Coronal mass ejection (CME) is a powerful solar phenomenon that can lead to severe space weather events. Forecasting whether and when the corresponding interplanetary coronal mass ejection (ICME) will reach the Earth is very important in space weather study and forecast. At present, many different kinds of models use the near-Sun CME observations as model inputs to predict its propagation with similar prediction accuracies for large sample events. Among a series of physics-based models, the best-performing version of the shock propagation model (SPM) for large sample events, i.e., SPM3, had achieved a good forecast effect for the 23rd Solar Cycle events (1997.02–2006.12). To further evaluate SPM3, we collected CME events from 2013 January to 2023 July from the Community Coordinated Modeling Center (CCMC) CME scoreboard as a new data set. SPM3 achieved a total prediction success rate of 57% for these new events with a mean absolute error of 8.93 hr and a rms error of 10.86 hr for the shock's arrival time. Interestingly, SPM3 provided better predictions for the CME/shock events during high solar activity years than low solar activity years. We also analyzed the influence of input parameters on CME propagation and found that the larger the angular width of the CME event, the higher the probability of the corresponding IP shock's reaching the Earth. Source latitude had little effect on the arrival probability of the corresponding shock, while source longitude did. The CMEs originating from around W15° had the largest probability of hitting the Earth.
{"title":"Predicting Arrival Times of the CCMC CME/Shock Events Based on the SPM3 Model","authors":"Yidan Liang, 一丹 梁, Xinhua Zhao, 新华 赵, Nanbin Xiang, 南彬 向, Shiwei Feng, 士伟 冯, Fuyu Li, 富羽 李, Linhua Deng, 林华 邓, Miao Wan, 苗 万, Ran Li and 冉 李","doi":"10.3847/1538-4357/ad84f0","DOIUrl":"https://doi.org/10.3847/1538-4357/ad84f0","url":null,"abstract":"Coronal mass ejection (CME) is a powerful solar phenomenon that can lead to severe space weather events. Forecasting whether and when the corresponding interplanetary coronal mass ejection (ICME) will reach the Earth is very important in space weather study and forecast. At present, many different kinds of models use the near-Sun CME observations as model inputs to predict its propagation with similar prediction accuracies for large sample events. Among a series of physics-based models, the best-performing version of the shock propagation model (SPM) for large sample events, i.e., SPM3, had achieved a good forecast effect for the 23rd Solar Cycle events (1997.02–2006.12). To further evaluate SPM3, we collected CME events from 2013 January to 2023 July from the Community Coordinated Modeling Center (CCMC) CME scoreboard as a new data set. SPM3 achieved a total prediction success rate of 57% for these new events with a mean absolute error of 8.93 hr and a rms error of 10.86 hr for the shock's arrival time. Interestingly, SPM3 provided better predictions for the CME/shock events during high solar activity years than low solar activity years. We also analyzed the influence of input parameters on CME propagation and found that the larger the angular width of the CME event, the higher the probability of the corresponding IP shock's reaching the Earth. Source latitude had little effect on the arrival probability of the corresponding shock, while source longitude did. The CMEs originating from around W15° had the largest probability of hitting the Earth.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713316","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 : 2024-11-26DOI: 10.3847/1538-4357/ad8cd6
M. Rigoselli, S. Mereghetti, J. P. Halpern, E. V. Gotthelf and C. G. Bassa
Calvera (1RXS J141256.0+792204) is a pulsar of characteristic age 285 kyr at a high Galactic latitude of b = +37°, detected only in soft thermal X-rays. We measure a new and precise proper motion for Calvera using Chandra High Resolution Camera observations obtained 10 yr apart. We also derive a new phase-connected ephemeris using 6 yr of NICER data, including the astrometric position and proper motion as fixed parameters in the timing solution. Calvera is located near the center of a faint, circular radio ring that was recently discovered by LOFAR and confirmed as a supernova remnant (SNR) by the detection of γ-ray emission with Fermi Large Area Telescope. The proper motion of 78.5 ± 2.9 mas yr−1 at position angle 241.°3 ± 2.°2 (in Galactic coordinates) points away from the center of the ring, a result which differs markedly from a previous low-significance measurement, and greatly simplifies the interpretation of the SNR/pulsar association. It argues that the supernova indeed birthed Calvera <10 kyr ago, with an initial spin period close to its present value of 59 ms. The tangential velocity of the pulsar depends on its uncertain distance, vt = (372 ± 14)d1 kpc km s−1, but is probably dominated by the supernova kick, while its progenitor could have been a runaway O or B star from the Galactic disk.
卡尔维拉（Calvera）（1RXS J141256.0+792204）是一颗特征年龄为 285 kyr 的脉冲星，位于银河系高纬度 b = +37°，只在软热 X 射线中被探测到。我们利用钱德拉高分辨率相机相隔 10 年的观测数据，为卡尔维拉测量了一个新的、精确的正确运动。我们还利用 6 年的 NICER 数据推导出了一个新的相位连接星历表，并将天体测量位置和正确运动作为固定参数纳入授时方案。卡尔维拉位于一个微弱的圆形射电环的中心附近，该射电环是最近由LOFAR发现的，并通过费米大面积望远镜对γ射线发射的探测确认为超新星遗迹（SNR）。在位置角为 241.°3 ± 2.°2（银河系坐标）时，其正确运动为 78.5 ± 2.9 mas yr-1，指向远离环的中心，这一结果与之前的一个低意义测量结果有明显不同，并大大简化了对 SNR/脉冲星关联的解释。它论证了超新星确实在<10 kyr前孕育了卡尔维拉，其初始自旋周期接近于现在的59 ms。脉冲星的切向速度取决于其不确定的距离，即 vt = (372 ± 14)d1 kpc km s-1，但很可能是由超新星踢所主导的，而其祖先可能是来自银河系盘的一颗失控的 O 星或 B 星。
{"title":"The Proper Motion of the High Galactic Latitude Pulsar Calvera","authors":"M. Rigoselli, S. Mereghetti, J. P. Halpern, E. V. Gotthelf and C. G. Bassa","doi":"10.3847/1538-4357/ad8cd6","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8cd6","url":null,"abstract":"Calvera (1RXS J141256.0+792204) is a pulsar of characteristic age 285 kyr at a high Galactic latitude of b = +37°, detected only in soft thermal X-rays. We measure a new and precise proper motion for Calvera using Chandra High Resolution Camera observations obtained 10 yr apart. We also derive a new phase-connected ephemeris using 6 yr of NICER data, including the astrometric position and proper motion as fixed parameters in the timing solution. Calvera is located near the center of a faint, circular radio ring that was recently discovered by LOFAR and confirmed as a supernova remnant (SNR) by the detection of γ-ray emission with Fermi Large Area Telescope. The proper motion of 78.5 ± 2.9 mas yr−1 at position angle 241.°3 ± 2.°2 (in Galactic coordinates) points away from the center of the ring, a result which differs markedly from a previous low-significance measurement, and greatly simplifies the interpretation of the SNR/pulsar association. It argues that the supernova indeed birthed Calvera <10 kyr ago, with an initial spin period close to its present value of 59 ms. The tangential velocity of the pulsar depends on its uncertain distance, vt = (372 ± 14)d1 kpc km s−1, but is probably dominated by the supernova kick, while its progenitor could have been a runaway O or B star from the Galactic disk.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"183 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713028","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 : 2024-11-26DOI: 10.3847/1538-4357/ad83cf
Yu Zhou, Volodymyr Takhistov and Kazuhisa Mitsuda
Astrophysical emission lines arising from particle decays can offer unique insights into the nature of dark matter (DM). Using dedicated simulations with background and foreground modeling, we comprehensively demonstrate that the recently launched X-Ray Imaging and Spectroscopy Mission (XRISM) space telescope with powerful X-ray spectroscopy capabilities is particularly well suited to probe decaying DM, such as sterile neutrinos and axion-like particles, in the mass range of a few to tens of keV. We analyze and map XRISM’s DM discovery potential parameter space by considering the Milky Way Galactic DM halo, including establishing an optimal line-of-sight search, as well as dwarf galaxies, where we identify Segue 1 as a remarkably promising target. We demonstrate that with only 100 ks exposure, the XRISM/Resolve instrument is capable of probing the underexplored DM parameter window around a few keV and testing DM couplings with a sensitivity that exceeds by two orders existing Segue 1 limits. Further, we demonstrate that XRISM/Xtend instrument sensitivity enables discovery of the nature of faint astrophysical X-ray sources, especially in Segue 1, which could shed light on star formation history. We discuss implications for decaying DM searches with improved detector energy resolution in future experiments.
{"title":"Unlocking Discovery Potential for Decaying Dark Matter and Faint X-Ray Sources with XRISM","authors":"Yu Zhou, Volodymyr Takhistov and Kazuhisa Mitsuda","doi":"10.3847/1538-4357/ad83cf","DOIUrl":"https://doi.org/10.3847/1538-4357/ad83cf","url":null,"abstract":"Astrophysical emission lines arising from particle decays can offer unique insights into the nature of dark matter (DM). Using dedicated simulations with background and foreground modeling, we comprehensively demonstrate that the recently launched X-Ray Imaging and Spectroscopy Mission (XRISM) space telescope with powerful X-ray spectroscopy capabilities is particularly well suited to probe decaying DM, such as sterile neutrinos and axion-like particles, in the mass range of a few to tens of keV. We analyze and map XRISM’s DM discovery potential parameter space by considering the Milky Way Galactic DM halo, including establishing an optimal line-of-sight search, as well as dwarf galaxies, where we identify Segue 1 as a remarkably promising target. We demonstrate that with only 100 ks exposure, the XRISM/Resolve instrument is capable of probing the underexplored DM parameter window around a few keV and testing DM couplings with a sensitivity that exceeds by two orders existing Segue 1 limits. Further, we demonstrate that XRISM/Xtend instrument sensitivity enables discovery of the nature of faint astrophysical X-ray sources, especially in Segue 1, which could shed light on star formation history. We discuss implications for decaying DM searches with improved detector energy resolution in future experiments.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713310","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 : 2024-11-26DOI: 10.3847/1538-4357/ad8640
Bin-Hui Chen, Juntai Shen and Zhong Liu
A vertical metallicity gradient (VMG) in the Milky Way bulge is well-established. Yet, its origin has not been fully understood under the Galactic secular evolution scenario. We construct single-disk and triple-disk N-body models with an initial radial metallicity gradient (RMG) for each disk. These models generate a VMG through a “two-step heating” mechanism: the outer, metal-poor particles move inward via the bar instability and subsequently undergo more significant vertical heating during the buckling instability, so they end up at greater vertical height. The “two-step heating” mechanism nearly linearly transforms the RMGs in precursor disks into VMGs. Comparing the models with a triple-disk model tagged with radially independent Gaussian metallicity, we find that, despite certain limitations, the “two-step heating” mechanism is still important in shaping the Galactic VMG. If the bar and buckling instabilities contributed to the formation of boxy/peanut-shaped bulges, then the “two-step heating” mechanism is inevitable in the secular evolution of a boxy/peanut-shaped bulge.
{"title":"Dynamical Origin of the Vertical Metallicity Gradient of the Milky Way Bulge","authors":"Bin-Hui Chen, Juntai Shen and Zhong Liu","doi":"10.3847/1538-4357/ad8640","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8640","url":null,"abstract":"A vertical metallicity gradient (VMG) in the Milky Way bulge is well-established. Yet, its origin has not been fully understood under the Galactic secular evolution scenario. We construct single-disk and triple-disk N-body models with an initial radial metallicity gradient (RMG) for each disk. These models generate a VMG through a “two-step heating” mechanism: the outer, metal-poor particles move inward via the bar instability and subsequently undergo more significant vertical heating during the buckling instability, so they end up at greater vertical height. The “two-step heating” mechanism nearly linearly transforms the RMGs in precursor disks into VMGs. Comparing the models with a triple-disk model tagged with radially independent Gaussian metallicity, we find that, despite certain limitations, the “two-step heating” mechanism is still important in shaping the Galactic VMG. If the bar and buckling instabilities contributed to the formation of boxy/peanut-shaped bulges, then the “two-step heating” mechanism is inevitable in the secular evolution of a boxy/peanut-shaped bulge.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713318","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 : 2024-11-26DOI: 10.3847/1538-4357/ad8659
Sofia Sheikh, Grayce C. Brown, Jackson MacTaggart, Thomas Nguyen, William D. Fletcher, Brenda L. Jones, Emma Koller, Veronica Petrus, Katie F. Pighini, Gray Rosario, Vincent A. Smedile, Adam T. Stone, Shawn You, Maura A. McLaughlin, Jacob E. Turner, Julia S. Deneva, Michael T. Lam and Brent J. Shapiro-Albert
A pulsar’s scintillation bandwidth is inversely proportional to the scattering delay, making accurate measurements of scintillation bandwidth critical to characterize unmitigated delays in efforts to measure low-frequency gravitational waves with pulsar timing arrays. In this pilot work, we searched for a subset of known pulsars within ∼97% of the data taken with the Puerto Rico Ultimate Pulsar Processing Instrument for the AO327 survey with the Arecibo telescope, attempting to measure the scintillation bandwidths in the data set by fitting to the 2D autocorrelation function of their dynamic spectra. We successfully measured 38 bandwidths from 23 pulsars (six without prior literature values), finding that: almost all of the measurements are larger than the predictions from NE2001 and YMW16 (two popular galactic models); NE2001 is more consistent with our measurements than YMW16; Gaussian fits to the bandwidth are more consistent with both electron density models than Lorentzian ones; and for the 17 pulsars with prior literature values, the measurements between various sources often vary by a few factors. The success of Gaussian fits may be due to the use of Gaussian fits to train models in previous work. The variance of literature values over time could relate to the scaling factor used to compare measurements, but also seems consistent with time-varying interstellar medium parameters. This work can be extended to the rest of AO327 to further investigate these trends, highlighting the continuing importance of large archival data sets for projects beyond their initial conception.
{"title":"Scintillation Bandwidth Measurements from 23 Pulsars from the AO327 Survey","authors":"Sofia Sheikh, Grayce C. Brown, Jackson MacTaggart, Thomas Nguyen, William D. Fletcher, Brenda L. Jones, Emma Koller, Veronica Petrus, Katie F. Pighini, Gray Rosario, Vincent A. Smedile, Adam T. Stone, Shawn You, Maura A. McLaughlin, Jacob E. Turner, Julia S. Deneva, Michael T. Lam and Brent J. Shapiro-Albert","doi":"10.3847/1538-4357/ad8659","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8659","url":null,"abstract":"A pulsar’s scintillation bandwidth is inversely proportional to the scattering delay, making accurate measurements of scintillation bandwidth critical to characterize unmitigated delays in efforts to measure low-frequency gravitational waves with pulsar timing arrays. In this pilot work, we searched for a subset of known pulsars within ∼97% of the data taken with the Puerto Rico Ultimate Pulsar Processing Instrument for the AO327 survey with the Arecibo telescope, attempting to measure the scintillation bandwidths in the data set by fitting to the 2D autocorrelation function of their dynamic spectra. We successfully measured 38 bandwidths from 23 pulsars (six without prior literature values), finding that: almost all of the measurements are larger than the predictions from NE2001 and YMW16 (two popular galactic models); NE2001 is more consistent with our measurements than YMW16; Gaussian fits to the bandwidth are more consistent with both electron density models than Lorentzian ones; and for the 17 pulsars with prior literature values, the measurements between various sources often vary by a few factors. The success of Gaussian fits may be due to the use of Gaussian fits to train models in previous work. The variance of literature values over time could relate to the scaling factor used to compare measurements, but also seems consistent with time-varying interstellar medium parameters. This work can be extended to the rest of AO327 to further investigate these trends, highlighting the continuing importance of large archival data sets for projects beyond their initial conception.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718261","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 : 2024-11-26DOI: 10.3847/1538-4357/ad8571
Frédéric Marcadon and Andrej Prša
Several hundreds of thousands of eclipsing binaries (EBs) are expected to be detected in the Transiting Exoplanet Survey Satellite (TESS) full frame images (FFIs). This represents a significant increase in the number of EBs available for eclipse timing variation studies. In this paper, we investigate the feasibility of performing precise eclipse timing of TESS EBs using the FFIs. To this end, we developed a fast, automated method and applied it to a sample of ∼100 EBs selected from the Villanova TESS EB catalog. Our timing analysis resulted in the detection of 10 new triple candidates with outer periods shorter than ∼1300 days. For five of them, we were able to constrain the outer orbit by analyzing independently the short-cadence (SC) and FFI data and to derive the minimum mass of the third body with a precision better than 4% for SC and 11% for FFI data. We then compared the results obtained from the two data sets and found that using the FFI data leads to (1) a degradation of both the accuracy and precision of the tertiary mass determination for the tightest EBs and (2) an overall underestimation of the third component’s mass. However, we stress that our main conclusions on the nature of the detected signals do not depend on which data set is used. This confirms the great potential of TESS FFIs, which will allow us to search for rare objects such as substellar circumbinary companions and compact triple stellar systems.
{"title":"Precision Timing of Eclipsing Binaries from TESS Full Frame Images: Method and Performance","authors":"Frédéric Marcadon and Andrej Prša","doi":"10.3847/1538-4357/ad8571","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8571","url":null,"abstract":"Several hundreds of thousands of eclipsing binaries (EBs) are expected to be detected in the Transiting Exoplanet Survey Satellite (TESS) full frame images (FFIs). This represents a significant increase in the number of EBs available for eclipse timing variation studies. In this paper, we investigate the feasibility of performing precise eclipse timing of TESS EBs using the FFIs. To this end, we developed a fast, automated method and applied it to a sample of ∼100 EBs selected from the Villanova TESS EB catalog. Our timing analysis resulted in the detection of 10 new triple candidates with outer periods shorter than ∼1300 days. For five of them, we were able to constrain the outer orbit by analyzing independently the short-cadence (SC) and FFI data and to derive the minimum mass of the third body with a precision better than 4% for SC and 11% for FFI data. We then compared the results obtained from the two data sets and found that using the FFI data leads to (1) a degradation of both the accuracy and precision of the tertiary mass determination for the tightest EBs and (2) an overall underestimation of the third component’s mass. However, we stress that our main conclusions on the nature of the detected signals do not depend on which data set is used. This confirms the great potential of TESS FFIs, which will allow us to search for rare objects such as substellar circumbinary companions and compact triple stellar systems.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713317","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 : 2024-11-26DOI: 10.3847/1538-4357/ad7384
Roger B. Scott, Jeffrey W. Reep, Mark G. Linton and Stephen J. Bradshaw
Thermal nonequilibrium (TNE) is a condition of the plasma in the solar corona in which the local rate of energy loss due to radiation increases to the point that it cannot be sustained by the various heating terms acting on the plasma, precluding the existence of a steady state. The limit cycles of precipitation and evaporation that result from TNE have been simulated in 1D models of coronal loops, as well as 2D and 3D models of the solar chromosphere and lower corona. However, a careful study of TNE in the solar wind has not been performed until now. Here, we demonstrate that for suitable combinations of local and global heating rates, it is possible for the plasma to exhibit a TNE condition, even in the context of a transonic solar wind with appreciable mass and energy fluxes. This implies limits on the amount of footpoint heating that can be withstood under steady-state conditions in the solar wind, and may help to explain the variability of solar wind streams that emanate from regions of highly concentrated magnetic flux on the solar surface. The implications of this finding pertain to various sources of high-density solar wind, including plumes that form above regions of mixed magnetic polarity in polar coronal holes and the slow solar wind that emanates from coronal hole boundaries.
{"title":"Simulation of Thermal Nonequilibrium Cycles in the Solar Wind","authors":"Roger B. Scott, Jeffrey W. Reep, Mark G. Linton and Stephen J. Bradshaw","doi":"10.3847/1538-4357/ad7384","DOIUrl":"https://doi.org/10.3847/1538-4357/ad7384","url":null,"abstract":"Thermal nonequilibrium (TNE) is a condition of the plasma in the solar corona in which the local rate of energy loss due to radiation increases to the point that it cannot be sustained by the various heating terms acting on the plasma, precluding the existence of a steady state. The limit cycles of precipitation and evaporation that result from TNE have been simulated in 1D models of coronal loops, as well as 2D and 3D models of the solar chromosphere and lower corona. However, a careful study of TNE in the solar wind has not been performed until now. Here, we demonstrate that for suitable combinations of local and global heating rates, it is possible for the plasma to exhibit a TNE condition, even in the context of a transonic solar wind with appreciable mass and energy fluxes. This implies limits on the amount of footpoint heating that can be withstood under steady-state conditions in the solar wind, and may help to explain the variability of solar wind streams that emanate from regions of highly concentrated magnetic flux on the solar surface. The implications of this finding pertain to various sources of high-density solar wind, including plumes that form above regions of mixed magnetic polarity in polar coronal holes and the slow solar wind that emanates from coronal hole boundaries.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713308","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 : 2024-11-26DOI: 10.3847/1538-4357/ad8919
Dongting Yang, Hong-Li Liu, Tie Liu, Anandmayee Tej, Xunchuan Liu, Jinhua He, Guido Garay, Amelia Stutz, Lei Zhu, Sheng-Li Qin, Fengwei Xu, Pak-Shing Li, Mika Juvela, Pablo García, Paul F. Goldsmith, Siju Zhang, Xindi Tang, Patricio Sanhueza, Shanghuo Li, Chang Won Lee, Swagat Ranjan Das, Wenyu Jiao, Xiaofeng Mai, Prasanta Gorai, Yichen Zhang, Zhiyuan Ren, L. Viktor Tóth, Jihye Hwang, Leonardo Bronfman, Ken’ichi Tatematsu, Lokesh Dewangan, James O. Chibueze, Suinan Zhang, Gang Wu and Jinjin Xie
In this paper, we present a detailed analysis of the IRS 17 filament within the intermediate-mass protocluster IRAS 08448-4343 (of ∼103L⊙), using ALMA data from the ATOMS 3 mm and QUARKS 1.3 mm surveys. The IRS 17 filament, which spans ∼54,000 au (0.26 pc) in length and ∼4000 au (0.02 pc) in width, exhibits a complex, multicomponent velocity field and harbors hierarchical substructures. These substructures include three bundles of seven velocity-coherent fibers and 29 dense (n ∼ 108 cm−3) condensations. The fibers have a median length of ∼4500 au and a median width of ∼1400 au. Among these fibers, four are identified as “fertile,” each hosting at least three dense condensations, which are regarded as the “seeds” of star formation. While the detected cores are randomly spaced within the IRS 17 filament based on the 3 mm dust continuum image, periodic spacing (∼1600 au) of condensations is observed in the fertile fibers according to the 1.3 mm dust map, consistent with the predictions of linear isothermal cylinder fragmentation models. These findings underscore the crucial role of fibers in star formation and suggest a hierarchical fragmentation process that extends from the filament to the fibers and, ultimately, to the smallest-scale condensations.
{"title":"The ALMA-QUARKS Survey: Fibers’ Role in Star Formation Unveiled in an Intermediate-mass Protocluster Region of the Vela D Cloud","authors":"Dongting Yang, Hong-Li Liu, Tie Liu, Anandmayee Tej, Xunchuan Liu, Jinhua He, Guido Garay, Amelia Stutz, Lei Zhu, Sheng-Li Qin, Fengwei Xu, Pak-Shing Li, Mika Juvela, Pablo García, Paul F. Goldsmith, Siju Zhang, Xindi Tang, Patricio Sanhueza, Shanghuo Li, Chang Won Lee, Swagat Ranjan Das, Wenyu Jiao, Xiaofeng Mai, Prasanta Gorai, Yichen Zhang, Zhiyuan Ren, L. Viktor Tóth, Jihye Hwang, Leonardo Bronfman, Ken’ichi Tatematsu, Lokesh Dewangan, James O. Chibueze, Suinan Zhang, Gang Wu and Jinjin Xie","doi":"10.3847/1538-4357/ad8919","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8919","url":null,"abstract":"In this paper, we present a detailed analysis of the IRS 17 filament within the intermediate-mass protocluster IRAS 08448-4343 (of ∼103L⊙), using ALMA data from the ATOMS 3 mm and QUARKS 1.3 mm surveys. The IRS 17 filament, which spans ∼54,000 au (0.26 pc) in length and ∼4000 au (0.02 pc) in width, exhibits a complex, multicomponent velocity field and harbors hierarchical substructures. These substructures include three bundles of seven velocity-coherent fibers and 29 dense (n ∼ 108 cm−3) condensations. The fibers have a median length of ∼4500 au and a median width of ∼1400 au. Among these fibers, four are identified as “fertile,” each hosting at least three dense condensations, which are regarded as the “seeds” of star formation. While the detected cores are randomly spaced within the IRS 17 filament based on the 3 mm dust continuum image, periodic spacing (∼1600 au) of condensations is observed in the fertile fibers according to the 1.3 mm dust map, consistent with the predictions of linear isothermal cylinder fragmentation models. These findings underscore the crucial role of fibers in star formation and suggest a hierarchical fragmentation process that extends from the filament to the fibers and, ultimately, to the smallest-scale condensations.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"119 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713025","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 : 2024-11-26DOI: 10.3847/1538-4357/ad8d5b
N. Menci, A. A. Sen and M. Castellano
Recent observations by JWST yield a large abundance of luminous galaxies at z ≳ 10 compared to that expected in the ΛCDM scenario based on extrapolations of the star formation efficiency measured at lower redshifts. While several astrophysical processes can be responsible for such observations, here we explore to what extent such an effect can be rooted in the assumed dark energy (DE) sector of the current cosmological model. This is motivated by recent results from different cosmological probes combined with the last data release of the Dark Energy Spectroscopic Instrument, which indicate a tension in the DE sector of the concordance ΛCDM model. We have considered the effect of assuming a DE characterized by a negative Λ as the ground state of a quintessence field on the galaxy luminosity function at high redshifts. We find that such models naturally affect the galaxy UV luminosities in the redshift range 10 ≲ z ≲ 15 needed to match the JWST observations, and with the value of ΩΛ = [−0.6, −0.3] remarkably consistent with that required by independent cosmological probes. A sharp prediction of such models is the steep decline of the abundance of bright galaxies in the redshift range 15 ≲ z ≲ 16.
JWST 最近的观测结果表明，在 z ≳ 10 处有大量的发光星系，而根据在较低红移下测量到的恒星形成效率的推断，在ΛCDM 情景下预计会有大量的发光星系。虽然有几个天体物理过程可以导致这样的观测结果，但我们在这里要探讨的是，这种效应在多大程度上可以植根于当前宇宙学模型的假定暗能量（DE）部门。这是由于不同宇宙学探测器的最新探测结果与暗能量光谱仪的最新数据相结合而产生的，这些结果表明在协和ΛCDM 模型的暗能量部分存在紧张关系。我们考虑了假设以负Λ为特征的DE作为五元场基态对高红移下星系光度函数的影响。我们发现，在与 JWST 观测结果相匹配所需的红移范围 10 ≲ z ≲ 15 内，这种模型会自然地影响星系的紫外发光度，而且ΩΛ = [-0.6, -0.3]的值与独立的宇宙学探测所要求的值非常一致。这类模型的一个显著预测是，在红移范围 15 ≲ z ≲ 16 时，明亮星系的丰度会急剧下降。
{"title":"The Excess of JWST Bright Galaxies: A Possible Origin in the Ground State of Dynamical Dark Energy in the Light of DESI 2024 Data","authors":"N. Menci, A. A. Sen and M. Castellano","doi":"10.3847/1538-4357/ad8d5b","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8d5b","url":null,"abstract":"Recent observations by JWST yield a large abundance of luminous galaxies at z ≳ 10 compared to that expected in the ΛCDM scenario based on extrapolations of the star formation efficiency measured at lower redshifts. While several astrophysical processes can be responsible for such observations, here we explore to what extent such an effect can be rooted in the assumed dark energy (DE) sector of the current cosmological model. This is motivated by recent results from different cosmological probes combined with the last data release of the Dark Energy Spectroscopic Instrument, which indicate a tension in the DE sector of the concordance ΛCDM model. We have considered the effect of assuming a DE characterized by a negative Λ as the ground state of a quintessence field on the galaxy luminosity function at high redshifts. We find that such models naturally affect the galaxy UV luminosities in the redshift range 10 ≲ z ≲ 15 needed to match the JWST observations, and with the value of ΩΛ = [−0.6, −0.3] remarkably consistent with that required by independent cosmological probes. A sharp prediction of such models is the steep decline of the abundance of bright galaxies in the redshift range 15 ≲ z ≲ 16.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713029","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 : 2024-11-26DOI: 10.3847/1538-4357/ad855f
Luke G. Bouma, Lynne A. Hillenbrand, Andrew W. Howard, Howard Isaacson, Kento Masuda and Elsa K. Palumbo
Recent analyses of FGK stars in open clusters have helped clarify the precision with which a star’s rotation rate and lithium content can be used as empirical indicators for its age. Here we apply this knowledge to stars observed by Kepler. Rotation periods are drawn from previous work; lithium is measured from new and archival Keck/HIRES spectra. We report rotation-based ages for 23,813 stars (harboring 795 known planets) for which our method is applicable. We find that our rotational ages recover the ages of stars in open clusters spanning 0.04–2.5 Gyr; they also agree with ≳90% of the independent lithium ages. The resulting yield includes 63 planets younger than 1 Gyr at 2σ, and 109 with median ages below 1 Gyr. This is about half the number expected under the classic assumption of a uniform star formation history. The age distribution that we observe, rather than being uniform, shows that the youngest stars in the Kepler field are 3–5 times rarer than stars 3 Gyr old. This trend holds for both known planet hosts and for the parent stellar sample. We attribute this “demographic cliff” to a combination of kinematic heating and a declining star formation rate in the Galaxy’s thin disk, and highlight its impact on the age distribution of known transiting exoplanets.
{"title":"Ages of Stars and Planets in the Kepler Field Younger than Four Billion Years","authors":"Luke G. Bouma, Lynne A. Hillenbrand, Andrew W. Howard, Howard Isaacson, Kento Masuda and Elsa K. Palumbo","doi":"10.3847/1538-4357/ad855f","DOIUrl":"https://doi.org/10.3847/1538-4357/ad855f","url":null,"abstract":"Recent analyses of FGK stars in open clusters have helped clarify the precision with which a star’s rotation rate and lithium content can be used as empirical indicators for its age. Here we apply this knowledge to stars observed by Kepler. Rotation periods are drawn from previous work; lithium is measured from new and archival Keck/HIRES spectra. We report rotation-based ages for 23,813 stars (harboring 795 known planets) for which our method is applicable. We find that our rotational ages recover the ages of stars in open clusters spanning 0.04–2.5 Gyr; they also agree with ≳90% of the independent lithium ages. The resulting yield includes 63 planets younger than 1 Gyr at 2σ, and 109 with median ages below 1 Gyr. This is about half the number expected under the classic assumption of a uniform star formation history. The age distribution that we observe, rather than being uniform, shows that the youngest stars in the Kepler field are 3–5 times rarer than stars 3 Gyr old. This trend holds for both known planet hosts and for the parent stellar sample. We attribute this “demographic cliff” to a combination of kinematic heating and a declining star formation rate in the Galaxy’s thin disk, and highlight its impact on the age distribution of known transiting exoplanets.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713313","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：