early-forming “primordial” disk.
{"title":"Candidate Members of the VMP/EMP Disk System of the Galaxy from the SkyMapper and SAGES Surveys","authors":"Jihye Hong, Timothy C. Beers, Young Sun Lee, Yang Huang, Yutaka Hirai, Jonathan Cabrera Garcia, Derek Shank, Shuai Xu, Haibo Yuan, Mohammad K. Mardini, Thomas Catapano, Gang Zhao, Zhou Fan, Jie Zheng, Wei Wang, Kefeng Tan, Jingkun Zhao, Chun Li","doi":"10.3847/1538-4365/ad4a6f","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4a6f","url":null,"abstract":"Photometric stellar surveys now cover a large fraction of the sky, probe to fainter magnitudes than large-scale spectroscopic surveys, and are relatively free from the target selection biases often associated with such studies. Photometric-metallicity estimates that include narrow/medium-band filters can achieve comparable accuracy and precision to existing low-resolution spectroscopic surveys such as Sloan Digital Sky Survey/SEGUE and LAMOST. Here we report on an effort to identify likely members of the Galactic disk system among the very metal-poor (VMP; [Fe/H] ≤ −2) and extremely metal-poor (EMP; [Fe/H] ≤ −3) stars. Our analysis is based on an initial sample of ∼11.5 million stars with full space motions selected from the SkyMapper Southern Survey (SMSS) and Stellar Abundance and Galactic Evolution Survey (SAGES). After applying a number of quality cuts to obtain the best available metallicity and dynamical estimates, we analyze a total of ∼5.86 million stars in the combined SMSS/SAGES sample. We employ two techniques that, depending on the method, identify between 876 and 1476 VMP stars (6.9%−11.7% of all VMP stars) and between 40 and 59 EMP stars (12.4%−18.3% of all EMP stars) that appear to be members of the Galactic disk system on highly prograde orbits (<italic toggle=\"yes\">v</italic>\u0000<sub>\u0000<italic toggle=\"yes\">ϕ</italic>\u0000</sub> > 150 km s<sup>−1</sup>). The total number of candidate VMP/EMP disklike stars is 1496, the majority of which have low orbital eccentricities, ecc ≤ 0.4; many have ecc ≤ 0.2. The large fractions of VMP/EMP stars associated with the Milky Way disk system strongly suggest the presence of an early-forming “primordial” disk.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141566710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-08DOI: 10.3847/1538-4365/ad3cd3
Daniel Maschmann, Janice C. Lee, David A. Thilker, Bradley C. Whitmore, Sinan Deger, Médéric Boquien, Rupali Chandar, Daniel A. Dale, Aida Wofford, Stephen Hannon, Kirsten L. Larson, Adam K. Leroy, Eva Schinnerer, Erik Rosolowsky, Leonardo Úbeda, Ashley T. Barnes, Eric Emsellem, Kathryn Grasha, Brent Groves, Rémy Indebetouw, Hwihyun Kim, Ralf S. Klessen, Kathryn Kreckel, Rebecca C. Levy, Francesca Pinna, M. Jimena Rodríguez, Qiushi Tian and Thomas G. Williams
We present the largest catalog to date of star clusters and compact associations in nearby galaxies. We have performed a V-band-selected census of clusters across the 38 spiral galaxies of the PHANGS–Hubble Space Telescope (HST) Treasury Survey, and measured integrated, aperture-corrected near-ultraviolet-U-B-V-I photometry. This work has resulted in uniform catalogs that contain ∼20,000 clusters and compact associations, which have passed human inspection and morphological classification, and a larger sample of ∼100,000 classified by neural network models. Here, we report on the observed properties of these samples, and demonstrate that tremendous insight can be gained from just the observed properties of clusters, even in the absence of their transformation into physical quantities. In particular, we show the utility of the UBVI color–color diagram, and the three principal features revealed by the PHANGS-HST cluster sample: the young cluster locus, the middle-age plume, and the old globular cluster clump. We present an atlas of maps of the 2D spatial distribution of clusters and compact associations in the context of the molecular clouds from PHANGS–Atacama Large Millimeter/submillimeter Array. We explore new ways of understanding this large data set in a multiscale context by bringing together once-separate techniques for the characterization of clusters (color–color diagrams and spatial distributions) and their parent galaxies (galaxy morphology and location relative to the galaxy main sequence). A companion paper presents the physical properties: ages, masses, and dust reddenings derived using improved spectral energy distribution fitting techniques.
{"title":"PHANGS-HST Catalogs for ∼100,000 Star Clusters and Compact Associations in 38 Galaxies. I. Observed Properties","authors":"Daniel Maschmann, Janice C. Lee, David A. Thilker, Bradley C. Whitmore, Sinan Deger, Médéric Boquien, Rupali Chandar, Daniel A. Dale, Aida Wofford, Stephen Hannon, Kirsten L. Larson, Adam K. Leroy, Eva Schinnerer, Erik Rosolowsky, Leonardo Úbeda, Ashley T. Barnes, Eric Emsellem, Kathryn Grasha, Brent Groves, Rémy Indebetouw, Hwihyun Kim, Ralf S. Klessen, Kathryn Kreckel, Rebecca C. Levy, Francesca Pinna, M. Jimena Rodríguez, Qiushi Tian and Thomas G. Williams","doi":"10.3847/1538-4365/ad3cd3","DOIUrl":"https://doi.org/10.3847/1538-4365/ad3cd3","url":null,"abstract":"We present the largest catalog to date of star clusters and compact associations in nearby galaxies. We have performed a V-band-selected census of clusters across the 38 spiral galaxies of the PHANGS–Hubble Space Telescope (HST) Treasury Survey, and measured integrated, aperture-corrected near-ultraviolet-U-B-V-I photometry. This work has resulted in uniform catalogs that contain ∼20,000 clusters and compact associations, which have passed human inspection and morphological classification, and a larger sample of ∼100,000 classified by neural network models. Here, we report on the observed properties of these samples, and demonstrate that tremendous insight can be gained from just the observed properties of clusters, even in the absence of their transformation into physical quantities. In particular, we show the utility of the UBVI color–color diagram, and the three principal features revealed by the PHANGS-HST cluster sample: the young cluster locus, the middle-age plume, and the old globular cluster clump. We present an atlas of maps of the 2D spatial distribution of clusters and compact associations in the context of the molecular clouds from PHANGS–Atacama Large Millimeter/submillimeter Array. We explore new ways of understanding this large data set in a multiscale context by bringing together once-separate techniques for the characterization of clusters (color–color diagrams and spatial distributions) and their parent galaxies (galaxy morphology and location relative to the galaxy main sequence). A companion paper presents the physical properties: ages, masses, and dust reddenings derived using improved spectral energy distribution fitting techniques.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141566712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-08DOI: 10.3847/1538-4365/ad4be5
Thomas G. Williams, Janice C. Lee, Kirsten L. Larson, Adam K. Leroy, Karin Sandstrom, Eva Schinnerer, David A. Thilker, Francesco Belfiore, Oleg V. Egorov, Erik Rosolowsky, Jessica Sutter, Joseph DePasquale, Alyssa Pagan, Travis A. Berger, Gagandeep S. Anand, Ashley T. Barnes, Frank Bigiel, Médéric Boquien, Yixian Cao, Jérémy Chastenet, Mélanie Chevance, Ryan Chown, Daniel A. Dale, Sinan Deger, Cosima Eibensteiner, Eric Emsellem, Christopher M. Faesi, Simon C. O. Glover, Kathryn Grasha, Stephen Hannon, Hamid Hassani, Jonathan D. Henshaw, María J. Jiménez-Donaire, Jaeyeon Kim, Ralf S. Klessen, Eric W. Koch, Jing Li, Daizhong Liu, Sharon E. Meidt, J. Eduardo Méndez-Delgado, Eric J. Murphy, Justus Neumann, Lukas Neumann, Nadine Neumayer, Elias K. Oakes, Debosmita Pathak, Jérôme Pety, Francesca Pinna, Miguel Querejeta, Lise Ramambason, Andrea Romanelli, Mattia C. Sormani, Sophia K. Stuber, Jiayi Sun, Yu-Hsuan Teng, Antonio Usero, Elizabeth J. Watkins and Tony D. Weinbeck
The exquisite angular resolution and sensitivity of JWST are opening a new window for our understanding of the Universe. In nearby galaxies, JWST observations are revolutionizing our understanding of the first phases of star formation and the dusty interstellar medium. Nineteen local galaxies spanning a range of properties and morphologies across the star-forming main sequence have been observed as part of the PHANGS-JWST Cycle 1 Treasury program at spatial scales of ∼5–50 pc. Here, we describe pjpipe, an image-processing pipeline developed for the PHANGS-JWST program that wraps around and extends the official JWST pipeline. We release this pipeline to the community as it contains a number of tools generally useful for JWST NIRCam and MIRI observations. Particularly for extended sources, pjpipe products provide significant improvements over mosaics from the MAST archive in terms of removing instrumental noise in NIRCam data, background flux matching, and calibration of relative and absolute astrometry. We show that slightly smoothing F2100W MIRI data to 0.″9 (degrading the resolution by about 30%) reduces the noise by a factor of ≈3. We also present the first public release (DR1.1.0) of the pjpipe processed eight-band 2–21 μm imaging for all 19 galaxies in the PHANGS-JWST Cycle 1 Treasury program. An additional 55 galaxies will soon follow from a new PHANGS-JWST Cycle 2 Treasury program.
{"title":"PHANGS-JWST: Data-processing Pipeline and First Full Public Data Release","authors":"Thomas G. Williams, Janice C. Lee, Kirsten L. Larson, Adam K. Leroy, Karin Sandstrom, Eva Schinnerer, David A. Thilker, Francesco Belfiore, Oleg V. Egorov, Erik Rosolowsky, Jessica Sutter, Joseph DePasquale, Alyssa Pagan, Travis A. Berger, Gagandeep S. Anand, Ashley T. Barnes, Frank Bigiel, Médéric Boquien, Yixian Cao, Jérémy Chastenet, Mélanie Chevance, Ryan Chown, Daniel A. Dale, Sinan Deger, Cosima Eibensteiner, Eric Emsellem, Christopher M. Faesi, Simon C. O. Glover, Kathryn Grasha, Stephen Hannon, Hamid Hassani, Jonathan D. Henshaw, María J. Jiménez-Donaire, Jaeyeon Kim, Ralf S. Klessen, Eric W. Koch, Jing Li, Daizhong Liu, Sharon E. Meidt, J. Eduardo Méndez-Delgado, Eric J. Murphy, Justus Neumann, Lukas Neumann, Nadine Neumayer, Elias K. Oakes, Debosmita Pathak, Jérôme Pety, Francesca Pinna, Miguel Querejeta, Lise Ramambason, Andrea Romanelli, Mattia C. Sormani, Sophia K. Stuber, Jiayi Sun, Yu-Hsuan Teng, Antonio Usero, Elizabeth J. Watkins and Tony D. Weinbeck","doi":"10.3847/1538-4365/ad4be5","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4be5","url":null,"abstract":"The exquisite angular resolution and sensitivity of JWST are opening a new window for our understanding of the Universe. In nearby galaxies, JWST observations are revolutionizing our understanding of the first phases of star formation and the dusty interstellar medium. Nineteen local galaxies spanning a range of properties and morphologies across the star-forming main sequence have been observed as part of the PHANGS-JWST Cycle 1 Treasury program at spatial scales of ∼5–50 pc. Here, we describe pjpipe, an image-processing pipeline developed for the PHANGS-JWST program that wraps around and extends the official JWST pipeline. We release this pipeline to the community as it contains a number of tools generally useful for JWST NIRCam and MIRI observations. Particularly for extended sources, pjpipe products provide significant improvements over mosaics from the MAST archive in terms of removing instrumental noise in NIRCam data, background flux matching, and calibration of relative and absolute astrometry. We show that slightly smoothing F2100W MIRI data to 0.″9 (degrading the resolution by about 30%) reduces the noise by a factor of ≈3. We also present the first public release (DR1.1.0) of the pjpipe processed eight-band 2–21 μm imaging for all 19 galaxies in the PHANGS-JWST Cycle 1 Treasury program. An additional 55 galaxies will soon follow from a new PHANGS-JWST Cycle 2 Treasury program.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141587306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.3847/1538-4365/ad40a1
Amanda Pagul, F. Javier Sánchez, Iary Davidzon, Anton M. Koekemoer, Bahram Mobasher, Mathilde Jauzac, Charles L. Steinhardt, Hakim Atek, Renyue Cen, Iryna Chemerynska, Lukas J. Furtak, David J. Lagattuta, Guillaume Mahler, Mireia Montes, Mario Nonino, Keren Sharon and John R. Weaver
This article presents new astronomical source catalogs using data from the BUFFALO Survey. These catalogs contain detailed information for over 100,000 astronomical sources in the six BUFFALO clusters: A370, A2744, AS1063, MACS 0416, MACS 0717, and MACS 1149 spanning a total of 240 arcmin2. The catalogs include positions and forced photometry measurements of these objects in the F275W, F336W, F435W, F606W, F814W, F105W, F125W, F140W, and F160W HST bands, Keck-NIRC2/VLT-HAWKI Ks band, and IRAC Channel 1 and 2 bands. Additionally, we include photometry measurements in the F475W, F625W, and F110W bands for A370. This catalog also includes photometric redshift estimates computed via template fitting using LePhare. When comparing to a spectroscopic reference, we obtain an outlier fraction of 8.6% and scatter, normalized median absolute deviation, of 0.059. The catalogs are publicly available for their use by the community (https://archive.stsci.edu/hlsp/buffalo/).
{"title":"Self-consistent Combined HST, K-band, and Spitzer Photometric Catalogs of the BUFFALO Survey Fields","authors":"Amanda Pagul, F. Javier Sánchez, Iary Davidzon, Anton M. Koekemoer, Bahram Mobasher, Mathilde Jauzac, Charles L. Steinhardt, Hakim Atek, Renyue Cen, Iryna Chemerynska, Lukas J. Furtak, David J. Lagattuta, Guillaume Mahler, Mireia Montes, Mario Nonino, Keren Sharon and John R. Weaver","doi":"10.3847/1538-4365/ad40a1","DOIUrl":"https://doi.org/10.3847/1538-4365/ad40a1","url":null,"abstract":"This article presents new astronomical source catalogs using data from the BUFFALO Survey. These catalogs contain detailed information for over 100,000 astronomical sources in the six BUFFALO clusters: A370, A2744, AS1063, MACS 0416, MACS 0717, and MACS 1149 spanning a total of 240 arcmin2. The catalogs include positions and forced photometry measurements of these objects in the F275W, F336W, F435W, F606W, F814W, F105W, F125W, F140W, and F160W HST bands, Keck-NIRC2/VLT-HAWKI Ks band, and IRAC Channel 1 and 2 bands. Additionally, we include photometry measurements in the F475W, F625W, and F110W bands for A370. This catalog also includes photometric redshift estimates computed via template fitting using LePhare. When comparing to a spectroscopic reference, we obtain an outlier fraction of 8.6% and scatter, normalized median absolute deviation, of 0.059. The catalogs are publicly available for their use by the community (https://archive.stsci.edu/hlsp/buffalo/).","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"130 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141552509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.3847/1538-4365/ad4bdf
Daniela Maci, Rony Keppens and Fabio Bacchini
Turbulent states are ubiquitous in plasmas, and the understanding of turbulence is fundamental in modern astrophysics. Numerical simulations, which are the state-of-the-art approach to the study of turbulence, require substantial computing resources. Recently, attention shifted to methods for generating synthetic turbulent magnetic fields, affordably creating fields with parameter-controlled characteristic features of turbulence. In this context, the BxC toolkit was developed and validated against direct numerical simulations (DNSs) of isotropic turbulent magnetic fields. Here, we demonstrate novel extensions of BxC to generate realistic turbulent magnetic fields in a fast, controlled, geometric approach. First, we perform a parameter study to determine quantitative relations between the BxC input parameters and the desired characteristic features of the turbulent power spectrum, such as the extent of the inertial range, its spectral slope, and the injection and dissipation scale. Second, we introduce in the model a set of structured background magnetic fields, B0, as a natural and more realistic extension to the purely isotropic turbulent fields. Third, we extend the model to include anisotropic turbulence properties in the generated fields. With all these extensions combined, our tool can quickly generate any desired structured magnetic field with controlled, anisotropic turbulent fluctuations, faster by orders of magnitude with respect to DNSs. These can be used, e.g., to provide initial conditions for DNSs or easily generate synthetic data for many astrophysical settings, all at otherwise unaffordable resolutions.
湍流状态在等离子体中无处不在，对湍流的了解是现代天体物理学的基础。数值模拟是研究湍流的最先进方法，需要大量计算资源。最近，人们的注意力转移到了生成合成湍流磁场的方法上，这种磁场具有参数控制的湍流特征。在此背景下，我们开发了 BxC 工具包，并根据各向同性湍流磁场的直接数值模拟（DNS）进行了验证。在此，我们展示了 BxC 的新扩展，以快速、可控的几何方法生成逼真的湍流磁场。首先，我们进行了参数研究，以确定 BxC 输入参数与所需的湍流功率谱特征之间的定量关系，如惯性范围、光谱斜率以及注入和耗散尺度。其次，我们在模型中引入了一组结构化背景磁场 B0，作为纯各向同性湍流场的自然和更现实的扩展。第三，我们对模型进行了扩展，将各向异性的湍流特性纳入生成的场中。结合所有这些扩展，我们的工具可以快速生成任何所需的结构磁场，并具有可控的各向异性湍流波动，速度比 DNS 快几个数量级。这些数据可用于为 DNS 提供初始条件，或为许多天体物理环境轻松生成合成数据，而所有这些数据的分辨率都是难以承受的。
{"title":"BxC Toolkit: Generating Tailored Turbulent 3D Magnetic Fields","authors":"Daniela Maci, Rony Keppens and Fabio Bacchini","doi":"10.3847/1538-4365/ad4bdf","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4bdf","url":null,"abstract":"Turbulent states are ubiquitous in plasmas, and the understanding of turbulence is fundamental in modern astrophysics. Numerical simulations, which are the state-of-the-art approach to the study of turbulence, require substantial computing resources. Recently, attention shifted to methods for generating synthetic turbulent magnetic fields, affordably creating fields with parameter-controlled characteristic features of turbulence. In this context, the BxC toolkit was developed and validated against direct numerical simulations (DNSs) of isotropic turbulent magnetic fields. Here, we demonstrate novel extensions of BxC to generate realistic turbulent magnetic fields in a fast, controlled, geometric approach. First, we perform a parameter study to determine quantitative relations between the BxC input parameters and the desired characteristic features of the turbulent power spectrum, such as the extent of the inertial range, its spectral slope, and the injection and dissipation scale. Second, we introduce in the model a set of structured background magnetic fields, B0, as a natural and more realistic extension to the purely isotropic turbulent fields. Third, we extend the model to include anisotropic turbulence properties in the generated fields. With all these extensions combined, our tool can quickly generate any desired structured magnetic field with controlled, anisotropic turbulent fluctuations, faster by orders of magnitude with respect to DNSs. These can be used, e.g., to provide initial conditions for DNSs or easily generate synthetic data for many astrophysical settings, all at otherwise unaffordable resolutions.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141552511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-30DOI: 10.3847/1538-4365/ad45f9
Hongrui Gu, 弘睿 顾, Haibo Yuan, 海波 苑, Subo Dong, 苏勃 东, Chenfa Zheng, 晨发 郑, Shenzhe Cui, 深哲 崔, Yi Ren, 逸 任, Haozhu Fu, 皓竹 付, Yang Huang, 样 黄, Zhou Fan and 舟 范
Utilizing high-cadence and continuous g- and r-band data over three nights acquired from the 3.6 m Canada–France–Hawaii Telescope, aiming to find short-duration microlensing events, we conduct a systematic search for variables, transients, and asteroids across a ∼1° field of view of the Andromeda galaxy (M31). We present a catalog of 5859 variable stars, yielding the most extensive compilation of short-period variable sources of M31. We also detected 19 flares, predominantly associated with foreground M dwarfs in the Milky Way. In addition, we discovered 17 previously unknown asteroid candidates, and we subsequently reported them to the Minor Planet Center. Lastly, we report a microlensing event candidate C-ML-1 and present a preliminary analysis.
我们利用从 3.6 米加拿大-法国-夏威夷望远镜上获取的三个晚上的高干度连续 g 波段和 r 波段数据，以寻找短时微透镜事件为目标，对仙女座星系（M31）1° 视场范围内的变星、瞬变星和小行星进行了系统搜索。我们提供了一份包含 5859 颗变星的星表，这是对 M31 短周期变源最广泛的汇编。我们还探测到了 19 个耀斑，主要与银河系中的前景 M 矮星有关。此外，我们还发现了 17 颗以前未知的候选小行星，并随后将它们报告给了小行星中心。最后，我们报告了一个候选微透镜事件 C-ML-1，并进行了初步分析。
{"title":"Searching for Short-period Variables in M31: Method and Catalogs","authors":"Hongrui Gu, 弘睿 顾, Haibo Yuan, 海波 苑, Subo Dong, 苏勃 东, Chenfa Zheng, 晨发 郑, Shenzhe Cui, 深哲 崔, Yi Ren, 逸 任, Haozhu Fu, 皓竹 付, Yang Huang, 样 黄, Zhou Fan and 舟 范","doi":"10.3847/1538-4365/ad45f9","DOIUrl":"https://doi.org/10.3847/1538-4365/ad45f9","url":null,"abstract":"Utilizing high-cadence and continuous g- and r-band data over three nights acquired from the 3.6 m Canada–France–Hawaii Telescope, aiming to find short-duration microlensing events, we conduct a systematic search for variables, transients, and asteroids across a ∼1° field of view of the Andromeda galaxy (M31). We present a catalog of 5859 variable stars, yielding the most extensive compilation of short-period variable sources of M31. We also detected 19 flares, predominantly associated with foreground M dwarfs in the Milky Way. In addition, we discovered 17 previously unknown asteroid candidates, and we subsequently reported them to the Minor Planet Center. Lastly, we report a microlensing event candidate C-ML-1 and present a preliminary analysis.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-27DOI: 10.3847/1538-4365/ad4da6
Qi Jia, Xiaodian Chen, Shu Wang, Licai Deng, Yangping Luo and Qingquan Jiang
We obtain the largest catalog of multimode δ Sct stars in the northern sky to date using the Zwicky Transient Facility (ZTF) Data Release 20. The catalog includes 2254 objects, of which 2181 are new to our study. Among these multimode δ Sct stars, 2142 objects are double-mode δ Sct, while 109 objects are triple-mode δ Sct and three are quadruple-mode δ Sct. By analyzing the light curves in the r and g bands of the ZTF, we determine the basic parameters of multimode δ Sct stars, including the periods and amplitudes. Periods are checked by comparison with the Optical Gravitational Lensing Experiment catalog of double-mode δ Sct stars. On the Petersen diagram, multimode δ Sct stars form six sequences. We find that in Galactic coordinates, the periods of 1O/F double-mode δ Sct stars at high latitudes are shorter than those of 1O/F double-mode δ Sct stars in the disk, due to metallicity variations. In the future, our catalog can be used to establish the period–luminosity relation and the period–metallicity relation of double-mode δ Sct stars, and to study the Galactic structure.
我们利用兹威基瞬变设施（ZTF）第20版数据，获得了迄今为止北天最大的多模δSct星表。星表包括2254个天体，其中2181个是我们研究的新天体。在这些多模δSct星中，2142个是双模δSct星，109个是三模δSct星，3个是四模δSct星。通过分析 ZTF r 波段和 g 波段的光曲线，我们确定了多模 δ Sct 星的基本参数，包括周期和振幅。周期是通过与光学引力透镜实验的双模δSct 星目录进行比较来检验的。在彼得森图上，多模δ Sct 星形成了六个序列。我们发现，在银河系坐标中，由于金属性的变化，高纬度地区的1O/F双模δSct恒星的周期要比盘面上的1O/F双模δSct恒星的周期短。今后，我们的星表可以用来建立双模δSct星的周期-光度关系和周期-金属性关系，以及研究银河系结构。
{"title":"Multimode δ Sct stars from the Zwicky Transient Facility Survey","authors":"Qi Jia, Xiaodian Chen, Shu Wang, Licai Deng, Yangping Luo and Qingquan Jiang","doi":"10.3847/1538-4365/ad4da6","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4da6","url":null,"abstract":"We obtain the largest catalog of multimode δ Sct stars in the northern sky to date using the Zwicky Transient Facility (ZTF) Data Release 20. The catalog includes 2254 objects, of which 2181 are new to our study. Among these multimode δ Sct stars, 2142 objects are double-mode δ Sct, while 109 objects are triple-mode δ Sct and three are quadruple-mode δ Sct. By analyzing the light curves in the r and g bands of the ZTF, we determine the basic parameters of multimode δ Sct stars, including the periods and amplitudes. Periods are checked by comparison with the Optical Gravitational Lensing Experiment catalog of double-mode δ Sct stars. On the Petersen diagram, multimode δ Sct stars form six sequences. We find that in Galactic coordinates, the periods of 1O/F double-mode δ Sct stars at high latitudes are shorter than those of 1O/F double-mode δ Sct stars in the disk, due to metallicity variations. In the future, our catalog can be used to establish the period–luminosity relation and the period–metallicity relation of double-mode δ Sct stars, and to study the Galactic structure.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141527980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-27DOI: 10.3847/1538-4365/ad4b17
Henggeng Han, Song Wang, Chuanjie Zheng, Xue Li, Kai Xiao and Jifeng Liu
Using the homogeneous X-ray catalog from ROSAT observations, we conducted a comprehensive investigation into stellar X-ray activity–rotation relations for both single and binary stars. Generally, the relation for single stars consists of two distinct regions: a weak decay region, indicating a continued dependence of the magnetic dynamo on stellar rotation rather than a saturation regime with constant activity, and a rapid decay region, where X-ray activity is strongly correlated with the Rossby number. Detailed analysis reveals more fine structures within the relation: in the extremely fast-rotating regime, a decrease in X-ray activity was observed with increasing rotation rate, referred to as supersaturation, while in the extremely slow-rotating region, the relation flattens, mainly due to the scattering of F stars. This scattering may result from intrinsic variability in stellar activities over one stellar cycle or the presence of different dynamo mechanisms. Binaries exhibit a similar relation to that of single stars while the limited sample size prevented the identification of fine structures in the relation for binaries. We calculated the mass-loss rates of planetary atmospheres triggered by X-ray emissions from host stars. Our findings indicate that for an Earthlike planet within the stellar habitable zone, it would easily lose its entire primordial H/He envelope (equating to about 1% of the planetary mass).
利用来自 ROSAT 观测的同质 X 射线星表，我们对单星和双星的恒星 X 射线活动-旋转关系进行了全面研究。一般来说，单星的关系由两个不同的区域组成：一个是弱衰减区，表明磁动力持续依赖于恒星旋转，而不是恒定活动的饱和状态；另一个是快速衰减区，X射线活动与罗斯比数密切相关。详细分析揭示了这一关系中的更多细微结构：在极速旋转区，观测到 X 射线活动随着旋转速率的增加而减少，这被称为过饱和；而在极慢速旋转区，这一关系趋于平缓，这主要是由于 F 星的散射造成的。这种散射可能是由于恒星活动在一个恒星周期内的内在可变性或存在不同的动力机制造成的。双星表现出与单星类似的关系，但由于样本量有限，无法识别双星关系中的精细结构。我们计算了宿主星的 X 射线辐射引发的行星大气质量损失率。我们的研究结果表明，对于恒星宜居带内的类地行星来说，它很容易就会失去整个原始H/He包层（约等于行星质量的1%）。
{"title":"Stellar X-Ray Activity and Habitability Revealed by the ROSAT Sky Survey","authors":"Henggeng Han, Song Wang, Chuanjie Zheng, Xue Li, Kai Xiao and Jifeng Liu","doi":"10.3847/1538-4365/ad4b17","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4b17","url":null,"abstract":"Using the homogeneous X-ray catalog from ROSAT observations, we conducted a comprehensive investigation into stellar X-ray activity–rotation relations for both single and binary stars. Generally, the relation for single stars consists of two distinct regions: a weak decay region, indicating a continued dependence of the magnetic dynamo on stellar rotation rather than a saturation regime with constant activity, and a rapid decay region, where X-ray activity is strongly correlated with the Rossby number. Detailed analysis reveals more fine structures within the relation: in the extremely fast-rotating regime, a decrease in X-ray activity was observed with increasing rotation rate, referred to as supersaturation, while in the extremely slow-rotating region, the relation flattens, mainly due to the scattering of F stars. This scattering may result from intrinsic variability in stellar activities over one stellar cycle or the presence of different dynamo mechanisms. Binaries exhibit a similar relation to that of single stars while the limited sample size prevented the identification of fine structures in the relation for binaries. We calculated the mass-loss rates of planetary atmospheres triggered by X-ray emissions from host stars. Our findings indicate that for an Earthlike planet within the stellar habitable zone, it would easily lose its entire primordial H/He envelope (equating to about 1% of the planetary mass).","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-25DOI: 10.3847/1538-4365/ad43ec
Albert Bruch
Based mainly on the months-long 2 minutes time-resolution light curves observed by the Transiting Exoplanet Survey Telescope (TESS) space mission of 48 eclipsing old novae and novalike variables (commonly referred to as NLs) selected from the Ritter & Kolb catalog, a synoptic view of some basic properties of these systems is provided. The supraorbital variations exhibit a large diversity of behavior. Data taken from the literature and many additional eclipse epochs measured in the TESS and in AAVSO light curves are used to update the orbital ephemerides of 21 targets. The large majority of these suffer period variations which defy current theoretical understanding. Orbital waveforms are constructed and, if possible, their variation over time is studied, revealing some common characteristics but also substantial differences between individual systems. The dependence of the eclipse depth on the out-of-eclipse flux reveals that in all systems a fraction of the light source responsible for the out-of-eclipse variations escapes eclipse and is probably located in the outer disk regions. In systems exhibiting superhumps, both eclipse width and epoch are modulated with the accretion disk precession period. This suggests an expansion and contraction of the eclipsed light source, as well as a periodic shift of its light center as a function of the accretion disk precession phase. The dependence of the orbital and superhump waveforms on the disk precession phase is also examined but does not lead to a consistent picture. Two cataclysmic variables are newly identified as eclipsing. Attention is drawn to specific peculiarities in some of the target stars.
{"title":"TESS Light Curves of Cataclysmic Variables. IV. A Synoptic View of Eclipsing Old Novae and Novalike Variables","authors":"Albert Bruch","doi":"10.3847/1538-4365/ad43ec","DOIUrl":"https://doi.org/10.3847/1538-4365/ad43ec","url":null,"abstract":"Based mainly on the months-long 2 minutes time-resolution light curves observed by the Transiting Exoplanet Survey Telescope (TESS) space mission of 48 eclipsing old novae and novalike variables (commonly referred to as NLs) selected from the Ritter & Kolb catalog, a synoptic view of some basic properties of these systems is provided. The supraorbital variations exhibit a large diversity of behavior. Data taken from the literature and many additional eclipse epochs measured in the TESS and in AAVSO light curves are used to update the orbital ephemerides of 21 targets. The large majority of these suffer period variations which defy current theoretical understanding. Orbital waveforms are constructed and, if possible, their variation over time is studied, revealing some common characteristics but also substantial differences between individual systems. The dependence of the eclipse depth on the out-of-eclipse flux reveals that in all systems a fraction of the light source responsible for the out-of-eclipse variations escapes eclipse and is probably located in the outer disk regions. In systems exhibiting superhumps, both eclipse width and epoch are modulated with the accretion disk precession period. This suggests an expansion and contraction of the eclipsed light source, as well as a periodic shift of its light center as a function of the accretion disk precession phase. The dependence of the orbital and superhump waveforms on the disk precession phase is also examined but does not lead to a consistent picture. Two cataclysmic variables are newly identified as eclipsing. Attention is drawn to specific peculiarities in some of the target stars.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：