Pub Date : 2024-06-01DOI: 10.3847/1538-4365/ad3fba
India Jackson, Petrus Martens
Solar energetic particles (SEPs) pose significant challenges to technology, astronaut health, and space missions. This initial paper in our two-part series undertakes a comprehensive analysis of the time to detection for SEPs, applying advanced statistical techniques and cloud-computing resources to deepen our understanding of SEP event probabilities over time. We employ a range of models encompassing nonparametric, semiparametric, and parametric approaches, such as the Kaplan–Meier estimator and Cox Proportional Hazards models. These are complemented by various distribution models—including exponential, Weibull, lognormal, and log-logistic distributions—to effectively tackle the challenges associated with “censored data,” a common issue in survival analysis. Employing Amazon Web Services and Python’s “lifelines” and “scikit-survival” libraries, we efficiently preprocess and analyze large data sets. This methodical approach not only enhances our current analysis, but also sets a robust statistical foundation for the development of predictive models, which will be the focus of the subsequent paper. In identifying the key determinants that affect the timing of SEP detection, we establish the vital features that will inform the machine-learning (ML) techniques explored in the second paper. There, we will utilize advanced ML models—such as survival trees and random survival forests—to evolve SEP event prediction capabilities. This research is committed to advancing space weather, strengthening the safety of space-borne technology, and safeguarding astronaut health.
{"title":"Advancing Solar Energetic Particle Event Prediction through Survival Analysis and Cloud Computing. I. Kaplan–Meier Estimation and Cox Proportional Hazards Modeling","authors":"India Jackson, Petrus Martens","doi":"10.3847/1538-4365/ad3fba","DOIUrl":"https://doi.org/10.3847/1538-4365/ad3fba","url":null,"abstract":"Solar energetic particles (SEPs) pose significant challenges to technology, astronaut health, and space missions. This initial paper in our two-part series undertakes a comprehensive analysis of the time to detection for SEPs, applying advanced statistical techniques and cloud-computing resources to deepen our understanding of SEP event probabilities over time. We employ a range of models encompassing nonparametric, semiparametric, and parametric approaches, such as the Kaplan–Meier estimator and Cox Proportional Hazards models. These are complemented by various distribution models—including exponential, Weibull, lognormal, and log-logistic distributions—to effectively tackle the challenges associated with “censored data,” a common issue in survival analysis. Employing Amazon Web Services and Python’s “lifelines” and “scikit-survival” libraries, we efficiently preprocess and analyze large data sets. This methodical approach not only enhances our current analysis, but also sets a robust statistical foundation for the development of predictive models, which will be the focus of the subsequent paper. In identifying the key determinants that affect the timing of SEP detection, we establish the vital features that will inform the machine-learning (ML) techniques explored in the second paper. There, we will utilize advanced ML models—such as survival trees and random survival forests—to evolve SEP event prediction capabilities. This research is committed to advancing space weather, strengthening the safety of space-borne technology, and safeguarding astronaut health.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"37 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141410498","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 : 2024-06-01DOI: 10.3847/1538-4365/ad487c
Woowon Byun, Minjin Kim, Y. Sheen, Dongseob Lee, L. C. Ho, Jongwan Ko, K. Seon, H. Shim, Dohyeong Kim, Yongjung Kim, J. Lee, Hyunjin Jeong, Jong-Hak Woo, Woong-Seob Jeong, Byeong-Gon Park, Sang Chul Kim, Yongseok Lee, S. Cha, Hyunmi Song, D. Son, Yujin Yang
{"title":"Erratum: “Photometric Selection of Unobscured QSOs at the Ecliptic Poles: KMTNet in the South Field and Pan-STARRS in the North Field” (2023, ApJS, 268, 57)","authors":"Woowon Byun, Minjin Kim, Y. Sheen, Dongseob Lee, L. C. Ho, Jongwan Ko, K. Seon, H. Shim, Dohyeong Kim, Yongjung Kim, J. Lee, Hyunjin Jeong, Jong-Hak Woo, Woong-Seob Jeong, Byeong-Gon Park, Sang Chul Kim, Yongseok Lee, S. Cha, Hyunmi Song, D. Son, Yujin Yang","doi":"10.3847/1538-4365/ad487c","DOIUrl":"https://doi.org/10.3847/1538-4365/ad487c","url":null,"abstract":"","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"56 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141409980","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 : 2024-06-01DOI: 10.3847/1538-4365/ad4107
Hai-Feng 海峰 Yang 杨, Rui 瑞 Wang 王, Jiang-Hui 江辉 Cai 蔡, A-Li 阿理 Luo 罗, Bing 冰 Du 杜, Yan-Ting 艳婷 He 贺, Mei-Hong 美红 Su 苏, Chen-Hui 晨辉 Shi 史, Xu-Jun 旭俊 Zhao 赵, Ya-Ling 亚玲 Xun 荀, Yi-Nan 艺楠 Yuan 员
Large samples of Am and Ap stars are helpful in studying the interplay between phenomena like atomic diffusion, magnetic fields, and stellar rotation in stellar astrophysics. Existing samples of Am and Ap stars, mostly obtained from spectral data with a signal-to-noise ratio in the g band (S/Ng) greater than 50, can benefit from expansion by exploring spectra with lower S/Ng. Therefore, this paper proposes an ensemble regression model applicable to spectra with a minimum S/Ng of 30. Using the model, we identify 21,361 Am candidates, of which 11,614 are new, and 6182 Ap candidates, of which 4978 are new, from LAMOST DR10. The Am sample size has increased by 60% and the Ap sample size has increased by 180% compared to the previous sample. In terms of effective temperature (T eff), the Am candidates range mainly from 6000 to 8500 K, while the Ap candidates range from 6000 to 11,700 K. The surface gravity ( logg ) distributions for Am and Ap candidates differ in the range of 3.25–4.75 dex. The number of Am candidates increases stepwise, in contrast to the relatively uniform distribution of Ap candidates across the entire surface gravity range. Regarding metallicity ([Fe/H]), Am candidates typically range from −0.75 to 0.38 dex, peaking near 0 dex, while Ap candidates are distributed from −1.38 to 0.38 dex, with a peak near −0.5 dex.
大量的Am和Ap恒星样本有助于研究恒星天体物理学中原子扩散、磁场和恒星旋转等现象之间的相互作用。现有的 Am 星和 Ap 星样本大多是从 g 波段信噪比（S/Ng）大于 50 的光谱数据中获得的。因此，本文提出了一个适用于最小信噪比为 30 的光谱的集合回归模型。利用该模型，我们从 LAMOST DR10 中识别出 21,361 个 Am 候选天体，其中 11,614 个是新天体；6182 个 Ap 候选天体，其中 4978 个是新天体。与之前的样本相比，Am 样本增加了 60%，Ap 样本增加了 180%。在有效温度（T eff）方面，Am候选星的范围主要在6000-8500 K之间，而Ap候选星的范围则在6000-11700 K之间。Am和Ap候选星的表面引力（logg）分布差异在3.25-4.75 dex之间。Am候选星的数量呈阶梯状增加，而Ap候选星则在整个表面引力范围内分布相对均匀。在金属性（[Fe/H]）方面，Am 候选星的典型分布范围为-0.75-0.38 dex，在 0 dex 附近达到峰值；而 Ap 候选星的分布范围为-1.38-0.38 dex，在-0.5 dex 附近达到峰值。
{"title":"A Sample of Am and Ap Candidates from LAMOST DR10 (v1.0) Based on the Ensemble Regression Model","authors":"Hai-Feng 海峰 Yang 杨, Rui 瑞 Wang 王, Jiang-Hui 江辉 Cai 蔡, A-Li 阿理 Luo 罗, Bing 冰 Du 杜, Yan-Ting 艳婷 He 贺, Mei-Hong 美红 Su 苏, Chen-Hui 晨辉 Shi 史, Xu-Jun 旭俊 Zhao 赵, Ya-Ling 亚玲 Xun 荀, Yi-Nan 艺楠 Yuan 员","doi":"10.3847/1538-4365/ad4107","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4107","url":null,"abstract":"Large samples of Am and Ap stars are helpful in studying the interplay between phenomena like atomic diffusion, magnetic fields, and stellar rotation in stellar astrophysics. Existing samples of Am and Ap stars, mostly obtained from spectral data with a signal-to-noise ratio in the g band (S/Ng) greater than 50, can benefit from expansion by exploring spectra with lower S/Ng. Therefore, this paper proposes an ensemble regression model applicable to spectra with a minimum S/Ng of 30. Using the model, we identify 21,361 Am candidates, of which 11,614 are new, and 6182 Ap candidates, of which 4978 are new, from LAMOST DR10. The Am sample size has increased by 60% and the Ap sample size has increased by 180% compared to the previous sample. In terms of effective temperature (T eff), the Am candidates range mainly from 6000 to 8500 K, while the Ap candidates range from 6000 to 11,700 K. The surface gravity ( logg ) distributions for Am and Ap candidates differ in the range of 3.25–4.75 dex. The number of Am candidates increases stepwise, in contrast to the relatively uniform distribution of Ap candidates across the entire surface gravity range. Regarding metallicity ([Fe/H]), Am candidates typically range from −0.75 to 0.38 dex, peaking near 0 dex, while Ap candidates are distributed from −1.38 to 0.38 dex, with a peak near −0.5 dex.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"3 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141396125","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 : 2024-06-01DOI: 10.3847/1538-4365/ad3633
Y. Wang, K. Wang, L. Liu, Y. Wu, F. Wang, J. G. Wang
The processes of single-electron charge exchange, excitation, and ionization during proton impact on H(2l) are investigated. We employ two different theoretical methods that are suitable for different collision energy regions: the full quantum-mechanical molecular orbital close-coupling method for energies from 0.001 to 1 keV u−1 and the two-center atomic orbital close-coupling (TC-AOCC) method for energies between 0.3 and 100 keV u−1. For charge exchange and excitation processes, the total and nl-resolved cross sections to the final reaction channels of H (nl, n = 1–4) have been obtained over a broad energy region. Moreover, the ionization cross sections in the TC-AOCC calculation are also reported for both H(2s) and H(2p) initial target states. The present results are all compared with those from other sources when available. It is found that the magnitude and energy behavior of nl-resolved excitation cross sections for H+–H(2p) collisions are significantly distinct from those of the H(2s) initial state in the entire energy range considered, particularly in the low-energy region. The energy behaviors of the nl-resolved charge exchange cross sections from the H(2p) initial state are similar to those from the H(2s) initial state, but their magnitudes are larger. The present accurate cross-section data are anticipated to provide insight into the research of astrophysics and controlled fusion plasmas.
{"title":"Theoretical Study of Electron Capture, Excitation, and Ionization Processes in H+−H(2l) Collisions","authors":"Y. Wang, K. Wang, L. Liu, Y. Wu, F. Wang, J. G. Wang","doi":"10.3847/1538-4365/ad3633","DOIUrl":"https://doi.org/10.3847/1538-4365/ad3633","url":null,"abstract":"The processes of single-electron charge exchange, excitation, and ionization during proton impact on H(2l) are investigated. We employ two different theoretical methods that are suitable for different collision energy regions: the full quantum-mechanical molecular orbital close-coupling method for energies from 0.001 to 1 keV u−1 and the two-center atomic orbital close-coupling (TC-AOCC) method for energies between 0.3 and 100 keV u−1. For charge exchange and excitation processes, the total and nl-resolved cross sections to the final reaction channels of H (nl, n = 1–4) have been obtained over a broad energy region. Moreover, the ionization cross sections in the TC-AOCC calculation are also reported for both H(2s) and H(2p) initial target states. The present results are all compared with those from other sources when available. It is found that the magnitude and energy behavior of nl-resolved excitation cross sections for H+–H(2p) collisions are significantly distinct from those of the H(2s) initial state in the entire energy range considered, particularly in the low-energy region. The energy behaviors of the nl-resolved charge exchange cross sections from the H(2p) initial state are similar to those from the H(2s) initial state, but their magnitudes are larger. The present accurate cross-section data are anticipated to provide insight into the research of astrophysics and controlled fusion plasmas.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"30 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141403554","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 : 2024-06-01DOI: 10.3847/1538-4365/ad45f8
Seong-Kook Lee, Myungshin Im, Bomi Park, M. Hyun, I. Paek, Dohyeong Kim
While galaxy clusters are dominated by quiescent galaxies in the local Universe, they show a wide range in quiescent galaxy fraction (QF) at higher redshifts. Here we present the discovery of two galaxy clusters at z ∼ 0.95 with contrasting QFs despite having similar masses (log (M 200/M ⊙) ∼ 14) and spectra and redshifts of 29 galaxies in these clusters and 76 galaxies in the surrounding area. The clusters are found in the Ultra Deep Survey field and confirmed through multiobject spectroscopic observation using the Inamori Magellan Areal Camera and Spectrograph on the Magellan telescope. The two clusters exhibit QFs of 0.094−0.032+0.11 and 0.38−0.11+0.14 , respectively. Analysis of large-scale structures (LSSs) surrounding these clusters finds that properties of these clusters are consistent with the anticorrelation trend between the QF and the extent of surrounding LSS, found in Lee et al., which can be interpreted as a result of the replenishment of young, star-forming galaxies keeping the QF low when galaxy clusters are accompanied by rich surrounding environments.
{"title":"Multiobject Spectroscopy of Galaxy Clusters at z ∼ 0.95 in the Ultra Deep Survey Field with Different Star Formation Properties and Large-scale Environments","authors":"Seong-Kook Lee, Myungshin Im, Bomi Park, M. Hyun, I. Paek, Dohyeong Kim","doi":"10.3847/1538-4365/ad45f8","DOIUrl":"https://doi.org/10.3847/1538-4365/ad45f8","url":null,"abstract":"While galaxy clusters are dominated by quiescent galaxies in the local Universe, they show a wide range in quiescent galaxy fraction (QF) at higher redshifts. Here we present the discovery of two galaxy clusters at z ∼ 0.95 with contrasting QFs despite having similar masses (log (M 200/M ⊙) ∼ 14) and spectra and redshifts of 29 galaxies in these clusters and 76 galaxies in the surrounding area. The clusters are found in the Ultra Deep Survey field and confirmed through multiobject spectroscopic observation using the Inamori Magellan Areal Camera and Spectrograph on the Magellan telescope. The two clusters exhibit QFs of 0.094−0.032+0.11 and 0.38−0.11+0.14 , respectively. Analysis of large-scale structures (LSSs) surrounding these clusters finds that properties of these clusters are consistent with the anticorrelation trend between the QF and the extent of surrounding LSS, found in Lee et al., which can be interpreted as a result of the replenishment of young, star-forming galaxies keeping the QF low when galaxy clusters are accompanied by rich surrounding environments.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"30 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141414564","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 : 2024-06-01DOI: 10.3847/1538-4365/ad4637
J. A. Guzman, V. Florinski, G. Tóth, S. Sharma, B. van der Holst, M. Opher
Test-particle simulations are an important tool for magnetospheric and heliophysics research. In this paper, we present the Space Plasma and Energetic Charged particle TRansport on Unstructured Meshes (SPECTRUM) software as a novel tool for performing these types of simulations in arbitrary astrophysical environments, specified either analytically or numerically (i.e., on a grid). We discuss and benchmark SPECTRUM’s interface with meshed magnetohydrodynamic backgrounds, including output from the Block Adaptive Tree Solar-wind Roe-type Upwind Scheme (BATS-R-US) code. We also investigate the effects of field discretization on both deterministic and stochastic particle motion, with emphasis on space science applications, concluding that the discretization error typically enhances the diffusive behavior of the ensemble.
{"title":"Numerical Modeling of Energetic Charged-particle Transport with SPECTRUM Software: General Approach and Artificial Effects due to Field Discretization","authors":"J. A. Guzman, V. Florinski, G. Tóth, S. Sharma, B. van der Holst, M. Opher","doi":"10.3847/1538-4365/ad4637","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4637","url":null,"abstract":"Test-particle simulations are an important tool for magnetospheric and heliophysics research. In this paper, we present the Space Plasma and Energetic Charged particle TRansport on Unstructured Meshes (SPECTRUM) software as a novel tool for performing these types of simulations in arbitrary astrophysical environments, specified either analytically or numerically (i.e., on a grid). We discuss and benchmark SPECTRUM’s interface with meshed magnetohydrodynamic backgrounds, including output from the Block Adaptive Tree Solar-wind Roe-type Upwind Scheme (BATS-R-US) code. We also investigate the effects of field discretization on both deterministic and stochastic particle motion, with emphasis on space science applications, concluding that the discretization error typically enhances the diffusive behavior of the ensemble.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"35 140","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141389690","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 : 2024-06-01DOI: 10.3847/1538-4365/ad4f7d
L. Roberti, M. Limongi, A. Chieffi
{"title":"Erratum: “Zero and Extremely Low-metallicity Rotating Massive Stars: Evolution, Explosion, and Nucleosynthesis Up to the Heaviest Nuclei” (2024, ApJS, 270, 28)","authors":"L. Roberti, M. Limongi, A. Chieffi","doi":"10.3847/1538-4365/ad4f7d","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4f7d","url":null,"abstract":"","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"260 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141412872","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 : 2024-06-01DOI: 10.3847/1538-4365/ad46f8
Yanjun Guo, Luqian 璐茜 Wang 王, C. Liu 刘, Y. Wu 吴, Z. Han 韩, X. Chen 陈
Runaway stars are OB-type stars ejected from their birthplace with large peculiar velocities. The leading hypothesis addressed in their formation includes the supernova ejection mechanism and the dynamic ejection scenario. Identification of runaway populations is the first step to investigating their formation and evolution. Here we present our work of searching for Galactic runaway candidate stars from the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) Medium Resolution Survey Data Release 8 (DR8) database. After studying the kinematic properties for a collection of 4432 early-type stars, predominantly B-type stars, using radial velocity measurements from LAMOST DR8 and astrometric solutions made by Gaia Data Release 3, we identified 229 runaway candidate stars. They span a wide distribution in projected rotational velocities. We investigated the Galactic spatial distribution of the runaway population and noticed that most of them likely reside within the Galactic thin disk. Based upon analyzing the Doppler shifts of the candidate stars, we found two binary runaway candidates displaying velocity variations with estimated orbital periods of 40 and 61 days.
失控恒星是从其诞生地以巨大的奇特速度喷射出来的 OB 型恒星。关于它们形成的主要假说包括超新星抛射机制和动态抛射设想。识别失控群是研究它们的形成和演化的第一步。在此，我们介绍了从大天区多目标光纤光谱望远镜（LAMOST）中分辨率巡天数据第8版（DR8）数据库中搜索银河失控候选星的工作。在利用 LAMOST DR8 的径向速度测量数据和 Gaia Data Release 3 的天体测量解法研究了 4432 颗早期型恒星（主要是 B 型恒星）的运动特性之后，我们确定了 229 颗失控候选恒星。它们的投影旋转速度分布很广。我们对失控恒星群的银河空间分布进行了研究，发现它们中的大多数可能都位于银河系薄盘内。根据对候选恒星多普勒频移的分析，我们发现有两颗双失控候选恒星显示出速度变化，估计轨道周期分别为 40 天和 61 天。
{"title":"A Catalog of Early-type Runaway Stars from LAMOST DR8","authors":"Yanjun Guo, Luqian 璐茜 Wang 王, C. Liu 刘, Y. Wu 吴, Z. Han 韩, X. Chen 陈","doi":"10.3847/1538-4365/ad46f8","DOIUrl":"https://doi.org/10.3847/1538-4365/ad46f8","url":null,"abstract":"Runaway stars are OB-type stars ejected from their birthplace with large peculiar velocities. The leading hypothesis addressed in their formation includes the supernova ejection mechanism and the dynamic ejection scenario. Identification of runaway populations is the first step to investigating their formation and evolution. Here we present our work of searching for Galactic runaway candidate stars from the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) Medium Resolution Survey Data Release 8 (DR8) database. After studying the kinematic properties for a collection of 4432 early-type stars, predominantly B-type stars, using radial velocity measurements from LAMOST DR8 and astrometric solutions made by Gaia Data Release 3, we identified 229 runaway candidate stars. They span a wide distribution in projected rotational velocities. We investigated the Galactic spatial distribution of the runaway population and noticed that most of them likely reside within the Galactic thin disk. Based upon analyzing the Doppler shifts of the candidate stars, we found two binary runaway candidates displaying velocity variations with estimated orbital periods of 40 and 61 days.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"9 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141407797","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}
This study focuses on the analysis of mid-infrared variability in a sample of high-mass young stellar objects (YSOs) associated with the cataloged sources from the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). The Near-Earth Object Wide-field Infrared Survey Explorer Reactivation Mission (NEOWISE) database was used to explore the long-term mid-infrared variability of these high-mass YSOs at a half-year scale. After matching with NEOWISE photometric measurements, a total of 2230 ATLASGAL sources were selected for the variability analysis, out of which 717 were identified as variables. The derived proportions of variables at different evolutionary stages show that the variability rate of high-mass YSOs is highest during the YSO stage and decreases with evolution toward the H ii region stage, resembling the behavior of low-mass YSOs. The variables can be classified into six types based on their light curves, divided into two categories: secular (linear, sin, sin+linear) and stochastic variables (burst, drop, and irregular). The magnitude–color variations observed in ∼160 secular variables can be mainly divided into “bluer when brighter/redder when dimming” and “redder when brighter/bluer when dimming,” likely originating from changes in accretion rate or the effect of extinction due to obscuration. Moreover, several episodic accretion candidates were selected for further observational studies.
{"title":"Sample and Statistical Analysis on NEOWISE Variability of ATLASGAL Sources","authors":"Ying Lu, Xi Chen, Shijie Song, Jun-Ting Liu, Tian Yang, You-Xin Wang, Yan-Kun Zhang, Shi-Jie Zhang","doi":"10.3847/1538-4365/ad41e2","DOIUrl":"https://doi.org/10.3847/1538-4365/ad41e2","url":null,"abstract":"This study focuses on the analysis of mid-infrared variability in a sample of high-mass young stellar objects (YSOs) associated with the cataloged sources from the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). The Near-Earth Object Wide-field Infrared Survey Explorer Reactivation Mission (NEOWISE) database was used to explore the long-term mid-infrared variability of these high-mass YSOs at a half-year scale. After matching with NEOWISE photometric measurements, a total of 2230 ATLASGAL sources were selected for the variability analysis, out of which 717 were identified as variables. The derived proportions of variables at different evolutionary stages show that the variability rate of high-mass YSOs is highest during the YSO stage and decreases with evolution toward the H ii region stage, resembling the behavior of low-mass YSOs. The variables can be classified into six types based on their light curves, divided into two categories: secular (linear, sin, sin+linear) and stochastic variables (burst, drop, and irregular). The magnitude–color variations observed in ∼160 secular variables can be mainly divided into “bluer when brighter/redder when dimming” and “redder when brighter/bluer when dimming,” likely originating from changes in accretion rate or the effect of extinction due to obscuration. Moreover, several episodic accretion candidates were selected for further observational studies.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"9 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141411714","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 : 2024-06-01DOI: 10.3847/1538-4365/ad488b
Xue Lu, Haibo Yuan, Shuai Xu, Ruoyi Zhang, K. Xiao, Yang Huang, T. Beers, Jihye Hong
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{"title":"Erratum: “Stellar Loci. VII. Photometric Metallicities of 5 Million FGK Stars Based on GALEX GR6+7 AIS and Gaia EDR3” (2024, ApJS, 271, 26)","authors":"Xue Lu, Haibo Yuan, Shuai Xu, Ruoyi Zhang, K. Xiao, Yang Huang, T. Beers, Jihye Hong","doi":"10.3847/1538-4365/ad488b","DOIUrl":"https://doi.org/10.3847/1538-4365/ad488b","url":null,"abstract":",","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"15 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141402464","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}
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