The Astrophysical Journal Letters最新文献

{"title":"The JCMT BISTRO Survey: Magnetic Fields Align with Orbital Structure in the Galactic Center","authors":"Janik Karoly, Derek Ward-Thompson, Kate Pattle, Steven N. Longmore, James Di Francesco, Anthony Whitworth, Doug Johnstone, Sarah Sadavoy, Patrick M. Koch, Meng-Zhe Yang, Ray Furuya, Xing Lu, Motohide Tamura, Victor P. Debattista, David Eden, Jihye Hwang, Frédérick Poidevin, Bijas N., Szu-Ting Chen, Eun Jung Chung, Simon Coudé, Sheng-Jun Lin, Yasuo Doi, Takashi Onaka, Lapo Fanciullo, Tie Liu, Guangxing Li, Pierre Bastien, Tetsuo Hasegawa, Woojin Kwon, Shih-Ping Lai and Keping Qiu","doi":"10.3847/2041-8213/adbc67","DOIUrl":"https://doi.org/10.3847/2041-8213/adbc67","url":null,"abstract":"We present the magnetic field in the dense material of the Central Molecular Zone (CMZ) of the Milky Way, traced in 850 μm polarized dust emission as part of the James Clerk Maxwell Telescope B-fields in STar-forming Region Observations survey. We observe a highly ordered magnetic field across the CMZ between Sgr B2 and Sgr C that is strongly preferentially aligned with the orbital gas flows within the clouds of the CMZ. We find that the observed relative orientations are nonrandom at a >99% confidence level and are consistent with models in which the magnetic field vectors are aligned within 30° to the gas flows in 3D. The deviations from aligned magnetic fields are most prominent at positive Galactic longitudes, where the CMZ clouds are more massive, denser, and more actively forming stars. Our observed strongly preferentially parallel magnetic field morphology leads us to hypothesize that in the absence of star formation, the magnetic field in the CMZ is entrained in the orbital gas flows around Sgr A*, while gravitational collapse and feedback in star-forming regions can locally reorder the field. This magnetic field behavior is similar to that observed in the CMZ of the nuclear starburst galaxy NGC 253. This suggests that despite its current low star formation rate, the CMZ of the Milky Way is analogous to those of more distant, actively star-forming, galaxies.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143677589","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":"Spectropolarimetry of SN 2023ixf Reveals Both Circumstellar Material and an Aspherical Helium Core","authors":"Manisha Shrestha, Sabrina DeSoto, David J. Sand, G. Grant Williams, Jennifer L. Hoffman, Paul S. Smith, Callum McCall, Justyn R. Maund, Iain A. Steele, Klaas Wiersema, Jennifer E. Andrews, Nathan Smith, Christopher Bilinski, Peter Milne, Ramya M. Anche, K. Azalee Bostroem, Griffin Hosseinzadeh, Jeniveve Pearson, Douglas C. Leonard, Brian Hsu, Yize Dong, 一泽 董, Emily Hoang, Daryl Janzen, Jacob E. Jencson, Saurabh W. Jha, M. J. Lundquist, Darshana Mehta, Nicolás Meza Retamal, Stefano Valenti, Joseph Farah, D. Andrew Howell, Curtis McCully, Megan Newsome, Estefania Padilla Gonzalez, Craig Pellegrino and Giacomo Terreran","doi":"10.3847/2041-8213/adbb63","DOIUrl":"https://doi.org/10.3847/2041-8213/adbb63","url":null,"abstract":"We present multi-epoch optical spectropolarimetric and imaging polarimetric observations of the nearby Type II supernova (SN) 2023ixf discovered in M101 at a distance of 6.85 Mpc. The first imaging polarimetric observations were taken +2.33 days (60085.08 MJD) after the explosion, while the last imaging polarimetric data points (+73.19 and +76.19 days) were acquired after the fall from the light-curve plateau. At +2.33 days there is strong evidence of circumstellar material (CSM) interaction in the spectra and the light curve. A significant level of intrinsic polarization pr = 1.02% ± 0.07% is seen during this phase, which indicates that this CSM is aspherical. We find that the polarization evolves with time toward the interstellar polarization level during the photospheric phase, which suggests that the recombination photosphere is spherically symmetric. There is a jump in polarization (pr = 0.45% ± 0.08% and pr = 0.62% ± 0.08%) at +73.19 and +76.19 days when the light curve falls from the plateau. This is a phase where polarimetric data are sensitive to nonspherical inner ejecta or a decrease in optical depth into the single-scattering regime. We also present spectropolarimetric data that reveal line (de)polarization during most of the observed epochs. In addition, at +14.50 days we see an “inverse P Cygni” profile in the H and He line polarization, which clearly indicates the presence of asymmetrically distributed material overlying the photosphere. The overall temporal evolution of the polarization is typical for Type II SNe, but the high level of polarization during the rising phase has only been observed in SN 2023ixf.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666019","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":"Detection of [C i] Emission in Nebular Spectra of a Peculiar Type Ia Supernova 2022pul","authors":"Jialian Liu, Xiaofeng Wang, Yi Yang, Alexei V. Filippenko, Thomas G. Brink, WeiKang Zheng, Jujia Zhang, Gaici Li and Shengyu Yan","doi":"10.3847/2041-8213/adba61","DOIUrl":"https://doi.org/10.3847/2041-8213/adba61","url":null,"abstract":"SN 2022pul gains special attention due to its possible origin as a super-Chandrasekhar-mass white dwarf (WD) explosion (also called a 03fg-like Type Ia supernova), which shows prominent [O i], [Ne i], and [Ca ii] lines in its late-time spectra taken at ∼+300 days after the time of peak brightness. In this Letter, we present new optical observations of this peculiar object, extending up to over 500 days after peak brightness. In particular, in the t ∼ +515 days spectrum, we identified for the first time the presence of narrow emission from [C i] λλ9824, 9850, which appears asymmetric and quite similar to the accompanied [O i] λ6300 line in strength and profile. Based on the violent merger model that accounts well for previous observations but leaves little carbon in the center of the ejecta, this carbon line can be reproduced by increasing the degree of clumping in the ejecta and setting the carbon mass the same as that of oxygen (∼0.06 M⊙) in the innermost region (≲2000 km s−1). In principle, the central carbon could come from the secondary WD if it is ignited when hit by the shock wave of the explosion of the primary WD and explodes as a Ca-rich supernova, whereas pure deflagration of a super-Chandrasekhar-mass WD can account for such unburnt carbon more naturally.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"95 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143677588","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":"Self-consistent Multidimensional Penrose Process Driven by Magnetic Reconnection","authors":"Filippo Camilloni and Luciano Rezzolla","doi":"10.3847/2041-8213/adbbef","DOIUrl":"https://doi.org/10.3847/2041-8213/adbbef","url":null,"abstract":"Astronomical observations and numerical simulations are providing increasing evidence that resistive effects in plasmas around black holes (BHs) play an important role in determining the phenomenology observed from these objects. In this spirit, we present a general approach to the study of a Penrose process driven by plasmoids that are produced at reconnection sites along current sheets. Our formalism is meant to determine the physical conditions that make a plasmoid-driven Penrose process energetically viable, and can be applied to scenarios that are dominated by matter or magnetic field, that is, in magnetohydrodynamical or force-free descriptions. By exploring reconnection from an axisymmetric but curved surface, our approach can be considered genuinely multidimensional and allows us to explore conditions that are beyond the ones explored so far and that have been restricted to the equatorial plane. Furthermore, it provides a direct contact with numerical simulations of accretion onto BHs, which exhibit an intense reconnection activity outside the equatorial plane. Finally, to describe the kinematics of the plasma self-consistently, we use the well-known configuration of an equilibrium torus with a purely toroidal magnetic field. For such a torus, we discuss the existence of an “ergobelt,” i.e., a nontrivial surface penetrating the ergosphere and acting as a natural site for the occurrence of reconnection, and from where we estimate the energetics of a plasmoid-driven Penrose process.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666018","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":"Discovery of a Low-mass Strong-lens System in SMACS J0723.3−7327","authors":"Limeng Deng, Yiping Shu, Lei Wang, Guoliang Li, Gabriel Bartosch Caminha, Jiang Dong, Zizhao He, Han Qu and Ruibiao Luo","doi":"10.3847/2041-8213/adbae5","DOIUrl":"https://doi.org/10.3847/2041-8213/adbae5","url":null,"abstract":"We report the discovery of an intriguing, low-mass galaxy-scale strong-lens system in the SMACS J0723.3−7327 galaxy cluster. By modeling James Webb Space Telescope imaging and Very Large Telescope Multi-Unit Spectroscopic Explorer spectroscopic data, we find that the lens is cluster member galaxy at z = 0.397 with an Einstein radius of 0 424 ± 0 012, stellar mass of M* = (3.3 ± 0.8) × 1010 M⊙, half-light radius of ∼1 kpc, and central stellar velocity dispersion of 140 ± 6 km s−1. This lens galaxy is one of the few strong lens galaxies known to date that have stellar mass as low as M* ∼ 1010.5 M⊙, offering an exceptional opportunity to peek into the population of low-mass galaxies that has largely remained unexplored in the context of strong-lensing studies. This strong lens system can also assist in assessing the systematic uncertainty in the lens modeling of cluster member galaxies.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661484","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-principles Measurement of Ion and Electron Energization in Collisionless Accretion Flows","authors":"Evgeny A. Gorbunov, Fabio Bacchini, Vladimir Zhdankin, Gregory R. Werner, Mitchell C. Begelman and Dmitri A. Uzdensky","doi":"10.3847/2041-8213/adbca4","DOIUrl":"https://doi.org/10.3847/2041-8213/adbca4","url":null,"abstract":"We present the largest 3D particle-in-cell shearing-box simulations of turbulence driven by the magnetorotational instability, for the first time employing the realistic proton-to-electron mass ratio. We investigate the energy partition between relativistically hot electrons and subrelativistic ions in turbulent accreting plasma, a regime relevant to collisionless, radiatively inefficient accretion flows around supermassive black holes such as those targeted by the Event Horizon Telescope. We provide a simple empirical formula to describe the measured heating ratio between ions and electrons, which can be used for more accurate global modeling of accretion flows with standard fluid approaches such as general-relativistic magnetohydrodynamics.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661486","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":"Decay of Turbulent Upper-hybrid Waves in Weakly Magnetized Solar Wind Plasmas","authors":"F. J. Polanco-Rodríguez, C. Krafft and P. Savoini","doi":"10.3847/2041-8213/adba64","DOIUrl":"https://doi.org/10.3847/2041-8213/adba64","url":null,"abstract":"Large-scale and long-term two-dimensional particle-in-cell simulations of high resolution are performed for the first time to study the dynamics of electrostatic decay of upper-hybrid wave turbulence generated by electron beams into Langmuir/ -mode ( ) waves in weakly to moderately magnetized plasmas, in conditions relevant to type III solar radio bursts. Simulations use parameters characteristic of beam–plasma interactions between ∼0.1 and 1 au. The impact of plasma magnetic field on decay is shown, and magnetic properties of waves are determined. During their energy transport through k wavevector scales, waves undergo several decay cascades, acquiring increasing magnetic energy until they reach electromagnetic -mode dispersion below the plasma frequency. Whereas the impact of magnetic field on decaying waves of large k = ∣k∣ is weak, important differences with respect to the unmagnetized plasma case manifest at small k-scales, where a boundary layer delimiting a spectral domain free of energy is revealed. It prevents decayed waves from reaching the -mode cutoff frequency and a high level of left-handed polarization, and it modifies the conditions for the appearance of modulational instabilities and strong turbulence phenomena at k ∼ 0. Ordinary -mode waves are generated jointly with -mode waves at comparable energy levels, via electromagnetic decay, whereas -mode emissions are much weaker in most cases. These results provide support for the interpretation of observations by satellites such as Parker Solar Probe and Solar Orbiter, and they supply a solid basis for tackling the more complex problem of dynamics of upper-hybrid wave turbulence in magnetized plasmas where random density fluctuations cannot be neglected.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666020","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 Massive H i-absorption-selected Galaxy at z ≈ 2.356","authors":"B. Kaur, N. Kanekar, M. Neeleman, Y. Zhu, J. X. Prochaska, M. Rafelski and G. Becker","doi":"10.3847/2041-8213/adb83d","DOIUrl":"https://doi.org/10.3847/2041-8213/adb83d","url":null,"abstract":"We use the Karl G. Jansky Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array to detect CO(1–0), CO(3–2), and rest-frame 349 GHz continuum emission from an H i-selected galaxy, DLA1020+2733g, at z ≈ 2.3568 in the field of the z = 2.3553 damped Lyα absorber (DLA) toward QSO J1020+2733. The VLA CO(1–0) detection yields a molecular gas mass of (2.84 ± 0.42) × 1011 × (αCO/4.36) M⊙, the largest ever measured in an H i-selected galaxy. The DLA metallicity is +0.28 ± 0.16, from the Zn iiλ2026 absorption line detected in a Keck Echellette Spectrograph and Imager spectrum. This continues the trend of high-metallicity DLAs being frequently associated with massive galaxies. We obtain a star formation rate (SFR) of ≲400 M⊙ yr−1 from the rest-frame 349 GHz continuum emission and a relatively long molecular gas depletion timescale of ≳0.6 Gyr. The excitation of the J = 3 rotational level is subthermal, with , suggesting that DLA1020+2733g has a low SFR surface density. The large velocity spread of the CO lines, ≈500 km s−1, and the long molecular gas depletion timescale suggest that DLA1020+2733g is likely to be a cold rotating-disk galaxy.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661405","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":"3D MC. I. X-Ray Tomography Begins to Unravel the 3D Structure of a Molecular Cloud in our Galaxy’s Center","authors":"Samantha W. Brunker, Cara Battersby, Danya Alboslani, Maïca Clavel, Daniel L. Walker, Dani Lipman, H Perry Hatchfield and Régis Terrier","doi":"10.3847/2041-8213/adba5e","DOIUrl":"https://doi.org/10.3847/2041-8213/adba5e","url":null,"abstract":"Astronomers have used observations of the Galactic gas and dust via infrared, microwave, and radio to study molecular clouds in extreme environments such as the Galactic center. More recently, X-ray telescopes have opened up a new wavelength range in which to study these molecular clouds. Previous flaring events from Sgr A* propagate X-rays outwards in all directions, and these X-rays interact with the surrounding molecular gas, illuminating different parts of the clouds over time. We use a combination of X-ray observations from Chandra and molecular gas tracers (line data from Herschel and the Submillimeter Array) to analyze specific features in the Sticks cloud, one of three clouds in the Three Little Pigs system in the Central Molecular Zone (Galactic longitude and latitude of 0 106 and −0 082 respectively). We also present a novel X-ray tomography method we used to create 3D map of the Sticks cloud. By combining X-ray and molecular tracer observations, we are able to learn more about the environment inside the Sticks cloud.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661485","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":"Upper Limits on the Mass of Cool Gas in the Circumgalactic Medium of Dwarf Galaxies","authors":"Yakov Faerman, Yong Zheng, 永 郑 and Benjamin D. Oppenheimer","doi":"10.3847/2041-8213/adba51","DOIUrl":"https://doi.org/10.3847/2041-8213/adba51","url":null,"abstract":"We use H i absorption measurements to constrain the amount of cool (≈104 K), photoionized gas in the circumgalactic medium (CGM) of dwarf galaxies with M* = 106.5−9.5M⊙ in the nearby Universe (z < 0.3). We show analytically that volume-filling gas gives an upper limit on the gas mass needed to reproduce a given H i column density profile. We introduce a power-law density profile for the gas distribution and fit our model to archival H i observations to infer the cool CGM gas mass, McCGM, as a function of halo mass. For volume-filling (fV = 1) models, we find McCGM = 5 × 108–2 × 109M⊙, constituting ≲10% of the halo baryon budget. For clumpy gas, with fV = 0.01, the masses are a factor of ≈11 lower, in agreement with our analytic approximation. Our assumption that the measured H i forms entirely in the cool CGM provides a conservative upper limit on McCGM, and possible contributions from the intergalactic medium or warm/hot CGM will further strengthen our result. We estimate the mass uncertainties due to the range of redshifts in our sample and the unknown gas metallicity to be ≈15% and ≈10%, respectively. Our results show that dwarf galaxies have only ≲15% of their baryon budget in stars and the cool CGM, with the rest residing in the warm/hot CGM or ejected from the dark matter halos.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661480","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}