Pub Date : 2026-04-14DOI: 10.3847/1538-4357/ae5804
Veronica Pratt, Jason R. Reeves, David V. Martin, Andy B. Zhang, Andrew Korkus and S. Edelman
Most flares on the Sun occur at random, but there is a small percentage of “sympathetic flaring”—the triggering of one flare by another. Previously there had been no widespread confirmation of sympathetic flares on other stars. In this work, we developed a new flare detection algorithm that is sensitive to closely separated and overlapping stellar flares. We applied it to the Transiting Exoplanet Survey Satellite (TESS) data and discovered ∼220,000 flares on ∼16,000 stars, the majority of which are M dwarfs. The wait time distribution between flares demonstrates an excess of closely separated flares relative to expectations from a Poisson process. We attribute this to sympathetic flares, occurring at a rate of between 4% and 9%, which matches the rate seen on the Sun. Our result is the first statistically robust detection of sympathetic flares on other stars, demonstrating a commonality between the Sun and low-mass stars.
{"title":"Evidence for Sympathetic Flaring in TESS Data","authors":"Veronica Pratt, Jason R. Reeves, David V. Martin, Andy B. Zhang, Andrew Korkus and S. Edelman","doi":"10.3847/1538-4357/ae5804","DOIUrl":"https://doi.org/10.3847/1538-4357/ae5804","url":null,"abstract":"Most flares on the Sun occur at random, but there is a small percentage of “sympathetic flaring”—the triggering of one flare by another. Previously there had been no widespread confirmation of sympathetic flares on other stars. In this work, we developed a new flare detection algorithm that is sensitive to closely separated and overlapping stellar flares. We applied it to the Transiting Exoplanet Survey Satellite (TESS) data and discovered ∼220,000 flares on ∼16,000 stars, the majority of which are M dwarfs. The wait time distribution between flares demonstrates an excess of closely separated flares relative to expectations from a Poisson process. We attribute this to sympathetic flares, occurring at a rate of between 4% and 9%, which matches the rate seen on the Sun. Our result is the first statistically robust detection of sympathetic flares on other stars, demonstrating a commonality between the Sun and low-mass stars.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147681946","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 : 2026-04-14DOI: 10.3847/1538-4357/ae4d3a
Elisabeth A.C. Mills, Natalie O. Butterfield, Hauyu Baobab Liu, Dani Lipman, Adam Ginsburg, Mattia C. Sormani, Jonathan D. Henshaw, Cara D. Battersby, Ashley T. Barnes, Simon C. O. Glover, Francisco Nogueras-Lara, Mark R. Morris, Juergen Ott, Cornelia Lang, Claire Cook and Xinyu Mai
The construction of an accurate 3D model of the Milky Way center is necessary to understand inflow processes that drive its overall evolution and to compare our Galactic nucleus to other galaxies’ nuclei. A main point of contention is the line-of-sight location of sources observed toward the central 10 pc of the Galaxy, including recent star formation (the Sgr A East supernova remnant and Sgr A H II regions) and copious gas (the 50 and 20 km s−1 molecular clouds, the circumnuclear disk, and the Sgr A West ionized “minispiral” that encircles the central supermassive black hole, Sgr A*). Some models place all of these structures within a radius of 5 pc from Sgr A*, while others place the 20 and 50 km s−1 clouds at a distance of at least 30−50 pc away from Sgr A* along the line of sight. We present new radio and millimeter observations of the molecular gas toward the central ∼10 pc, from which we have constructed an alternative 3D model that is consistent with both prior radio observations and orbital gas kinematics. Our model places the 20 km s−1 cloud, 50 km s−1 cloud, and Sgr A East more than 10 pc in front of Sgr A*. While this model does not conclusively rule out a connection between the 50 and 20 km s−1 clouds and the circumnuclear disk, we argue that prior evidence for these connections is tenuous, especially given the complex spatial and kinematic overlap of structures along the line of sight.
为了了解推动银河系整体演化的流入过程，并将我们的星系核与其他星系的核进行比较，建立银河系中心的精确3D模型是必要的。一个主要的争论点是观测到的星系中心10%的源的视线位置，包括最近的恒星形成（Sgr A东部超新星遗迹和Sgr A H II区域）和丰富的气体（50和20公里的s - 1分子云，环核盘和Sgr A西部电离的“迷你”，环绕中心超大质量黑洞Sgr A*）。一些模型将所有这些结构放置在距离人马座a * 5个单位的半径内，而另一些模型则将20和50公里s - 1的云放置在距离人马座a *至少30 - 50个单位的视线范围内。我们提出了新的射电和毫米观测到的分子气体向中心~ 10pc，我们已经建立了一个替代的3D模型，与之前的射电观测和轨道气体运动学一致。我们的模型将20 km s - 1云团、50 km s - 1云团和Sgr A East放在Sgr A*前面超过10%的位置。虽然该模型并不能最终排除50和20 km s - 1云团与环核盘之间的联系，但我们认为，关于这些联系的先前证据是脆弱的，特别是考虑到视线上结构的复杂空间和运动学重叠。
{"title":"Reconciling 3D Models for the Central 10 pc of the Milky Way","authors":"Elisabeth A.C. Mills, Natalie O. Butterfield, Hauyu Baobab Liu, Dani Lipman, Adam Ginsburg, Mattia C. Sormani, Jonathan D. Henshaw, Cara D. Battersby, Ashley T. Barnes, Simon C. O. Glover, Francisco Nogueras-Lara, Mark R. Morris, Juergen Ott, Cornelia Lang, Claire Cook and Xinyu Mai","doi":"10.3847/1538-4357/ae4d3a","DOIUrl":"https://doi.org/10.3847/1538-4357/ae4d3a","url":null,"abstract":"The construction of an accurate 3D model of the Milky Way center is necessary to understand inflow processes that drive its overall evolution and to compare our Galactic nucleus to other galaxies’ nuclei. A main point of contention is the line-of-sight location of sources observed toward the central 10 pc of the Galaxy, including recent star formation (the Sgr A East supernova remnant and Sgr A H II regions) and copious gas (the 50 and 20 km s−1 molecular clouds, the circumnuclear disk, and the Sgr A West ionized “minispiral” that encircles the central supermassive black hole, Sgr A*). Some models place all of these structures within a radius of 5 pc from Sgr A*, while others place the 20 and 50 km s−1 clouds at a distance of at least 30−50 pc away from Sgr A* along the line of sight. We present new radio and millimeter observations of the molecular gas toward the central ∼10 pc, from which we have constructed an alternative 3D model that is consistent with both prior radio observations and orbital gas kinematics. Our model places the 20 km s−1 cloud, 50 km s−1 cloud, and Sgr A East more than 10 pc in front of Sgr A*. While this model does not conclusively rule out a connection between the 50 and 20 km s−1 clouds and the circumnuclear disk, we argue that prior evidence for these connections is tenuous, especially given the complex spatial and kinematic overlap of structures along the line of sight.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147681748","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 : 2026-04-14DOI: 10.3847/1538-4357/ae510a
I. A. Lebedev, A. I. Fedosimova, Kh. K. Olimov, P. M. Krassovitskiy, N. O. Yerezhep, S. A. Ibraimova and E. A. Bondar
In this work, we study the anisotropy of elemental groups of cosmic rays using data from the KASCADE experiment. The problems of determining primary energy and mass associated with fluctuations in the development of extensive air showers are discussed in detail. To address these issues, a method is used that suppresses the influence of these fluctuations on the estimation of primary energy and mass. The proposed approach is based on the use of lessening fluctuation curves, whose behavior is largely insensitive to shower-to-shower fluctuations during the development of extensive air showers. This allows, firstly, to significantly reduce errors in primary energy estimation and, secondly, to analyze individual showers. The approach also enables simultaneous analysis of showers arriving at substantially different zenith angles θ. To study cosmic-ray anisotropy, we analyzed right ascension versus declination distributions for five elemental groups (p, He, C, Si, and Fe). Analysis of experimental data from the KASCADE collaboration revealed significant differences in the distributions of these groups in equatorial coordinates, which may indicate a directed structure in cosmic-ray fluxes of different elemental composition. The observed features may point to the influence of nearby spiral arms and the Galactic magnetic field structure on the propagation of cosmic rays.
{"title":"Indications of Anisotropy of Cosmic-Ray Elemental Groups Based on KASCADE Data","authors":"I. A. Lebedev, A. I. Fedosimova, Kh. K. Olimov, P. M. Krassovitskiy, N. O. Yerezhep, S. A. Ibraimova and E. A. Bondar","doi":"10.3847/1538-4357/ae510a","DOIUrl":"https://doi.org/10.3847/1538-4357/ae510a","url":null,"abstract":"In this work, we study the anisotropy of elemental groups of cosmic rays using data from the KASCADE experiment. The problems of determining primary energy and mass associated with fluctuations in the development of extensive air showers are discussed in detail. To address these issues, a method is used that suppresses the influence of these fluctuations on the estimation of primary energy and mass. The proposed approach is based on the use of lessening fluctuation curves, whose behavior is largely insensitive to shower-to-shower fluctuations during the development of extensive air showers. This allows, firstly, to significantly reduce errors in primary energy estimation and, secondly, to analyze individual showers. The approach also enables simultaneous analysis of showers arriving at substantially different zenith angles θ. To study cosmic-ray anisotropy, we analyzed right ascension versus declination distributions for five elemental groups (p, He, C, Si, and Fe). Analysis of experimental data from the KASCADE collaboration revealed significant differences in the distributions of these groups in equatorial coordinates, which may indicate a directed structure in cosmic-ray fluxes of different elemental composition. The observed features may point to the influence of nearby spiral arms and the Galactic magnetic field structure on the propagation of cosmic rays.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147681749","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 : 2026-04-14DOI: 10.3847/1538-4357/ae5792
Youqian Qi, Mingzhe Guo, Zhenghua Huang, Tom Van Doorsselaere, Bo Li, Lidong Xia, Hengyuan Wei and Hui Fu
Coronal plumes and chromospheric jetlike structures are believed to be highly dynamic. We report the first direct observations of a propagating kink wave in a chromospheric jetlike structure and its associated plumelet structure in the upper corona of the solar polar region, using data from the High Resolution Imager of the Extreme Ultraviolet Imager on board Solar Orbiter. The dark jetlike structure exhibits transverse oscillation during upward propagation, with a period of approximately 95 s and a displacement of about 193 km. The corresponding plumelet also displays transverse motion, with an oscillation period of around 99 s and a displacement of about 315 km. Given that both the dark jetlike structure and the plumelet share the same magnetic skeleton and have similar oscillation period, we suggest that these oscillations are the same transverse propagating wave originating in the chromosphere. This scenario is further supported by a 3D magnetohydrodynamic (MHD) simulation, in which both vertical and transverse perturbations were introduced in a stratified magnetic flux tube. The simulation successfully reproduces the upward propagation of a kink wave through both the chromospheric jetlike structure and the coronal plumelet. These results highlight the potential role of transverse waves in transferring energy from the lower solar atmosphere to the corona.
{"title":"Propagating Kink Waves in Chromospheric Jetlike Structures and Coronal Plumelets","authors":"Youqian Qi, Mingzhe Guo, Zhenghua Huang, Tom Van Doorsselaere, Bo Li, Lidong Xia, Hengyuan Wei and Hui Fu","doi":"10.3847/1538-4357/ae5792","DOIUrl":"https://doi.org/10.3847/1538-4357/ae5792","url":null,"abstract":"Coronal plumes and chromospheric jetlike structures are believed to be highly dynamic. We report the first direct observations of a propagating kink wave in a chromospheric jetlike structure and its associated plumelet structure in the upper corona of the solar polar region, using data from the High Resolution Imager of the Extreme Ultraviolet Imager on board Solar Orbiter. The dark jetlike structure exhibits transverse oscillation during upward propagation, with a period of approximately 95 s and a displacement of about 193 km. The corresponding plumelet also displays transverse motion, with an oscillation period of around 99 s and a displacement of about 315 km. Given that both the dark jetlike structure and the plumelet share the same magnetic skeleton and have similar oscillation period, we suggest that these oscillations are the same transverse propagating wave originating in the chromosphere. This scenario is further supported by a 3D magnetohydrodynamic (MHD) simulation, in which both vertical and transverse perturbations were introduced in a stratified magnetic flux tube. The simulation successfully reproduces the upward propagation of a kink wave through both the chromospheric jetlike structure and the coronal plumelet. These results highlight the potential role of transverse waves in transferring energy from the lower solar atmosphere to the corona.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147681945","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}
The recently reported Cosmic Himalayas (CH)—an extreme quasar overdensity at z ∼ 2—poses an apparent challenge to the Lambda cold dark matter (ΛCDM) framework, with a reported significance of δ = 16.9σ under Gaussian assumptions. Such an event appears improbably rare, with a formal probability of P ∼ 10−68. In this work, we investigate whether CH-like structures can naturally arise in cosmological hydrodynamic simulations. Using the CROCODILE simulation, which self-consistently models galaxy–black hole coevolution, we examine quasar clustering through two complementary approaches: the count-in-cells (CIC) statistic, which probes large-scale overdensities, and the nearest-neighbor distribution (NND), sensitive to small-scale environments. CIC analysis reveals that the underlying distribution is heavy-tailed and non-Gaussian, and that conventional Gaussian-based evaluation substantially overestimates the significance of extreme events. When modeled with an asymmetric generalized normal distribution (AGND), the inferred rarity of the CH is substantially reduced and reconciled with standard ΛCDM; for instance, regions appearing as 12σGauss outliers under Gaussian assumptions (P ∼ 10−33) are found to occur in AGND regimes with a probability of P ∼ 10−4. NND analysis further demonstrates that extreme overdense regions within the simulation can naturally sustain two-point correlation function values similar to those observed in the CH ( ), suggesting that the strong clustering stems from sample selection biases and local environmental variations. These two analyses conclusively highlight the importance of adopting non-Gaussian statistics when quantifying extreme overdensities of quasars and establish that the CH is not an anomaly, but a natural outcome of structure formation in the ΛCDM universe.
{"title":"Cosmic Himalayas in CROCODILE: Probing the Extreme Quasar Overdensities by Count-in-cells Analysis and Nearest-neighbor Distribution","authors":"Yuto Kuwayama, 裕斗 桑山, Yongming Liang, 永明 梁, Kentaro Nagamine, 健太郎 長峯, Yuri Oku, 裕理 奥, Daisuke Nishihama, 大将 西濱, Daisuke Toyouchi, 大輔 豊内, Keita Fukushima, 啓太 福島, Hidenobu Yajima, 秀伸 矢島, Hyunbae Park, 현배 박, Masami Ouchi and 正己 大内","doi":"10.3847/1538-4357/ae5798","DOIUrl":"https://doi.org/10.3847/1538-4357/ae5798","url":null,"abstract":"The recently reported Cosmic Himalayas (CH)—an extreme quasar overdensity at z ∼ 2—poses an apparent challenge to the Lambda cold dark matter (ΛCDM) framework, with a reported significance of δ = 16.9σ under Gaussian assumptions. Such an event appears improbably rare, with a formal probability of P ∼ 10−68. In this work, we investigate whether CH-like structures can naturally arise in cosmological hydrodynamic simulations. Using the CROCODILE simulation, which self-consistently models galaxy–black hole coevolution, we examine quasar clustering through two complementary approaches: the count-in-cells (CIC) statistic, which probes large-scale overdensities, and the nearest-neighbor distribution (NND), sensitive to small-scale environments. CIC analysis reveals that the underlying distribution is heavy-tailed and non-Gaussian, and that conventional Gaussian-based evaluation substantially overestimates the significance of extreme events. When modeled with an asymmetric generalized normal distribution (AGND), the inferred rarity of the CH is substantially reduced and reconciled with standard ΛCDM; for instance, regions appearing as 12σGauss outliers under Gaussian assumptions (P ∼ 10−33) are found to occur in AGND regimes with a probability of P ∼ 10−4. NND analysis further demonstrates that extreme overdense regions within the simulation can naturally sustain two-point correlation function values similar to those observed in the CH ( ), suggesting that the strong clustering stems from sample selection biases and local environmental variations. These two analyses conclusively highlight the importance of adopting non-Gaussian statistics when quantifying extreme overdensities of quasars and establish that the CH is not an anomaly, but a natural outcome of structure formation in the ΛCDM universe.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"133 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147682049","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 : 2026-04-14DOI: 10.3847/1538-4357/ae5633
Xunzhou Chen, Tiancheng Sun, Yuxi (Lucy) Lu, Zixuan Lu and Lifei Ye
The radius valley—a bimodal feature in the size distribution of close-in small exoplanets—is widely interpreted as a signature of atmospheric loss and therefore provides a key constraint on the formation and atmospheric evolution of these planets. We investigate its dependence on host-star properties using 769 planets orbiting 558 stars, for which we derive stellar ages, chromospheric activity ( ), and Galactic birth radii, together with elemental abundances. We find that the radius valley is not fully established at ages ≲ 3 Gyr and evolves over gigayear timescales, with its prominence strongly affected by stellar population mixing. The dependence on magnetic activity is nonmonotonic: a clear valley is present even among magnetically quiet stars, while highly active systems do not show systematically stronger depletion. The valley morphology also varies with stellar composition: the valley is strongest in metal-poor stars, weakens near solar metallicity, and partially strengthens again at the highest metallicities. In addition, the valley shows sensitivity to refractory element ratios such as [Mg/Si], while correlations with [C/O] are weaker, indicating a dependence on planetary interior structure. Our results are more consistent with a dominant role for core-powered atmospheric mass loss than with purely irradiation-driven photoevaporation. Finally, the radius valley also depends on the Galactic birth environment, with systems near the estimated solar birth radius (Rbirth ≃ 4.5 ± 0.4 kpc) showing a high fraction of Earth-like planets and a well-defined bimodal structure, suggesting that the solar system formed in a region with a well-developed Earth-sized planet population.
{"title":"Insights into the Exoplanet Radius Valley from Host-star Ages, Activity, Chemistry, and Birth Radii","authors":"Xunzhou Chen, Tiancheng Sun, Yuxi (Lucy) Lu, Zixuan Lu and Lifei Ye","doi":"10.3847/1538-4357/ae5633","DOIUrl":"https://doi.org/10.3847/1538-4357/ae5633","url":null,"abstract":"The radius valley—a bimodal feature in the size distribution of close-in small exoplanets—is widely interpreted as a signature of atmospheric loss and therefore provides a key constraint on the formation and atmospheric evolution of these planets. We investigate its dependence on host-star properties using 769 planets orbiting 558 stars, for which we derive stellar ages, chromospheric activity ( ), and Galactic birth radii, together with elemental abundances. We find that the radius valley is not fully established at ages ≲ 3 Gyr and evolves over gigayear timescales, with its prominence strongly affected by stellar population mixing. The dependence on magnetic activity is nonmonotonic: a clear valley is present even among magnetically quiet stars, while highly active systems do not show systematically stronger depletion. The valley morphology also varies with stellar composition: the valley is strongest in metal-poor stars, weakens near solar metallicity, and partially strengthens again at the highest metallicities. In addition, the valley shows sensitivity to refractory element ratios such as [Mg/Si], while correlations with [C/O] are weaker, indicating a dependence on planetary interior structure. Our results are more consistent with a dominant role for core-powered atmospheric mass loss than with purely irradiation-driven photoevaporation. Finally, the radius valley also depends on the Galactic birth environment, with systems near the estimated solar birth radius (Rbirth ≃ 4.5 ± 0.4 kpc) showing a high fraction of Earth-like planets and a well-defined bimodal structure, suggesting that the solar system formed in a region with a well-developed Earth-sized planet population.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147681943","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 : 2026-04-14DOI: 10.3847/1538-4357/ae5658
Yong Yuan, Minghui Du, Benyang Zhu, Xin-Yi Lin, Wen-Fan Feng, Peng Xu and Xilong Fan
The cosmic distance duality relation (CDDR), expressed as dL(z) = (1 + z)2DA(z), is a fundamental relation in modern cosmology. In this work, we apply a method to test the CDDR using simulated strongly lensed gravitational-wave (SLGW) signals from massive binary black holes as observed by proposed space-based detector networks. Our analysis is conducted under the point-mass lens model, considering the strong lensing scenario that produces two images. We generate 90 days of simulated SLGW data for 10 events based on the Population III stellar formation model, with source redshifts in the range zs ∈ [2, 6] and lens redshifts in zL ∈ [0.2, 1]. The deviation of CDDR is parameterized by η1(z) = 1 + η0z and η2(z) = 1 + η0z/(1 + z), and we incorporate the deviation parameter η0 directly into the waveform model. Parameter estimation is performed within a Bayesian statistical framework, combining simulated data from both Taiji and LISA. For a single lensed event, the joint Taiji+LISA analysis improves the measurement precision of η0 by roughly a factor of 2 compared with Taiji-only observations. By combining 10 simulated events, the population-level constraints on η0, quantified by the half width of the 95% credible interval, reach approximately 2.61 × 10−4 (1.72 × 10−4) for the η1(z) parameterization and 1.22 × 10−3 (6.86 × 10−4) for η2(z) in the Taiji-only (Taiji+LISA) scenario, respectively. The inferred values of η0 remain consistent with η0 = 0 within the estimated uncertainties, with no statistically significant evidence for deviations from the CDDR at the achieved precision. These results demonstrate the significant advantage of joint space-based observations for high-precision tests of the CDDR.
{"title":"An Opacity-free Test of the Cosmic Distance Duality Relation Using Strongly Lensed Gravitational-wave Signals with Space-based Detector Networks","authors":"Yong Yuan, Minghui Du, Benyang Zhu, Xin-Yi Lin, Wen-Fan Feng, Peng Xu and Xilong Fan","doi":"10.3847/1538-4357/ae5658","DOIUrl":"https://doi.org/10.3847/1538-4357/ae5658","url":null,"abstract":"The cosmic distance duality relation (CDDR), expressed as dL(z) = (1 + z)2DA(z), is a fundamental relation in modern cosmology. In this work, we apply a method to test the CDDR using simulated strongly lensed gravitational-wave (SLGW) signals from massive binary black holes as observed by proposed space-based detector networks. Our analysis is conducted under the point-mass lens model, considering the strong lensing scenario that produces two images. We generate 90 days of simulated SLGW data for 10 events based on the Population III stellar formation model, with source redshifts in the range zs ∈ [2, 6] and lens redshifts in zL ∈ [0.2, 1]. The deviation of CDDR is parameterized by η1(z) = 1 + η0z and η2(z) = 1 + η0z/(1 + z), and we incorporate the deviation parameter η0 directly into the waveform model. Parameter estimation is performed within a Bayesian statistical framework, combining simulated data from both Taiji and LISA. For a single lensed event, the joint Taiji+LISA analysis improves the measurement precision of η0 by roughly a factor of 2 compared with Taiji-only observations. By combining 10 simulated events, the population-level constraints on η0, quantified by the half width of the 95% credible interval, reach approximately 2.61 × 10−4 (1.72 × 10−4) for the η1(z) parameterization and 1.22 × 10−3 (6.86 × 10−4) for η2(z) in the Taiji-only (Taiji+LISA) scenario, respectively. The inferred values of η0 remain consistent with η0 = 0 within the estimated uncertainties, with no statistically significant evidence for deviations from the CDDR at the achieved precision. These results demonstrate the significant advantage of joint space-based observations for high-precision tests of the CDDR.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147681944","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 : 2026-04-14DOI: 10.3847/1538-4357/ae4de8
Fu-Xing Li, Sheng-Bang Qian, Eduardo Fernández Lajús, Lin-Jia Li, Er-Gang Zhao, Li-Ying Zhu, Cheng-Liang Jiao, Qi-Bin Sun, Wen-Xu Lin, Wen-Ping Liao, Xiang-Dong Shi and Min-Yu Li
The formation and structural configuration of V Pup have not yet been fully understood. Here we report the detection that V Pup is a massive hierarchical quadruple system. Through long-term photometric monitoring and a comprehensive analysis of multiple survey datasets, we have constructed an updated O − C curve showing two significant periodic variations. These cyclic modulations strongly suggest the presence of two additional stellar companions orbiting the central binary. Both the tertiary and quaternary components have B-type spectral classifications and are located at separations that are unresolved by Gaia. These findings indicate that V Pup is a massive hierarchical quadruple system. The mass ratios among the four components are approximately 4:2:2:1, corresponding to the primary, secondary, tertiary, and quaternary stars, respectively. The tertiary and quaternary components are approximately 1:2 apart from the central binary, and their orbital periods around the binary are approximately 1:3. It is likely that this system originated through disk fragmentation. This discovery suggests that V Pup may be an exceptional test bed. It could shed further light on the formation of massive multiple-star systems.
{"title":"V Pup: A Hierarchical Massive Quadruple System","authors":"Fu-Xing Li, Sheng-Bang Qian, Eduardo Fernández Lajús, Lin-Jia Li, Er-Gang Zhao, Li-Ying Zhu, Cheng-Liang Jiao, Qi-Bin Sun, Wen-Xu Lin, Wen-Ping Liao, Xiang-Dong Shi and Min-Yu Li","doi":"10.3847/1538-4357/ae4de8","DOIUrl":"https://doi.org/10.3847/1538-4357/ae4de8","url":null,"abstract":"The formation and structural configuration of V Pup have not yet been fully understood. Here we report the detection that V Pup is a massive hierarchical quadruple system. Through long-term photometric monitoring and a comprehensive analysis of multiple survey datasets, we have constructed an updated O − C curve showing two significant periodic variations. These cyclic modulations strongly suggest the presence of two additional stellar companions orbiting the central binary. Both the tertiary and quaternary components have B-type spectral classifications and are located at separations that are unresolved by Gaia. These findings indicate that V Pup is a massive hierarchical quadruple system. The mass ratios among the four components are approximately 4:2:2:1, corresponding to the primary, secondary, tertiary, and quaternary stars, respectively. The tertiary and quaternary components are approximately 1:2 apart from the central binary, and their orbital periods around the binary are approximately 1:3. It is likely that this system originated through disk fragmentation. This discovery suggests that V Pup may be an exceptional test bed. It could shed further light on the formation of massive multiple-star systems.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147682044","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 : 2026-04-14DOI: 10.3847/1538-4357/ae53e9
Germán Molpeceres and Joan Enrique-Romero
Motivated by the value of CN-bearing molecules as tracers of interstellar physical conditions, we investigate the reactions of adsorbed CN radicals with acetylene and ethylene (C2H2 and C2H4) on interstellar dust-grain analogs using quantum chemical calculations. We find that reactivity is strongly controlled by the relative orientation of the reactants. We further show that, on ice, these reactions differ qualitatively from their gas-phase counterparts, stalling at the formation of the adduct complexes and and exhibiting newly emerged kinetic barriers for the neutral-radical association. We contextualize our calculations in the same reaction–diffusion framework that would be employed in astrochemical models, finding that, depending on the diffusion energy of the hydrocarbons, these reactions can be either negligible or efficient, highlighting the importance of the local ice structure in interstellar grain chemistry. These findings caution against the use of CN-based tracers that assume barrierless, bimolecular surface reactions involving CN radicals.
{"title":"Can Cyanide Radicals Drive Molecular Backbone Growth on Interstellar Icy Grains?","authors":"Germán Molpeceres and Joan Enrique-Romero","doi":"10.3847/1538-4357/ae53e9","DOIUrl":"https://doi.org/10.3847/1538-4357/ae53e9","url":null,"abstract":"Motivated by the value of CN-bearing molecules as tracers of interstellar physical conditions, we investigate the reactions of adsorbed CN radicals with acetylene and ethylene (C2H2 and C2H4) on interstellar dust-grain analogs using quantum chemical calculations. We find that reactivity is strongly controlled by the relative orientation of the reactants. We further show that, on ice, these reactions differ qualitatively from their gas-phase counterparts, stalling at the formation of the adduct complexes and and exhibiting newly emerged kinetic barriers for the neutral-radical association. We contextualize our calculations in the same reaction–diffusion framework that would be employed in astrochemical models, finding that, depending on the diffusion energy of the hydrocarbons, these reactions can be either negligible or efficient, highlighting the importance of the local ice structure in interstellar grain chemistry. These findings caution against the use of CN-based tracers that assume barrierless, bimolecular surface reactions involving CN radicals.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"138 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147682045","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 : 2026-04-14DOI: 10.3847/1538-4357/ae5177
Katherine E. Whitaker, Sam E. Cutler, Rupali Chandar, Richard Pan, David J. Setton, Lukas J. Furtak, Rachel Bezanson, Ivo Labbe, Joel Leja, Katherine A. Suess, Bingjie Wang, 冰洁 王, John R. Weaver, Hakim Atek, Gabriel B. Brammer, Robert Feldmann, Natascha M. Förster Schreiber, Karl Glazebrook, Anna de Graaff, Jenny E. Greene, Gourav Khullar, Danilo Marchesini, Michael V. Maseda, Tim B. Miller, Houjun Mo, Lamiya A. Mowla, Themiya Nanayakkara, Erica J. Nelson, Sedona H. Price, Francesca Rizzo, Pieter van Dokkum, Christina C. Williams, Yanzhe Zhang, Yunchong Zhang and Adi Zitrin
Globular clusters (GCs) are some of the oldest bound structures in the Universe, holding clues to the earliest epochs of star formation and galaxy assembly. However, accurate age measurements of ancient clusters are challenging due to the age–metallicity degeneracy. Here, we report the discovery of 36 compact stellar systems within the “Relic,” a massive, quiescent galaxy at z = 2.53. The Relic resides in an overdensity behind the Abell 2744 cluster, with a prominent tidal tail extending towards two low-mass companions. Using deep data from the UNCOVER/MegaScience JWST Surveys, we find that clusters formed in age intervals ranging from 8 Myr up to ∼2 Gyr, suggesting a rich formation history starting at z ∼ 10. While the cluster-based star formation history is broadly consistent with the high past star formation rates derived from the diffuse host galaxy light, one potential discrepancy is a tentative ∼2–3× higher rate in the cluster population for the past Gyr. Taken together with the spatial distribution and low inferred metallicities of these young-to-intermediate age clusters, we may be seeing direct evidence for the accretion of star clusters in addition to their early in situ formation. The cluster masses are high, ∼106–107M⊙, which may explain why we are able to detect them around this likely post-merger galaxy. Overall, the Relic clusters are consistent with being precursors of the most-massive present-day GCs. This unique laboratory enables the first connection between long-lived, high-redshift clusters and local stellar populations, offering insights into the early stages of GC evolution and the broader processes of galaxy assembly.
{"title":"Discovery of Ancient Globular Cluster Candidates in the Relic, a Quiescent Galaxy at z = 2.5","authors":"Katherine E. Whitaker, Sam E. Cutler, Rupali Chandar, Richard Pan, David J. Setton, Lukas J. Furtak, Rachel Bezanson, Ivo Labbe, Joel Leja, Katherine A. Suess, Bingjie Wang, 冰洁 王, John R. Weaver, Hakim Atek, Gabriel B. Brammer, Robert Feldmann, Natascha M. Förster Schreiber, Karl Glazebrook, Anna de Graaff, Jenny E. Greene, Gourav Khullar, Danilo Marchesini, Michael V. Maseda, Tim B. Miller, Houjun Mo, Lamiya A. Mowla, Themiya Nanayakkara, Erica J. Nelson, Sedona H. Price, Francesca Rizzo, Pieter van Dokkum, Christina C. Williams, Yanzhe Zhang, Yunchong Zhang and Adi Zitrin","doi":"10.3847/1538-4357/ae5177","DOIUrl":"https://doi.org/10.3847/1538-4357/ae5177","url":null,"abstract":"Globular clusters (GCs) are some of the oldest bound structures in the Universe, holding clues to the earliest epochs of star formation and galaxy assembly. However, accurate age measurements of ancient clusters are challenging due to the age–metallicity degeneracy. Here, we report the discovery of 36 compact stellar systems within the “Relic,” a massive, quiescent galaxy at z = 2.53. The Relic resides in an overdensity behind the Abell 2744 cluster, with a prominent tidal tail extending towards two low-mass companions. Using deep data from the UNCOVER/MegaScience JWST Surveys, we find that clusters formed in age intervals ranging from 8 Myr up to ∼2 Gyr, suggesting a rich formation history starting at z ∼ 10. While the cluster-based star formation history is broadly consistent with the high past star formation rates derived from the diffuse host galaxy light, one potential discrepancy is a tentative ∼2–3× higher rate in the cluster population for the past Gyr. Taken together with the spatial distribution and low inferred metallicities of these young-to-intermediate age clusters, we may be seeing direct evidence for the accretion of star clusters in addition to their early in situ formation. The cluster masses are high, ∼106–107M⊙, which may explain why we are able to detect them around this likely post-merger galaxy. Overall, the Relic clusters are consistent with being precursors of the most-massive present-day GCs. This unique laboratory enables the first connection between long-lived, high-redshift clusters and local stellar populations, offering insights into the early stages of GC evolution and the broader processes of galaxy assembly.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"124 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147695393","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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