Pub Date : 2024-06-23DOI: 10.3847/1538-4365/ad452e
Przemek Mróz, Andrzej Udalski, Michał K. Szymański, Mateusz Kapusta, Igor Soszyński, Łukasz Wyrzykowski, Paweł Pietrukowicz, Szymon Kozłowski, Radosław Poleski, Jan Skowron, Dorota Skowron, Krzysztof Ulaczyk, Mariusz Gromadzki, Krzysztof Rybicki, Patryk Iwanek, Marcin Wrona and Milena Ratajczak
Measurements of the microlensing optical depth and event rate toward the Large Magellanic Cloud (LMC) can be used to probe the distribution and mass function of compact objects in the direction toward that galaxy—in the Milky Way disk, the Milky Way dark matter halo, and the LMC itself. The previous measurements, based on small statistical samples of events, found that the optical depth is an order of magnitude smaller than that expected from the entire dark matter halo in the form of compact objects. However, these previous studies were not sensitive to long-duration events with Einstein timescales longer than 2.5–3 yr, which are expected from massive (10–100 M⊙) and intermediate-mass (102–105M⊙) black holes. Such events would have been missed by the previous studies and would not have been taken into account in calculations of the optical depth. Here, we present the analysis of nearly 20 yr long photometric monitoring of 78.7 million stars in the LMC by the Optical Gravitational Lensing Experiment (OGLE) from 2001 through 2020. We describe the observing setup, the construction of the 20 yr OGLE data set, the methods used for searching for microlensing events in the light-curve data, and the calculation of the event detection efficiency. In total, we find 16 microlensing events (13 using an automated pipeline and three with manual searches), all of which have timescales shorter than 1 yr. We use a sample of 13 events to measure the microlensing optical depth toward the LMC τ = (0.121 ± 0.037) × 10−7 and the event rate Γ = (0.74 ± 0.25) × 10−7 yr−1 star−1. These numbers are consistent with lensing by stars in the Milky Way disk and the LMC itself, and they demonstrate that massive and intermediate-mass black holes cannot comprise a significant fraction of the dark matter.
{"title":"Microlensing Optical Depth and Event Rate toward the Large Magellanic Cloud Based on 20 yr of OGLE Observations","authors":"Przemek Mróz, Andrzej Udalski, Michał K. Szymański, Mateusz Kapusta, Igor Soszyński, Łukasz Wyrzykowski, Paweł Pietrukowicz, Szymon Kozłowski, Radosław Poleski, Jan Skowron, Dorota Skowron, Krzysztof Ulaczyk, Mariusz Gromadzki, Krzysztof Rybicki, Patryk Iwanek, Marcin Wrona and Milena Ratajczak","doi":"10.3847/1538-4365/ad452e","DOIUrl":"https://doi.org/10.3847/1538-4365/ad452e","url":null,"abstract":"Measurements of the microlensing optical depth and event rate toward the Large Magellanic Cloud (LMC) can be used to probe the distribution and mass function of compact objects in the direction toward that galaxy—in the Milky Way disk, the Milky Way dark matter halo, and the LMC itself. The previous measurements, based on small statistical samples of events, found that the optical depth is an order of magnitude smaller than that expected from the entire dark matter halo in the form of compact objects. However, these previous studies were not sensitive to long-duration events with Einstein timescales longer than 2.5–3 yr, which are expected from massive (10–100 M⊙) and intermediate-mass (102–105M⊙) black holes. Such events would have been missed by the previous studies and would not have been taken into account in calculations of the optical depth. Here, we present the analysis of nearly 20 yr long photometric monitoring of 78.7 million stars in the LMC by the Optical Gravitational Lensing Experiment (OGLE) from 2001 through 2020. We describe the observing setup, the construction of the 20 yr OGLE data set, the methods used for searching for microlensing events in the light-curve data, and the calculation of the event detection efficiency. In total, we find 16 microlensing events (13 using an automated pipeline and three with manual searches), all of which have timescales shorter than 1 yr. We use a sample of 13 events to measure the microlensing optical depth toward the LMC τ = (0.121 ± 0.037) × 10−7 and the event rate Γ = (0.74 ± 0.25) × 10−7 yr−1 star−1. These numbers are consistent with lensing by stars in the Milky Way disk and the LMC itself, and they demonstrate that massive and intermediate-mass black holes cannot comprise a significant fraction of the dark matter.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504885","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 : 2024-06-23DOI: 10.3847/1538-4365/ad435c
Leisa K. Townsley, Patrick S. Broos and Matthew S. Povich
The Tarantula Nebula (30 Doradus, 30 Dor) is the most important star-forming complex in the Local Group, offering a microscope on starburst astrophysics. At its heart lies the exceptionally rich young stellar cluster R136, containing the most massive stars known. Stellar winds and supernovae have carved 30 Dor into an amazing display of arcs, pillars, and bubbles. We present first results and advanced data-processing products from the 2 Ms Chandra X-ray Visionary Project, “The Tarantula—Revealed by X-rays” (T-ReX). The 3615 point sources in the T-ReX catalog include massive stars, compact objects, binaries, bright pre-main-sequence stars, and compact young stellar (sub)clusters in 30 Dor. After removing point sources and excluding the exceptionally bright supernova remnant N157B (30 Dor B), the global diffuse X-ray maps reveal hot plasma structures resolved at 1–10 pc scales, with an absorption-corrected total-band (0.5–7 keV) X-ray luminosity of 2.110 × 1037 erg s−1. Spatially resolved spectral modeling provides evidence for emission lines enhanced by charge-exchange processes at the interfaces. We identify a candidate for the oldest X-ray pulsar detected to date in 30 Dor, PSR J0538-6902, inside a newly resolved arcuate X-ray wind nebula, the Manta Ray. The long temporal baseline of T-ReX allowed monitoring of dozens of massive stars, several showing periodic variability tied to binary orbital periods, and captured strong flares from at least three low-mass Galactic foreground stars.
蜘蛛星云（30 Doradus，30 Dor）是本星系群中最重要的恒星形成复合体，是研究星爆天体物理学的显微镜。它的中心是异常丰富的年轻恒星群R136，其中包含了已知质量最大的恒星。恒星风和超新星将 30 Dor 星雕刻成令人惊叹的弧形、柱形和气泡。我们将介绍钱德拉 X 射线愿景项目 "X 射线揭示的狼蛛（T-Revealed by X-rays，T-ReX）"的首批成果和高级数据处理产品。T-ReX 星表中的 3615 个点源包括大质量恒星、紧凑天体、双星、明亮的前主序恒星和 30 Dor 中紧凑的年轻恒星（子）星团。剔除点源和异常明亮的超新星残余物 N157B（30 Dor B）后，全球漫射 X 射线图显示了 1-10 pc 尺度的热等离子体结构，吸收校正后的总波段（0.5-7 keV）X 射线光度为 2.110 × 1037 erg s-1。空间分辨光谱建模为界面上电荷交换过程增强的发射线提供了证据。我们在一个新解析的弧状X射线风星云--Manta Ray--内发现了一颗迄今为止在30 Dor探测到的最古老的X射线脉冲星的候选者--PSR J0538-6902。T-ReX 的长时间基线允许对数十颗大质量恒星进行监测，其中几颗恒星显示出与双星轨道周期相关的周期性变化，并捕捉到至少三颗低质量银河系前景恒星的强烈耀斑。
{"title":"T-ReX: The Tarantula—Revealed by X-Rays","authors":"Leisa K. Townsley, Patrick S. Broos and Matthew S. Povich","doi":"10.3847/1538-4365/ad435c","DOIUrl":"https://doi.org/10.3847/1538-4365/ad435c","url":null,"abstract":"The Tarantula Nebula (30 Doradus, 30 Dor) is the most important star-forming complex in the Local Group, offering a microscope on starburst astrophysics. At its heart lies the exceptionally rich young stellar cluster R136, containing the most massive stars known. Stellar winds and supernovae have carved 30 Dor into an amazing display of arcs, pillars, and bubbles. We present first results and advanced data-processing products from the 2 Ms Chandra X-ray Visionary Project, “The Tarantula—Revealed by X-rays” (T-ReX). The 3615 point sources in the T-ReX catalog include massive stars, compact objects, binaries, bright pre-main-sequence stars, and compact young stellar (sub)clusters in 30 Dor. After removing point sources and excluding the exceptionally bright supernova remnant N157B (30 Dor B), the global diffuse X-ray maps reveal hot plasma structures resolved at 1–10 pc scales, with an absorption-corrected total-band (0.5–7 keV) X-ray luminosity of 2.110 × 1037 erg s−1. Spatially resolved spectral modeling provides evidence for emission lines enhanced by charge-exchange processes at the interfaces. We identify a candidate for the oldest X-ray pulsar detected to date in 30 Dor, PSR J0538-6902, inside a newly resolved arcuate X-ray wind nebula, the Manta Ray. The long temporal baseline of T-ReX allowed monitoring of dozens of massive stars, several showing periodic variability tied to binary orbital periods, and captured strong flares from at least three low-mass Galactic foreground stars.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141527981","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 : 2024-06-19DOI: 10.3847/1538-4365/ad46f5
Amir Aghabiglou, Chung San Chu, Arwa Dabbech and Yves Wiaux
Radio-interferometric imaging entails solving high-resolution high-dynamic-range inverse problems from large data volumes. Recent image reconstruction techniques grounded in optimization theory have demonstrated remarkable capability for imaging precision, well beyond CLEAN’s capability. These range from advanced proximal algorithms propelled by handcrafted regularization operators, such as the SARA family, to hybrid plug-and-play (PnP) algorithms propelled by learned regularization denoisers, such as AIRI. Optimization and PnP structures are however highly iterative, which hinders their ability to handle the extreme data sizes expected from future instruments. To address this scalability challenge, we introduce a novel deep-learning approach, dubbed “Residual-to-Residual DNN series for high-Dynamic-range imaging” or in short R2D2. R2D2's reconstruction is formed as a series of residual images, iteratively estimated as outputs of deep neural networks (DNNs) taking the previous iteration’s image estimate and associated data residual as inputs. It thus takes a hybrid structure between a PnP algorithm and a learned version of the matching pursuit algorithm that underpins CLEAN. We present a comprehensive study of our approach, featuring its multiple incarnations distinguished by their DNN architectures. We provide a detailed description of its training process, targeting a telescope-specific approach. R2D2's capability to deliver high precision is demonstrated in simulation, across a variety of image and observation settings using the Very Large Array. Its reconstruction speed is also demonstrated: with only a few iterations required to clean data residuals at dynamic ranges up to 105, R2D2 opens the door to fast precision imaging. R2D2 codes are available in the BASPLib (https://basp-group.github.io/BASPLib/) library on GitHub.
{"title":"The R2D2 Deep Neural Network Series Paradigm for Fast Precision Imaging in Radio Astronomy","authors":"Amir Aghabiglou, Chung San Chu, Arwa Dabbech and Yves Wiaux","doi":"10.3847/1538-4365/ad46f5","DOIUrl":"https://doi.org/10.3847/1538-4365/ad46f5","url":null,"abstract":"Radio-interferometric imaging entails solving high-resolution high-dynamic-range inverse problems from large data volumes. Recent image reconstruction techniques grounded in optimization theory have demonstrated remarkable capability for imaging precision, well beyond CLEAN’s capability. These range from advanced proximal algorithms propelled by handcrafted regularization operators, such as the SARA family, to hybrid plug-and-play (PnP) algorithms propelled by learned regularization denoisers, such as AIRI. Optimization and PnP structures are however highly iterative, which hinders their ability to handle the extreme data sizes expected from future instruments. To address this scalability challenge, we introduce a novel deep-learning approach, dubbed “Residual-to-Residual DNN series for high-Dynamic-range imaging” or in short R2D2. R2D2's reconstruction is formed as a series of residual images, iteratively estimated as outputs of deep neural networks (DNNs) taking the previous iteration’s image estimate and associated data residual as inputs. It thus takes a hybrid structure between a PnP algorithm and a learned version of the matching pursuit algorithm that underpins CLEAN. We present a comprehensive study of our approach, featuring its multiple incarnations distinguished by their DNN architectures. We provide a detailed description of its training process, targeting a telescope-specific approach. R2D2's capability to deliver high precision is demonstrated in simulation, across a variety of image and observation settings using the Very Large Array. Its reconstruction speed is also demonstrated: with only a few iterations required to clean data residuals at dynamic ranges up to 105, R2D2 opens the door to fast precision imaging. R2D2 codes are available in the BASPLib (https://basp-group.github.io/BASPLib/) library on GitHub.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529049","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}
We present a study of the molecular gas in early-mid stage major mergers, with a sample of 43 major-merger galaxy pairs selected from the Mapping Nearby Galaxies at Apache Point Observatory survey and a control sample of 195 isolated galaxies selected from the xCOLD GASS survey. Adopting kinematic asymmetry as a new effective indicator to describe the merger stage, we aim to study the role of molecular gas in the merger-induced star formation enhancement along the merger sequence of galaxy pairs. We obtain the molecular gas properties from CO observations with the James Clerk Maxwell Telescope, Institut de Radioastronomie Milimetrique 30 m telescope, and the MaNGA-ARO Survey of CO Targets survey. Using these data, we investigate the differences in molecular gas fraction ( ), star formation rate (SFR), star formation efficiency (SFE), molecular-to-atomic gas ratio ( /MH i), total gas fraction (fgas), and the SFE of total gas (SFEgas) between the pair and control samples. In the full pair sample, our results suggest the of paired galaxies is significantly enhanced, while the SFE is comparable to that of isolated galaxies. We detect significantly increased and /MH i in paired galaxies at the pericenter stage, indicating an accelerated transition from atomic gas to molecular gas due to interactions. Our results indicate that the elevation of plays a major role in the enhancement of global SFR in paired galaxies at the pericenter stage, while the contribution of enhanced SFE in specific regions requires further explorations through spatially resolved observations of a larger sample spanning a wide range of merger stages.
我们从阿帕奇角天文台（Apache Point Observatory）的近邻星系测绘调查（Mapping Nearby Galaxies at Apache Point Observatory survey）中选取了43对大合并星系，并从xCOLD GASS调查中选取了195个孤立星系作为对照样本，对早中期大合并星系中的分子气体进行了研究。采用运动不对称作为描述合并阶段的新的有效指标，我们的目的是研究分子气体在星系对合并序列中合并引起的恒星形成增强中的作用。我们通过詹姆斯-克拉克-麦克斯韦望远镜、Institut de Radioastronomie Milimetrique 30米望远镜和MaNGA-ARO CO目标巡天观测获得了分子气体的性质。利用这些数据，我们研究了分子气体分数（ ）、恒星形成率（SFR）、恒星形成效率（SFE）、分子与原子气体比（ /MH i）、总气体分数（fgas）以及总气体的 SFE（SFEgas）在成对样本和对照样本之间的差异。在全配对样本中，我们的结果表明配对星系的化学气体与原子气体之比（/MH i）显著提高，而总气体的SFE则与孤立星系相当。我们探测到配对星系在近心阶段的/MH i和/MH i明显增加，这表明由于相互作用，原子气体向分子气体的过渡加速了。我们的研究结果表明，对偶星系在围中心阶段的全局 SFR 的增强主要是由于 /MH i 的升高，而特定区域 SFE 的增强则需要通过对跨越各种合并阶段的更大样本进行空间分辨观测来进一步探索。
{"title":"CO Observations of Early-mid Stage Major Mergers in the MaNGA Survey","authors":"Qingzheng Yu, 清正 余, Taotao Fang, 陶陶 方, Cong Kevin Xu, 聪 徐, Shuai Feng, 帅 冯, Siyi Feng, 思轶 冯, Yu Gao, 煜 高, Xue-Jian Jiang, 雪健 蒋 and Ute Lisenfeld","doi":"10.3847/1538-4365/ad4547","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4547","url":null,"abstract":"We present a study of the molecular gas in early-mid stage major mergers, with a sample of 43 major-merger galaxy pairs selected from the Mapping Nearby Galaxies at Apache Point Observatory survey and a control sample of 195 isolated galaxies selected from the xCOLD GASS survey. Adopting kinematic asymmetry as a new effective indicator to describe the merger stage, we aim to study the role of molecular gas in the merger-induced star formation enhancement along the merger sequence of galaxy pairs. We obtain the molecular gas properties from CO observations with the James Clerk Maxwell Telescope, Institut de Radioastronomie Milimetrique 30 m telescope, and the MaNGA-ARO Survey of CO Targets survey. Using these data, we investigate the differences in molecular gas fraction ( ), star formation rate (SFR), star formation efficiency (SFE), molecular-to-atomic gas ratio ( /MH i), total gas fraction (fgas), and the SFE of total gas (SFEgas) between the pair and control samples. In the full pair sample, our results suggest the of paired galaxies is significantly enhanced, while the SFE is comparable to that of isolated galaxies. We detect significantly increased and /MH i in paired galaxies at the pericenter stage, indicating an accelerated transition from atomic gas to molecular gas due to interactions. Our results indicate that the elevation of plays a major role in the enhancement of global SFR in paired galaxies at the pericenter stage, while the contribution of enhanced SFE in specific regions requires further explorations through spatially resolved observations of a larger sample spanning a wide range of merger stages.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141527982","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 : 2024-06-16DOI: 10.3847/1538-4365/ad4642
Zahra Tajik, Nastaran Farhang, Hossein Safari and Michael S. Wheatland
Solar and stellar magnetic patches (i.e., magnetic fluxes that reach the surface from the interior) are believed to be the primary sources of a star’s atmospheric conditions. Here, we apply the complex network approach and investigate its efficacy in the identification of these features. For this purpose, we use the line-of-sight magnetograms provided by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. We construct the magnetic network following a specific visibility graph condition between pairs of pixels with opposite polarities and search for possible links between these regions. The complex network facilitates the construction of node degrees and PageRank images, and applying the downhill algorithm to node-degree images allows for the grouping of pixels into features corresponding to one-to-one matches with magnetogram patches. This approach promisingly serves to identify the nontrivial morphological structure of the magnetic patches for small and large sizes. We observe that the changes in the features of the node-degree images effectively correspond to the cospatial magnetic patches over time. Through visual assessment, we estimate an average false-negative error rate of approximately 1% in identifying small-scale features (one or two pixels in size).
太阳和恒星磁斑（即从内部到达表面的磁通量）被认为是恒星大气状况的主要来源。在此，我们应用复杂网络方法，研究其在识别这些特征方面的功效。为此，我们使用了太阳动力学天文台（Solar Dynamics Observatory）上的太阳地震和磁成像仪（Helioseismic and Magnetic Imager）提供的视线磁图。我们根据极性相反的像素对之间的特定可见度图条件构建磁网络，并搜索这些区域之间可能存在的联系。复杂的网络有助于构建节点度和 PageRank 图像，将下坡算法应用于节点度图像可将像素分组为与磁图斑块一一对应的特征。这种方法有望识别大小磁图斑块的非复杂形态结构。我们观察到，随着时间的推移，节点度图像特征的变化与空间磁斑块有效对应。通过目测评估，我们估计识别小尺度特征（一或两个像素大小）的平均误差率约为 1%。
{"title":"Complex Network View of the Sun’s Magnetic Patches. I. Identification","authors":"Zahra Tajik, Nastaran Farhang, Hossein Safari and Michael S. Wheatland","doi":"10.3847/1538-4365/ad4642","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4642","url":null,"abstract":"Solar and stellar magnetic patches (i.e., magnetic fluxes that reach the surface from the interior) are believed to be the primary sources of a star’s atmospheric conditions. Here, we apply the complex network approach and investigate its efficacy in the identification of these features. For this purpose, we use the line-of-sight magnetograms provided by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. We construct the magnetic network following a specific visibility graph condition between pairs of pixels with opposite polarities and search for possible links between these regions. The complex network facilitates the construction of node degrees and PageRank images, and applying the downhill algorithm to node-degree images allows for the grouping of pixels into features corresponding to one-to-one matches with magnetogram patches. This approach promisingly serves to identify the nontrivial morphological structure of the magnetic patches for small and large sizes. We observe that the changes in the features of the node-degree images effectively correspond to the cospatial magnetic patches over time. Through visual assessment, we estimate an average false-negative error rate of approximately 1% in identifying small-scale features (one or two pixels in size).","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141527885","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 : 2024-06-11DOI: 10.3847/1538-4365/ad434f
Jie Song, GuanWen Fang, Shuo Ba, Zesen Lin, Yizhou Gu, Chichun Zhou, Tao Wang, Cai-Na Hao, Guilin Liu, Hongxin Zhang, Yao Yao, Xu Kong
Morphological classification conveys abundant information on the formation, evolution, and environment of galaxies. In this work, we refine a two-step galaxy morphological classification framework (USmorph), which employs a combination of unsupervised machine-learning and supervised machine-learning techniques, along with a self-consistent and robust data-preprocessing step. The updated method is applied to galaxies with Imag < 25 at 0.2 < z < 1.2 in the COSMOS field. Based on their Hubble Space Telescope/Advanced Camera for Survey I-band images, we classify them into five distinct morphological types: spherical (SPH, 15,200), early-type disk (17,369), late-type disk (21,143), irregular disk (IRR, 28,965), and unclassified (UNC, 17,129). In addition, we have conducted both parametric and nonparametric morphological measurements. For galaxies with stellar masses exceeding 109M☉, a gradual increase in effective radius from SPHs to IRRs is observed, accompanied by a decrease in the Sérsic index. Nonparametric morphologies reveal distinct distributions of galaxies across the Gini−M20 and C−A parameter spaces for different categories. Moreover, different categories exhibit significant dissimilarity in their G2 and Ψ distributions. We find morphology to be strongly correlated with redshift and stellar mass. The consistency of these classification results with expected correlations among multiple parameters underscores the validity and reliability of our classification method, rendering it a valuable tool for future studies.
{"title":"USmorph: An Updated Framework of Automatic Classification of Galaxy Morphologies and Its Application to Galaxies in the COSMOS Field","authors":"Jie Song, GuanWen Fang, Shuo Ba, Zesen Lin, Yizhou Gu, Chichun Zhou, Tao Wang, Cai-Na Hao, Guilin Liu, Hongxin Zhang, Yao Yao, Xu Kong","doi":"10.3847/1538-4365/ad434f","DOIUrl":"https://doi.org/10.3847/1538-4365/ad434f","url":null,"abstract":"Morphological classification conveys abundant information on the formation, evolution, and environment of galaxies. In this work, we refine a two-step galaxy morphological classification framework (<monospace>USmorph</monospace>), which employs a combination of unsupervised machine-learning and supervised machine-learning techniques, along with a self-consistent and robust data-preprocessing step. The updated method is applied to galaxies with <italic toggle=\"yes\">I</italic>\u0000<sub>mag</sub> < 25 at 0.2 < <italic toggle=\"yes\">z</italic> < 1.2 in the COSMOS field. Based on their Hubble Space Telescope/Advanced Camera for Survey <italic toggle=\"yes\">I</italic>-band images, we classify them into five distinct morphological types: spherical (SPH, 15,200), early-type disk (17,369), late-type disk (21,143), irregular disk (IRR, 28,965), and unclassified (UNC, 17,129). In addition, we have conducted both parametric and nonparametric morphological measurements. For galaxies with stellar masses exceeding 10<sup>9</sup>\u0000<italic toggle=\"yes\">M</italic>\u0000<sub>☉</sub>, a gradual increase in effective radius from SPHs to IRRs is observed, accompanied by a decrease in the Sérsic index. Nonparametric morphologies reveal distinct distributions of galaxies across the <italic toggle=\"yes\">G</italic>ini−<italic toggle=\"yes\">M</italic>\u0000<sub>20</sub> and <italic toggle=\"yes\">C</italic>−<italic toggle=\"yes\">A</italic> parameter spaces for different categories. Moreover, different categories exhibit significant dissimilarity in their <italic toggle=\"yes\">G</italic>\u0000<sub>2</sub> and Ψ distributions. We find morphology to be strongly correlated with redshift and stellar mass. The consistency of these classification results with expected correlations among multiple parameters underscores the validity and reliability of our classification method, rendering it a valuable tool for future studies.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141527886","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 : 2024-06-10DOI: 10.3847/1538-4365/ad41b6
Jinghua Zhang, Maosheng Xiang, Jie Yu, Jian Ge, Ji-Wei Xie, Hui Zhang, Yaguang Li, You Wu, Chun-Qian Li, Shaolan Bi, Hong-Liang Yan, Jian-Rong Shi
Accurately characterizing the intrinsic stellar photometric noise induced by stellar astrophysics, such as stellar activity, granulation, and oscillations, is of crucial importance for detecting transiting exoplanets. In this study, we investigate the relation between the intrinsic stellar photometric noise, quantified by the Kepler combined differential photometric precision (CDPP) metric, and the level of stellar chromospheric activity, indicated by the S-index of Ca ii H K lines derived from LAMOST spectra. Our results reveal a clear positive correlation between the S-index and robust rms values of CDPP, with the correlation becoming more significant at higher activity levels and on longer timescales. We have therefore built an empirical relation between the robust rms values of CDPP and the S-index as well as Teff, logg, [Fe/H], and the apparent magnitude, with the XGBoost regression algorithm, using the LAMOST–Kepler common star sample as the training set. This method achieves a precision of ∼20 ppm for inferring the intrinsic noise from the S-index and other stellar labels on a 6 hr integration duration. We have applied this empirical relation to the full LAMOST DR7 spectra database and obtained the intrinsic noise predictions for 1,358,275 stars. The resultant catalog is publicly available and expected to be valuable for optimizing target selection for future exoplanet-hunting space missions, such as the Earth 2.0 mission.
准确描述由恒星天体物理（如恒星活动、颗粒化和振荡）引起的内在恒星测光噪声对于探测凌日系外行星至关重要。在这项研究中，我们研究了由开普勒综合差分光度精度（CDPP）指标量化的恒星固有光度噪声与恒星色球活动水平之间的关系，恒星色球活动水平由从LAMOST光谱中获得的Ca ii H K线的S指数来表示。我们的研究结果表明，S 指数与 CDPP 的稳健均方根值之间存在明显的正相关，在活动水平较高和时间尺度较长的情况下，这种相关性变得更加显著。因此，我们使用 XGBoost 回归算法，以 LAMOST-Kepler 共同恒星样本为训练集，建立了 CDPP 的稳健均方根值与 S 指数以及 Teff、logg、[Fe/H] 和视星等之间的经验关系。在 6 小时的积分时间内，这种方法从 S 指数和其他恒星标签推断出的内在噪声的精度达到了 ∼20 ppm。我们将这一经验关系应用于完整的 LAMOST DR7 光谱数据库，得到了 1,358,275 颗恒星的本征噪声预测值。所得到的星表是公开的，预计将对优化未来系外行星搜寻太空任务（如地球 2.0 任务）的目标选择非常有价值。
{"title":"Reconstructing Intrinsic Stellar Noise with Stellar Atmospheric Parameters and Chromospheric Activity","authors":"Jinghua Zhang, Maosheng Xiang, Jie Yu, Jian Ge, Ji-Wei Xie, Hui Zhang, Yaguang Li, You Wu, Chun-Qian Li, Shaolan Bi, Hong-Liang Yan, Jian-Rong Shi","doi":"10.3847/1538-4365/ad41b6","DOIUrl":"https://doi.org/10.3847/1538-4365/ad41b6","url":null,"abstract":"Accurately characterizing the intrinsic stellar photometric noise induced by stellar astrophysics, such as stellar activity, granulation, and oscillations, is of crucial importance for detecting transiting exoplanets. In this study, we investigate the relation between the intrinsic stellar photometric noise, quantified by the Kepler combined differential photometric precision (CDPP) metric, and the level of stellar chromospheric activity, indicated by the <italic toggle=\"yes\">S</italic>-index of Ca <sc>ii</sc> H K lines derived from LAMOST spectra. Our results reveal a clear positive correlation between the <italic toggle=\"yes\">S</italic>-index and robust rms values of CDPP, with the correlation becoming more significant at higher activity levels and on longer timescales. We have therefore built an empirical relation between the robust rms values of CDPP and the <italic toggle=\"yes\">S</italic>-index as well as <italic toggle=\"yes\">T</italic>\u0000<sub>eff</sub>, <inline-formula>\u0000<tex-math>\u0000<?CDATA $mathrm{log}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi>log</mml:mi></mml:math>\u0000<inline-graphic xlink:href=\"apjsad41b6ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>\u0000<italic toggle=\"yes\">g</italic>, [Fe/H], and the apparent magnitude, with the <monospace>XGBoost</monospace> regression algorithm, using the LAMOST–Kepler common star sample as the training set. This method achieves a precision of ∼20 ppm for inferring the intrinsic noise from the <italic toggle=\"yes\">S</italic>-index and other stellar labels on a 6 hr integration duration. We have applied this empirical relation to the full LAMOST DR7 spectra database and obtained the intrinsic noise predictions for 1,358,275 stars. The resultant catalog is publicly available and expected to be valuable for optimizing target selection for future exoplanet-hunting space missions, such as the Earth 2.0 mission.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141527888","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 : 2024-06-10DOI: 10.3847/1538-4365/ad409d
Z. L. Wen, J. L. Han
Based on the DESI Legacy Imaging Surveys released data and available spectroscopic redshifts, we identify 1.58 million clusters of galaxies by searching for the overdensity of the stellar mass distribution of galaxies within redshift slices around preselected massive galaxies, with 877,806 clusters being found for the first time. The identified clusters have an equivalent mass of M500 ≥ 0.47 × 1014M⊙ with an uncertainty of 0.2 dex. The redshift distribution of clusters extends to z ∼ 1.5, and 338,841 clusters have spectroscopic redshifts. Our cluster sample includes most of the rich optical clusters in previous catalogs, more than 95% of the massive Sunyaev–Zeldovich clusters, and 90% of the ROSAT and eROSITA X-ray clusters. From the light distributions of the member galaxies, we derive the dynamical state parameters for 27,685 rich clusters and find no significant evolution of the dynamical state with redshift. We find that the stellar mass of the brightest cluster galaxies grows by a factor of 2 since z = 1.
基于DESI遗留成像巡天发布的数据和现有的光谱红移，我们通过搜索预选大质量星系周围红移切片内星系恒星质量分布的过密度，识别出158万个星系团，其中877806个星系团是首次发现。确定的星团等效质量为 M500 ≥ 0.47 × 1014M⊙，不确定度为 0.2 dex。星团的红移分布延伸到 z ∼ 1.5，338,841 个星团具有光谱红移。我们的星团样本包括了以前星表中大部分丰富的光学星团，95%以上的大质量苏尼亚耶夫-泽尔多维奇星团，以及90%的ROSAT和eROSITA X射线星团。根据成员星系的光分布，我们推导出了27,685个富集星团的动力学状态参数，发现动力学状态并没有随红移发生显著的演变。我们发现自 z = 1 起，最亮星团星系的恒星质量增长了 2 倍。
{"title":"A Catalog of 1.58 Million Clusters of Galaxies Identified from the DESI Legacy Imaging Surveys","authors":"Z. L. Wen, J. L. Han","doi":"10.3847/1538-4365/ad409d","DOIUrl":"https://doi.org/10.3847/1538-4365/ad409d","url":null,"abstract":"Based on the DESI Legacy Imaging Surveys released data and available spectroscopic redshifts, we identify 1.58 million clusters of galaxies by searching for the overdensity of the stellar mass distribution of galaxies within redshift slices around preselected massive galaxies, with 877,806 clusters being found for the first time. The identified clusters have an equivalent mass of <italic toggle=\"yes\">M</italic>\u0000<sub>500</sub> ≥ 0.47 × 10<sup>14</sup>\u0000<italic toggle=\"yes\">M</italic>\u0000<sub>⊙</sub> with an uncertainty of 0.2 dex. The redshift distribution of clusters extends to <italic toggle=\"yes\">z</italic> ∼ 1.5, and 338,841 clusters have spectroscopic redshifts. Our cluster sample includes most of the rich optical clusters in previous catalogs, more than 95% of the massive Sunyaev–Zeldovich clusters, and 90% of the ROSAT and eROSITA X-ray clusters. From the light distributions of the member galaxies, we derive the dynamical state parameters for 27,685 rich clusters and find no significant evolution of the dynamical state with redshift. We find that the stellar mass of the brightest cluster galaxies grows by a factor of 2 since <italic toggle=\"yes\">z</italic> = 1.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504886","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 : 2024-06-10DOI: 10.3847/1538-4365/ad4110
Riley W. Clarke, James R. A. Davenport, John Gizis, Melissa L. Graham, Xiaolong Li, Willow Fortino, Easton J. Honaker, Ian Sullivan, Yusra Alsayyad, James Bosch, Robert A. Knop, Federica B. Bianco
Due to their short timescale, stellar flares are a challenging target for the most modern synoptic sky surveys. The upcoming Vera C. Rubin Legacy Survey of Space and Time (LSST), a project designed to collect more data than any precursor survey, is unlikely to detect flares with more than one data point in its main survey. We developed a methodology to enable LSST studies of stellar flares, with a focus on flare temperature and temperature evolution, which remain poorly constrained compared to flare morphology. By leveraging the sensitivity expected from the Rubin system, differential chromatic refraction (DCR) can be used to constrain flare temperature from a single-epoch detection, which will enable statistical studies of flare temperatures and constrain models of the physical processes behind flare emission using the unprecedentedly high volume of data produced by Rubin over the 10 yr LSST. We model the refraction effect as a function of the atmospheric column density, photometric filter, and temperature of the flare, and show that flare temperatures at or above ∼4000 K can be constrained by a single g-band observation at air mass X ≳ 1.2, given the minimum specified requirement on the single-visit relative astrometric accuracy of LSST, and that a surprisingly large number of LSST observations are in fact likely be conducted at X ≳ 1.2, in spite of image quality requirements pushing the survey to preferentially low X. Having failed to measure flare DCR in LSST precursor surveys, we make recommendations on survey design and data products that enable these studies in LSST and other future surveys.
{"title":"Every Data Point Counts: Stellar Flares as a Case Study of Atmosphere-aided Studies of Transients in the LSST Era","authors":"Riley W. Clarke, James R. A. Davenport, John Gizis, Melissa L. Graham, Xiaolong Li, Willow Fortino, Easton J. Honaker, Ian Sullivan, Yusra Alsayyad, James Bosch, Robert A. Knop, Federica B. Bianco","doi":"10.3847/1538-4365/ad4110","DOIUrl":"https://doi.org/10.3847/1538-4365/ad4110","url":null,"abstract":"Due to their short timescale, stellar flares are a challenging target for the most modern synoptic sky surveys. The upcoming Vera C. Rubin Legacy Survey of Space and Time (LSST), a project designed to collect more data than any precursor survey, is unlikely to detect flares with more than one data point in its main survey. We developed a methodology to enable LSST studies of stellar flares, with a focus on flare temperature and temperature evolution, which remain poorly constrained compared to flare morphology. By leveraging the sensitivity expected from the Rubin system, differential chromatic refraction (DCR) can be used to constrain flare temperature from a single-epoch detection, which will enable statistical studies of flare temperatures and constrain models of the physical processes behind flare emission using the unprecedentedly high volume of data produced by Rubin over the 10 yr LSST. We model the refraction effect as a function of the atmospheric column density, photometric filter, and temperature of the flare, and show that flare temperatures at or above ∼4000 K can be constrained by a single <italic toggle=\"yes\">g</italic>-band observation at air mass <italic toggle=\"yes\">X</italic> ≳ 1.2, given the minimum specified requirement on the single-visit relative astrometric accuracy of LSST, and that a surprisingly large number of LSST observations are in fact likely be conducted at <italic toggle=\"yes\">X</italic> ≳ 1.2, in spite of image quality requirements pushing the survey to preferentially low <italic toggle=\"yes\">X</italic>. Having failed to measure flare DCR in LSST precursor surveys, we make recommendations on survey design and data products that enable these studies in LSST and other future surveys.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141527887","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 : 2024-06-03DOI: 10.3847/1538-4365/ad410a
Robert A. Fesen, Marcel Drechsler, Xavier Strottner, Bray Falls, Yann Sainty, Nicolas Martino, Richard Galli, Mathew Ludgate, Markus Blauensteiner, Wolfgang Reich, Sean Walker, Dennis di Cicco, David Mittelman, Curtis Morgan, Aziz Ettahar Kaeouach, Justin Rupert and Zouhair Benkhaldoun
Deep optical emission-line images are presented for nine known plus three new Galactic supernova remnants (SNRs), all but one having at least one angular dimension >1°. Wide-field images taken in Hα and [O iii] λ5007 reveal many new and surprising remnant structures including large remnant shock extensions and “breakout” features not seen in published optical or radio data. These images represent over 12,000 individual images totaling more than 1000 hr of exposure time taken over the last 2 yr mainly using small aperture telescopes, which detected fainter nebular line emissions than published emission-line images. During the course of this imaging program, we discovered three new SNRs, namely G107.5-5.1 (the Nereides Nebula), G209.9-8.2, and G210.5+1.3, two of which have diameters >1.°5. In addition to offering greater structural detail on the nine already known SNRs, a key finding of this study is the importance of [O iii] emission-line imaging for mapping the complete shock emissions of Galactic SNRs.
{"title":"Deep Optical Emission-line Images of Nine Known and Three New Galactic Supernova Remnants","authors":"Robert A. Fesen, Marcel Drechsler, Xavier Strottner, Bray Falls, Yann Sainty, Nicolas Martino, Richard Galli, Mathew Ludgate, Markus Blauensteiner, Wolfgang Reich, Sean Walker, Dennis di Cicco, David Mittelman, Curtis Morgan, Aziz Ettahar Kaeouach, Justin Rupert and Zouhair Benkhaldoun","doi":"10.3847/1538-4365/ad410a","DOIUrl":"https://doi.org/10.3847/1538-4365/ad410a","url":null,"abstract":"Deep optical emission-line images are presented for nine known plus three new Galactic supernova remnants (SNRs), all but one having at least one angular dimension >1°. Wide-field images taken in Hα and [O iii] λ5007 reveal many new and surprising remnant structures including large remnant shock extensions and “breakout” features not seen in published optical or radio data. These images represent over 12,000 individual images totaling more than 1000 hr of exposure time taken over the last 2 yr mainly using small aperture telescopes, which detected fainter nebular line emissions than published emission-line images. During the course of this imaging program, we discovered three new SNRs, namely G107.5-5.1 (the Nereides Nebula), G209.9-8.2, and G210.5+1.3, two of which have diameters >1.°5. In addition to offering greater structural detail on the nine already known SNRs, a key finding of this study is the importance of [O iii] emission-line imaging for mapping the complete shock emissions of Galactic SNRs.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141253177","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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