Pub Date : 2024-11-22DOI: 10.3847/1538-4357/ad88f2
L. Xiang, K. H. Lee, L. C. Lee, D. J. Wu, L. Chen, H. Q. Feng, G. Q. Zhao and T. C. Tsai
Kinetic Alfvén waves (KAWs) and ion cyclotron waves (ICWs) are believed to play a significant role in the solar wind heating and acceleration and are pervasive in space and astrophysical plasmas. However, the generation mechanism for the coexistence of both wave modes remains unclear. The present work proposes a novel generation scenario of KAWs and parallel ICWs in a homogeneous solar wind plasma using hybrid simulations. Our numerical study reveals that the emissions of KAWs and parallel ICWs can be triggered by the ion beam (IB) mode in a homogeneous alpha or proton beam plasma with a beam velocity of ≥1.2vA for alpha particles or ≥1.6vA for proton beams, where vA represents the local Alfvén velocity. The growth rates of both KAWs and parallel ICWs are significantly higher than that of the IB mode. Moreover, the initial background proton beta exhibits an inverse correlation with the growth of KAWs. Ultimately, the saturation energy of these triggered emissions could rival that of the IB mode. Given the prevalent occurrence of IBs in the solar wind, this triggering process provides a credible explanation for the origin of KAWs and parallel ICWs and their coexistence within the beam plasma environments.
{"title":"Triggered Emissions of Kinetic Alfvén Waves and Parallel Ion Cyclotron Waves by Ion Beam Mode in the Solar Wind","authors":"L. Xiang, K. H. Lee, L. C. Lee, D. J. Wu, L. Chen, H. Q. Feng, G. Q. Zhao and T. C. Tsai","doi":"10.3847/1538-4357/ad88f2","DOIUrl":"https://doi.org/10.3847/1538-4357/ad88f2","url":null,"abstract":"Kinetic Alfvén waves (KAWs) and ion cyclotron waves (ICWs) are believed to play a significant role in the solar wind heating and acceleration and are pervasive in space and astrophysical plasmas. However, the generation mechanism for the coexistence of both wave modes remains unclear. The present work proposes a novel generation scenario of KAWs and parallel ICWs in a homogeneous solar wind plasma using hybrid simulations. Our numerical study reveals that the emissions of KAWs and parallel ICWs can be triggered by the ion beam (IB) mode in a homogeneous alpha or proton beam plasma with a beam velocity of ≥1.2vA for alpha particles or ≥1.6vA for proton beams, where vA represents the local Alfvén velocity. The growth rates of both KAWs and parallel ICWs are significantly higher than that of the IB mode. Moreover, the initial background proton beta exhibits an inverse correlation with the growth of KAWs. Ultimately, the saturation energy of these triggered emissions could rival that of the IB mode. Given the prevalent occurrence of IBs in the solar wind, this triggering process provides a credible explanation for the origin of KAWs and parallel ICWs and their coexistence within the beam plasma environments.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684478","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 : 2024-11-22DOI: 10.3847/1538-4357/ad6f03
Bo Peng, 博 彭 and Diana Valencia
The recent advancements in exoplanet observations enable the potential detection of exo-Venuses, rocky planets with carbon-rich atmospheres. How extended these atmospheres can be, given high carbon abundances, has not been studied. To answer this, we present a model for a theoretical class of exoplanets—puffy Venuses—characterized by thick, carbon-dominated atmospheres in equilibrium with global magma oceans (MOs). Our model accounts for carbon and hydrogen partition between the atmosphere and the MO, as well as the C–H–O equilibrium chemistry throughout a semi-gray, radiative-convective atmosphere. We find that radius inflation by puffy Venus atmospheres is significant on small and irradiated planets: carbon content of 1200 ppm (or that of ordinary chondrites) can generate an atmosphere of ∼0.16–0.3 R⊕ for an Earth-mass planet with equilibrium temperatures of 1500–2000 K. We identify TOI-561 b as an especially promising puffy Venus candidate, whose underdensity could be attributed to a thick C-rich atmosphere. We also advocate for a puffy Venus interpretation of 55 Cancri e, where a recent JWST observation indicates the presence of a CO/CO2 atmosphere. Puffy Venuses may thus constitute a testable alternative interpretation for the interior structure of underdense low-mass exoplanets.
最近在系外行星观测方面取得的进展使我们有可能探测到具有富碳大气层的岩石行星--系外行星。至于在碳丰度较高的情况下，这些大气层会有多大的范围，目前还没有研究。为了回答这个问题，我们提出了一类系外行星--蓬松金星的理论模型，其特征是以碳为主的厚大气层与全球岩浆海洋（MOs）处于平衡状态。我们的模型考虑了大气层和岩浆海洋之间的碳和氢分配，以及整个半灰色辐射对流大气层中的 C-H-O 平衡化学反应。我们发现，浮肿金星大气对小行星和辐照行星的半径膨胀非常显著：对于平衡温度为 1500-2000 K 的地球质量行星，1200 ppm 的碳含量（或普通软玉的碳含量）可以产生 ∼0.16-0.3 R⊕ 的大气。我们还主张对 55 Cancri e 进行蓬状金星的解释，JWST 最近的观测表明那里存在一个 CO/CO2 大气层。因此，"浮肿金星 "可能是对密度不足的低质量系外行星内部结构的另一种可检验的解释。
{"title":"Puffy Venuses: The Mass–Radius Impact of Carbon-rich Atmospheres on Lava Worlds","authors":"Bo Peng, 博 彭 and Diana Valencia","doi":"10.3847/1538-4357/ad6f03","DOIUrl":"https://doi.org/10.3847/1538-4357/ad6f03","url":null,"abstract":"The recent advancements in exoplanet observations enable the potential detection of exo-Venuses, rocky planets with carbon-rich atmospheres. How extended these atmospheres can be, given high carbon abundances, has not been studied. To answer this, we present a model for a theoretical class of exoplanets—puffy Venuses—characterized by thick, carbon-dominated atmospheres in equilibrium with global magma oceans (MOs). Our model accounts for carbon and hydrogen partition between the atmosphere and the MO, as well as the C–H–O equilibrium chemistry throughout a semi-gray, radiative-convective atmosphere. We find that radius inflation by puffy Venus atmospheres is significant on small and irradiated planets: carbon content of 1200 ppm (or that of ordinary chondrites) can generate an atmosphere of ∼0.16–0.3 R⊕ for an Earth-mass planet with equilibrium temperatures of 1500–2000 K. We identify TOI-561 b as an especially promising puffy Venus candidate, whose underdensity could be attributed to a thick C-rich atmosphere. We also advocate for a puffy Venus interpretation of 55 Cancri e, where a recent JWST observation indicates the presence of a CO/CO2 atmosphere. Puffy Venuses may thus constitute a testable alternative interpretation for the interior structure of underdense low-mass exoplanets.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684462","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 : 2024-11-22DOI: 10.3847/1538-4357/ad83be
K. R. Gold, D. R. Schmidt and L. M. Ziurys
Molecular observations of four planetary nebulae (PNe), M4-17, Hu 1-1, M1-59, and Na 2, were conducted at 1–3 mm using the Arizona Radio Observatory’s 12 m antenna and Submillimeter Telescope, and the Institut de Radioastronomie Millimétrique 30 m Telescope. Toward M4-17, HNC (J = 3 → 2), CCH (N = 2 → 1, N = 3 → 2), CN (N = 1 → 0, N = 2 → 1), H2CO (JKa,Kc = 21,2 → 11,1, JKa,Kc = 20,2 → 10,1, JKa,Kc = 21,1 → 11,0), CS (J = 3 → 2, J = 5 → 4), and H13CN (J = 2 → 1) were detected. An almost identical set of transitions was identified toward Hu 1-1. Moreover, c–C3H2 was detected in Hu 1-1 via three 2 mm lines: JKa,Kc = 31,2 → 22,1, JKa,Kc = 41,4 → 30,3, and JKa,Kc = 32, 2 → 21,1. HNC, CCH, CN, CS, and H13CN were found in M1-59, as well as H2S via its JKa,Kc = 11,0 → 10,1 line—the first detection of this key sulfur species in PNe. In addition, CCH and CN were identified in the 27,000 yr old Na 2. Among these four sources, CN and CCH were the most prevalent molecules (after CO and H2) with fractional abundances, relative to H2, of f ∼ 0.9–7.5 × 10−7 and 0.8–7.5 × 10−7, respectively. CS and HNC have abundances in the range f ∼ 0.5–5 × 10−8, the latter resulting in HCN/HNC ∼ 3 across all three PNe. The unusual species H2CO, c–C3H2, and H2S had f ∼ 3–4 × 10−7, 10−8, and 6 × 10−8. This study suggests that elliptical PNe such as Hu 1-1 can have a diverse molecular composition. The presence of CN, CCH, and HCO+ in Na 2, with comparable abundances to younger PNe, demonstrates that molecular content is maintained into the late PN stage.
{"title":"Expanding the Inventory of Molecule-rich Planetary Nebulae: New Observations of M4-17, Hu 1-1, M1-59, and Na 2","authors":"K. R. Gold, D. R. Schmidt and L. M. Ziurys","doi":"10.3847/1538-4357/ad83be","DOIUrl":"https://doi.org/10.3847/1538-4357/ad83be","url":null,"abstract":"Molecular observations of four planetary nebulae (PNe), M4-17, Hu 1-1, M1-59, and Na 2, were conducted at 1–3 mm using the Arizona Radio Observatory’s 12 m antenna and Submillimeter Telescope, and the Institut de Radioastronomie Millimétrique 30 m Telescope. Toward M4-17, HNC (J = 3 → 2), CCH (N = 2 → 1, N = 3 → 2), CN (N = 1 → 0, N = 2 → 1), H2CO (JKa,Kc = 21,2 → 11,1, JKa,Kc = 20,2 → 10,1, JKa,Kc = 21,1 → 11,0), CS (J = 3 → 2, J = 5 → 4), and H13CN (J = 2 → 1) were detected. An almost identical set of transitions was identified toward Hu 1-1. Moreover, c–C3H2 was detected in Hu 1-1 via three 2 mm lines: JKa,Kc = 31,2 → 22,1, JKa,Kc = 41,4 → 30,3, and JKa,Kc = 32, 2 → 21,1. HNC, CCH, CN, CS, and H13CN were found in M1-59, as well as H2S via its JKa,Kc = 11,0 → 10,1 line—the first detection of this key sulfur species in PNe. In addition, CCH and CN were identified in the 27,000 yr old Na 2. Among these four sources, CN and CCH were the most prevalent molecules (after CO and H2) with fractional abundances, relative to H2, of f ∼ 0.9–7.5 × 10−7 and 0.8–7.5 × 10−7, respectively. CS and HNC have abundances in the range f ∼ 0.5–5 × 10−8, the latter resulting in HCN/HNC ∼ 3 across all three PNe. The unusual species H2CO, c–C3H2, and H2S had f ∼ 3–4 × 10−7, 10−8, and 6 × 10−8. This study suggests that elliptical PNe such as Hu 1-1 can have a diverse molecular composition. The presence of CN, CCH, and HCO+ in Na 2, with comparable abundances to younger PNe, demonstrates that molecular content is maintained into the late PN stage.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"81 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684260","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 : 2024-11-22DOI: 10.3847/1538-4357/ad8576
Llŷr Dafydd Humphries, Huw Morgan and David Kuridze
Small-scale brightenings are ubiquitous, dynamic, and energetic phenomena found in the chromosphere. An advanced filter-detection algorithm applied to high-resolution observations from the Interface Region Imaging Spectrograph enables the detection of these brightenings close to the noise level. This algorithm also tracks the movement of these brightenings and extracts their characteristics. This work outlines the results of an in-depth analysis of a quiet-Sun data set including a comparison of a brighter domain—associated with a supergranular boundary—to the quiescent internetwork domains. Several characteristics of brightenings from both domains are extracted and analysed, providing a range of sizes, durations, brightness values, travel distances, and speeds. The “active” quiet-Sun events tend to travel shorter distances and at slower speeds across the plane of the sky than their “true” quiet-Sun counterparts. These results are consistent with the magnetic field model of supergranular photospheric structures and the magnetic canopy model of the chromosphere above. Spectroscopic analyses reveal that bright points demonstrate blueshift (as well as some bidirectionality) and that they may rise from the chromosphere into the transition region. We believe that these bright points are magnetic in nature, are likely the result of magnetic reconnection, and follow current sheets between magnetic field gradients, rather than travel along magnetic field lines themselves.
{"title":"An In-depth Analysis of Quiet-Sun IRIS Brightenings","authors":"Llŷr Dafydd Humphries, Huw Morgan and David Kuridze","doi":"10.3847/1538-4357/ad8576","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8576","url":null,"abstract":"Small-scale brightenings are ubiquitous, dynamic, and energetic phenomena found in the chromosphere. An advanced filter-detection algorithm applied to high-resolution observations from the Interface Region Imaging Spectrograph enables the detection of these brightenings close to the noise level. This algorithm also tracks the movement of these brightenings and extracts their characteristics. This work outlines the results of an in-depth analysis of a quiet-Sun data set including a comparison of a brighter domain—associated with a supergranular boundary—to the quiescent internetwork domains. Several characteristics of brightenings from both domains are extracted and analysed, providing a range of sizes, durations, brightness values, travel distances, and speeds. The “active” quiet-Sun events tend to travel shorter distances and at slower speeds across the plane of the sky than their “true” quiet-Sun counterparts. These results are consistent with the magnetic field model of supergranular photospheric structures and the magnetic canopy model of the chromosphere above. Spectroscopic analyses reveal that bright points demonstrate blueshift (as well as some bidirectionality) and that they may rise from the chromosphere into the transition region. We believe that these bright points are magnetic in nature, are likely the result of magnetic reconnection, and follow current sheets between magnetic field gradients, rather than travel along magnetic field lines themselves.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684471","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 : 2024-11-22DOI: 10.3847/1538-4357/ad8882
Jiaxin He, Wenting Wang, Zhaozhou Li, Jiaxin Han, Vicente Rodriguez-Gomez, Donghai Zhao, Xianguang Meng, Yipeng Jing, Shi Shao, Rui Shi and Zhenlin Tan
We investigate the mass (M200) and concentration (c200) dependencies of the velocity anisotropy (β) profiles for different components in the dark matter halo—including halo stars, dark matter, and subhalos—using systems from the IllustrisTNG simulations. Beyond a critical radius, β becomes more radial with the increase of M200, reflecting more prominent radial accretion around massive halos. The critical radius is r ∼ rs, 0.3 rs, and rs for halo stars, dark matter, and subhalos, with rs being the scale radius of the host halos. This dependence on M200 is the strongest for subhalos and the weakest for halo stars. In central regions, the β of halo stars and dark matter particles get more isotropic with the increase of M200 in TNG300 due to baryons. By contrast, the β of dark matter from the dark-matter-only TNG300-Dark run shows much weaker dependence on M200 within rs. Dark matter in TNG300 is slightly more isotropic than in TNG300-Dark at 0.2 rs < r < 10 rs and . Halo stars and dark matter also become more radial with the increase in c200, at fixed M200. Halo stars are more radial than the β profile of dark matter by approximately a constant beyond rs. Dark matter particles are more radial than subhalos. The differences can be understood, as subhalos on more radial orbits are more easily stripped, contributing more stars and dark matter to the diffuse components. We provide the fitting formula for the differences between the β of halo stars and dark matter at rs < r < 3 rs as for and as βstar − βDM = 0.328 for .
{"title":"How Do the Velocity Anisotropies of Halo Stars, Dark Matter, and Satellite Galaxies Depend on Host Halo Properties?","authors":"Jiaxin He, Wenting Wang, Zhaozhou Li, Jiaxin Han, Vicente Rodriguez-Gomez, Donghai Zhao, Xianguang Meng, Yipeng Jing, Shi Shao, Rui Shi and Zhenlin Tan","doi":"10.3847/1538-4357/ad8882","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8882","url":null,"abstract":"We investigate the mass (M200) and concentration (c200) dependencies of the velocity anisotropy (β) profiles for different components in the dark matter halo—including halo stars, dark matter, and subhalos—using systems from the IllustrisTNG simulations. Beyond a critical radius, β becomes more radial with the increase of M200, reflecting more prominent radial accretion around massive halos. The critical radius is r ∼ rs, 0.3 rs, and rs for halo stars, dark matter, and subhalos, with rs being the scale radius of the host halos. This dependence on M200 is the strongest for subhalos and the weakest for halo stars. In central regions, the β of halo stars and dark matter particles get more isotropic with the increase of M200 in TNG300 due to baryons. By contrast, the β of dark matter from the dark-matter-only TNG300-Dark run shows much weaker dependence on M200 within rs. Dark matter in TNG300 is slightly more isotropic than in TNG300-Dark at 0.2 rs < r < 10 rs and . Halo stars and dark matter also become more radial with the increase in c200, at fixed M200. Halo stars are more radial than the β profile of dark matter by approximately a constant beyond rs. Dark matter particles are more radial than subhalos. The differences can be understood, as subhalos on more radial orbits are more easily stripped, contributing more stars and dark matter to the diffuse components. We provide the fitting formula for the differences between the β of halo stars and dark matter at rs < r < 3 rs as for and as βstar − βDM = 0.328 for .","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684477","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 : 2024-11-22DOI: 10.3847/1538-4357/ad8bc2
Zachary Davis, Jesús M. Rueda-Becerril and Dimitrios Giannios
A wide range of astrophysical sources exhibit extreme and rapidly varying electromagnetic emission indicative of efficient nonthermal particle acceleration. Understanding these sources often involves comparing data with a broad range of theoretical scenarios. To this end, it is beneficial to have tools that enable not only fast and efficient parametric investigation of the predictions of a specific scenario but also the flexibility to explore different theoretical ideas. In this paper, we introduce Tleco, a versatile and lightweight toolkit for developing numerical models of relativistic outflows, including their particle acceleration mechanisms and resultant electromagnetic signature. Built on the Rust programming language and wrapped into a Python library, Tleco offers efficient algorithms for evolving relativistic particle distributions and for solving the resulting emissions in a customizable fashion. Tleco uses a fully implicit discretization algorithm to solve the Fokker–Planck equation with user-defined diffusion, advection, cooling, injection, and escape and offers prescriptions for radiative emission and cooling. These include, but are not limited to, synchrotron, inverse-Compton, and self-synchrotron absorption. Tleco is designed to be user friendly and adaptable to model particle acceleration and the resulting electromagnetic spectrum and temporal variability in a wide variety of astrophysical scenarios, including, but not limited to, gamma-ray bursts, pulsar wind nebulae, and jets from active galactic nuclei. In this work, we outline the core algorithms and proceed to evaluate and demonstrate their effectiveness. The code is open source and available in the GitHub repository: https://github.com/zkdavis/Tleco.
{"title":"Tleco: A Toolkit for Modeling Radiative Signatures from Relativistic Outflows","authors":"Zachary Davis, Jesús M. Rueda-Becerril and Dimitrios Giannios","doi":"10.3847/1538-4357/ad8bc2","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8bc2","url":null,"abstract":"A wide range of astrophysical sources exhibit extreme and rapidly varying electromagnetic emission indicative of efficient nonthermal particle acceleration. Understanding these sources often involves comparing data with a broad range of theoretical scenarios. To this end, it is beneficial to have tools that enable not only fast and efficient parametric investigation of the predictions of a specific scenario but also the flexibility to explore different theoretical ideas. In this paper, we introduce Tleco, a versatile and lightweight toolkit for developing numerical models of relativistic outflows, including their particle acceleration mechanisms and resultant electromagnetic signature. Built on the Rust programming language and wrapped into a Python library, Tleco offers efficient algorithms for evolving relativistic particle distributions and for solving the resulting emissions in a customizable fashion. Tleco uses a fully implicit discretization algorithm to solve the Fokker–Planck equation with user-defined diffusion, advection, cooling, injection, and escape and offers prescriptions for radiative emission and cooling. These include, but are not limited to, synchrotron, inverse-Compton, and self-synchrotron absorption. Tleco is designed to be user friendly and adaptable to model particle acceleration and the resulting electromagnetic spectrum and temporal variability in a wide variety of astrophysical scenarios, including, but not limited to, gamma-ray bursts, pulsar wind nebulae, and jets from active galactic nuclei. In this work, we outline the core algorithms and proceed to evaluate and demonstrate their effectiveness. The code is open source and available in the GitHub repository: https://github.com/zkdavis/Tleco.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684481","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 : 2024-11-22DOI: 10.3847/1538-4357/ad88f1
Francesco Sylos Labini
The circular velocity curve traced by stars provides a direct means of investigating the potential and mass distribution of the Milky Way. Recent measurements of the Galaxy’s rotation curve have revealed a significant decrease in velocity for Galactic radii larger than approximately 15 kpc. While these determinations have primarily focused on the Galactic plane, the Gaia DR3 data also offer information about off-plane velocity components. By assuming the Milky Way is in a state of Jeans equilibrium, we derived the generalized rotation curve for radial distances spanning from 8.5 kpc to 25 kpc and vertical heights ranging from −2 kpc to 2 kpc. These measurements were employed to constrain the matter distribution using two distinct mass models. The first is the canonical Navarro–Frenk–White (NFW) halo model, while the second, the dark matter disk (DMD) model, posits that dark matter is confined to the Galactic plane and follows the distribution of neutral hydrogen. The best-fitting NFW model yields a virial mass of Mvir = (6.5 ± 0.5) × 1011 M⊙, whereas the DMD model indicates a total mass of MDMD = (1.7 ± 0.2) × 1011 M⊙. Our findings indicate that the DMD model generally shows a better fit to both the on-plane and off-plane behaviors at large radial distances of the generalized rotation curves than the NFW model. We emphasize that studying the generalized rotation curves at different vertical heights has the potential to provide better constraints on the geometrical properties of the dark matter distribution.
{"title":"Generalized Rotation Curves of the Milky Way from the GAIA DR3 Data Set: Constraints on Mass Models","authors":"Francesco Sylos Labini","doi":"10.3847/1538-4357/ad88f1","DOIUrl":"https://doi.org/10.3847/1538-4357/ad88f1","url":null,"abstract":"The circular velocity curve traced by stars provides a direct means of investigating the potential and mass distribution of the Milky Way. Recent measurements of the Galaxy’s rotation curve have revealed a significant decrease in velocity for Galactic radii larger than approximately 15 kpc. While these determinations have primarily focused on the Galactic plane, the Gaia DR3 data also offer information about off-plane velocity components. By assuming the Milky Way is in a state of Jeans equilibrium, we derived the generalized rotation curve for radial distances spanning from 8.5 kpc to 25 kpc and vertical heights ranging from −2 kpc to 2 kpc. These measurements were employed to constrain the matter distribution using two distinct mass models. The first is the canonical Navarro–Frenk–White (NFW) halo model, while the second, the dark matter disk (DMD) model, posits that dark matter is confined to the Galactic plane and follows the distribution of neutral hydrogen. The best-fitting NFW model yields a virial mass of Mvir = (6.5 ± 0.5) × 1011 M⊙, whereas the DMD model indicates a total mass of MDMD = (1.7 ± 0.2) × 1011 M⊙. Our findings indicate that the DMD model generally shows a better fit to both the on-plane and off-plane behaviors at large radial distances of the generalized rotation curves than the NFW model. We emphasize that studying the generalized rotation curves at different vertical heights has the potential to provide better constraints on the geometrical properties of the dark matter distribution.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142690666","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 : 2024-11-22DOI: 10.3847/1538-4357/ad8562
Konstantin V. Getman, Eric D. Feigelson, Abygail R. Waggoner, L. Ilsedore Cleeves, Jan Forbrich, Joe P. Ninan, Oleg Kochukhov, Vladimir S. Airapetian, Sergio A. Dzib, Charles J. Law and Christian Rab
The most powerful stellar flares driven by magnetic energy occur during the early pre-main-sequence (PMS) phase. The Orion Nebula represents the nearest region populated by young stars, showing the greatest number of flares accessible to a single pointing of Chandra. This study is part of a multi-observatory project to explore stellar surface magnetic fields (with the Hobby–Eberly Telescope Habitable-zone Planet Finder, HET-HPF), particle ejections (with the Very Long Baseline Array, VLBA), and disk ionization (with the Atacama Large Millimeter/submillimeter Array, ALMA) immediately following the detection of PMS superflares with Chandra. In 2023 December, we successfully conducted such a multi-telescope campaign. Additionally, by analyzing Chandra data from 2003, 2012, and 2016, we examine the multi-epoch behavior of PMS X-ray emission related to PMS magnetic cyclic activity and ubiquitous versus sample-confined megaflaring. Our findings are as follows. (1) We report detailed stellar quiescent and flare X-ray properties for numerous HET/ALMA/VLBA targets, facilitating ongoing multiwavelength analyses. (2) For numerous moderately energetic flares, we report correlations (or lack thereof) between flare energies and stellar mass/size (presence/absence of disks) for the first time. The former is attributed to the correlation between convection-driven dynamo and stellar volume, while the latter suggests the operation of solar-type flare mechanisms in PMS stars. (3) We find that most PMS stars exhibit minor long-term baseline variations, indicating the absence of intrinsic magnetic dynamo cycles or observational mitigation of cycles by saturated PMS X-rays. (4) We conclude that X-ray megaflares are ubiquitous phenomena in PMS stars, which suggests that all protoplanetary disks and nascent planets are subject to violent high-energy emission and particle irradiation events.
{"title":"Multi-Observatory Research of Young Stellar Energetic Flares (MORYSEF): X-Ray-flare-related Phenomena and Multi-epoch Behavior","authors":"Konstantin V. Getman, Eric D. Feigelson, Abygail R. Waggoner, L. Ilsedore Cleeves, Jan Forbrich, Joe P. Ninan, Oleg Kochukhov, Vladimir S. Airapetian, Sergio A. Dzib, Charles J. Law and Christian Rab","doi":"10.3847/1538-4357/ad8562","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8562","url":null,"abstract":"The most powerful stellar flares driven by magnetic energy occur during the early pre-main-sequence (PMS) phase. The Orion Nebula represents the nearest region populated by young stars, showing the greatest number of flares accessible to a single pointing of Chandra. This study is part of a multi-observatory project to explore stellar surface magnetic fields (with the Hobby–Eberly Telescope Habitable-zone Planet Finder, HET-HPF), particle ejections (with the Very Long Baseline Array, VLBA), and disk ionization (with the Atacama Large Millimeter/submillimeter Array, ALMA) immediately following the detection of PMS superflares with Chandra. In 2023 December, we successfully conducted such a multi-telescope campaign. Additionally, by analyzing Chandra data from 2003, 2012, and 2016, we examine the multi-epoch behavior of PMS X-ray emission related to PMS magnetic cyclic activity and ubiquitous versus sample-confined megaflaring. Our findings are as follows. (1) We report detailed stellar quiescent and flare X-ray properties for numerous HET/ALMA/VLBA targets, facilitating ongoing multiwavelength analyses. (2) For numerous moderately energetic flares, we report correlations (or lack thereof) between flare energies and stellar mass/size (presence/absence of disks) for the first time. The former is attributed to the correlation between convection-driven dynamo and stellar volume, while the latter suggests the operation of solar-type flare mechanisms in PMS stars. (3) We find that most PMS stars exhibit minor long-term baseline variations, indicating the absence of intrinsic magnetic dynamo cycles or observational mitigation of cycles by saturated PMS X-rays. (4) We conclude that X-ray megaflares are ubiquitous phenomena in PMS stars, which suggests that all protoplanetary disks and nascent planets are subject to violent high-energy emission and particle irradiation events.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684469","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 : 2024-11-22DOI: 10.3847/1538-4357/ad8a5a
Mengxuan Ma, Liping Yang, Fang Shen, Chenglong Shen, Yutian Chi, Yuming Wang, Yufen Zhou, Man Zhang, Daniel Heyner, Uli Auster, Ingo Richter and Beatriz Sanchez-Cano
The magnetic orientation of coronal mass ejections (CMEs) is of great importance to understand their space weather effects. Although plenty of evidence suggests that CMEs can undergo significant rotation during the early phases of evolution in the solar corona, there are few reports that CMEs rotate in the interplanetary space. In this work, we use multispacecraft observations and a numerical simulation starting from the lower corona close to the solar surface to understand the CME event on 2021 December 4, with an emphatic investigation of its rotation. This event is observed as a partial halo CME from the back side of the Sun by coronagraphs and reaches the BepiColombo spacecraft and the Mars Atmosphere and Volatile EvolutioN/Tianwen-1 as a magnetic flux-rope-like structure. The simulation discloses that in the solar corona the CME is approximately a translational motion, while the interplanetary propagation process evidences a gradual change of axis orientation of the CME’s flux-rope-like structure. It is also found that the downside and the right flank of the CME moves with the fast solar wind, and the upside does in the slow-speed stream. The different parts of the CME with different speeds generate the nonidentical displacements of its magnetic structure, resulting in the rotation of the CME in the interplanetary space. Furthermore, at the right flank of the CME exists a corotating interaction region, which makes the orientation of the CME alter and also deviates from its route due to the CME. These results provide new insight into interpreting CMEs’ dynamics and structures during their traveling through the heliosphere.
{"title":"Interplanetary Rotation of 2021 December 4 Coronal Mass Ejection on Its Journey to Mars","authors":"Mengxuan Ma, Liping Yang, Fang Shen, Chenglong Shen, Yutian Chi, Yuming Wang, Yufen Zhou, Man Zhang, Daniel Heyner, Uli Auster, Ingo Richter and Beatriz Sanchez-Cano","doi":"10.3847/1538-4357/ad8a5a","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8a5a","url":null,"abstract":"The magnetic orientation of coronal mass ejections (CMEs) is of great importance to understand their space weather effects. Although plenty of evidence suggests that CMEs can undergo significant rotation during the early phases of evolution in the solar corona, there are few reports that CMEs rotate in the interplanetary space. In this work, we use multispacecraft observations and a numerical simulation starting from the lower corona close to the solar surface to understand the CME event on 2021 December 4, with an emphatic investigation of its rotation. This event is observed as a partial halo CME from the back side of the Sun by coronagraphs and reaches the BepiColombo spacecraft and the Mars Atmosphere and Volatile EvolutioN/Tianwen-1 as a magnetic flux-rope-like structure. The simulation discloses that in the solar corona the CME is approximately a translational motion, while the interplanetary propagation process evidences a gradual change of axis orientation of the CME’s flux-rope-like structure. It is also found that the downside and the right flank of the CME moves with the fast solar wind, and the upside does in the slow-speed stream. The different parts of the CME with different speeds generate the nonidentical displacements of its magnetic structure, resulting in the rotation of the CME in the interplanetary space. Furthermore, at the right flank of the CME exists a corotating interaction region, which makes the orientation of the CME alter and also deviates from its route due to the CME. These results provide new insight into interpreting CMEs’ dynamics and structures during their traveling through the heliosphere.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684479","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 : 2024-11-22DOI: 10.3847/1538-4357/ad87ef
David H. Brooks, Harry P. Warren, Deborah Baker, Sarah A. Matthews and Stephanie L. Yardley
Plasma composition measurements are a vital tool for the success of current and future solar missions, but density- and temperature-insensitive spectroscopic diagnostic ratios are sparse, and their underlying accuracy in determining the magnitude of the first ionization potential (FIP) effect in the solar atmosphere remains an open question. Here we assess the Fe viii 185.213 Å/Ne viii 770.428 Å intensity ratio that can be observed as a multispacecraft combination between Solar Orbiter/SPICE and Hinode/EUV Imaging Spectrometer (EIS). We find that it is fairly insensitive to temperature and density in the range of log (T/K) = 5.65–6.05 and is therefore useful, in principle, for analyzing on-orbit EUV spectra. We also perform an empirical experiment, using Hinode/EIS measurements of coronal fan loop temperature distributions weighted by randomly generated FIP bias values, to show that our diagnostic method can provide accurate results as it recovers the input FIP bias to within 10%–14%. This is encouraging since it is smaller than the magnitude of variations seen throughout the solar corona. We apply the diagnostic to coordinated observations from 2023 March and show that the combination of SPICE and EIS allows measurements of the Fe/Ne FIP bias in the regions where the footpoints of the magnetic field connected to Solar Orbiter are predicted to be located. The results show an increase in FIP bias between the main leading polarity and the trailing decayed polarity that broadly agrees with Fe/O in situ measurements from Solar Orbiter/Solar Wind Analyser. Multispacecraft coordinated observations are complex, but this diagnostic also falls within the planned wavebands for Solar-C/Extreme UltraViolet high-throughput Spectroscopic Telescope.
等离子体成分测量是当前和未来太阳任务取得成功的重要工具，但对密度和温度不敏感的光谱诊断比率却很稀少，而且它们在确定太阳大气中第一电离势（FIP）效应大小方面的基本准确性仍是一个未决问题。在这里，我们评估了太阳轨道器/SPICE 和 Hinode/EUV 成像分光计（EIS）之间的多航天器组合所能观测到的 Fe viii 185.213 Å/Ne viii 770.428 Å 强度比。我们发现，在 log (T/K) = 5.65-6.05 的范围内，它对温度和密度相当不敏感，因此原则上可用于分析在轨欧紫外光谱。我们还利用日冕扇形环温度分布的日冕/EIS 测量数据，通过随机生成的 FIP 偏差值进行加权，进行了一次经验实验，结果表明我们的诊断方法可以提供准确的结果，因为它可以将输入的 FIP 偏差恢复到 10%-14% 的范围内。这是令人鼓舞的，因为它比整个日冕的变化幅度要小。我们将该诊断方法应用于 2023 年 3 月的协调观测，结果表明，结合 SPICE 和 EIS，可以测量与太阳轨道器相连的磁场脚点所在区域的铁/钕 FIP 偏差。结果表明，在主前导极性和尾随衰减极性之间的 FIP 偏差有所增加，这与太阳轨道器/太阳风分析仪的 Fe/O 实地测量结果基本一致。多航天器协调观测非常复杂，但这一诊断也属于太阳-C/极紫外线高通量分光望远镜的计划波段。
{"title":"An Elemental Abundance Diagnostic for Coordinated Solar Orbiter/SPICE and Hinode/EIS Observations","authors":"David H. Brooks, Harry P. Warren, Deborah Baker, Sarah A. Matthews and Stephanie L. Yardley","doi":"10.3847/1538-4357/ad87ef","DOIUrl":"https://doi.org/10.3847/1538-4357/ad87ef","url":null,"abstract":"Plasma composition measurements are a vital tool for the success of current and future solar missions, but density- and temperature-insensitive spectroscopic diagnostic ratios are sparse, and their underlying accuracy in determining the magnitude of the first ionization potential (FIP) effect in the solar atmosphere remains an open question. Here we assess the Fe viii 185.213 Å/Ne viii 770.428 Å intensity ratio that can be observed as a multispacecraft combination between Solar Orbiter/SPICE and Hinode/EUV Imaging Spectrometer (EIS). We find that it is fairly insensitive to temperature and density in the range of log (T/K) = 5.65–6.05 and is therefore useful, in principle, for analyzing on-orbit EUV spectra. We also perform an empirical experiment, using Hinode/EIS measurements of coronal fan loop temperature distributions weighted by randomly generated FIP bias values, to show that our diagnostic method can provide accurate results as it recovers the input FIP bias to within 10%–14%. This is encouraging since it is smaller than the magnitude of variations seen throughout the solar corona. We apply the diagnostic to coordinated observations from 2023 March and show that the combination of SPICE and EIS allows measurements of the Fe/Ne FIP bias in the regions where the footpoints of the magnetic field connected to Solar Orbiter are predicted to be located. The results show an increase in FIP bias between the main leading polarity and the trailing decayed polarity that broadly agrees with Fe/O in situ measurements from Solar Orbiter/Solar Wind Analyser. Multispacecraft coordinated observations are complex, but this diagnostic also falls within the planned wavebands for Solar-C/Extreme UltraViolet high-throughput Spectroscopic Telescope.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"253 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684476","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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