The Astrophysical Journal Letters最新文献

{"title":"Fine-tuned Supernova or Failed Explosion? Decoding the Origins of the G3425 Binary","authors":"Zsolt Regály, Viktória Fröhlich and József Vinkó","doi":"10.3847/2041-8213/ade9b2","DOIUrl":"https://doi.org/10.3847/2041-8213/ade9b2","url":null,"abstract":"A binary system (G3425) consisting of a massive unseen component and a red giant star on a nearly circular orbit was recently discovered. The formation of such a system is puzzling because orbital stability generally breaks down due to the large mass loss from the system caused by the supernova (SN) explosion while forming the unseen component. Analytical solutions of the variable-mass two-body problem suggest that the explosion should have occurred when the component was close to its apocenter to explain the near-circular remnant system. This provides a strong constraint on the total mass and orbital configuration of the progenitor system. The nearly circular orbit of G3425 rules out Type II SN scenarios and allows only for a fine-tuned SN Ib/c explosion to occur when the secondary was close to its apocenter. Such a scenario, although possible, is highly unlikely. However, the most likely scenario is a failed SN that produced a black hole (BH), for which no additional constraints on the position of the secondary are needed. We propose that the unseen component of G3425 is a mass-gap BH with a mass constrained between the theoretical minimum for failed SN progenitors (4 M⊙) and the observed upper limit (4.4 M⊙). Our analysis can be applied to any wide binary system containing an unseen component on a nearly circular orbit.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144639640","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 Binary Origin for Ultralong-period Radio Pulsars","authors":"Ying-Han Mao, Xiang-Dong Li, Dong Lai, Zhu-Ling Deng and Hao-Ran Yang","doi":"10.3847/2041-8213/ade80c","DOIUrl":"https://doi.org/10.3847/2041-8213/ade80c","url":null,"abstract":"We propose a possible binary evolution model for the formation of ultralong-period pulsars. The model involves two key stages: first, a neutron star (NS) in wide binaries undergoes an effective spin-down phase through wind-fed accretion from its massive stellar companion; second, the supernova explosion of the companion leads to the disruption of the binary system and produces two isolated compact stars. One of the them is the first-born, slowly rotating NS, and our binary and spin evolution calculations show that the spin periods range from ≲0.1 to ≳108 s. This offers a possible formation channel for some of the long-period radio transients. We estimate that the formation rate of such systems in the Milky Way is approximately 10−6 yr−1.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144639635","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":"Observability of Isolated Stellar-mass Black Holes","authors":"Lena Murchikova and Kailash C. Sahu","doi":"10.3847/2041-8213/ade7f8","DOIUrl":"https://doi.org/10.3847/2041-8213/ade7f8","url":null,"abstract":"Stellar-mass black holes (BHs) represent the natural end states of massive stars. It is estimated that 108 stellar-mass BHs are present in the Milky Way galaxy, a significant fraction of which are expected to be isolated. Despite their expected abundance, only about 20 have been detected so far—mostly in binary systems—with just one confirmed isolated black hole (IsoBH) identified via astrometric microlensing. In this study, we investigate the potential for detecting electromagnetic emissions from IsoBHs by generating synthetic model spectra of their emissions in different types of interstellar medium environments. These model spectra are then compared with current observational capabilities. We show that photons emitted by IsoBHs—especially those accreting material in dense environments or within the solar neighborhood—should be readily detectable. However, confidently identifying these sources remains highly challenging. We conclude that a number of IsoBHs must already exist in current astronomical catalogs but have not been identified as such. We outline possible strategies for the detection and identification of IsoBHs using the current and upcoming telescopes.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144639636","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":"CAPERS Observations of Two UV-bright Galaxies at z > 10. More Evidence for Bursting Star Formation in the Early Universe","authors":"Vasily Kokorev, Óscar A. Chávez Ortiz, Anthony J. Taylor, Steven L. Finkelstein, Pablo Arrabal Haro, Mark Dickinson, John Chisholm, Seiji Fujimoto, Julian B. Mu noz, Ryan Endsley, Weida Hu, Lorenzo Napolitano, Stephen M. Wilkins, Hollis B. Akins, Ricardo Amoriín, Caitlin M. Casey, Yingjie Cheng, Nikko J. Cleri, Justin Cole, Fergus Cullen, Emanuele Daddi, Kelcey Davis, Callum T. Donnan, James S. Dunlop, Vital Fernández, Mauro Giavalisco, Norman A. Grogin, Nimish Hathi, Michaela Hirschmann, Jeyhan S. Kartaltepe, Anton M. Koekemoer, Ho-Hin Leung, Ray A. Lucas, Derek McLeod, Casey Papovich, Laura Pentericci, Pablo G. Pérez-González, Rachel S. Somerville, Xin Wang, L. Y. Aaron Yung and Jorge A. Zavala","doi":"10.3847/2041-8213/ade8f5","DOIUrl":"https://doi.org/10.3847/2041-8213/ade8f5","url":null,"abstract":"We present the first results from the CANDELS-Area Prism Epoch of Reionization Survey (CAPERS), utilizing PRISM observations with the JWST/NIRSpec microshutter assembly in the PRIMER-UDS field. With just 14% of the total planned data volume, we spectroscopically confirm two new bright galaxies (MUV ∼ −20.4) at redshifts z = 10.562 ± 0.034 and z = 11.013 ± 0.028. We examine their physical properties, morphologies, and star formation histories, finding evidence for recent bursting star formation in at least one galaxy thanks to the detection of strong rest-frame equivalent width (EW0 ∼ 70 Å) Hγ emission. Combining our findings with previous studies of similarly bright objects at high z, we further assess the role of stochastic star formation processes in shaping early galaxy populations. Our analysis finds that the majority of bright (MUV ≲ −20) spectroscopically confirmed galaxies at z > 10 were likely observed during a starburst episode, characterized by a median star formation rate (SFR) ratio of SFR10/SFR100 ∼ 2, although with substantial scatter of 0.24 dex. Our work also finds tentative evidence that z > 10 galaxies are more preferentially in a bursting phase than similarly bright z ∼ 6 galaxies. We finally discuss the prospects of deeper spectroscopic observations of a statistically significant number of bright galaxies to quantify the true impact of bursting star formation on the evolution of the bright end of the UV luminosity function at these early epochs.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144639637","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":"First Detection of Circular Polarization in Radio Continuum Toward a Massive Protostar","authors":"A. G. Cheriyan, S. Vig, Nirupam Roy, Samir Mandal, C. Carrasco-González, A. Rodríguez-Kamenetzky and A. Pasetto","doi":"10.3847/2041-8213/ade99b","DOIUrl":"https://doi.org/10.3847/2041-8213/ade99b","url":null,"abstract":"Polarization measurements provide strong constraints on magnetic fields in star-forming systems. While magnetic field estimates of a few kG have been obtained near the surfaces of low-mass protostars, there are no analogous measurements in the immediate vicinity of the surface of massive protostars. We report the measurement of radio continuum circular polarization (CP) toward a massive protostar, IRAS 18162–2048, for the first time, using Karl G. Jansky Very Large Array observations. The fractional CP varies between 3% and 5% across the observed frequency range of 4–6 GHz. We consider multiple hypotheses for the production of CP and propose (i) gyrosynchrotron emission and (ii) Faraday conversion due to turbulence in the magnetic medium—both driven by mildly relativistic electrons as plausible mechanisms. We estimate, for the first time, a magnetic field B ≳ 20–35 G close to the massive protostar. The Lorentz factor of the low-energy electrons is estimated to be in the range γmin ∼ 5–7 for gyrosynchrotron emission and 80–100 for Faraday conversion from our observations. The magnetic field estimate can provide important constraints to the formation models of massive stars.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144639638","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":"Cosmic Clues from Amaterasu: Blazar-driven Ultrahigh-energy Cosmic Rays?","authors":"Saikat Das, Srijita Hazra and Nayantara Gupta","doi":"10.3847/2041-8213/ade99f","DOIUrl":"https://doi.org/10.3847/2041-8213/ade99f","url":null,"abstract":"The detection of the Amaterasu event of energy 244 EeV by the Telescope Array, one of the most energetic ultrahigh-energy cosmic rays (UHECRs; E ≳ 0.1 EeV) observed to date, invites scrutiny of its potential source. We investigate whether the nearby blazar PKS 1717+177 at redshift z = 0.137, located within of the reconstructed arrival direction, could explain the event under a proton-primary hypothesis. Using a one-zone jet model, we fit the multiwavelength spectral energy distribution of the source, incorporating both leptonic and hadronic cascade emissions from photohadronic interactions inside the jet. Our model supports a cosmic-ray origin of the very-high-energy (εγ ≳ 100 GeV) γ-ray flux and predicts a subdominant neutrino flux, 1 one order of magnitude lower than from TXS 0506+056. Under Lorentz invariance violation, UHECRs escaping the blazar jet above a specific energy can propagate unattenuated over hundreds of Mpc due to an increase in energy loss length for certain parameter choices. In such a scenario, the Amaterasu event can have a plausible origin from this blazar. Our analysis indicates negligible deflection in the Galactic magnetic field, implying a strong extragalactic magnetic field is required. Our findings provide a compelling multimessenger framework linking UHECRs, γ-rays, and neutrinos and motivate targeted searches by current and future high-energy neutrino telescopes during increased γ-ray or X-ray activity of this blazar.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"669 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144639639","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 ∞ Galaxy: A Candidate Direct-collapse Supermassive Black Hole between Two Massive, Ringed Nuclei","authors":"Pieter van Dokkum, Gabriel Brammer, Josephine F. W. Baggen, Michael A. Keim, Priyamvada Natarajan and Imad Pasha","doi":"10.3847/2041-8213/addcfe","DOIUrl":"https://doi.org/10.3847/2041-8213/addcfe","url":null,"abstract":"We report the discovery of an unusual z = 1.14 object, dubbed the ∞ galaxy, in JWST imaging of the COSMOS field. Its rest-frame near-IR light is dominated by two compact nuclei with stellar masses of ∼1011M⊙ and a projected separation of 10 kpc. Both nuclei have a prominent ring or shell around them, giving the galaxy the appearance of a figure eight or an ∞ symbol. The morphology resembles that of the nearby system II Hz 4, where the head-on collision of two galaxies with parallel disks led to the formation of collisional rings around both of their bulges. Keck spectroscopy, Very Large Array radio data, and Chandra X-ray data show that the ∞ galaxy hosts an actively accreting supermassive black hole (SMBH) with quasar-like radio and X-ray luminosity. Remarkably, the SMBH is not associated with either of the two nuclei but is in between them in both position and radial velocity. Furthermore, from excess emission in the NIRCAM F150W filter, we infer that the SMBH is embedded in an extended distribution of Hα-emitting gas, with a rest-frame equivalent width ranging from 400 Å to 2000 Å. The gas spans the entire width of the system and was likely shocked and compressed at the collision site in a galaxy-scale equivalent of what happened in the bullet cluster. We suggest that the SMBH formed within this gas in the immediate aftermath of the collision, when it was dense and highly turbulent. If corroborated with simulations and follow-up JWST spectroscopy, this would demonstrate that “direct” SMBH formation by a runaway gravitational collapse is possible in extreme conditions.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144629954","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":"Origins of Carbon Dust in a JWST-observed Primeval Galaxy at z ∼ 6.7","authors":"Ambra Nanni, Michael Romano, Darko Donevski, Joris Witstok, Irene Shivaei, Michel Fioc and Prasad Sawant","doi":"10.3847/2041-8213/ade2e5","DOIUrl":"https://doi.org/10.3847/2041-8213/ade2e5","url":null,"abstract":"JADES-GS-z6-0, a high-redshift galaxy (z ∼ 6.7) recently observed as part of the James Webb Space Telescope Advanced Deep Extragalactic Survey (JADES), exhibits a distinct bump in its rest-frame ultraviolet (UV) spectrum indicative of a large quantity of hydrocarbon grains, a sign of rapid metal and dust enrichment in its interstellar medium (ISM). This galaxy serves as an ideal case for examining rapid dust formation processes in the early Universe. We investigated diverse dust production channels from a possible maximal formation redshift of zform ≈ 17, enabling dust contributions from asymptotic giant branch (AGB) stars over the longest possible timescale. Our model simultaneously reproduces key spectral features of JADES-GS-z6-0 such as its Balmer decrement, UV slope, and UV bump. The match is obtained by adopting a star formation history in which a burst at ∼600 Myr accounts for approximately 30% of the galaxy’s final stellar mass. Our findings indicate two pathways for the formation of hydrocarbon grains, such as polycyclic aromatic hydrocarbons (PAHs): (1) efficient dust accretion within the ISM, necessitating a low depletion of metals into dust grains from Type II supernovae (≈10%), or (2) dust production predominantly by Type II supernovae, requiring a high depletion fraction (≈73%) without dust accretion. We further demonstrate that PAHs are unlikely to originate solely from AGB stars or from shattering of large grains in the ISM. The evolution of the UV slope with redshift points to a complex and bursty star formation history for galaxies observed by JADES.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144622282","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":"Hundreds of TESS Exoplanets Might Be Larger than We Thought","authors":"Te Han, Paul Robertson, Timothy D. Brandt, Shubham Kanodia, Caleb Cañas, Avi Shporer, George Ricker and Corey Beard","doi":"10.3847/2041-8213/ade794","DOIUrl":"https://doi.org/10.3847/2041-8213/ade794","url":null,"abstract":"The radius of a planet is a fundamental parameter that probes its composition and habitability. Precise radius measurements are typically derived from the fraction of starlight blocked when a planet transits its host star. The wide-field Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new exoplanets, but its low angular resolution means that the light from a star hosting a transiting exoplanet can be blended with the light from background stars. If not fully corrected, this extra light can dilute the transit signal and result in a smaller measured planet radius. In a study of hundreds of TESS planet discoveries using deblended light curves from our validated methodology, we show that systematically incorrect planet radii are common in the literature: studies using various public TESS photometry pipelines have underestimated the planet radius by a weighted median of 6.1% ± 0.3%, leading to a ∼20% overestimation of planet density. The widespread presence of these biases in the literature has profoundly shaped—and potentially misrepresented—our understanding of the exoplanet population. Addressing these biases will refine the exoplanet mass–radius relation, reshape our understanding of exoplanet atmospheric and bulk composition, and potentially inform prevailing planet formation theories.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144622280","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 Relationship of Stellar Radius Inflation to Rotation and Magnetic Starspots at 10–670 Myr","authors":"Lyra Cao and Keivan G. Stassun","doi":"10.3847/2041-8213/ade875","DOIUrl":"https://doi.org/10.3847/2041-8213/ade875","url":null,"abstract":"Active, low-mass stars are widely observed to have radii that are larger than predicted by standard stellar models. Proposed mechanisms for this radius inflation generally involve stellar magnetism, either in the form of added pressure support in the outer layers or suppression of convection via starspots. We have assembled a large sample of 261 low-mass stars in the young clusters Upper Scorpius, α Persei, Pleiades, and Praesepe (spanning ages 10–670 Myr) for which the data exist to empirically measure the stellar radii, rotation periods, and starspot covering fractions. We find a clear, strong relationship between the degree of radius inflation and stellar rotation as represented by the Rossby number; this inflation–rotation relationship bears striking resemblance to canonical activity–rotation relationships, including both the so-called linear and saturated regimes. We also demonstrate here for the first time that the radius inflation depends directly on the starspot covering fraction. We furthermore find that the stars’ effective temperatures decrease with decreasing Rossby number as well, and that this temperature suppression balances the radius inflation so as to preserve the stellar bolometric luminosity. These relationships are consistent across the age range sampled here, which spans from the pre–main sequence to the zero-age main sequence. The favorable comparison of our findings to the predictions of modern starspot-based stellar evolution models suggests that, while rotation is clearly the underlying driver, magnetism may be the most likely direct cause of the radius inflation phenomenon.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611021","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}