The Astrophysical Journal Letters最新文献_第4页

ALMA Observations of the Gamma-Ray Binary System PSR B1259-63/LS 2883 during the 2024 Periastron Passage

The Astrophysical Journal Letters Pub Date : 2024-12-05 DOI: 10.3847/2041-8213/ad93d1

Yutaka Fujita, Akiko Kawachi, Atsuo T. Okazaki, Hiroshi Nagai, Norita Kawanaka and Takuya Akahori

{"title":"ALMA Observations of the Gamma-Ray Binary System PSR B1259-63/LS 2883 during the 2024 Periastron Passage","authors":"Yutaka Fujita, Akiko Kawachi, Atsuo T. Okazaki, Hiroshi Nagai, Norita Kawanaka and Takuya Akahori","doi":"10.3847/2041-8213/ad93d1","DOIUrl":"https://doi.org/10.3847/2041-8213/ad93d1","url":null,"abstract":"We present observations of the gamma-ray binary PSR B1259-63/LS 2883 with the Atacama Large Millimeter/submillimeter Array (ALMA) at Band 3 (97 GHz), Band 6 (233 GHz), and Band 7 (343 GHz). PSR B1259-63/LS 2883 consists of a pulsar in a highly eccentric orbit around a massive companion star, with the pulsar passing through the circumstellar disk near periastron. Our new data were obtained over several epochs, ranging from −61 to +29 days from the periastron passage in 2024. We report an increase in flux in all bands near the periastron. The significant change in Band 3 flux suggests synchrotron emission from the interaction between the pulsar wind and the stellar wind or disk. The Band 6 flux shows an increase around periastron and a transition from thermal emission from the circumstellar disk to synchrotron emission. The Band 7 observation +24 days after periastron shows a brightening, suggesting that the pulsar's passage through the disk does not result in its immediate destruction. We discuss the implications of these results for the interaction between the pulsar wind and the circumstellar disk, such as the possible disk expansion after periastron.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142782540","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

Acceleration of Ultra-high-energy Cosmic Rays in the Kiloparsec-scale Jets of Nearby Radio Galaxies

The Astrophysical Journal Letters Pub Date : 2024-12-05 DOI: 10.3847/2041-8213/ad9589

Jie-Shuang Wang, 界双王, Brian Reville, Frank M. Rieger and Felix A. Aharonian

{"title":"Acceleration of Ultra-high-energy Cosmic Rays in the Kiloparsec-scale Jets of Nearby Radio Galaxies","authors":"Jie-Shuang Wang, 界双王, Brian Reville, Frank M. Rieger and Felix A. Aharonian","doi":"10.3847/2041-8213/ad9589","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9589","url":null,"abstract":"Radio galaxies have long been considered as potential sources of ultra-high-energy cosmic rays (UHECRs). Recent analyses of the UHECR spectrum, composition, and arrival directions indicate that the nearest radio galaxy, Centaurus A, could be linked to the reported dipole anisotropy, though the mechanism underlying the acceleration remains elusive. In this Letter, we explore UHECR acceleration in the kiloparsec-scale jets of radio galaxies, exemplified by Centaurus A. Using high-resolution relativistic magnetohydrodynamic and test-particle simulations without subgrid physics, we investigate the acceleration of the highest-energy particles in the turbulent sheath of a fast-moving jet. Our findings demonstrate that acceleration close to the maximum theoretical expectation is possible. When extrapolated to nearby radio galaxies, our results suggest that the kiloparsec-scale jets of Centaurus A could account for the dipole anisotropy in UHECRs, while more potent Fanaroff–Riley type II radio galaxies may account for the observed UHECR spectrum with a rigidity cutoff at a few Exavolts.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142782538","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

Silicon Isotopic Composition of Mainstream Presolar SiC Grains Revisited: The Impact of Nuclear Reaction Rate Uncertainties

The Astrophysical Journal Letters Pub Date : 2024-12-05 DOI: 10.3847/2041-8213/ad91ab

Hung Kwan Fok, Marco Pignatari, Benoît Côté and Reto Trappitsch

{"title":"Silicon Isotopic Composition of Mainstream Presolar SiC Grains Revisited: The Impact of Nuclear Reaction Rate Uncertainties","authors":"Hung Kwan Fok, Marco Pignatari, Benoît Côté and Reto Trappitsch","doi":"10.3847/2041-8213/ad91ab","DOIUrl":"https://doi.org/10.3847/2041-8213/ad91ab","url":null,"abstract":"Presolar grains are stardust particles that condensed in the ejecta or in the outflows of dying stars and can today be extracted from meteorites. They recorded the nucleosynthetic fingerprint of their parent stars and thus serve as valuable probes of these astrophysical sites. The most common types of presolar silicon carbide grains (called mainstream SiC grains) condensed in the outflows of asymptotic giant branch stars. Their measured silicon isotopic abundances are not significantly influenced by nucleosynthesis within the parent star but rather represent the pristine stellar composition. Silicon isotopes can thus be used as a proxy for galactic chemical evolution (GCE). However, the measured correlation of 29Si/28Si versus 30Si/28Si does not agree with any current chemical evolution model. Here, we use a Monte Carlo model to vary nuclear reaction rates within their theoretical or experimental uncertainties and process them through stellar nucleosynthesis and GCE models to study the variation of silicon isotope abundances based on these nuclear reaction rate uncertainties. We find that these uncertainties can indeed be responsible for the discrepancy between measurements and models and that the slope of the silicon isotope correlation line measured in mainstream SiC grains agrees with chemical evolution models within the nuclear reaction rate uncertainties. Our result highlights the importance of future precision reaction rate measurements for resolving the apparent data–model discrepancy.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"84 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788412","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

Detection of Gas Inflow during the Onset of a Starburst in a Low-mass Galaxy at z = 2.45

The Astrophysical Journal Letters Pub Date : 2024-12-05 DOI: 10.3847/2041-8213/ad93d0

Erin Coleman, Keerthi Vasan G.C., Yuguang Chen, 昱光陈, Tucker Jones, Sunny Rhoades, Richard Ellis, Dan Stark, Nicha Leethochawalit, Ryan Sanders, Kris Mortensen, Karl Glazebrook and Glenn G. Kacprzak

{"title":"Detection of Gas Inflow during the Onset of a Starburst in a Low-mass Galaxy at z = 2.45","authors":"Erin Coleman, Keerthi Vasan G.C., Yuguang Chen, 昱光陈, Tucker Jones, Sunny Rhoades, Richard Ellis, Dan Stark, Nicha Leethochawalit, Ryan Sanders, Kris Mortensen, Karl Glazebrook and Glenn G. Kacprzak","doi":"10.3847/2041-8213/ad93d0","DOIUrl":"https://doi.org/10.3847/2041-8213/ad93d0","url":null,"abstract":"The baryon cycle is crucial for understanding galaxy formation, as gas inflows and outflows vary throughout a galaxy’s lifetime and affect its star formation rate. Despite the necessity of accretion for galaxy growth at high redshifts, direct observations of inflowing gas have proven elusive, especially at z ≳ 2. We present a spectroscopic analysis of a galaxy at redshift z = 2.45, which exhibits signs of inflow in several ultraviolet interstellar absorption lines, with no clear outflow signatures. The absorption lines are redshifted by ∼250 km s−1 with respect to the systemic redshift, and C iv shows a prominent inverse P-Cygni profile. Simple stellar population models suggest that this galaxy has a low metallicity (∼5% solar), with a very young starburst of age ∼4 Myr dominating the ultraviolet luminosity. The gas inflow velocity and nebular velocity dispersion suggest an approximate halo mass of order ∼1011M⊙, a regime in which simulations predict that bursty star formation is common at this redshift. We conclude that this system is likely in the beginning of a cycle of bursty star formation, where inflow and star formation rates are high, but where supernovae and other feedback processes have not yet launched strong outflows. In this scenario, we expect the inflow-dominated phase to be observable (e.g., with net redshifted interstellar medium absorption) for only a short timescale after a starburst onset. This result represents a promising avenue for probing the full baryon cycle, including inflows, during the formative phases of low-mass galaxies at high redshifts.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"111 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142782537","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

Observed Fluctuation Enhancement and Departure from WKB Theory in Sub-Alfvénic Solar Wind

The Astrophysical Journal Letters Pub Date : 2024-12-05 DOI: 10.3847/2041-8213/ad9727

David Ruffolo, Panisara Thepthong, Peera Pongkitiwanichakul, Sohom Roy, Francesco Pecora, Riddhi Bandyopadhyay, Rohit Chhiber, Arcadi V. Usmanov, Michael Stevens, Samuel Badman, Orlando Romeo, Jiaming Wang, 嘉明王, Joshua Goodwill, Melvyn L. Goldstein and William H. Matthaeus

引用次数: 0

Ultra-High-Energy Cosmic Rays Accelerated by Magnetically Dominated Turbulence

The Astrophysical Journal Letters Pub Date : 2024-12-04 DOI: 10.3847/2041-8213/ad955f

Luca Comisso, Glennys R. Farrar and Marco S. Muzio

{"title":"Ultra-High-Energy Cosmic Rays Accelerated by Magnetically Dominated Turbulence","authors":"Luca Comisso, Glennys R. Farrar and Marco S. Muzio","doi":"10.3847/2041-8213/ad955f","DOIUrl":"https://doi.org/10.3847/2041-8213/ad955f","url":null,"abstract":"Ultra-high-energy cosmic rays (UHECRs), particles characterized by energies exceeding 1018 eV, are generally believed to be accelerated electromagnetically in high-energy astrophysical sources. One promising mechanism of UHECR acceleration is magnetized turbulence. We demonstrate from first principles, using fully kinetic particle-in-cell simulations, that magnetically dominated turbulence accelerates particles on a short timescale, producing a power-law energy distribution with a rigidity-dependent, sharply defined cutoff well approximated by the form . Particle escape from the turbulent accelerating region is energy dependent, with tesc ∝ E−δ and δ ∼ 1/3. The resulting particle flux from the accelerator follows , with s ∼ 2.1. We fit the Pierre Auger Observatory’s spectrum and composition measurements, taking into account particle interactions between acceleration and detection, and show that the turbulence-associated energy cutoff is well supported by the data, with the best-fitting spectral index being . Our first-principles results indicate that particle acceleration by magnetically dominated turbulence may constitute the physical mechanism responsible for UHECR acceleration.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142777001","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

Information-theory-based System-level Babcock–Leighton Flux Transport Model–Data Comparisons

The Astrophysical Journal Letters Pub Date : 2024-12-04 DOI: 10.3847/2041-8213/ad94db

Simon Wing, Jay R. Johnson, Mausumi Dikpati and Yosia I. Nurhan

引用次数: 0

Fermi-LAT Detection of the Low-luminosity Radio Galaxy NGC 4278 during the LHAASO Campaign

The Astrophysical Journal Letters Pub Date : 2024-12-03 DOI: 10.3847/2041-8213/ad93cf

Ettore Bronzini, Paola Grandi, Eleonora Torresi and Sara Buson

{"title":"Fermi-LAT Detection of the Low-luminosity Radio Galaxy NGC 4278 during the LHAASO Campaign","authors":"Ettore Bronzini, Paola Grandi, Eleonora Torresi and Sara Buson","doi":"10.3847/2041-8213/ad93cf","DOIUrl":"https://doi.org/10.3847/2041-8213/ad93cf","url":null,"abstract":"We present a study of the high-energy properties of the compact symmetric object NGC 4278, recently associated with a TeV source by the Large High Altitude Air Shower Observatory (LHAASO) collaboration. We conducted a dedicated analysis of a Fermi Large Area Telescope (LAT) region around NGC 4278, limited to the LHAASO campaign conducted from 2021 March to 2022 October. A statistically significant emission (∼4.3σ) was revealed, spatially consistent with the radio position of NGC 4278 and the LHAASO source. The Fermi-LAT source is detected above 8 GeV, exhibiting a hard spectrum (photon index Γ = 1.3 ± 0.3) and a γ-ray luminosity of L>100 MeV ≃ 4 × 1041 erg s–1. A serendipitous Swift X-Ray Telescope (XRT) observation of NGC 4278 during the TeV campaign reveals the source in a high state, with a flux , compatible with the highest luminosity level observed in previous Chandra pointings. The high-energy spectral energy distribution of the source and the intense flux variation observed in the X-ray band support a jet origin for the observed radiation. We suggest that the significant enhancement of the high-energy flux observed during the LHAASO campaign is due to a transient, highly energetic perturbation in the jet. The detection of NGC 4278 at both high and very high energies opens new frontiers in studying particle acceleration processes. It reveals that even compact, low-power radio galaxies can exceed the sensitivity thresholds of GeV and TeV instruments, becoming promising targets for the upcoming Cherenkov Telescope Array Observatory.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763206","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

Two Novel Hot Jupiter Formation Pathways: How White Dwarf Kicks Shape the Hot Jupiter Population

The Astrophysical Journal Letters Pub Date : 2024-12-03 DOI: 10.3847/2041-8213/ad94d8

Alexander P. Stephan, David V. Martin, Smadar Naoz, Nathan R. Hughes and Cheyanne Shariat

{"title":"Two Novel Hot Jupiter Formation Pathways: How White Dwarf Kicks Shape the Hot Jupiter Population","authors":"Alexander P. Stephan, David V. Martin, Smadar Naoz, Nathan R. Hughes and Cheyanne Shariat","doi":"10.3847/2041-8213/ad94d8","DOIUrl":"https://doi.org/10.3847/2041-8213/ad94d8","url":null,"abstract":"The origin of Hot Jupiters (HJs) is disputed between a variety of in situ and ex situ formation scenarios. One of the early proposed ex situ scenarios was the Eccentric Kozai–Lidov (EKL) mechanism combined with tidal circularization, which can produce HJs with the aid of a stellar or planetary companion. However, observations have revealed a lack of stellar companions to HJs, which challenges the importance of the binary star-driven-EKL-plus-tides scenario. In this work, we explore so far unaccounted-for stellar evolution effects on HJ formation, in particular the effect of white dwarf (WD) formation. Gaia observations have revealed that WDs often undergo a kick during formation, which can alter a binary’s orbital configuration or even unbind it. Based on this WD kick, in this Letter, we propose and explore two novel HJ formation pathways: (1) HJs that are presently orbiting single stars but were initially formed in a binary that was later unbound by a WD kick; (2) binaries that survive the WD kick can trigger enhanced EKL oscillations and lead to second-generation HJ formation. We demonstrate that the majority of seemingly single HJs could have formed in binary star systems. As such, HJ formation in binaries via the EKL mechanism could be one of the dominant HJ formation pathways, and our results highlight that unaccounted-for stellar evolution effects, like WD formation, can obscure the actual origin of observed exoplanet populations.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760536","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

XMM-Newton High-resolution Spectroscopy of EXO 0748–676 after Its Reemergence from a Long Quiescence

The Astrophysical Journal Letters Pub Date : 2024-12-03 DOI: 10.3847/2041-8213/ad9337

Sayantan Bhattacharya, Sudip Bhattacharyya and Gargi Shaw

{"title":"XMM-Newton High-resolution Spectroscopy of EXO 0748–676 after Its Reemergence from a Long Quiescence","authors":"Sayantan Bhattacharya, Sudip Bhattacharyya and Gargi Shaw","doi":"10.3847/2041-8213/ad9337","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9337","url":null,"abstract":"EXO 0748–676 is a well-studied, high-inclination, dipping and eclipsing neutron star low-mass X-ray binary that has recently emerged from 16 yr of quiescence into a new outburst. We present results from 55.5 ks of XMM-Newton observation, focusing on high-resolution spectroscopy with the same instrument (the Reflection Grating Spectrometer) that produced significant insights during the previous outburst. The XMM-Newton European Photon Imaging Camera light curve reveals a type I X-ray burst that leads to a corresponding optical burst by 3 s. To understand the effects of the burst on the ionization structure, the data are divided into burstless and pre- and postburst spectra, with additional analysis for dip and nondip phases. The primary spectral feature in all phases is a broad O vii recombination line, accompanied by velocity-broadened O viii, N vii, and Ne ix lines. Notably, the Ne ix line shows different ionization states for the preburst (11.65 Å) and postburst (13.56 Å) phases, while the dips also substantially affect the spectral lines. The current outburst mirrors many traits from the earlier one, such as a similar spectral state, plasma components with similar ionization structure, and spectral features from the same elements, implying a stable long-term accretion behavior across outbursts.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"261 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763205","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