1,130 research outputs found

    The persistent shadow of the supermassive black hole of M 87

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    In April 2019, the Event Horizon Telescope (EHT) Collaboration reported the first-ever event-horizon-scale images of a black hole, resolving the central compact radio source in the giant elliptical galaxy M 87. These images reveal a ring with a southerly brightness distribution and a diameter of ∼42 μas, consistent with the predicted size and shape of a shadow produced by the gravitationally lensed emission around a supermassive black hole. These results were obtained as part of the April 2017 EHT observation campaign, using a global very long baseline interferometric radio array operating at a wavelength of 1.3 mm. Here, we present results based on the second EHT observing campaign, taking place in April 2018 with an improved array, wider frequency coverage, and increased bandwidth. In particular, the additional baselines provided by the Greenland telescope improved the coverage of the array. Multiyear EHT observations provide independent snapshots of the horizon-scale emission, allowing us to confirm the persistence, size, and shape of the black hole shadow, and constrain the intrinsic structural variability of the accretion flow. We have confirmed the presence of an asymmetric ring structure, brighter in the southwest, with a median diameter of 43.3−3.1+1.5 μas. The diameter of the 2018 ring is remarkably consistent with the diameter obtained from the previous 2017 observations. On the other hand, the position angle of the brightness asymmetry in 2018 is shifted by about 30° relative to 2017. The perennial persistence of the ring and its diameter robustly support the interpretation that the ring is formed by lensed emission surrounding a Kerr black hole with a mass ∼6.5 × 109 M⊙. The significant change in the ring brightness asymmetry implies a spin axis that is more consistent with the position angle of the large-scale jet

    PHANGS-JWST first results: a combined HST and JWST analysis of the nuclear star cluster in NGC 628

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    © 2023. The Author(s). Artículo firmado por 32 autores. This research is based on observations made with the NASA/ESA Hubble Space Telescope obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 526555. These observations are associated with program 15654. This work is based on observations made with the NASA/ESA/CSA JWST. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127. The observations are associated with JWST program 02107. This research has made use of the Spanish Virtual Observatory (https://svo.cab.intacsic.es) project funded by MCIN/AEI/10.13039/ 501100011033/ through grant PID2020-112949GB-I00. N.H. and A.W.H.K. are fellows of the International Max Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg (IMPRS-HD) and acknowledge their support. N.H. acknowledges support from Thomas Müller (HdA/MPIA) with generating part of Figure 1 and Katja Fahrion and Torsten Böker for useful discussions. A.T.B. and F.B. would like to acknowledge funding from the European Research Council (ERC) under the European Unionʼs Horizon 2020 research and innovation program (grant agreement No. 726384/Empire). E.J.W. acknowledges the funding provided by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project-ID 138713538—SFB 881 (“The Milky Way System,” subproject P1) T.G.W. and J.N. acknowledge funding from the European Research Council (ERC) under the European Unionʼs Horizon 2020 research and innovation program (grant agreement No. 694343). J.M.D.K. gratefully acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program via the ERC Starting Grant MUSTANG (grant agreement No. 714907). COOL Research DAO is a Decentralized Autonomous Organization supporting research in astrophysics aimed at uncovering our cosmic origins. R.S.K. acknowledges funding from the European Research Council via the ERC Synergy Grant “ECOGAL” (project ID 855130), the Deutsche Forschungsgemeinschaft (DFG) via the Collaborative Research Center “The Milky Way System” (SFB 881—funding ID 138713538—subprojects A1, B1, B2 and B8), and the Heidelberg Cluster of Excellence (EXC 2181-390900948) “STRUCTURES,” funded by the German Excellence Strategy. R.S.K. also thanks the German Ministry for Economic Affairs and Climate Action for funding in the project “MAINN” (funding ID 50OO2206). E.R. acknowledges the support of the Natural Sciences and Engineering Research Council of Canada (NSERC), funding reference No. RGPIN-2022-03499. M.B. acknowledges support from FONDECYT regular grant 1211000 and by ANID BASAL project FB210003. K.G. is supported by the Australian Research Council through the Discovery Early Career Researcher Award (DECRA) Fellowship DE220100766 funded by the Australian Government. K.G. is supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) through project No. CE170100013. F.N.-L. gratefully acknowledges the sponsorship provided by the Federal Ministry for Education and Research of Germany through the Alexander von Humboldt Foundation. P.S.B. acknowledges financial support from MCIN/AEI/10.13039/501100011033 under grant PID2019-107427GB-C31 A.K.L. gratefully acknowledges support by grants 1653300 and 2205628 from the National Science Foundation, award JWST-GO-02107.009-A, and a Humboldt Research Award from the Alexander von Humboldt Foundation. G.A.B. acknowledges the support from ANID Basal project FB210003.We combine archival Hubble Space Telescope and new James Webb Space Telescope imaging data covering the ultraviolet to mid-infrared regime to morphologically analyze the nuclear star cluster (NSC) of NGC 628, a granddesign spiral galaxy. The cluster is located in a 200 pc × 400 pc cavity lacking both dust and gas. We find roughly constant values for the effective radius (r_(eff) ∼ 5 pc) and ellipticity (∈ ∼ 0.05), while the Sérsic index (n) and position angle (PA) drop from n ∼ 3 to ∼2 and PA ∼ 130° to 90°, respectively. In the mid-infrared, r_(eff) ∼ 12 pc, ∈ ∼ 0.4, and n ∼ 1–1.5, with the same PA ∼ 90°. The NSC has a stellar mass of log_(10) (M^(nsc)_(*) / M_(ꙩ) = 7.06 0.31, as derived through B − V, confirmed when using multiwavelength data, and in agreement with the literature value. Fitting the spectral energy distribution (SED), excluding the mid-infrared data, yields a main stellar population age of (8 ± 3) Gyr with a metallicity of Z = 0.012 ± 0.006. There is no indication of any significant star formation over the last few gigayears. Whether gas and dust were dynamically kept out or evacuated from the central cavity remains unclear. The best fit suggests an excess of flux in the mid-infrared bands, with further indications that the center of the mid-infrared structure is displaced with respect to the optical center of the NSC. We discuss five potential scenarios, none of them fully explaining both the observed photometry and structure.Depto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEAssociation of Universities for Research in Astronomy, Inc., under NASA contractAssociation of Universities for Research in Astronomy, Inc., under NASA contractSpanish Virtual Observatory funded by MCIN/AEI/10.13039/ 501100011033/International Max Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg (IMPRS-HD)Thomas Müller (HdA/MPIA)European Research Council (ERC) under the European Unionʼs Horizon 2020Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)European Research Council via the ERC SynergyDeutsche Forschungsgemeinschaft (DFG) via the Collaborative Research Center “The Milky Way System”Heidelberg Cluster of Excellence “STRUCTURES,” funded by the German Excellence StrategyGerman Ministry for Economic Affairs and Climate ActionNatural Sciences and Engineering Research Council of Canada (NSERC)Australian Research Council through the Discovery Early Career Researcher Award (DECRA)Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D)Federal Ministry for Education and Research of Germany through the Alexander von Humboldt FoundationMCIN/AEI/10.13039/501100011033National Science FoundationAlexander von Humboldt FoundationANID Basal projectpu

    2023-2024 Graduate School Catalog

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    You and your peers represent more than 67 countries and your shared scholarship spans 140 programs - from business administration and biomedical engineering to history, horticulture, musical performance, marine science, and more. Your ideas and interests will inform public health, create opportunities for art and innovation, contribute to the greater good, and positively impact economic development in Maine and beyond

    The Politics of Platformization: Amsterdam Dialogues on Platform Theory

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    What is platformization and why is it a relevant category in the contemporary political landscape? How is it related to cybernetics and the history of computation? This book tries to answer such questions by engaging in multidisciplinary dialogues about the first ten years of the emerging fields of platform studies and platform theory. It deploys a narrative and playful approach that makes use of anecdotes, personal histories, etymologies, and futurable speculations to investigate both the fragmented genealogy that led to platformization and the organizational and economic trends that guide nowadays platform sociotechnical imaginaries

    Физика космоса : труды 50-й Международной студенческой научной конференции (Екатеринбург, 30 января — 3 февраля. 2023 г.)

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    В сборнике представлены доклады и сообщения студенческой научной конференции, которая ежегодно проводится в Астрономической обсерватории Уральского федерального университета. Цель конференции — обобщить достижения в области астрономии и астрофизики и способствовать формированию навыков и способностей молодых исследователей. Сборник предназначен для профессиональных астрономов и физиков, студентов и аспирантов соответствующих специальностей.Отдел по делам молодежи администрации Октябрьского района г. Екатеринбурга; Уральский федеральный университет имени первого Президента России Б.Н. Ельцин

    Learning with Astronomy: Neural Network Studies of Galaxy Evolution and Inspiring, Skill Based Learning

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    This study focuses on two different types of learning that can be derived from as-tronomy: machine learning to examine galaxies and inform their evolution, andusing astronomy as an inspiring vehicle to develop skills useful to underrepresentedaudiences.Upcoming large-area narrow-band photometric surveys will observe a largenumber of galaxies efficiently. However, it will be computationally challenging toanalyse the stellar populations of galaxies from such big data to investigate theirformation and evolutionary histories. We have applied a convolutional neural net-work (CNN) technique to retrieve the metallicity and age from narrow-band dataefficiently. The CNN was trained using synthetic photometry from the integral fieldunit spectra and the age and metallicity obtained from spectral analysis. We showthat our CNN model can recover age and metallicity from narrow-band data. Wealso find that the diversity of the dataset for training the CNN has a significant im-pact on the accuracy of its predictions. Hence, future applications of CNNs requirehigh quality spectroscopic data from a diverse population of galaxies.This study also presents a way to use astronomy to engage with the novel au-dience of jobseekers to co-create a mutually beneficial method of engagement. Weworked with people looking for work in the cultural sector. We ran an online sur-vey to assess participants’ interest in science and what career-relevant skills theydesired. We found that many of the skills which our participants are interested inare aligned with skills needed for astronomy research. Though our participants feltdisconnected from science they still maintained an interest in learning about astron-omy. We also ran a co-creation session to collaboratively create a skills-focused astronomy pilot workshop. We find three themes arising from the co-creation ses-sion, which have implications for effective engagement with audiences who feeldisconnected from science

    The eighteenth data release of the Sloan Digital Sky Surveys : targeting and first spectra from SDSS-V

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    The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is the first one for SDSS-V, the fifth generation of the survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole Mapper (BHM), and Local Volume Mapper (LVM). This data release contains extensive targeting information for the two multi-object spectroscopy programs (MWM and BHM), including input catalogs and selection functions for their numerous scientific objectives. We describe the production of the targeting databases and their calibration- and scientifically-focused components. DR18 also includes ~25,000 new SDSS spectra and supplemental information for X-ray sources identified by eROSITA in its eFEDS field. We present updates to some of the SDSS software pipelines and preview changes anticipated for DR19. We also describe three value-added catalogs (VACs) based on SDSS-IV data that have been published since DR17, and one VAC based on the SDSS-V data in the eFEDS field.Publisher PDFPeer reviewe

    The Forward Physics Facility at the High-Luminosity LHC

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    High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential

    The Forward Physics Facility at the High-Luminosity LHC

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    High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential
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