The Astrophysical Journal Letters最新文献_第3页

A Disintegrating Rocky World Shrouded in Dust and Gas: Mid-infrared Observations of K2-22 b Using JWST 一个被尘埃和气体笼罩的破碎的岩石世界：利用JWST对K2-22 b的中红外观测

The Astrophysical Journal Letters Pub Date : 2025-06-24 DOI: 10.3847/2041-8213/addfd0

Nick Tusay, Jason T. Wright, Thomas G. Beatty, Steve Desch, Knicole Colón, Tushar Mittal, Hugh P. Osborn, Beatriz Campos Estrada, James E. Owen, Jessica Libby-Roberts, Arvind F. Gupta, Brad Foley, Erik Meier Valdés, Daniel J. Stevens and Ashley Herbst

{"title":"A Disintegrating Rocky World Shrouded in Dust and Gas: Mid-infrared Observations of K2-22 b Using JWST","authors":"Nick Tusay, Jason T. Wright, Thomas G. Beatty, Steve Desch, Knicole Colón, Tushar Mittal, Hugh P. Osborn, Beatriz Campos Estrada, James E. Owen, Jessica Libby-Roberts, Arvind F. Gupta, Brad Foley, Erik Meier Valdés, Daniel J. Stevens and Ashley Herbst","doi":"10.3847/2041-8213/addfd0","DOIUrl":"https://doi.org/10.3847/2041-8213/addfd0","url":null,"abstract":"The disintegrating ultrashort period rocky exoplanet K2-22 b periodically emits dusty clouds in a dynamically chaotic process resulting in a variable transit depth from 0% to 1.3%. The effluents that sublimate off the surface and condense out in space are probably representative of the formerly interior layers convectively transported to the molten surface. Transmission spectroscopy of these transiting clouds reveals spectral fingerprints of the interior composition of this rocky world. We used JWST’s Mid-Infrared Instrument as a low-resolution slitless spectrograph to observe four predicted transit windows for K2-22 b. For each observation, we extracted a transmission spectrum over the spectral range of 4.4–11.8 μm. Over the spectral range of 4.4–8 μm, where the spectral precision is highest, we detect one transit at high significance and two at low significance. While the signal-to-noise ratio of the spectrum limits our ability to draw firm conclusions, we find that the data (1) disfavor featureless, iron-dominated core material, (2) are consistent with some form of magnesium silicate minerals, likely from mantle material, and (3) show a distinct and unexpected feature at ∼5 μm. The unexpected feature, also seen weakly in the low-significance transits, is consistent with an unknown gaseous absorber, possibly NO and/or CO2. These findings warrant further study to improve the constraints on the composition of this disintegrating rocky world.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"246 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488896","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}

引用次数: 0

Deciphering the Formation and Dynamics of Double-decker Filaments through Component Magnetic Reconnection 通过分量磁重联解读双层细丝的形成和动力学

The Astrophysical Journal Letters Pub Date : 2025-06-23 DOI: 10.3847/2041-8213/addfca

Dongxu Liu, Yuandeng Shen, Yi Bi, Zehao Tang, Chengrui Zhou and Surui Yao

{"title":"Deciphering the Formation and Dynamics of Double-decker Filaments through Component Magnetic Reconnection","authors":"Dongxu Liu, Yuandeng Shen, Yi Bi, Zehao Tang, Chengrui Zhou and Surui Yao","doi":"10.3847/2041-8213/addfca","DOIUrl":"https://doi.org/10.3847/2041-8213/addfca","url":null,"abstract":"The formation of double-decker filaments has long been an enigma in the field of solar physics. Using stereoscopic observations from the Solar Dynamics Observatory and the Solar Terrestrial Relations Observatory, we show that the double-decker filament formed on 2013 August 30 resulted from the splitting of a braided magnetic flux rope. The splitting was driven by component magnetic reconnection between intertwined field lines, triggered by the rotational motion in a part of one filament footpoint. This mechanism, inferred from observed small jets, brightenings, and bidirectional mass flows, differs from the previous conclusion attributing filament splitting to magnetic reconnection between the legs of confining magnetic field lines within or above the filament. The splitting speed might be modulated by the reconnection speed, as evidenced by the correspondence between the filament’s slow and fast rising phases and the intermittent and violent brightening stages. Following the splitting, the upper branch of the double-decker filament erupted as a coronal mass ejection, giving rise to a GOES soft X-ray M1.2 flare. In conclusion, our observations present a new formation mechanism for double-decker filaments, and the subsequent partial eruption is likely attributable to the torus instability of the background coronal magnetic field. Moreover, the detection of small jets within the filament provides new insights into the role of component magnetic reconnection in localized coronal heating processes.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"248 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144478958","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}

引用次数: 0

Intense Hard X-Ray Emissions in C-class Flares: A Statistical Study with ASO-S/HXI Data c级耀斑的强硬x射线辐射：基于ASO-S/HXI数据的统计研究

The Astrophysical Journal Letters Pub Date : 2025-06-23 DOI: 10.3847/2041-8213/addf2f

Changxue Chen, Yang Su, Wei Chen, Jingwei Li, Fu Yu and Weiqun Gan

{"title":"Intense Hard X-Ray Emissions in C-class Flares: A Statistical Study with ASO-S/HXI Data","authors":"Changxue Chen, Yang Su, Wei Chen, Jingwei Li, Fu Yu and Weiqun Gan","doi":"10.3847/2041-8213/addf2f","DOIUrl":"https://doi.org/10.3847/2041-8213/addf2f","url":null,"abstract":"In the standard model of solar eruptive events, coronal mass ejections (CMEs) and flares are associated with each other through magnetic reconnection initiated by erupting flux ropes. Observations also reveal an increasing association ratio between flares and CMEs with flare intensity. However, the fundamental relationship between flares and CMEs, and that between thermal and nonthermal processes, remains unknown. Here we investigate energetic C-class flares (ECFs)—Geostationary Operational Environmental Satellite (GOES) C-class flares with hard X-ray (HXR) emissions above 30 keV—using observations from Advanced Space-based Solar Observatory/Hard X-ray Imager (HXI), Solar Dynamic Observatory, and GOES. Among 1331 C-class flares detected by HXI, 127 ECFs (9.5%) were identified for statistical analysis of their properties and associations with CMEs and other flare-related features. Our statistical results reveal that ECFs have relatively shorter durations and harder spectra (the mean electron power-law index is 4.65), with no significant correlation between soft X-ray flux and nonthermal parameters (e.g., HXR peak flux). Among the 127 events, 53 (42%) were associated with type III bursts, 38 (30%) with jets, at least 13 (∼11%) with 360 nm brightenings, and only 5 (∼4%) with CMEs. Crucially, all five CME events were narrow CMEs associated with jets. The surprising weak correlation between these ECFs and CMEs suggests that noneruptive or confined magnetic field configurations in these flares may favor electron acceleration, resulting in harder X-ray spectra. We discuss the potential formation mechanisms and efficient electron acceleration processes in these atypical flares, providing valuable insights into nonstandard flare behavior.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144370959","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}

引用次数: 0

Responses of a Coronal Hole to a Fast Flare-driven Coronal Wave 日冕洞对快速耀斑驱动的日冕波的响应

The Astrophysical Journal Letters Pub Date : 2025-06-22 DOI: 10.3847/2041-8213/ade38c

Xiaofan Zhang, Huadong Chen, Guiping Zhou, Li Feng, Yang Su, Jinhan Guo, Leping Li, Wei Lin, Suli Ma, Yuandeng Shen, Ruisheng Zheng, Suo Liu, Xianyong Bai, Yuanyong Deng and Jingxiu Wang

{"title":"Responses of a Coronal Hole to a Fast Flare-driven Coronal Wave","authors":"Xiaofan Zhang, Huadong Chen, Guiping Zhou, Li Feng, Yang Su, Jinhan Guo, Leping Li, Wei Lin, Suli Ma, Yuandeng Shen, Ruisheng Zheng, Suo Liu, Xianyong Bai, Yuanyong Deng and Jingxiu Wang","doi":"10.3847/2041-8213/ade38c","DOIUrl":"https://doi.org/10.3847/2041-8213/ade38c","url":null,"abstract":"Coronal waves, significant solar phenomena, act as diagnostic tools for scientists studying solar atmosphere properties. Here, we present a novel observation detailing how a coronal wave event, associated with an X5.0 class flare, influenced the properties of an adjacent coronal hole (CH) through interaction. The coronal wave was observed in both extreme-ultraviolet (EUV) observations from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and Lyα observations from the Solar Disk Imager on board the Advanced Space-based Solar Observatory. Utilizing the method of differential emission measure, we found that as the coronal wave passed through, the adjacent CH experienced an increase in temperature from 1.31 to 1.43 MK and a rise in density from ∼1.62 × 108 to 1.76 × 108 cm−3 within the rising period of ∼7 minutes. Subsequently, after the wave passed, the entire CH transitioned to a new state with a slight temperature increase and a 14% decrease in density, with more pronounced changes observed at the CH’s boundary. Taking into account the impacts of radiative loss and heat conduction, the coronal wave was estimated to provide an average energy of 2.2 × 108 erg cm−2 to the CH during the short rising period. This study highlights the identification of the coronal wave in both EUV and Lyα observations, shedding light on the significant energy input, particularly within the CH. These findings provide new insights into better understanding kinematics of fast coronal waves, energy transfer processes open versus closed magnetic topologies, and the possible acceleration of solar winds.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144370777","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}

引用次数: 0

Dissecting the Massive Pristine, Neutral Gas Reservoir of a Remarkably Bright Galaxy at z = 14.179 解析z = 14.179的一个非常明亮的星系的巨大原始中性气藏

The Astrophysical Journal Letters Pub Date : 2025-06-22 DOI: 10.3847/2041-8213/ade393

Kasper E. Heintz, Clara L. Pollock, Joris Witstok, Stefano Carniani, Kevin N. Hainline, Francesco D’Eugenio, Chamilla Terp, Aayush Saxena and Darach Watson

{"title":"Dissecting the Massive Pristine, Neutral Gas Reservoir of a Remarkably Bright Galaxy at z = 14.179","authors":"Kasper E. Heintz, Clara L. Pollock, Joris Witstok, Stefano Carniani, Kevin N. Hainline, Francesco D’Eugenio, Chamilla Terp, Aayush Saxena and Darach Watson","doi":"10.3847/2041-8213/ade393","DOIUrl":"https://doi.org/10.3847/2041-8213/ade393","url":null,"abstract":"At cosmic dawn, the first stars and galaxies are believed to form from and be deeply embedded in clouds of dense, pristine gas. Here we present a study of the James Webb Space Telescope/NIRSpec data of the most distant, spectroscopically confirmed galaxy observed to date, JADES-GS-z14-0 (GS-z14 for short), at z = 14.179, combined with recently reported far-infrared measurements of the [O iii]-88 μm and [C ii]-158 μm line transitions and underlying dust-continuum emission. Based on the observed prominent damped Lyα (DLA) absorption profile, we determine a substantial neutral atomic hydrogen (H i) column density, , consistent with previous estimates though seemingly at odds with the dynamical and gas mass of the galaxy. Using various independent but complementary approaches, considering the implied neutral gas mass from the DLA measurement, the star formation rate surface density, and the metal abundance, we demonstrate that the total gas mass of GS-z14 is of the order Mgas = 109.5–109.8M⊙. This implies a substantial gas mass fraction, fgas ≈ 0.7–0.9 and that the bulk of the interstellar medium (ISM) is in the form of H i, with mass ratios . We show that the derived gas mass is fully consistent with the nondetection of [C ii]-158 μm, assuming an appropriate scaling to the neutral gas. The low dust-to-gas ratio, AV/NHI = (1.3 ± 0.6) × 10−23 mag cm2, derived in the line of sight through the DLA further indicates that the absorbing gas is more pristine than the central, star-forming regions probed by the [O iii]-88 μm emission. These results highlight the implications for far-infrared line-detection searchers attainable with the Atacama Large Millimeter/submillimeter Array and demonstrate that the bright, relatively massive galaxy GS-z14 at z = 14.179 is deeply embedded in a substantial, pristine H i gas reservoir dominating its baryonic matter content.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144370780","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}

引用次数: 0

Constraining Ongoing Volcanic Outgassing Rates and Interior Compositions of Extrasolar Planets with Mass Measurements of Plasma Tori 用等离子环面的质量测量来限制正在进行的火山放出气体率和太阳系外行星的内部组成

The Astrophysical Journal Letters Pub Date : 2025-06-22 DOI: 10.3847/2041-8213/adde5e

V. Abby Boehm, Darryl Z. Seligman and Nikole K. Lewis

{"title":"Constraining Ongoing Volcanic Outgassing Rates and Interior Compositions of Extrasolar Planets with Mass Measurements of Plasma Tori","authors":"V. Abby Boehm, Darryl Z. Seligman and Nikole K. Lewis","doi":"10.3847/2041-8213/adde5e","DOIUrl":"https://doi.org/10.3847/2041-8213/adde5e","url":null,"abstract":"We present a novel method of constraining volcanic activity on extrasolar terrestrial worlds via characterization of circumstellar plasma tori. Our work generalizes the physics of the Io plasma torus to propose a hypothetical circumstellar plasma torus generated by exoplanetary volcanism. The quasi-steady torus mass is determined by a balance between material injection and ejection rates from volcanic activity and corotating magnetospheric convection, respectively. By estimating the Alfvén surfaces of planet-hosting stars, we calculate the torus mass-removal timescale for a number of exoplanets with properties amenable to plasma torus construction. Assuming a uniform toroidal geometry comparable to Io’s “warm” torus, we calculate quasi-steady torus masses inferable from the optical depth of atomic spectral features in torus-contaminated stellar spectra. The calculated quasi-steady masses can be used to constrain the volcanic outgassing rates of each species detected in the torus, providing quantitative estimates of bulk volcanic activity and interior composition with minimal assumptions. Such insight into the interior state of an exoplanet is otherwise accessible only after destruction via tidal forces. We demonstrate the feasibility of our method by showcasing known exoplanets that are susceptible to tidal heating and could generate readily detectable tori with realistic outgassing rates of order 1 t s−1, comparable to the Io plasma torus mass injection rate. This methodology may be applied to stellar spectra measured with ultraviolet instruments with sufficient resolution to detect atomic lines and sensitivity to recover the ultraviolet continuum of GKM dwarf stars. This further motivates the need for ultraviolet instrumentation above Earth’s atmosphere.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"243 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144370783","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}

引用次数: 0

Thermonuclear Superburst of MAXI J1752−457 Observed with NinjaSat and MAXI 用NinjaSat和MAXI观测到的MAXI J1752−457热核超爆

The Astrophysical Journal Letters Pub Date : 2025-06-19 DOI: 10.3847/2041-8213/addd00

Amira Aoyama, Teruaki Enoto, Takuya Takahashi, Sota Watanabe, Tomoshi Takeda, Wataru Iwakiri, Kaede Yamasaki, Satoko Iwata, Naoyuki Ota, Arata Jujo, Toru Tamagawa, Tatehiro Mihara, Chin-Ping Hu, Akira Dohi, Nobuya Nishimura, Motoko Serino, Motoki Nakajima, Takao Kitaguchi, Yo Kato, Nobuyuki Kawai and (NinjaSat collaboration)

{"title":"Thermonuclear Superburst of MAXI J1752−457 Observed with NinjaSat and MAXI","authors":"Amira Aoyama, Teruaki Enoto, Takuya Takahashi, Sota Watanabe, Tomoshi Takeda, Wataru Iwakiri, Kaede Yamasaki, Satoko Iwata, Naoyuki Ota, Arata Jujo, Toru Tamagawa, Tatehiro Mihara, Chin-Ping Hu, Akira Dohi, Nobuya Nishimura, Motoko Serino, Motoki Nakajima, Takao Kitaguchi, Yo Kato, Nobuyuki Kawai and (NinjaSat collaboration)","doi":"10.3847/2041-8213/addd00","DOIUrl":"https://doi.org/10.3847/2041-8213/addd00","url":null,"abstract":"An uncatalogued bright X-ray transient was detected with MAXI on 2024 November 9, named MAXI J1752−457. The NinjaSat X-ray observatory promptly observed the source from November 10 to 18, while the small angular separation from the Sun hampered follow-up campaigns by other X-ray observatories. The MAXI and NinjaSat light curves in the 2–10 keV band showed first and second decaying components at the early and late phases, approximated by exponential functions with e-folding constants of 1.2 ± 0.2 and 14.9 ± 0.9 hr (1σ errors), respectively. A single blackbody model reproduces the X-ray spectrum with a softening trend of its temperature decreasing from 1.8 ± 0.1 keV to 0.59 ± 0.06 keV. Assuming the unknown source distance at 8 kpc, at which the initial X-ray luminosity roughly corresponds to the Eddington limit, the shrinking blackbody radius was estimated at 5–11 km. This X-ray brightening is interpreted as a superburst in a Galactic low-mass X-ray binary, which is powered by thermonuclear burning triggered presumably by carbon ignition close to the outer crust of the neutron star. The transition between two decaying components occurred at 5.5–7.7 hr, corresponding to the thermal timescale of the burning layer. The ignition column density is estimated to be (1.8–2.8) × 1012 g cm−2.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"237 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329230","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}

引用次数: 0

The Temperature Anisotropy and Helium Abundance Features of Alfvénic Slow Solar Wind Observed by Parker Solar Probe, Helios, and Wind Missions 帕克太阳探测器、太阳神号和Wind任务观测到的alfv<s:1>慢太阳风的温度各向异性和氦丰度特征

The Astrophysical Journal Letters Pub Date : 2025-06-19 DOI: 10.3847/2041-8213/ade0ac

Jia Huang, Davin E. Larson, Tamar Ervin, Mingzhe Liu, Oscar Ortiz, Mihailo M. Martinović, Zhenguang Huang, Alexandros Chasapis, Xiangning Chu, B. L. Alterman, Zesen Huang, Wenwen Wei, J. L. Verniero, Lan K. Jian, Adam Szabo, Orlando Romeo, Ali Rahmati, Roberto Livi, Phyllis Whittlesey, Samer T. Alnussirat, Justin C. Kasper, Michael Stevens and Stuart D. Bale

{"title":"The Temperature Anisotropy and Helium Abundance Features of Alfvénic Slow Solar Wind Observed by Parker Solar Probe, Helios, and Wind Missions","authors":"Jia Huang, Davin E. Larson, Tamar Ervin, Mingzhe Liu, Oscar Ortiz, Mihailo M. Martinović, Zhenguang Huang, Alexandros Chasapis, Xiangning Chu, B. L. Alterman, Zesen Huang, Wenwen Wei, J. L. Verniero, Lan K. Jian, Adam Szabo, Orlando Romeo, Ali Rahmati, Roberto Livi, Phyllis Whittlesey, Samer T. Alnussirat, Justin C. Kasper, Michael Stevens and Stuart D. Bale","doi":"10.3847/2041-8213/ade0ac","DOIUrl":"https://doi.org/10.3847/2041-8213/ade0ac","url":null,"abstract":"Slow solar wind is typically characterized as having low Alfvénicity, but the occasional occurrence of highly Alfvénic slow solar wind (HASSW) raises questions about its source regions and evolution. In this work, we conduct a statistical analysis of temperature anisotropy and helium abundance in HASSW using data from the Parker Solar Probe (PSP) within 0.25 au, Helios between 0.3 au and 1 au, and Wind near 1 au. Our findings reveal that HASSW is prevalent close to the Sun, with PSP observations displaying a distinct “U-shaped” Alfvénicity distribution with respect to increasing solar wind speed, unlike the monotonic increase trend seen in Helios and Wind data. This highlights a previously unreported population of unusually low-speed HASSW, which is found in both sub-Alfvénic and super-Alfvénic regimes. The observed decreasing overlap in temperature anisotropy between HASSW and fast solar wind (FSW) with increasing heliocentric distance suggests different underlying heating processes. Additionally, HASSW exhibits two distinct helium abundance populations, particularly evident in PSP data, with generally higher helium abundance compared to less Alfvénic slow solar wind. Moreover, the decreasing overlap in temperature anisotropy versus helium abundance distributions between HASSW and FSW with decreasing radial distance implies that not all HASSW originates from the same source region as FSW.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329231","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}

引用次数: 0

Measuring Scaling Relations: Fitting Technique Matters 测量尺度关系：拟合技术问题

The Astrophysical Journal Letters Pub Date : 2025-06-19 DOI: 10.3847/2041-8213/ade13c

Bryanne McDonough, Olivia Curtis and Tereasa G. Brainerd

{"title":"Measuring Scaling Relations: Fitting Technique Matters","authors":"Bryanne McDonough, Olivia Curtis and Tereasa G. Brainerd","doi":"10.3847/2041-8213/ade13c","DOIUrl":"https://doi.org/10.3847/2041-8213/ade13c","url":null,"abstract":"Scaling relationships, both integrated and spatially resolved, arise owing to the physical processes that govern galaxy evolution and are frequently measured in both observed and simulated data. However, the accuracy and comparability of these measurements are hindered by various differences between studies such as spatial resolution, sample selection criteria, and fitting technique. In this Letter, we compare variations of standard least-squares techniques to the ridge line method for identifying spatially resolved scaling relations (Σ*−ΣSFR, Σ*−Σgas, and Σgas−ΣSFR) for TNG100 galaxies. We find that using the ridge line technique to fit these scaling relations with a double linear function (in logarithmic space) results in significantly better fits than fitting with ordinary least squares. We further illustrate the utility of the ridge line technique with an investigation into the dependence of resolved star formation main-sequence (rSFMS) measurements on spatial resolution and smoothing scale. Specifically, we find that the slope of the rSFMS at low Σ* is independent (within 2σ) of spatial resolution and smoothing scale. Finally, we discuss the need for a consistent reanalysis of resolved scaling relations in the literature and physically motivate adoption of the ridge line technique over other fitting methods.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"19 1","pages":"L32"},"PeriodicalIF":0.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144335091","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}

引用次数: 0

A Novel Method of Modeling Extended Emission of Compact Jets: Application to Swift J1727.8−1613 一种新型紧凑型射流扩展发射建模方法：在Swift J1727.8−1613上的应用

The Astrophysical Journal Letters Pub Date : 2025-06-19 DOI: 10.3847/2041-8213/ade13b

Andrzej A. Zdziarski, Callan M. Wood and Francesco Carotenuto

{"title":"A Novel Method of Modeling Extended Emission of Compact Jets: Application to Swift J1727.8−1613","authors":"Andrzej A. Zdziarski, Callan M. Wood and Francesco Carotenuto","doi":"10.3847/2041-8213/ade13b","DOIUrl":"https://doi.org/10.3847/2041-8213/ade13b","url":null,"abstract":"Flat radio spectra of compact jets launched by both supermassive and stellar-mass black holes (BHs) are explained by an interplay of self-absorbed synchrotron emission up to some distance along the jet and optically thin synchrotron at larger distances. Their spatial structure is usually studied using core shifts, in which the position of the peak (core) of the emission depends on the frequency. Here, we propose a novel and powerful method to fit the spatial dependence of the flux density at a given frequency of the jet and counterjet (when observed), using the theoretical spatial dependencies provided as simple analytical formulae. We apply our method to the spatial structure of the jets in the luminous hard spectral state of the BH X-ray binary Swift J1727.8−1613. It was the most resolved continuous jet from an X-ray binary ever observed. We find that the observed approaching jet is significantly intrinsically stronger than the receding one, which we attribute to an increase in the emission of both jets with time (observationally confirmed), together with the light travel effect, causing the receding jet to be observed at an earlier epoch than the approaching one. The jets are relatively slow, with a velocity of ∼(0.3–0.4)c. Our findings imply that the magnetic field strength increased with time. Additionally, the magnetic flux is significantly lower than in jets launched by “magnetically arrested disks.” Our method is general, and we propose that it be applied to jets launched by both stellar-mass and supermassive BHs.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"1 1","pages":"L35"},"PeriodicalIF":0.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144335031","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}

引用次数: 0