The Astrophysical Journal Letters最新文献

{"title":"On the Formation of S stars from a Recent Massive Black Hole Merger in the Galactic Center","authors":"Tatsuya Akiba, Smadar Naoz and Ann-Marie Madigan","doi":"10.3847/2041-8213/addc5d","DOIUrl":"https://doi.org/10.3847/2041-8213/addc5d","url":null,"abstract":"The Galactic center hosts a rotating disk of young stars between 0.05 and 0.5 pc of Sgr A*. The “S stars” at a distance <0.04 pc, however, are on eccentric orbits with nearly isotropically distributed inclinations. The dynamical origin of the S-star cluster has remained a theoretical challenge. Using a series of N-body simulations, we show that a recent massive black hole merger with Sgr A* can self-consistently produce many of the orbital properties of the Galactic nuclear star cluster within 0.5 pc. A black hole merger results in a gravitational-wave recoil kick, which causes the surrounding cluster to form an apse-aligned eccentric disk. We show that stars near the inner edge of an eccentric disk migrate inward and are driven to high eccentricities and inclinations due to secular torques similar to the eccentric Kozai–Lidov mechanism. In our fiducial model, starting with a thin eccentric disk with e = 0.3, the initially unoccupied region within 0.04 pc is populated with high-eccentricity, high-inclination S stars within a few Myr. This formation channel requires a black hole of mass to have merged with Sgr A* within the last 10 Myr.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144547621","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":"Was Earth’s Water Acquired Locally during the Earliest Phases of the Solar System Formation?","authors":"Lise Boitard-Crépeau, Cecilia Ceccarelli, Pierre Beck, Lionel Vacher and Piero Ugliengo","doi":"10.3847/2041-8213/ade5aa","DOIUrl":"https://doi.org/10.3847/2041-8213/ade5aa","url":null,"abstract":"The origin of the terrestrial water remains debated, as standard solar system formation models suggest that Earth formed from dry grains, inside the snowline of the protosolar nebula (PSN). Here, we revisit this issue through the lens of computational chemistry. While the classically used snowline relies on a single condensation temperature, recent work in quantum chemistry shows that the binding energy (BE) of water on icy grains has a Gaussian distribution, which implies a gradual sublimation of water rather than a sharp transition. We use the computed distribution of BEs to estimate the radial distribution of adsorbed ice on the dust grains across the PSN protoplanetary disk. Our model reproduces the full range of estimated water abundances on Earth and matches the hydration trends observed in chondrite groups at their predicted formation distances. Thus, we suggest that a significant fraction of Earth’s water may have been acquired locally at early stages of the solar system formation, without requiring delivery from beyond the classical snowline.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144547612","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 Relativistic Jet in the Radio-quiet Active Galactic Nucleus Mrk 110","authors":"Ailing Wang, Tao An, Kenneth I. Kellermann, Hua Feng, Emmanuel K. Bempong-Manful, Roland Timmerman and Shaoguang Guo","doi":"10.3847/2041-8213/ade14a","DOIUrl":"https://doi.org/10.3847/2041-8213/ade14a","url":null,"abstract":"We report the discovery of a relativistic jet in Mrk 110, a narrow-line Seyfert 1 galaxy historically classified as a radio-quiet active galactic nucleus (AGN). Very long baseline interferometry observations reveal intermittent jet activity during 2015–2016 and 2022–2024, with proper-motion measurements yielding superluminal velocities of ∼3.6 ± 0.6c and ∼2.1 ± 0.2c, respectively. The recent jet component decelerates to ∼1.5 ± 0.2c at a projected distance of 1.1 pc from the core, coinciding with the transition zone between broad-line and narrow-line regions. This deceleration accompanies dramatic spectral evolution from steep (spectral index α ≈ −0.63 ± 0.04) to inverted (α ≈ +0.69 ± 0.10) as the 7.6 GHz flux density more than doubled. These episodic jet ejections and their evolutionary pattern match theoretical predictions from magnetically arrested disk (MAD) models for temporary jet formation in systems with Mrk 110’s physical parameters on timescales of months to years. The observed jet deceleration distance matches expectations for relativistic outflows interacting with the circumnuclear environment. These findings demonstrate that the traditional radio-loud/quiet AGN dichotomy may reflect time-averaged states rather than intrinsic capabilities, suggesting that jets may form across the AGN population but become observable only during specific accretion phases when MAD conditions are temporarily established. Mrk 110 serves as a critical “missing link” between radio-loud and radio-quiet AGN, providing insight into jet formation mechanisms, environmental interactions, and physical processes that unify various AGN classifications.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144547616","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":"How Reconnection-unfavored Magnetic Flux Emergence Suppresses Solar Filament Eruptions","authors":"Chengrui Zhou, Yuandeng Shen, Chun Xia, Hao Liang, Zehao Tang, Dongxu Liu and Surui Yao","doi":"10.3847/2041-8213/ade051","DOIUrl":"https://doi.org/10.3847/2041-8213/ade051","url":null,"abstract":"Magnetic flux emergence is traditionally considered to be a key trigger of solar filament eruptions, yet its role in suppressing filament eruptions remains less understood. Using multiwavelength observations from the Solar Dynamics Observatory, this study investigates a unique case of flux emergence below a quiescent filament from 2016 January 3 to 5, where the newly emerging magnetic flux suppressed rather than promoted the eruption of the filament. It is found that the emerging magnetic bipole within the filament channel directly interacted and reconnected with the overlying filament magnetic field and produced a series of two-sided coronal jets along the filament axis. Instead of eruption, the filament kept stable but broke into two segments at the reconnection site. Further magnetic cancellation or recession of the emerged bipole allowed the filament to recover its original structure. Our analysis results revealed that the flux emergence suppressed the filament eruption by reducing the upward net force. The formation and evolution of the filament fine structures (such as filament threads) are closely linked to the reconnection processes between the emerging bipole and the filament’s horizontal magnetic field. This study provides direct observational evidence for accounting for the stabilization of solar filaments driven by flux emergence, offering new insights into magnetic emergence’s dual role in triggering and suppressing solar eruptions.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144547492","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":"Polarized Multiwavelength Emission from Pulsar Wind—Accretion Disk Interaction in a Transitional Millisecond Pulsar","authors":"Maria Cristina Baglio, Francesco Coti Zelati, Alessandro Di Marco, Fabio La Monaca, Alessandro Papitto, Andrew K. Hughes, Sergio Campana, David M. Russell, Diego F. Torres, Francesco Carotenuto, Stefano Covino, Domitilla de Martino, Stefano Giarratana, Sara E. Motta, Kevin Alabarta, Paolo D’Avanzo, Giulia Illiano, Marco M. Messa, Arianna Miraval Zanon and Nanda Rea","doi":"10.3847/2041-8213/add7d2","DOIUrl":"https://doi.org/10.3847/2041-8213/add7d2","url":null,"abstract":"Transitional millisecond pulsars (tMSPs) bridge the evolutionary gap between accreting neutron stars in low-mass X-ray binaries and millisecond radio pulsars. These systems exhibit a unique subluminous X-ray state characterized by the presence of an accretion disk and rapid switches between high and low X-ray emission modes. The high mode features coherent millisecond pulsations spanning from the X-ray to the optical band. We present multiwavelength polarimetric observations of the tMSP PSR J1023+0038 aimed at conclusively identifying the physical mechanism powering its emission in the subluminous X-ray state. During the high mode, we report a probable detection of polarized emission in the 2–6 keV energy range, with a polarization degree of (12 ± 3)% and a polarization angle of −2∘ ± 9∘measured counterclockwise from the north celestial pole toward the east (99.7% confidence level, c.l.; uncertainties are quoted at 1σ). At optical wavelengths, we find a polarization degree of (1.41 ± 0.04)% and a polarization angle aligned with that in the X-rays, suggesting a common physical mechanism operating across these bands. Remarkably, the polarized flux spectrum matches the pulsed emission spectrum from optical to X-rays. The polarization properties differ markedly from those observed in other accreting neutron stars and isolated rotation-powered pulsars and are also inconsistent with an origin in a compact jet. Our results provide direct evidence that the polarized and pulsed emissions both originate from synchrotron radiation at the boundary region formed where the pulsar wind interacts with the inner regions of the accretion disk.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"111 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144533016","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":"Asymmetries in Fe ix 17.1 nm and Fe xii 19.5 nm Line Profiles as Possible Signatures of Obscuration Dimming in Sun-as-a-star Spectra","authors":"Yi-Bing Chen, Hong-Peng Lu, Hui Tian, He-Chao Chen, Ying Li, Zi-Hao Yang, Zheng Sun and Zhen-Yong Hou","doi":"10.3847/2041-8213/ade685","DOIUrl":"https://doi.org/10.3847/2041-8213/ade685","url":null,"abstract":"We report the possible detection of obscuration dimming, inferred from spectral line asymmetries in Sun-as-a-star extreme ultraviolet spectra. By analyzing asymmetries in the Fe ix 17.1 nm and Fe xii 19.5 nm line profiles obtained from the Solar Dynamics Observatory/Extreme Ultraviolet Variability Experiment during coronal dimming events from 2011 to 2014, we identify two candidate obscuration dimming events associated with M9.3- and X5.4-class flares, respectively. Both events demonstrated prominent irradiance reductions, characterized by greater decreases in blue-wing emission relative to the red wing. These line-profile asymmetries may be attributed to cooler filament material ejected during the flares, moving along the line of sight and partially obscuring hotter coronal emission. The possible obscuration dimming accounted for roughly 18% of the total irradiance loss and persisted for approximately 5–6 hr. Doppler velocity analysis of line profiles enabled us to infer possible motion trends of filament eruptions, which may represent the core regions of coronal mass ejections (CMEs). For event 1, the filament eruption possibly experienced deceleration with partial fallback toward the solar surface or deflection away from the Sun–Earth line, consistent with minimal geomagnetic activity. In contrast, event 2 showed potential acceleration toward Earth, correlating with a significant geomagnetic storm. Our results suggest that the obscuration dimming method presented in this study may serve as a useful diagnostic for constraining CME properties and informing space weather forecasts. In addition, this observational approach may provide a pathway toward identifying stellar CMEs and assessing whether they display the typical three-part structure seen in solar CMEs.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144533023","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 Double Tidal Disruption Event AT 2022dbl Implies that at Least Some “Standard” Optical Tidal Disruption Events Are Partial Disruptions","authors":"Lydia Makrygianni, Iair Arcavi, Megan Newsome, Ananya Bandopadhyay, Eric R. Coughlin, Itai Linial, Brenna Mockler, Eliot Quataert, Chris Nixon, Benjamin Godson, Miika Pursiainen, Giorgos Leloudas, K. Decker French, Adi Zitrin, Sara Faris, Marco C. Lam, Assaf Horesh, Itai Sfaradi, Michael Fausnaugh, Ehud Nakar, Kendall Ackley, Moira Andrews, Panos Charalampopoulos, Benjamin D. R. Davies, Yael Dgany, Martin J. Dyer, Joseph Farah, Rob Fender, David A. Green, D. Andrew Howell, Thomas Killestein, Niilo Koivisto, Joseph Lyman, Curtis McCully, Morgan A. Mitchell, Estefania Padilla Gonzalez, Lauren Rhodes, Anwesha Sahu, Giacomo Terreran and Ben Warwick","doi":"10.3847/2041-8213/ade155","DOIUrl":"https://doi.org/10.3847/2041-8213/ade155","url":null,"abstract":"Flares produced following the tidal disruption of stars by supermassive black holes can reveal the properties of the otherwise dormant majority of black holes and the physics of accretion. In the past decade, a class of optical-ultraviolet tidal disruption flares has been discovered whose emission properties do not match theoretical predictions. This has led to extensive efforts to model the dynamics and emission mechanisms of optical-ultraviolet tidal disruptions in order to establish them as probes of supermassive black holes. Here we present the optical-ultraviolet tidal disruption event AT 2022dbl, which showed a nearly identical repetition 700 days after the first flare. Ruling out gravitational lensing and two chance unrelated disruptions, we conclude that at least the first flare represents the partial disruption of a star, possibly captured through the Hills mechanism. Since both flares are typical of the optical-ultraviolet class of tidal disruptions in terms of their radiated energy, temperature, luminosity, and spectral features, it follows that either the entire class are partial rather than full stellar disruptions, contrary to the prevalent assumption, or some members of the class are partial disruptions, having nearly the same observational characteristics as full disruptions. Whichever option is true, these findings could require revised models for the emission mechanisms of optical-ultraviolet tidal disruption flares and a reassessment of their expected rates.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144533022","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":"Predictions for New Horizons’ SWAP Measurements Downstream of the Heliospheric Termination Shock","authors":"E. J. Zirnstein, D. J. McComas, B. L. Shrestha, H. A. Elliott, P. C. Brandt, S. A. Stern, A. R. Poppe, J. Parker, E. Provornikova, K. Singer, A. Verbiscer and New Horizons Heliophysics Team","doi":"10.3847/2041-8213/ade670","DOIUrl":"https://doi.org/10.3847/2041-8213/ade670","url":null,"abstract":"Currently ∼62 au from the Sun, the New Horizons spacecraft is en route to the outer heliosphere boundaries. The first boundary it will encounter is the heliospheric termination shock (HTS), where the solar wind ion (SWI) and interstellar pickup ion (PUI) plasma mixture is slowed down to subsonic speeds, compressed, and heated. Some particles, mostly PUIs, undergo preferential acceleration at the HTS due to their higher energies and thus gain the capability to reflect from the shock and undergo, e.g., shock drift acceleration. This produces a tail in the downstream PUI energy distribution, with the potential for multiple power-law breaks. In anticipation of crossing the HTS, we have constructed a test particle model with synthetic turbulence to simulate New Horizons’ Solar Wind Around Pluto (SWAP) observations downstream of the HTS. SWAP can measure the energy/charge of multiple particle populations (thermal solar wind (SW) protons, alphas, and PUIs). Here, we calculate what SWAP might observe after it crosses the HTS. Our model shows that the count rate distribution will be very different from what is observed in the supersonic SW, with a hotter SW+PUI distribution and no sharp PUI cutoff. This will require a different method to quantify the moments of the SWIs and PUIs in the heliosheath. SWAP may be able to observe part of the PUI tail downstream of the HTS, if the upstream SW speed is 300 km s−1. Moreover, if the shock compression ratio is also 2, SWAP may observe multiple populations of the accelerated PUI distribution.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144533025","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 Nanosecond-duration Radio Pulse Originating from the Defunct Relay 2 Satellite","authors":"C. W. James, A. T. Deller, T. Dial, M. Glowacki, S. J. Tingay, K. W. Bannister, A. Bera, N. D. R. Bhat, R. D. Ekers, V. Gupta, A. Jaini, J. Morgan, J. N. Jahns-Schindler, R. M. Shannon, M. Sukhov, J. Tuthill and Z. Wang","doi":"10.3847/2041-8213/ade3d3","DOIUrl":"https://doi.org/10.3847/2041-8213/ade3d3","url":null,"abstract":"We report the detection of a burst of emission over a 695.5–1031.5 MHz bandwidth by the Australian Square Kilometre Array Pathfinder. The burst was localized through analysis of near-field time delays to the long-decommissioned Relay 2 satellite and exhibited a dispersion measure of 2.26 × 10−5 pc cm−3—69.7 total electron content units, consistent with expectations for a single pass through the ionosphere. After coherent dedispersion, the burst was determined to be less than 30 ns in width, with an average flux density of at least 300 kJy. We consider an electrostatic discharge (ESD) or plasma discharge following a micrometeoroid impact to be plausible explanations for the burst. ESDs have previously been observed with the Arecibo radio telescope, but on 1000 times longer timescales. Our observation opens new possibilities for the remote sensing of ESD, which poses a serious threat to spacecraft, and reveals a new source of false events for observations of astrophysical transients.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144520609","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":"Colors and Dynamics of a Near-Sun Orbital Asteroid Family: 2021 PH27 and 2025 GN1","authors":"Scott S. Sheppard, Henry H. Hsieh, Petr Pokorný, David J. Tholen, Audrey Thirouin, Carlos Contreras, Marcelo D. Mora, Mauricio Martinez and Ivonne Toro","doi":"10.3847/2041-8213/ade3da","DOIUrl":"https://doi.org/10.3847/2041-8213/ade3da","url":null,"abstract":"We observed the dynamically similar near-Sun asteroids 2021 PH27 and 2025 GN1 for their optical colors. These objects have the lowest known semimajor axes of any asteroids. 2021 PH27 has the largest general relativistic effects of any known solar system object. The small semimajor axis and very close passage to the Sun suggest the extreme thermal and gravitational environment should highly modify these asteroids’ surfaces. From g’-, r’-, i’-, and z’-band imaging, we find the colors of 2021 PH27 ( , , and mag) to be between the two major asteroid types: the S and C classes. With a spectral slope of 6.8 ± 0.03 percent per 100 nm, 2021 PH27 is an X-type asteroid and requires albedo or spectral features to further identify its composition. We find the dynamically similar 2025 GN1 also has very similar colors ( and ) as 2021 PH27, suggesting these objects are fragments from a once larger parent asteroid or 2021 PH27 is shedding material. The colors are not blue like some other near-Sun asteroids such as 3200 Phaethon that have been interpreted to be from the loss of reddening substances from the extreme temperatures. There is no evidence of activity or a large amplitude period for 2021 PH27, whereas 2025 GN1 might have a more significant rotational light curve. 2025 GN1 may have a very close encounter or hit Venus in about 2300 yr and likely separated from 2021 PH27 in the last ∼10 kyr.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144520610","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}