Astrophysical Journal Letters最新文献

{"title":"Production of ⁴⁴Ti and Iron-group Nuclei in the Ejecta of 3D Neutrino-driven Supernovae","authors":"Andre Sieverding, Daniel Kresse, Hans-Thomas Janka","doi":"10.3847/2041-8213/ad045b","DOIUrl":"https://doi.org/10.3847/2041-8213/ad045b","url":null,"abstract":"Abstract The radioactive isotopes 44 Ti and 56 Ni are important products of explosive nucleosynthesis, which play a key role in supernova (SN) diagnostics and have been detected in several nearby young SN remnants. However, most SN models based on nonrotating single stars predict yields of 44 Ti that are much lower than the values inferred from observations. We present, for the first time, the nucleosynthesis yields from a self-consistent three-dimensional SN simulation of a ∼19 M ⊙ progenitor star that reaches an explosion energy comparable to that of SN 1987A and that covers the evolution of the neutrino-driven explosion until more than 7 s after core bounce. We find a significant enhancement of the Ti/Fe yield compared to recent spherically symmetric (1D) models and demonstrate that the long-time evolution is crucial to understanding the efficient production of 44 Ti due to the nonmonotonic temperature and density history of the ejected material. Additionally, we identify characteristic signatures of the nucleosynthesis in proton-rich ejecta, in particular high yields of 45 Sc and 64 Zn.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"24 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135510490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constraining the Jet Composition of GRB 221009A with the Prompt TeV Emission Limit","authors":"Cui-Yuan Dai, Xiang-Yu Wang, Ruo-Yu Liu, Bing Zhang","doi":"10.3847/2041-8213/ad0720","DOIUrl":"https://doi.org/10.3847/2041-8213/ad0720","url":null,"abstract":"Abstract Recent LHAASO observations of the prompt emission phase of the brightest-of-all-time GRB 221009A imposes a stringent limit on the flux ratio between the TeV and MeV emissions, F TeV / F MeV ≤ 2 × 10 −5 , during the period 220–230 s after the trigger. This period covers the peak of the main MeV burst and is just before the TeV afterglow emerges. Within the framework of internal shocks, we study the internal γγ absorption in GRB 221009A by generating a set of synthetic bursts in a simulation that reproduces the observed feature of GRB 221009A. We find that the γγ absorption does not lead to an exponential cutoff, but rather a power-law spectrum, consistent with previous works. We further find that the attenuation due to γγ absorption alone cannot explain the flux limit ratio of GRB 221009A, suggesting a low ratio between synchrotron self-Compton (SSC) and synchrotron emission outputs. This requires the magnetic field energy density to be much larger than the synchrotron photon energy density so that the SSC flux is greatly suppressed. This indicates that the jet composition of GRB 221009A is likely Poynting flux dominated.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"114 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135610074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"JWST Constraints on the UV Luminosity Density at Cosmic Dawn: Implications for 21 cm Cosmology","authors":"Sultan Hassan, Christopher C Lovell, Piero Madau, Marc Huertas-Company, Rachel S Somerville, Blakesley Burkhart, Keri L Dixon, Robert Feldmann, Tjitske K Starkenburg, John F Wu, Christian Kragh Jespersen, Joseph D Gelfand, Ankita Bera","doi":"10.3847/2041-8213/ad0239","DOIUrl":"https://doi.org/10.3847/2041-8213/ad0239","url":null,"abstract":"Abstract An unprecedented array of new observational capabilities are starting to yield key constraints on models of the epoch of first light in the Universe. In this Letter we discuss the implications of the UV radiation background at cosmic dawn inferred by recent JWST observations for radio experiments aimed at detecting the redshifted 21 cm hyperfine transition of diffuse neutral hydrogen. Under the basic assumption that the 21 cm signal is activated by the Ly α photon field produced by metal-poor stellar systems, we show that a detection at the low frequencies of the EDGES and SARAS3 experiments may be expected from a simple extrapolation of the declining UV luminosity density inferred at z ≲ 14 from JWST early galaxy data. Accounting for an early radiation excess above the cosmic microwave background suggests a shallower or flat evolution to simultaneously reproduce low- and high- z current UV luminosity density constraints, which cannot be entirely ruled out, given the large uncertainties from cosmic variance and the faint-end slope of the galaxy luminosity function at cosmic dawn. Our findings raise the intriguing possibility that a high star formation efficiency at early times may trigger the onset of intense Ly α emission at redshift z ≲ 20 and produce a cosmic 21 cm absorption signal 200 Myr after the Big Bang.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"248 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136132973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"JWST Reveals Excess Cool Water near the Snow Line in Compact Disks, Consistent with Pebble Drift","authors":"Andrea Banzatti, Klaus M. Pontoppidan, John S. Carr, Evan Jellison, Ilaria Pascucci, Joan R. Najita, Carlos E. Muñoz-Romero, Karin I. Öberg, Anusha Kalyaan, Paola Pinilla, Sebastiaan Krijt, Feng Long, Michiel Lambrechts, Giovanni Rosotti, Gregory J. Herczeg, Colette Salyk, Ke Zhang, Edwin A. Bergin, Nicholas P. Ballering, Michael R. Meyer, Simon Bruderer","doi":"10.3847/2041-8213/acf5ec","DOIUrl":"https://doi.org/10.3847/2041-8213/acf5ec","url":null,"abstract":"Abstract Previous analyses of mid-infrared water spectra from young protoplanetary disks observed with the Spitzer-IRS found an anticorrelation between water luminosity and the millimeter dust disk radius observed with ALMA. This trend was suggested to be evidence for a fundamental process of inner disk water enrichment proposed decades ago to explain some properties of the solar system, in which icy pebbles drift inward from the outer disk and sublimate after crossing the snow line. Previous analyses of IRS water spectra, however, were uncertain due to the low spectral resolution that blended lines together. We present new JWST-MIRI spectra of four disks, two compact and two large with multiple radial gaps, selected to test the scenario that water vapor inside the snow line is regulated by pebble drift. The higher spectral resolving power of MIRI-MRS now yields water spectra that separate individual lines, tracing upper level energies from 900 to 10,000 K. These spectra clearly reveal excess emission in the low-energy lines in compact disks compared to large disks, demonstrating an enhanced cool component with T ≈ 170–400 K and equivalent emitting radius R eq ≈ 1–10 au. We interpret the cool water emission as ice sublimation and vapor diffusion near the snow line, suggesting that there is indeed a higher inward mass flux of icy pebbles in compact disks. Observation of this process opens up multiple exciting prospects to study planet formation chemistry in inner disks with JWST.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"37 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135564276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"VVV-WIT-12 and Its Fashionable Nebula: A 4 yr Long-period Young Stellar Object with a Light Echo?","authors":"Roberto K. Saito, Bringfried Stecklum, Dante Minniti, Philip W. Lucas, Zhen Guo, Leigh C. Smith, Luciano Fraga, Felipe Navarete, Juan Carlos Beamín, Calum Morris","doi":"10.3847/2041-8213/ad07e6","DOIUrl":"https://doi.org/10.3847/2041-8213/ad07e6","url":null,"abstract":"Abstract We report the serendipitous discovery of VVV-WIT-12, an unusual variable source that seems to induce variability in its surrounding nebula. The source belongs to the rare objects that we call WITs (short for What Is This?) discovered within the VISTA Variables in the Vía Láctea (VVV) survey. VVV-WIT-12 was discovered during a pilot search for light echoes from distant supernovae in the Milky Way using the near-IR images of the VVV survey. This source has an extremely red spectral energy distribution, consistent with a very reddened ( A V ∼ 100 mag) long-period variable star ( P ∼ 1525 days). Furthermore, it is enshrouded in a nebula that changes brightness and color with time, apparently in sync with the central source variations. The near-IR light curve and complementary follow-up spectroscopy observations are consistent with a variable young stellar object illuminating its surrounding nebula. In this case the source periodic variation along the cycles produces an unprecedented light echo in the different regions of the nebula.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"32 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135763512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Is the M81 Fast Radio Burst Host Globular Cluster Special?","authors":"Kristen C. Dage, Arash Bahramian, Clancy W. James, Arunav Kundu, Katherine L. Rhode, Jay Strader, Enrico Vesperini, Stephen E. Zepf","doi":"10.3847/2041-8213/ad03e4","DOIUrl":"https://doi.org/10.3847/2041-8213/ad03e4","url":null,"abstract":"Abstract We use multiband archival Hubble Space Telescope (HST) observations to measure the photometric and structural parameters of the M81 globular cluster (GC) that hosts the fast radio burst FRB 20200120E. Our best-fitting King model has an effective radius r h = 3.06 pc with a moderate King model concentration of c = 53, and an inferred core radius of 0.81 pc. We revisit the exact astrometric location of the FRB within the cluster, and find that FRB 20200120E is located 1.92 pc from the center, but within the projected half-light radius. We estimate the relative encounter rate of the FRB host, along with the corresponding rates of 210 other GCs in M81, and compare these values with the encounter rates of Galactic GCs. The FRB resides in a GC with an encounter rate that is moderately higher than the median stellar encounter rate in our two comparison samples. While the estimated encounter rate of the FRB host cluster (e.g., ∼50% of a cluster like 47 Tuc) is sufficient to allow the possibility that the FRB formed dynamically, our results do not place strong constraints on this scenario due to the limitations of the available HST data and the possible systematic uncertainties and selection effects in the comparison data.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"13 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135410476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kinematical Fluctuations Vary with Galaxy Surface Mass Density","authors":"Ze-Hao Zhong, Gang Zhao, Hans-Walter Rix, Luis C. Ho","doi":"10.3847/2041-8213/acffca","DOIUrl":"https://doi.org/10.3847/2041-8213/acffca","url":null,"abstract":"Abstract The Galaxy inner parts are generally considered to be optically symmetric, as well as kinematically symmetric for most massive early-type galaxies. At the lower-mass end, many galaxies contain lots of small patches in their velocity maps, causing their kinematics to be nonsmooth in small scales and far from symmetry. These small patches can easily be mistaken for measurement uncertainties and have not been well discussed. We used the comparison of observations and numerical simulations to demonstrate the small patches existence beyond uncertainties. For the first time we have found that the fluctuation degrees have an approximate inverse loglinear relation with the galaxy stellar surface mass densities. This tight relation among galaxies that do not show obvious optical asymmetry that traces environmental perturbations indicates that stellar motion in galaxies has inherent asymmetry besides external environment influences. The degree of the kinetic asymmetry is closely related to and constrained by the intrinsic properties of the host galaxy.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135412204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"UNCOVER: Illuminating the Early Universe—JWST/NIRSpec Confirmation of z &gt; 12 Galaxies","authors":"Bingjie 冰洁 Wang 王, Seiji Fujimoto, Ivo Labbé, Lukas J. Furtak, Tim B. Miller, David J. Setton, Adi Zitrin, Hakim Atek, Rachel Bezanson, Gabriel Brammer, Joel Leja, Pascal A. Oesch, Sedona H. Price, Iryna Chemerynska, Sam E. Cutler, Pratika Dayal, Pieter van Dokkum, Andy D. Goulding, Jenny E. Greene, Y. Fudamoto, Gourav Khullar, Vasily Kokorev, Danilo Marchesini, Richard Pan, John R. Weaver, Katherine E. Whitaker, Christina C. Williams","doi":"10.3847/2041-8213/acfe07","DOIUrl":"https://doi.org/10.3847/2041-8213/acfe07","url":null,"abstract":"Abstract Observations of high-redshift galaxies provide a critical direct test to the theories of early galaxy formation, yet to date, only three have been spectroscopically confirmed at z &gt; 12. Due to strong gravitational lensing over a wide area, the galaxy cluster field A2744 is ideal for searching for the earliest galaxies. Here we present JWST/NIRSpec observations of two galaxies: a robust detection at <?CDATA ${z}_{mathrm{spec}}={12.393}_{-0.001}^{+0.004}$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:msub> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>spec</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>12.393</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.001</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.004</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> , and a plausible candidate at <?CDATA ${z}_{mathrm{spec}}={13.079}_{-0.001}^{+0.013}$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:msub> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>spec</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>13.079</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.001</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.013</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> . The galaxies are discovered in JWST/NIRCam imaging and their distances are inferred with JWST/NIRSpec spectroscopy, all from the JWST Cycle 1 UNCOVER Treasury survey. Detailed stellar population modeling using JWST NIRCam and NIRSpec data corroborates the primeval characteristics of these galaxies: low mass (∼10 8 M ⊙ ), young, rapidly assembling, metal-poor, and star-forming. Interestingly, both galaxies are spatially resolved, having lensing-corrected rest-UV effective radii on the order of 300–400 pc, which are notably larger than other spectroscopically confirmed systems at similar redshifts. The observed dynamic range of z ≳ 10 sizes spans over 1 order of magnitude, implying a significant scatter in the size–mass relation at early times. Deep into the epoch of reionization, these discoveries elucidate the emergence of the first galaxies.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"16 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135714734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AC Her: Evidence of the First Polar Circumbinary Planet","authors":"Rebecca G. Martin, Stephen H. Lubow, David Vallet, Narsireddy Anugu, Douglas R. Gies","doi":"10.3847/2041-8213/ad0730","DOIUrl":"https://doi.org/10.3847/2041-8213/ad0730","url":null,"abstract":"Abstract We examine the geometry of the post–asymptotic giant branch (AGB) star binary AC Her and its circumbinary disk. We show that the observations describe a binary orbit that is perpendicular to the disk with an angular momentum vector that is within 9° of the binary eccentricity vector, meaning that the disk is close to a stable polar alignment. The most likely explanation for the very large inner radius of the dust is a planet within the circumbinary disk. This is therefore both the first reported detection of a polar circumbinary disk around a post-AGB binary and the first evidence of a polar circumbinary planet. We consider the dynamical constraints on the circumbinary disk size and mass. The polar circumbinary disk feeds circumstellar disks with gas on orbits that are highly inclined with respect to the binary orbit plane. The resulting circumstellar disk inclination could be anywhere from coplanar to polar depending upon the competition between the mass accretion and binary torques.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"24 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135516061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dwindling Surface Cooling of a Rotating Jovian Planet Leads to a Convection Zone That Grows to a Finite Depth","authors":"Bradley W. Hindman, J. R. Fuentes","doi":"10.3847/2041-8213/ad0642","DOIUrl":"https://doi.org/10.3847/2041-8213/ad0642","url":null,"abstract":"Abstract Recent measurements of Jupiter's gravitational field (by Juno) and seismology of Saturn's rings (by Cassini) strongly suggest that both planets have a stably stratified core that still possesses a primordial gradient in the concentration of heavy elements. The existence of such a “diffusely” stratified core has been a surprise as it was long expected that the Jovian planets should be fully convective and hence fully mixed. A vigorous zone of convection, driven by surface cooling, forms at the surface and deepens through entrainment of fluid from underneath. In fact, it was believed that this convection zone should grow so rapidly that the entire planet would be consumed in less than a million years. Here we suggest that two processes, acting in concert, present a solution to this puzzle. All of the giant planets are rapidly rotating and have a cooling rate that declines with time. Both of these effects reduce the rate of fluid entrainment into the convection zone. Through the use of an analytic prescription of entrainment in giant planets, we demonstrate that these two effects, rotation and dwindling surface cooling, result in a convection zone that initially grows but eventually stalls. The depth to which the convective interface asymptotes depends on the rotation rate and on the stratification of the stable interior. Conversely, in a nonrotating planet, or in a planet that maintains a higher level of cooling than current models suggest, the convection zone deepens forever, eventually spanning the entire planet.","PeriodicalId":55567,"journal":{"name":"Astrophysical Journal Letters","volume":"43 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135509598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}