The Astrophysical Journal Letters最新文献

{"title":"An X-Ray Shell Reveals the Supernova Explosion for Galactic Microquasar SS 433","authors":"Yi-Heng Chi, 奕恒 池, Jiahui Huang, 佳辉 黄, Ping Zhou, 平 周, Hua Feng, 骅 冯, Xiang-Dong Li, 向东 李, Sera B. Markoff, Samar Safi-Harb and Laura Olivera-Nieto","doi":"10.3847/2041-8213/ad84ed","DOIUrl":"https://doi.org/10.3847/2041-8213/ad84ed","url":null,"abstract":"How black holes are formed remains an open and fundamental question in astrophysics. Despite theoretical predictions, it lacks observations to understand whether the black hole formation experiences a supernova explosion. Here we report the discovery of an X-ray shell north of the Galactic microquasar SS 433 harboring a stellar-mass black hole spatially associated with radio continuum and polarization emissions and an H i cloud. Its spectrum can be reproduced by a 1 keV underionized plasma, from which the shell is inferred to have been created by a supernova explosion 20–30 kyr ago, and its properties constitute evidence for canonical supernova explosions to create some black holes. Our analysis precludes other possible origins including heated by jets or blown by disk winds. According to the lower mass limit of the compact object in SS 433, we roughly deduced that the progenitor should be more massive than 25 M⊙. The existence of such a young remnant in SS 433 can also lead to new insights into the supercritical accretion in young microquasars and the γ-ray emission of this system. The fallback ejecta may provide accretion materials within tens of thousands of years, while the shock of the supernova remnant may play a crucial role in the cosmic-ray (re)acceleration.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574341","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":"ALMA Observations of Proper Motions of the Dust Clumps in the Protoplanetary Disk MWC 758","authors":"I-Hsuan Genevieve Kuo, Hsi-Wei Yen and Pin-Gao Gu","doi":"10.3847/2041-8213/ad86c1","DOIUrl":"https://doi.org/10.3847/2041-8213/ad86c1","url":null,"abstract":"To study the dust dynamics in the dust-trapping vortices in the protoplanetary disk around MWC 758, we analyzed the 1.3 mm continuum images of the MWC 758 disk obtained with the Atacama Large Millimeter/submillimeter Array in 2017 and 2021. We detect proper motions of 22 mas and 24 mas in the two dust clumps at radii of 0.″32 and 0.″54 in the disk on the plane of the sky, respectively. On the assumption that the dust clumps are located in the disk midplane, the velocities of the observed proper motions along the azimuthal direction of the inner and outer dust clumps are sub- and super-Keplerian, respectively, and both have angular velocities corresponding to the Keplerian angular velocity at a radius of 0.″46 ± 0.″04. This deviation from the Keplerian motion is not expected in the conventional theory of vortices formed by the Rossby wave instability. The observed non-Keplerian proper motions of the dust clumps are unlikely due to the disk warp and eccentricity, nor are they associated with any predicted planets. The two dust clumps are likely spatially coincident with the infrared spirals. In addition, we detect the changes in the intensity profiles of the dust clumps over the 4 yr span. Therefore, we suggest that the observed proper motions are possibly due to changes in the density distributions in the dust clumps caused by their interaction with the spirals in the disk.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579981","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":"PKS 2254+074: A Blazar in Likely Association with the Neutrino Event IceCube-190619A","authors":"Shunhao Ji and Zhongxiang Wang","doi":"10.3847/2041-8213/ad87ea","DOIUrl":"https://doi.org/10.3847/2041-8213/ad87ea","url":null,"abstract":"We report our study of the field of the ≃0.2 PeV neutrino event IC-190619A. This neutrino belongs to Gold events, which more likely have an astrophysical origin. Among the two γ-ray sources within the neutrino’s positional uncertainty region, we find that one of them, the BL Lac–type blazar PKS 2254+074, had a γ-ray flare at the arrival time of the neutrino. The flare is determined to have lasted ∼2.5 yr in a 180 day binned light curve, constructed from the data collected with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. Accompanying the flare, optical and mid-infrared brightening is also seen. In addition, ≥10 GeV high-energy photons from the source have been detected, suggesting a hardening of the emission during the flare. Given both the positional and temporal coincidence of PKS 2254+074 with IC-190619A, we suggest that this blazar is likely another member of a few recently identified (candidate) neutrino-emitting blazars.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"242 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142580019","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":"Unified Theory of Negative and Positive Spectral Lags in the Gamma-Ray Burst Prompt Phase due to Shear Comptonization from a Structured Jet","authors":"Mukesh Kumar Vyas, Asaf Pe’er and Shabnam Iyyani","doi":"10.3847/2041-8213/ad887c","DOIUrl":"https://doi.org/10.3847/2041-8213/ad887c","url":null,"abstract":"Positive spectral lags are commonly observed in gamma-ray burst (GRB) prompt phase where soft photons lag behind hard ones in their spectral studies. In contrast to this pattern, a fraction of GRBs show a negative spectral lag where hard photons arrive later compared to soft photons. Similarly, recent Fermi-Large Area Telescope observations show a late onset of high-energy photons in most GRB observations. A fraction of GRBs show a transition from positive to negative lags. Such negative lags and the spectral lag transition have no convincing explanation. We show that a structured GRB jet with velocity shear naturally produces both positive and negative spectral lags. The high-energy photons gain energy from repeated scattering with shearing layers and subsequently escape from higher altitudes. Hence, these photons are delayed compared to soft photons producing a negative spectral lag. The inner jet has no shear, and a positive lag appears to provide a unified picture of spectral lags in GRBs. The theory predicts a flip in spectral lag from positive to negative within the evolution of the prompt phase. Comparison of the observed lags with the prediction of the theory limits the possible range of GRB jet Lorentz factors to a few tens.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142580012","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":"Triggering the Untriggered: The First Einstein Probe-detected Gamma-Ray Burst 240219A and Its Implications","authors":"Yi-Han Iris Yin, Bin-Bin Zhang, Jun Yang, Hui Sun, Chen Zhang, Yi-Xuan Shao, You-Dong Hu, Zi-Pei Zhu, Dong Xu, Li An, He Gao, Xue-Feng Wu, Bing Zhang, Alberto Javier Castro-Tirado, Shashi B. Pandey, Arne Rau, Weihua Lei, Wei Xie, Giancarlo Ghirlanda, Luigi Piro, Paul O’Brien, Eleonora Troja, Peter Jonker, Yun-Wei Yu, Jie An, Run-Chao Chen, Yi-Jing Chen, Xiao-Fei Dong, Rob Eyles-Ferris, Zhou Fan, Shao-Yu Fu, Johan P. U. Fynbo, Xing Gao, Yong-Feng Huang, Shuai-Qing Jiang, Ya-Hui Jiang, Yashaswi Julakanti, Erik Kuulkers, Qing-Hui Lao, Dongyue Li, Zhi-Xing Ling, Xing Liu, Yuan Liu, Jia-Yu Mou, Xin Pan, Varun, Daming Wei, Qinyu Wu, Muskan Yadav, Yu-Han Yang, Weimin Yuan and Shuang-Nan Zhang","doi":"10.3847/2041-8213/ad8652","DOIUrl":"https://doi.org/10.3847/2041-8213/ad8652","url":null,"abstract":"The Einstein Probe (EP) achieved its first detection and localization of a bright X-ray flare, EP240219a, on 2024 February 19, during its commissioning phase. Subsequent targeted searches triggered by the EP240219a alert identified a faint, untriggered gamma-ray burst (GRB) in the archived data of Fermi Gamma-ray Burst Monitor (GBM), Swift Burst Alert Telescope (BAT), and Insight-HXMT/HE. The EP Wide-field X-ray Telescope (WXT) light curve reveals a long duration of approximately 160 s with a slow decay, whereas the Fermi/GBM light curve shows a total duration of approximately 70 s. The peak in the Fermi/GBM light curve occurs slightly later with respect to the peak seen in the EP/WXT light curve. Our spectral analysis shows that a single cutoff power-law (PL) model effectively describes the joint EP/WXT–Fermi/GBM spectra in general, indicating coherent broad emission typical of GRBs. The model yielded a photon index of ∼–1.70 ± 0.05 and a peak energy of ∼257 ± 134 keV. After detection of GRB 240219A, long-term observations identified several candidates in optical and radio wavelengths, none of which was confirmed as the afterglow counterpart during subsequent optical and near-infrared follow-ups. The analysis of GRB 240219A classifies it as an X-ray-rich GRB (XRR) with a high peak energy, presenting both challenges and opportunities for studying the physical origins of X-ray flashes, XRRs, and classical GRBs. Furthermore, linking the cutoff PL component to nonthermal synchrotron radiation suggests that the burst is driven by a Poynting flux-dominated outflow.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"106 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142580059","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":"Astroparticles from X-Ray Binary Coronae","authors":"K. Fang, Francis Halzen, Sebastian Heinz and John S. Gallagher","doi":"10.3847/2041-8213/ad887b","DOIUrl":"https://doi.org/10.3847/2041-8213/ad887b","url":null,"abstract":"The recent observation of high-energy neutrinos from the Galactic plane implies an abundant population of hadronic cosmic-ray sources in the Milky Way. We explore the role of the coronae of accreting stellar-mass black holes as such astroparticle emitters. We show that the particle acceleration and interaction timescales in the coronal region are tied to the compactness of the X-ray source. Thus, neutrino emission processes may similarly happen in the cores of active galactic nuclei and black hole X-ray binaries (XRBs), despite their drastically different masses and physical sizes. We apply the model to the well-measured XRB Cygnus X-1 and find that the cascaded gamma rays accompanying the neutrino emission naturally explain the GeV emission that only presents during the source’s hard state, while the state-averaged gamma-ray emission explains the LHAASO observation above 20 TeV. We show that XRB coronae could contribute significantly to the Galactic cosmic-ray and Galactic plane neutrino fluxes. Our model predicts variable high-energy neutrino emission from bright Galactic XRBs that may be observed by IceCube and future neutrino observatories.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588640","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":"Hints of New Physics for the Hubble Tension: Violation of Cosmological Principle","authors":"J. P. Hu, X. D. Jia, J. Hu and F. Y. Wang","doi":"10.3847/2041-8213/ad85cf","DOIUrl":"https://doi.org/10.3847/2041-8213/ad85cf","url":null,"abstract":"Discrepancy between the measurements of Hubble constant H0 from the cosmic microwave background and the local distance ladder is the most serious challenge to the standard ΛCDM model. Recent research has pointed out that it might be related with the violation of cosmological principle. Here, we investigate the impact of dipole–monopole correction on the constraints of H0 utilizing the dipole-fitting method based on the ΛCDM model and cosmography method. Our results show that the dipole–monopole correction can reduce the constraints of H0 from a larger value consistent with SH0ES results to a smaller value consistent with Planck results. This finding can effectively alleviate the Hubble tension. Through making redshift tomography and model-independent analyses, we confirm that our findings are independent of the redshift and cosmological model. In addition, the theoretical prediction of H(z)/(1 + z) reconstructed by the constraints of the ΛCDM model with the dipole correction is in agreement with baryon acoustic oscillation (BAO) measurements, including five Dark Energy Spectroscopic Instrument BAOs within the 1σ range except a data point at z = 0.51. Our research suggests that the Hubble tension originates from new physics beyond the standard ΛCDM model, which might lead to a violation of the cosmological principle.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579980","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":"Probing the Low-velocity Regime of Nonradiative Shocks with Neutron Star Bow Shocks","authors":"Stella Koch Ocker and Maren Cosens","doi":"10.3847/2041-8213/ad87cf","DOIUrl":"https://doi.org/10.3847/2041-8213/ad87cf","url":null,"abstract":"Nonradiative shocks accelerate particles and heat astrophysical plasmas. While supernova remnants are the most well-studied example, neutron star (NS) bow shocks are also nonradiative and Balmer dominated. NS bow shocks are likely ubiquitous in the interstellar medium due to their large speeds imparted at birth, and they are thought to be a discrete source population contributing to the Galactic cosmic-ray spectrum. To date, nine NS bow shocks have been directly observed in Hα images. Most of these shocks have been characterized using narrowband Hα imaging and slit spectroscopy, which do not resolve the multicomponent velocity structure of the shocks and their spatial geometry. Here we present integral field spectroscopy of three NS bow shocks: J0742−2822, J1741−2054, and J2225+6535 (the Guitar Nebula). We measure the shock properties simultaneously in four dimensions: the 2D projected shock morphology, the radial velocity structure, and the Hα flux. The broad-to-narrow line ratio (Ib/In) is inferred from radial velocity profiles, and for J1741−2054, the narrow line is detected in multiple regions of the shock. The inferred line ratios and widths suggest that NS bow shocks represent a low-shock velocity regime (V ≲ 200 km s−1) in which Ib/In is high, distinct from the shock regime probed by supernova remnants. Our results illustrate a need for nonradiative shock models at velocities lower than previously considered, which will reveal the electron–ion temperature ratios and particle acceleration efficiencies of these bow shocks.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142580011","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":"Effects of Dust Coagulation on Streaming Instability","authors":"Ka Wai Ho, Hui Li and Shengtai Li","doi":"10.3847/2041-8213/ad8655","DOIUrl":"https://doi.org/10.3847/2041-8213/ad8655","url":null,"abstract":"Streaming instability (SI) in dust has long been thought to be a promising process in triggering planetesimal formation in the protoplanetary disks (PPDs). In this study, we present the first numerical investigation that models the SI in the vertically stratified disk together with the dust coagulation process. Our simulations reveal that, even with the initially small dust sizes, because dust coagulation promotes dust size growth, SI can eventually still be triggered. Specifically, dust coagulation, limited only by dust fragmentation, broadens the parameter boundaries obtained from previous SI studies using single dust species. We describe the various stages of dust dynamics along with their size evolution and explore the impact of different dust fragmentation velocities. Implications of these results for realistic PPDs are also discussed.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574334","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 Polar Vortex Hypothesis: Evolving, Spectrally Distinct Polar Regions Explain Short- and Long-term Light-curve Evolution and Color–Inclination Trends in Brown Dwarfs and Giant Exoplanets","authors":"Nguyen Fuda and Dániel Apai","doi":"10.3847/2041-8213/ad87e9","DOIUrl":"https://doi.org/10.3847/2041-8213/ad87e9","url":null,"abstract":"Recent studies revealed viewing-angle-dependent color and spectral trends in brown dwarfs, as well as long-term photometric variability (∼100 hr). The origins of these trends are yet unexplained. Here, we propose that these seemingly unrelated sets of observations stem from the same phenomenon: the polar regions of brown dwarfs and directly imaged exoplanets are spectrally different from lower-latitude regions, and they evolve over longer timescales, possibly driven by polar vortices. We explore this hypothesis via a spatiotemporal atmosphere model capable of simulating time series and disk-integrated spectra of ultracool atmospheres. We study three scenarios with different spectral and temporal components: a null hypothesis without polar vortex, and two scenarios with polar vortices. We find that the scenarios with polar vortex can explain the observed infrared color–inclination trend and the variability amplitude–inclination trend. The presence of spectrally distinct, time-evolving polar regions in brown dwarfs and giant exoplanet atmospheres raises the possibility that one-dimensional static atmospheric models may be insufficient for reproducing ultracool atmospheres in detail.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"138 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142580026","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}