The Astrophysical Journal最新文献

{"title":"Nonparallel Wave Propagation in an Asymmetric Magnetic Slab","authors":"Antreas Tsiapalis, Noémi Kinga Zsámberger, Balázs Asztalos and Robert Erdélyi","doi":"10.3847/1538-4357/addc69","DOIUrl":"https://doi.org/10.3847/1538-4357/addc69","url":null,"abstract":"Theoretical and numerical analyses of the behavior of magnetohydrodynamic (MHD) waves in solar atmospheric structures have a vital role in understanding the plasma dynamics of the Sun. Magneto-helioseismology is indebted to the insight gained from simple magnetic slab structures accompanied by varying conditions within the slab and its environment. This paper builds on the existing literature on these structures by presenting an analytical approach to deriving the dispersion relation for MHD wave propagation in a nonparallel case. Analogous to the parallel case, a plethora of modes emerges that can be classified into quasi-kink or quasi-sausage, body or surface, as well as fast or slow waves. The slab itself can be viewed as thin or wide similarly to previous works, however due to the nonparallel condition it can also be categorised as short or long in the direction of the tilt of the wavevector. This is the analog of the thin or wide slab classification in the parallel direction, expanding our established knowledge regarding propagating MHD waves in magnetic slabs. The variance of the wavenumber along the nonparallel dimension brings to light a number of intriguing features, such as modes changing character with variation of the angle of the wavevector while the propagation speed remains the same. Further new information is provided by the newly derived classification limits, u±, which act as a form of generalised Alfvén and sound speeds in the dispersion relation.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611284","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":"SLAMS-propelled Electron Acceleration at High-Mach-number Astrophysical Shocks","authors":"Vladimir Zeković, Anatoly Spitkovsky and Zachary Hemler","doi":"10.3847/1538-4357/ade05f","DOIUrl":"https://doi.org/10.3847/1538-4357/ade05f","url":null,"abstract":"Short large-amplitude magnetic structures (SLAMS) are frequently detected during spacecraft crossings over Earth's bow shock. We investigate the existence of such structures at astrophysical shocks, where they could result from the steepening of cosmic-ray (CR) driven waves. Using kinetic particle-in-cell simulations, we study the growth of SLAMS and the appearance of associated transient shocks in the upstream region of parallel, nonrelativistic, high-Mach-number collisionless shocks. We find that high-energy CRs significantly enhance the transverse magnetic field within SLAMS, producing highly inclined field lines. As SLAMS are advected toward the shock, these field lines form an intermittent superluminal configuration that traps magnetized electrons at fast shocks. Due to their oscillatory nature, SLAMS are periodically separated by subluminal gaps with lower transverse magnetic field strength. In these regions, electrons diffuse and accelerate by bouncing between the shock and the approaching SLAMS' region through a mechanism that we call quasi-periodic shock acceleration (QSA). We analytically derive the distribution of electrons accelerated via QSA, f(p) ∼ p[−4.7,−5.7], which agrees well with the simulation spectra. We find that the electron power law remains steep until the end of our longest runs, providing a possible explanation for the steep electron spectra observed at least up to GeV energies in young and fast supernova remnants.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144603041","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":"Bright Bursts with Submillisecond Structures of FRB 20230607A in a Highly Magnetized Environment","authors":"DeJiang Zhou, J. L. Han, Bing Zhang, WeiWei Zhu, Wei-yang Wang, Yuan-Pei Yang, Yuanhong Qu, Yong-Kun Zhang, Yi Yan, Wei-Cong Jing, Shuo Cao, Jintao Xie, Xuan Yang, Shiyan Tian, Ye Li, Dongzi Li, Jia-Rui Niu, Zi-Wei Wu, Qin Wu, Yi Feng, Fayin Wang and Pei Wang","doi":"10.3847/1538-4357/addfdb","DOIUrl":"https://doi.org/10.3847/1538-4357/addfdb","url":null,"abstract":"We report the observations of a repeating FRB 20230607A for 15.6 hr spanning 16 months using the Five-hundred-meter Aperture Spherical Radio Telescope with the detection of 565 bursts. We present three bright bursts with detailed temporal/spectral structures. We also report that one burst carries a narrow component with a width of only 0.3 ms, which is surrounded by broader components. This suggests that repeaters can make both narrow and broad components in one burst. With the narrow spike, we precisely measure the dispersion measure of 362.85 ± 0.15 pc cm−3 and the Faraday rotation measures (RMs) of −12249.0 ± 1.5 rad m−2. We also analyze the statistical distribution of the burst parameters, including waiting times, temporal widths, central frequencies and frequency widths, fluences and energies, all showing typical distributions of known active repeaters. In particular, most bursts show narrow spectra with Δν/ν0 = 0.125 ± 0.001. This fact, together with the narrow 0.3 ms spike, strongly suggests a magnetospheric origin of the FRB emission. Based on a predicted correlation between RM and the luminosity of a persistent radio source (PRS) by Yang et al., we predict that the PRS should have a specific luminosity of the order of 1029 erg s−1 Hz−1 and encourage a search for such a PRS.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611013","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":"MWA and VLA Observations of Diffuse Radio Lobes in M87","authors":"Linhui Wu, Fu-Guo Xie, Qian Zheng, Quan Guo, Huanyuan Shan, Dan Hu, Stefan W. Duchesne, Nick Seymour, Jingying Wang, Junhua Gu, Qingwen Wu, Zhenghao Zhu, Melanie Johnston-Hollitt, Christopher J. Riseley and Xu-Liang Fan","doi":"10.3847/1538-4357/adddb7","DOIUrl":"https://doi.org/10.3847/1538-4357/adddb7","url":null,"abstract":"This study investigates the projected, quasi-symmetric ∼46 kiloparsec-scale diffuse radio lobes surrounding the giant elliptical galaxy M87, utilizing well-sampled wideband (60 MHz–10.55 GHz) observations from the Murchison Widefield Array and Very Large Array, supplemented by data from the Low-frequency Array and Effelsberg. The observed structures feature sharp edges and filaments, with nearly uniform and moderately steep spectral indices (α, mostly within −1.2 ≤ α ≤ −0.8), indicating turbulence. Well-sampled radio spectra for the lobes’ diffuse region are derived using the continuous injection (CI) model (with αinj ≃ −0.86 and νb ≃ 1.72 GHz), and for its three localized regions using the impulsive injection model (e.g., the Jaffe–Perola (JP) model). From energy equipartition analysis, we estimate the typical magnetic field strength in the lobes’ diffuse region to be Beq ≃ 10 μG. The age of the lobes is estimated as ∼30–50 Myr, based on lifetimes derived from the CI and JP models and sound crossing time. Outflow powers of ∼(0.2–2) × 1044 erg s–1 for the lobes’ diffuse components and ∼(1–11) × 1044 erg s–1 for the whole source are calculated. With this power assessment, we conclude that the galactic stellar wind has a negligible effect, and the active galactic nucleus (AGN)-driven jet can provide the necessary energy for the whole system. Furthermore, we argue that while the wind driven by current AGN activity is unlikely to power the lobes’ diffuse components, an average enhancement of AGN activity by a factor of ∼102 over the past ∼30–50 Myr remains plausible.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611014","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 Onset of Feedback in A1885: Evidence for Large-scale Quenching Despite a Young Central Active Galactic Nucleus","authors":"Laurel White, Michael McDonald, Francesco Ubertosi, Massimo Gaspari, Julie Hlavacek-Larrondo, Helen Russell and Taweewat Somboonpanyakul","doi":"10.3847/1538-4357/ade14b","DOIUrl":"https://doi.org/10.3847/1538-4357/ade14b","url":null,"abstract":"We present a new 8.5 ks Chandra observation of A1885 (z = 0.089), obtained as part of the Cluster Evolution Reference Ensemble At Low-z (CEREAL) survey of ∼200 low-z galaxy groups and clusters. These data reveal that A1885 is a strong cool core, with a central cooling time of Gyr, and that the central galaxy hosts an X-ray-luminous point source at its center (L erg s−1), indicative of a rapidly accreting supermassive black hole (SMBH). In the context of the larger CEREAL sample, we constrain the fraction of clusters at z ∼ 0.15 with X-ray-bright (L2−10 > 1042 erg s−1) central active galactic nuclei (AGN) to be no more than 4.1% at 95% confidence. Including radio data from LOFAR, the Giant Metrewave Radio Telescope, ASKAP, and the Very Large Array, spanning 44 MHz–150 GHz, and optical integral field unit data from the Sloan Digital Sky Survey's MaNGA, we probe the details of cooling, feeding, and feedback in this system. These data reveal that cooling of the intracluster medium is highly suppressed on large (>10 kpc) scales despite a central SMBH that is in the early stages of the self-regulation cycle (characterized by rapid accretion, physically small jets, and no large-scale low-frequency radio emission). To reconcile the large-scale quenching with a lack of visible large-scale feedback, we propose that the timescale on which energy is dissipated on large scales (>10 kpc) is significantly longer than the timescale on which black hole feeding operates on small (∼parsec) scales. This interpretation disfavors a model in which the energy is rapidly dissipated (e.g., shocks), which would synchronize the feeding and feedback timescales, and favors a model in which the heating effects of AGN feedback can linger long after the outburst has passed (e.g., turbulent mixing).","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"149 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611015","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":"Spectroastrometry and Reverberation Mapping of Active Galactic Nuclei. II. Measuring Geometric Distances and Black Hole Masses of Four Nearby Quasars","authors":"Yan-Rong Li, Jinyi Shangguan, Jian-Min Wang, Ric Davies, Daryl J. D. Santos, Frank Eisenhauer, Yu-Yang Songsheng, Hartmut Winkler, Jesús Aceituno, Hua-Rui Bai, Jin-Ming Bai, Michael S. Brotherton, Yixian Cao, Yong-Jie Chen, Pu Du, Feng-Na Fang, Jia-Qi Feng, Helmut Feuchtgruber, Natascha M. Förster Schreiber, Yi-Xin Fu, Reinhard Genzel, Stefan Gillessen, Luis C. Ho, Chen Hu, Jun-Rong Liu, Dieter Lutz, Thomas Ott, Romain G. Petrov, Sebastian Rabien, Taro Shimizu, Eckhard Sturm, Linda J. Tacconi, Yi-Lin Wang, Zhu-Heng Yao, Shuo Zhai, Hao Zhang, Yi-Peng Zhao, Yu Zhao and (SARM Collaboration)","doi":"10.3847/1538-4357/addf40","DOIUrl":"https://doi.org/10.3847/1538-4357/addf40","url":null,"abstract":"The geometric distances of active galactic nuclei (AGNs) are challenging to measure because of their exceptionally compact structure, yet vast cosmic distances. A combination of spectroastrometry and reverberation mapping (SARM) of broad-line regions (BLRs) constitutes a novel means to probe the geometric distance of AGNs, which has recently become practically feasible owing to successful interferometric observations with the Very Large Telescope Interferometer/GRAVITY. Here, we perform SARM analysis of four nearby quasars: Mrk 509, PDS 456, 3C 273, and NGC 3783. Results for the former two are reported for the first time, and the latter two are revisited using our improved BLR dynamical modeling that includes the radial-dependent responsivity of BLRs. This allows us to self-consistently account for the emissivity weighting of the BLR in spectroastrometry and responsivity weighting in reverberation mapping. We obtain angular-diameter distances of the four quasars, from which we derive a Hubble constant of . Although this constitutes a large uncertainty for a measurement of H0, it is anticipated that the precision will improve to a competitive level once a greater number of AGNs are accessible following the upgrade of GRAVITY in the near future. From SARM analysis, the black hole masses of the four quasars are also measured with the statistical uncertainty ranging from 0.06 to 0.23 dex, consistent with the correlations between black hole masses and properties of the host bulges.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611030","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":"Coronal Magnetometry with EUV Permitted Lines","authors":"Nataliia G. Shchukina, Javier Trujillo Bueno, Supriya Hebbur Dayananda, Rafael Manso Sainz and Andrii V. Sukhorukov","doi":"10.3847/1538-4357/addc61","DOIUrl":"https://doi.org/10.3847/1538-4357/addc61","url":null,"abstract":"A major challenge in solar physics is to obtain empirical information on the magnetic field of the million-degree plasma of the solar corona. To this end, we need observables of the solar radiation sensitive to the coronal magnetic field. The most familiar observables are the polarization signals of visible and near-infrared forbidden lines of highly ionized species and some ultraviolet permitted lines, like hydrogen Lyα. While the coronal radiation in these spectral lines can only be detected for off-limb lines of sight, the coronal radiation from permitted extreme ultraviolet (EUV) lines can be observed also on the solar disk. These coronal lines are mainly collisionally excited, but it has been pointed out that some permitted EUV lines can actually be linearly polarized if their lower level carries atomic alignment, and that their linear polarization is sensitive to the orientation of the coronal magnetic field . Here we theoretically investigate the linear polarization in permitted EUV lines of a variety of ions: Fe x, Fe xi, Fe xiii, Fe xiv, Si ix, and Si x. To this end, we have developed a numerical code, which we have applied to investigate the linear polarization and magnetic sensitivity of many permitted EUV lines in a one-dimensional model of the solar corona, providing a list of the most promising lines to be further investigated for polarimetry with future space telescopes. Our next step will be to extend this work by using state-of-the-art three-dimensional coronal models.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"107 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611283","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":"In Search of the First Stars: An Ultra-compact and Very-low-metallicity Lyα Emitter Deep within the Epoch of Reionization","authors":"Chris J. Willott, Yoshihisa Asada, Kartheik G. Iyer, Jon Judež, Gregor Rihtaršič, Nicholas S. Martis, Ghassan T. E. Sarrouh, Guillaume Desprez, Anishya Harshan, Lamiya Mowla, Gaël Noirot, Giordano Felicioni, Maruša Bradač, Gabe Brammer, Adam Muzzin, Marcin Sawicki, Jacqueline Antwi-Danso, Vladan Markov and Roberta Tripodi","doi":"10.3847/1538-4357/addf49","DOIUrl":"https://doi.org/10.3847/1538-4357/addf49","url":null,"abstract":"We present JWST observations of a gravitationally lensed, extremely metal-poor galaxy at redshift z = 8.203 ± 0.001 from the CANUCS survey. Based on the low oxygen to Balmer line ratios, we infer a gas-phase metallicity of 12 + log(O/H) = 6.85 (1.4% solar), making CANUCS-A370-z8-LAE one of the most metal-poor galaxies known at z > 7. The galaxy has a high Hβ equivalent width of 225 ± 50 Å, small half-light radius of only pc, and high star formation rate density of 50–100 M⊙ yr−1 kpc−2. The galaxy shows high-equivalent-width Lyα emission with an inferred Lyα escape fraction of 0.21 ± 0.05. The high escape fraction of Lyα is likely due to the compact starbursting nature of the galaxy combined with its location in an overdensity traced by at least two other galaxies spectroscopically confirmed to lie within δz = 0.01 that have helped to reionize the environment. The low metallicity of CANUCS-A370-z8-LAE is best explained by a model where infalling metal-poor gas dilutes the interstellar medium, rather than being a young galaxy forming its first stellar populations.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144603040","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":"Correlation Between U/Th and Pb/Os Abundance Ratios and its Application in Nuclear Cosmochronology","authors":"Y. Y. Huang, 黄盈予, Q. Q. Cui, 崔青青, X. H. Wu, 吴鑫辉, S. Q. Zhang and 张双全","doi":"10.3847/1538-4357/ade390","DOIUrl":"https://doi.org/10.3847/1538-4357/ade390","url":null,"abstract":"The abundance ratios of radioactive elements U/Th and stable elements Pb/Os from the r-process are found to have a strong correlation. This correlation is quite robust with respect to astrophysical conditions. The U/Th–Pb/Os correlation is applied to provide customized initial abundance ratios U/Th from the observed abundance ratios Pb/Os for six r-process enhanced metal-poor stars. The ages of these six metal-poor stars are predicted by the U/Th chronometer, which are approximately between 11 and 15 Gyr. Their ages are compatible with the cosmic age of 13.8 billion years predicted from the cosmic microwave background radiation.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611018","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":"Searching for Radio Pulsars in Old Open Clusters from the Parkes Archive","authors":"S. B. Zhang, J. J. Wei, X. Yang, S. Dai, J. S. Wang, L. Toomey, S. Q. Wang, G. Hobbs, X. F. Wu and L. Staveley-Smith","doi":"10.3847/1538-4357/ade802","DOIUrl":"https://doi.org/10.3847/1538-4357/ade802","url":null,"abstract":"Motivated by the discovery of a pulsar in the direction of the old open cluster NGC 6791, we conducted a search for radio pulsars in archival Parkes observations targeting similar old open clusters. We reprocessed 224 observations totalling 75.02 hr from four clusters: Theia 1661, NGC 6259, Pismis 3, and Trumpler 20. Our analysis identified five known pulsars and three new rotating radio transient (RRAT) candidates. By comparing the measured dispersion measures (DMs) with the expected DM values for each cluster derived from YMW16 and NE2001 models, we conclude that most detected sources are likely background pulsars. However, RRAT J1749−25 in Theia 1661 and RRAT J1237−60 in Trumpler 20 have DMs reasonably close to their respective clusters, suggesting possible membership. The association between PSR J1750−2536 and Theia 1661 remains ambiguous due to its intermediate DM. These candidate cluster-associated neutron stars warrant follow-up with more sensitive telescopes such as MeerKAT or the Square Kilometre Array, potentially offering valuable insights into neutron star retention mechanisms and evolution in open cluster environments.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"137 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611020","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}