The Astrophysical Journal Letters最新文献

{"title":"The Giant Eruption in Solar Cycle 25 Caused by Collisional Shearing","authors":"Tao Ding, Jun Zhang and Yijun Hou","doi":"10.3847/2041-8213/add32c","DOIUrl":"https://doi.org/10.3847/2041-8213/add32c","url":null,"abstract":"On 2024 October 3, solar active region (AR) 13842 produced an X9.0 flare, which is the largest one in Solar Cycle 25 so far. Our study is to answer the question of what process caused this flare. Based on the magnetic field observations from the Solar Dynamics Observatory (SDO), we find that the nonconjugated sunspots of opposite polarities of the AR core region underwent a persistent collision process with strong shearing motions. Moreover, flux cancellation was observed at the collision region, e.g., 1021 Mx of unsigned flux canceled at the local area within 2 hr, suggesting the occurrence of collisional shearing. Meanwhile, a collisional polarity inversion line (PIL) was produced in the AR core region as a result of the collision of the nonconjugated polarities during flux emergence. The SDO/Atmospheric Imaging Assembly extreme-ultraviolet observations show that two flux ropes formed above the PIL. Due to the photospheric magnetic field evolution, the two flux ropes destabilized and then erupted simultaneously. Using nonlinear force-free field modeling, we notice that there were three flux ropes at the PIL, including the two ropes mentioned above and another unobserved one. We suggest that the formation of flux ropes that carry massive accumulated free energy by the collisional shearing process and the eruption of the flux rope system are responsible for the giant flare in Solar Cycle 25.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"122 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066825","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}

{"title":"The Critical Role of LIGO-India in the Era of Next-generation Observatories","authors":"Shiksha Pandey, Ish Gupta, Koustav Chandra and Bangalore S. Sathyaprakash","doi":"10.3847/2041-8213/add15f","DOIUrl":"https://doi.org/10.3847/2041-8213/add15f","url":null,"abstract":"We examine the role of LIGO-India in facilitating multimessenger astronomy in the era of next-generation observatories. A network with two L-shaped Cosmic Explorer (CE) detectors and one triangular Einstein Telescope (ET) would precisely localize nearly the entire annual binary neutron star (NS) merger population up to a redshift of 0.5—over 10,000 events would be localized within 10 deg2, including approximately 150 events within 0.1 deg2. Luminosity distance would be measured to within 10% for over 9000 events and within 1% for ∼100 events. Surprisingly, replacing the 20 km CE detector with LIGO-India operating at A♯ sensitivity (I♯) yields a nearly identical performance. The factor-of-5 shorter arms are offset by a fourfold increase in baseline relative to a second CE in the US, preserving localization accuracy, with over 9000 events within 10 deg2 and ∼90 events within 0.1 deg2. This configuration detects ∼6000 events with luminosity distance uncertainties under 10%, including ∼50 with under 1%. Both networks provide early-warning detections up to 10 minutes before merger, with localization areas ≤10 deg2. While I♯ enables excellent localization and early warnings, its shorter arms and narrower sensitivity band would limit its reach for other science goals, such as detecting Population III binary black hole mergers at z ≳ 10, NS mergers at z ∼ 2, or constraining cosmological parameters.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"204 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066858","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}

{"title":"High Optical-to-X-Ray Polarization Ratio Reveals Compton Scattering in BL Lacertae’s Jet","authors":"Iván Agudo, Ioannis Liodakis, Jorge Otero-Santos, Riccardo Middei, Alan Marscher, Svetlana Jorstad, Haocheng Zhang, Hui Li, Laura Di Gesu, Roger W. Romani, Dawoon E. Kim, Francesco Fenu, Herman L. Marshall, Luigi Pacciani, Juan Escudero Pedrosa, Francisco José Aceituno, Beatriz Agís-González, Giacomo Bonnoli, Víctor Casanova, Daniel Morcuende, Vilppu Piirola, Alfredo Sota, Pouya M. Kouch, Elina Lindfors, Callum McCall, Helen E. Jermak, Iain A. Steele, George A. Borman, Tatiana S. Grishina, Vladimir A. Hagen-Thorn, Evgenia N. Kopatskaya, Elena G. Larionova, Daria A. Morozova, Sergey S. Savchenko, Ekaterina V. Shishkina, Ivan S. Troitskiy, Yulia V. Troitskaya, Andrey A. Vasilyev, Alexey V. Zhovtan, Ioannis Myserlis, Mark Gurwell, Garrett Keating, Ramprasad Rao, Sincheol Kang, Sang-Sung Lee, Sanghyun Kim, Whee Yeon Cheong, Hyeon-Woo Jeong, Emmanouil Angelakis, Alexander Kraus, Dmitry Blinov, Siddharth Maharana, Rumen Bachev, Jenni Jormanainen, Kari Nilsson, Vandad Fallah Ramazan..","doi":"10.3847/2041-8213/adc572","DOIUrl":"https://doi.org/10.3847/2041-8213/adc572","url":null,"abstract":"Blazars, supermassive black hole systems with highly relativistic jets aligned with the line of sight, are the most powerful long-lived emitters of electromagnetic emission in the Universe. We report here on a radio-to-gamma-ray multiwavelength campaign on the blazar BL Lacertae with unprecedented polarimetric coverage from radio to X-ray wavelengths. The observations caught an extraordinary event on 2023 November 10–18, when the degree of linear polarization of optical synchrotron radiation reached a record value of 47.5%. In stark contrast, the Imaging X-ray Polarimetry Explorer found that the X-ray (Compton scattering or hadron-induced) emission was polarized at less than 7.4% (3σ confidence level). We argue here that this observational result rules out a hadronic origin of the high-energy emission and strongly favors a leptonic (Compton scattering) origin, thereby breaking the degeneracy between hadronic and leptonic emission models for BL Lacertae and demonstrating the power of multiwavelength polarimetry to address this question. Furthermore, the multiwavelength flux and polarization variability, featuring an extremely prominent rise and decay of the optical polarization degree, is interpreted for the first time by the relaxation of a magnetic “spring” embedded in the newly injected plasma. This suggests that the plasma jet can maintain a predominant toroidal magnetic field component parsecs away from the central engine.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066857","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}

{"title":"Identifying LL Chondrite Near-Earth Asteroids Using LL Chondrite Reflectance Spectra","authors":"Pengyue Wang, 鹏越 王, Edward Cloutis, Ye Su, 烨 苏, Man-To Hui and 文韬 许","doi":"10.3847/2041-8213/adce6e","DOIUrl":"https://doi.org/10.3847/2041-8213/adce6e","url":null,"abstract":"Most near-Earth objects are thought to originate from the collisional fragments of the main asteroid belt. One question that remains to be resolved is the proportion of near-Earth objects sampling the core area material of the parent body to the outer layers. In this study, we developed a method to determine the petrologic type of ordinary chondrite parent bodies based on reflectance spectroscopy. We also calculated the petrologic type of asteroid (25143) Itokawa, which is consistent with the returned samples from the JAXA Hayabusa mission. Finally, we calculate the petrologic type of 28 LL near-Earth asteroids. Our results show that the surface material of most LL chondrite near-Earth asteroids is of petrologic grade higher than 4. The ratio of LL chondrite near-Earth asteroids with high petrologic type (5 and 6) to LL chondrite near-Earth asteroids with low petrologic type is 0.79. This also means that LL chondrite near-Earth asteroids may originate primarily from the core area of the main belt parent body or bodies.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144067031","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}

{"title":"A Coherent Radio Burst from an X-Ray Neutron Star in the Carina Nebula","authors":"K. M. Rajwade, J. Tian, G. Younes, B. Posselt, B. Stappers, Z. Wadiasingh, E. D. Barr, M. C. Bezuidenhout, M. Caleb, F. Jankowski, M. Kramer, I. Pastor-Marazuela and M. Surnis","doi":"10.3847/2041-8213/add0a8","DOIUrl":"https://doi.org/10.3847/2041-8213/add0a8","url":null,"abstract":"The neutron star zoo comprises several subpopulations that range from energetic magnetars and thermally emitting X-ray neutron stars to radio-emitting pulsars. Despite studies over the last five decades, it has been challenging to obtain a clear physical link between the various populations of neutron stars, vital to constrain their formation and evolutionary pathways. Here we report the detection of a burst of coherent radio emission from a known radio-quiet, thermally emitting neutron star 2XMM J104608.7−594306 in the Carina Nebula. The burst has a distinctive sharp rise followed by a decay made up of multiple components, which is unlike anything seen from other radio-emitting neutron stars. It suggests an episodic event from the neutron star surface, akin to transient radio emission seen from magnetars. The radio burst confirms that the X-ray source is a neutron star and suggests a new link between these apparently radio-quiet X-ray-emitting sources and other transient or persistent radio-emitting neutron stars. It also suggests that a common physical mechanism for emission might operate over a range of magnetic field strengths and neutron star ages. We propose that 2XMM J104608.7−594306 straddles the boundary between young, energetic neutron stars and their evolved radio-emitting cousins and may bridge these two populations. The detection of such a radio burst also shows that other radio-quiet neutron stars may also emit such sporadic radio emission that has been missed by previous radio surveys and highlights the need for regular monitoring of this unique subpopulation of neutron stars.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066468","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}

{"title":"The Effect of Turbulence on the Angular Momentum of the Solar Wind","authors":"Rohit Chhiber, Arcadi V. Usmanov, William H. Matthaeus and Francesco Pecora","doi":"10.3847/2041-8213/add325","DOIUrl":"https://doi.org/10.3847/2041-8213/add325","url":null,"abstract":"The transfer of a star’s angular momentum to its atmosphere is a topic of considerable and wide-ranging interest in astrophysics. This Letter considers the effect of kinetic and magnetic turbulence on the solar wind’s angular momentum. The effects are quantified in a theoretical framework that employs Reynolds-averaged mean field magnetohydrodynamics, allowing for fluctuations of arbitrary amplitude. The model is restricted to the solar equatorial (r–ϕ) plane with axial symmetry, which permits the effect of turbulence to be expressed in analytical form as a modification to the classic E. J. Weber & L. Davis theory, dependent on the r, ϕ shear component of the Reynolds stress tensor. A solar wind simulation with turbulence transport modeling and Parker Solar Probe observations at the Alfvén surface are employed to quantify this turbulent modification to the solar wind’s angular momentum, which is found to be ∼3%–10% and tends to be negative. Implications for solar and stellar rotational evolution are discussed.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066523","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}

{"title":"Escaping Helium and a Highly Muted Spectrum Suggest a Metal-enriched Atmosphere on Sub-Neptune GJ 3090 b from JWST Transit Spectroscopy","authors":"Eva-Maria Ahrer, Michael Radica, Caroline Piaulet-Ghorayeb, Eshan Raul, Lindsey Wiser, Luis Welbanks, Lorena Acuña, Romain Allart, Louis-Philippe Coulombe, Amy Louca, Ryan MacDonald, Morgan Saidel, Thomas M. Evans-Soma, Björn Benneke, Duncan Christie, Thomas G. Beatty, Charles Cadieux, Ryan Cloutier, René Doyon, Jonathan J. Fortney, Anna Gagnebin, Cyril Gapp, Hamish Innes, Heather A. Knutson, Thaddeus Komacek, Joshua Krissansen-Totton, Yamila Miguel, Raymond Pierrehumbert, Pierre-Alexis Roy and Hilke E. Schlichting","doi":"10.3847/2041-8213/add010","DOIUrl":"https://doi.org/10.3847/2041-8213/add010","url":null,"abstract":"Sub-Neptunes, the most common planet type, remain poorly understood. Their atmospheres are expected to be diverse, but their compositions are challenging to determine, even with JWST. Here, we present the first JWST spectroscopic study of the warm sub-Neptune GJ 3090 b (2.13 R⊕, Teq,A = 0.3 ∼ 700 K), which orbits an M2V star, making it a favorable target for atmosphere characterization. We observed four transits of GJ 3090 b: two each using JWST NIRISS/SOSS and NIRSpec/G395H, yielding wavelength coverage from 0.6 to 5.2 μm. We detect the signature of the 10833 Å metastable helium triplet at a statistical significance of 5.5σ with an amplitude of 434 ± 79 ppm, marking the first such detection in a sub-Neptune with JWST. This amplitude is significantly smaller than predicted by solar-metallicity forward models, suggesting a metal-enriched atmosphere that decreases the mass-loss rate and attenuates the helium feature amplitude. Moreover, we find that stellar contamination, in the form of the transit light source effect, dominates the NIRISS transmission spectra, with unocculted spot and faculae properties varying across the two visits separated in time by approximately 6 months. Free retrieval analyses on the NIRSpec/G395H spectrum find tentative evidence for highly muted features and a lack of CH4. These findings are best explained by a high-metallicity atmosphere (>100× solar at 3σ confidence for clouds at ∼μbar pressures) using chemically consistent retrievals and self-consistent model grids. Further observations of GJ 3090 b are needed for tighter constraints on the atmospheric abundances and to gain a deeper understanding of the processes that led to its potential metal enrichment.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"130 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066527","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}

{"title":"Dual Directional Expansion of Classical Cepheids in the Small Magellanic Cloud Revealed by Gaia Data Release 3","authors":"Satoya Nakano, 覚矢 中野, Kengo Tachihara and 研悟 立原","doi":"10.3847/2041-8213/adce0b","DOIUrl":"https://doi.org/10.3847/2041-8213/adce0b","url":null,"abstract":"We present the three-dimensional kinematics of classical Cepheids (CCs) in the Small Magellanic Cloud (SMC) using Gaia DR3 data. By crossmatching the CCs obtained from the fourth phase of the Optical Gravitational Lensing Experiment with Gaia DR3, we obtain distances and proper motions (PMs) for 4236 CCs. Among them, radial velocities (RVs) are available for 91 stars, measured by Gaia, enabling the construction of an accurate relationship between distance and RV. Furthermore, we calculate the internal PMs of the CCs, providing the internal dynamics of the SMC while removing the distance projection effects. The CCs exhibit a northeast–southwest distance gradient, with internal PMs pointing northeast for nearer stars and southwest for more distant stars, indicating a northeast–southwest elongation. The RVs of the CCs show a northwest–southeast gradient, consistent with RVs of other stellar populations, and suggesting that the SMC’s northwest–southeast elongation results from interactions with the Large Magellanic Cloud. The distances and RVs of the CCs are nearly uncorrelated, implying that the two elongations arise from distinct causes.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"73 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143979547","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}

{"title":"High-resolution Observations of a Small-scale Cancellation Nanoflare: Supporting Evidence for the Cancellation Nanoflare Model","authors":"Zehao Tang, Yuandeng Shen, Chengrui Zhou, Surui Yao and Dongxu Liu","doi":"10.3847/2041-8213/adca3a","DOIUrl":"https://doi.org/10.3847/2041-8213/adca3a","url":null,"abstract":"An analytical cancellation nanoflare model has recently been established to show the fundamental role that ubiquitous small-scale cancellation nanoflares play in solar atmospheric heating. Although this model is well supported by simulations, observational evidence is needed to deepen our understanding of cancellation nanoflares. We present observations of a small-scale cancellation nanoflare event, analyzing its magnetic topology evolution, triggers, and physical parameters. Using coordinated observations from the Solar Dynamics Observatory and Goode Solar Telescope, we identify a photospheric flow-driven cancellation event with a flux cancellation rate of ∼1015 Mx s−1 and a heating rate of 8.7 × 106 erg cm−2 s−1. The event shows the characteristic transition from π-shaped to X-shaped magnetic configuration before the formation of a 2″ current sheet, closely matching model predictions. This event provides critical observational support for the cancellation nanoflare model and its role in solar atmospheric heating.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066467","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}

{"title":"Squeezing Full-shape Dynamical Dark Energy Constraints with Galaxy Alignments","authors":"Junsup Shim, Teppei Okumura and Atsushi Taruya","doi":"10.3847/2041-8213/add1dd","DOIUrl":"https://doi.org/10.3847/2041-8213/add1dd","url":null,"abstract":"Recent 2σ–4σ deviations from the cosmological constant suggest that dark energy (DE) may be dynamical, based on baryon acoustic oscillations and full-shape galaxy clustering (FS GC) analyses. This calls for even tighter DE constraints to narrow down its true nature. In this Letter, we explore how galaxy intrinsic alignments (IA) can enhance the FS GC–based DE constraints, using Fisher forecasts on various extensions of dynamical DE models, including scenarios with curvature, massive neutrinos, and modified gravity. Incorporating IA improves the DE figure of merit by 42%–57% and tightens the primordial power spectrum amplitude constraints by 17%–19%. Our findings highlight IA’s potential as a valuable cosmological probe complementary to GC.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"120 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144066522","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}