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Here There Be (Dusty) Monsters: High-redshift Active Galactic Nuclei Are Dustier than Their Hosts

The Astrophysical Journal 2025年第2期986卷 177-177页

作者： Madisyn Brooks Raymond C. Simons Jonathan R. Trump Anthony J. Taylor Micaela B. Bagley Bren Backhaus Kelcey Davis Véronique Buat Nikko J. Cleri Alexander de la Vega Steven L. Finkelstein Michaela Hirschmann Benne W. Holwerda Dale D. Kocevski Anton M. Koekemoer Ray A. Lucas Fabio Pacucci Lise-Marie Seillé Department of Physics 196A Auditorium Road Unit 3046 University of Connecticut Storrs CT 06269 USA Department of Engineering and Physics Providence College 1 Cunningham Square Providence RI 02918 USA Department of Astronomy The University of Texas at Austin Austin TX USA Astrophysics Science Division NASA Goddard Space Flight Center 8800 Greenbelt Road Greenbelt MD 20771 USA Department of Physics and Astronomy University of Kansas Lawrence KS 66045 USA Aix Marseille Univ CNRS CNES LAM Marseille France Institut Universitaire de France (IUF) Paris France Department of Astronomy and Astrophysics The Pennsylvania State University University Park PA 16802 USA Institute for Computational and Data Sciences The Pennsylvania State University University Park PA 16802 USA Institute for Gravitation and the Cosmos The Pennsylvania State University University Park PA 16802 USA Department of Physics and Astronomy University of California 900 University Avenue Riverside CA 92521 USA Cosmic Frontier Center The University of Texas at Austin Austin TX USA Institute of Physics Laboratory of Galaxy Evolution Ecole Polytechnique Fédérale de Lausanne (EPFL) Observatoire de Sauverny 1290 Versoix Switzerland Department of Physics University of Louisville Natural Science Building 102 Louisville KY 40292 USA Department of Physics and Astronomy Colby College Waterville ME 04901 USA Space Telescope Science Institute 3700 San Martin Drive Baltimore MD 21218 USA Center for Astrophysics ∣ Harvard & Smithsonian 60 Garden Street Cambridge MA 02138 USA Black Hole Initiative Harvard University 20 Garden Street Cambridge MA 02138 USA

JWST spectroscopy has discovered a population of z ≳ 3.5 galaxies with broad Balmer emission lines and narrow forbidden lines that are consistent with hosting active galactic nuclei (AGN). Many of these systems, now known as "little red dots," are compact and have unique colors that are very red in the optical/near-infrared and blue in the ultraviolet. The relative contribution of galaxy starlight and AGN to these systems remains uncertain, especially for the galaxies with unusual blue+red spectral energy distributions. In this work, we use Balmer decrements to measure the independent dust attenuation of the broad and narrow emission-line components of a sample of 29 broad-line AGN identified from three public JWST spectroscopy surveys: CEERS, JADES, and RUBIES. Stacking the narrow components from the spectra of 25 sources with broad Hα and no broad Hβ results in a median narrow Hα/Hβ = $2.4{7}_{-0.05}^{+0.05}$

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Discovery and Characterization of an Eccentric, Warm Saturn Transiting the Solar Analog TOI-4994∗

arXiv

引用

arXiv 2024年

作者： Martínez, Romy Rodríguez Eastman, Jason D. Collins, Karen A. Rodriguez, Joseph E. Charbonneau, David Quinn, Samuel N. Latham, David W. Ziegler, Carl Brahm, Rafael Fairnington, Tyler R. Ulmer-Moll, Solène Stassun, Keivan G. Suarez, Olga Guillot, Tristan Hobson, Melissa J. Winn, Joshua N. Kanodia, Shubham Schlecker, Martin Butler, R.P. Crane, Jeffrey D. Shectman, Steve Teske, Johanna K. Osip, David Beletsky, Yuri Battley, Matthew P. Psaridi, Angelica Figueira, Pedro Lendl, Monika Bouchy, François Udry, Stéphane Kunimoto, Michelle Mékarnia, Djamel Abe, Lyu Trifonov, Trifon Pinto, Marcelo Tala Eberhardt, Jan Espinoza, Nestor Henning, Thomas Jordán, Andrés Rojas, Felipe I. Barkaoui, Khalid Relles, Howard M. Srdoc, Gregor Collins, Kevin I. Seager, Sara Shporer, Avi Vezie, Michael Hedges, Christina Mireles, Ismael Center for Astrophysics Harvard & Smithsonian 60 Garden St CambridgeMA02138 United States Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University East LansingMI48824 United States Department of Physics Engineering and Astronomy Stephen F. Austin State University 1936 North St NacogdochesTX75962 United States Facultad de Ingeniera y Ciencias Universidad Adolfo Ibáñez Av. Diagonal las Torres 2640 Peñalolén Santiago Chile Millennium Institute for Astrophysics Chile Centre for Astrophysics University of Southern Queensland West Street ToowoombaQLD4350 Australia Observatoire astronomique de l Université de Genève 51 Chemin Pegasi Versoix1290 Switzerland Physikalisches Institut University of Bern Gesellschaftsstrasse 6 Bern3012 Switzerland Department of Physics and Astronomy Vanderbilt University NashvilleTN37235 United States Université Côte d’Azur Observatoire de la Côte d’Azur CNRS Laboratoire Lagrange Bd de l’Observatoire CS 34229 Nicecedex 4 06304 France Department of Astrophysical Sciences Princeton University PrincetonNJ08544 United States Carnegie Science Earth and Planets Laboratory 5241 Broad Branch Road NW WashingtonDC20015 United States Department of Astronomy Steward Observatory University of Arizona TucsonAZ85721 United States Department of Physics Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology 77 Massachusetts Avenue CambridgeMA02139 United States Max-Planck-Institut für Astronomie Königstuhl 17 HeidelbergD-69117 Germany Department of Astronomy Sofia University "St Kliment Ohridski" 5 James Bourchier Blvd SofiaBG-1164 Bulgaria Landessternwarte Zentrum für Astronomie der Universität Heidelberg Königstuhl 12 HeidelbergD-69117 Germany Space Telescope Science Institute BaltimoreMD21218 United States Instituto de Astrofísica Facultad de Física Pontificia Universidad Católica de Chile Av. Vicuña Mackenna 4860 Sant

We present the detection and characterization of TOI-4994b (TIC 277128619b), a warm Saturn-sized planet discovered by the NASA Transiting Exoplanet Survey Satellite (TESS). TOI-4994b transits a G-type star (V = 12.6 mag) with a mass, radius, and effective temperature of M☆ = 1.005+0.064−0.061M☉, R☆ = 1.055+0.040−0.037R☉, and Teff = 5640±110 K. We obtained follow-up ground-based photometry from the Las Cumbres Observatory (LCO) and the Antarctic Search for Transiting ExoPlanets (ASTEP) telescopes, and we confirmed the planetary nature of TOI-4994b with multiple radial velocity observations from the PFS, CHIRON, HARPS, FEROS, and CORALIE instruments. From a global fit to the photometry and radial velocities, we determine that TOI-4994b is in a 21.5-day, eccentric orbit (e = 0.32 ± 0.04) and has a mass of MP = 0.280+0.037−0.034MJ, a radius of RP = 0.762+0.030−0.027RJ, and a Saturn-like bulk density of ρp = 0.78+0.16−0.14 g/cm3. We find that TOI-4994 is a potentially viable candidate for follow-up stellar obliquity measurements. TOI-4994b joins the small sample of warm Saturn analogs and thus sheds light on our understanding of these rare and unique worlds. © 2024, CC BY.

关键词： NASA

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Cooperator-driven and defector-driven punishments: How do they influence cooperation?

arXiv

引用

arXiv 2019年

作者： Cui, Pengbi Wu, Zhi-Xi Zhou, Tao Chen, Xiaojie School of Astronautics Northwestern Polytechnical University Xi’an710072 China School of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu610054 China Institute of Computational Physics and Complex Systems Lanzhou University Lanzhou Gansu730000 China Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education Lanzhou University Lanzhou Gansu730000 China Big Data Research Center University of Electronic Science and Technology of China Chengdu611731 China Institute of Fundamental and Frontier Science University of Electronic Science and Technology of China Chengdu610073 China School of Mathematical Sciences University of Electronic Science and Technology of China Chengdu611731 China

Economic studies have shown that there are two types of regulation schemes which can be considered as a vital part of today’s global economy: self-regulation enforced by self-regulation organizations to govern industry practices, and government regulation which is considered as another scheme to sustain corporate adherence. An outstanding problem of particular interest is to understand quantitatively the role of these regulation schemes in evolutionary dynamics. Typically, punishment usually occurs for enforcement of regulations. Taking into account both types of punishments to curve the regulations, we develop a game model where six evolutionary situations with corresponding combinations of strategies are considered. Furthermore, a semi-analytical method is developed to allow us to give an accurate estimations of the boundaries between the phases of full defection and nondefection. We find that, associated with the evolutionary dynamics, for infinite well-mixed population, the mix of both punishments performs better than one punishment alone in promoting public cooperation, but for networked population the cooperator-driven punishment turns out to be a better choice. We also uncover monotonous facilitating effects of synergy effect, punishment fine and feedback sensitivity on the public cooperation for infinite well-mixed population. Conversely, for networked population an optimal intermediate range of feedback sensitivity is needed to best promote punishers’ populations. Overall, networked structure is overall more favorable for punishers and further for public cooperation, because of both network reciprocity and mutualism between punishers and cooperators who do not punish defectors. We provide physical understandings of the observed phenomena, through a detailed statistical analysis of frequencies of different strategies and spatial pattern formations in different evolution situations. These results provide valuable insights into how to select and enforce suitab

关键词： Deregulation

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TESS photometry of the nova eruption in V606 Vul: asymmetric photosphere and multiple ejections?

arXiv

引用

arXiv 2023年

作者： Sokolovsky, Kirill V. Aydi, Elias Malanchev, Konstantin Burke, Colin J. Mukai, Koji Sokoloski, J.L. Metzger, Brian D. Atapin, Kirill E. Belinski, Aleksandre A. Chen, Yu-Ching Chomiuk, Laura Dubovský, Pavol A. Faucher-Giguère, Claude-André Hounsell, Rebekah A. Ikonnikova, Natalia P. Lander, Vsevolod Yu Li, Junyao Linford, Justin D. Mioduszewski, Amy J. Molina, Isabella Munari, Ulisse Potanin, Sergey A. Quimby, Robert M. Rupen, Michael P. Scaringi, Simone Shatsky, Nicolai I. Shen, Yue Steinberg, Elad Stone, Zachary Tatarnikov, Andrey M. Vurm, Indrek Williams, And Montana N. Azcona, Antonio Agudo Boyd, David Bean, Stewart Braunwarth, Horst Blackwell, John Bolzoni, Simone Casas, Ricard Fernandez, David Cejudo Dubois, Franky Foster, James Farfán, Rafael Galdies, Charles Hodge, John Gallego, Jose Prieto Lane, David J. Larsson, Magnus Lindner, Peter Logie, Ludwig Mantero, Andrea Aimar, Mario Morales Menzies, Kenneth Nakonechny, Keith Philpot, Jerry Filho, Antonio Padilla Ramey, Brian Rau, Steve Reina, Esteban Romanov, Filipp D. Ruocco, Nello Shears, Jeremy Serreau, Marc Schmidt, Richard Solomonov, Yuri Tracy, Bob Tulloch, Gord Tomlin, Ray Tordai, Tamás Vanaverbeke, Siegfried Wenzel, Klaus Department of Astronomy University of Illinois at Urbana-Champaign 1002 W. Green Street UrbanaIL61801 United States Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University 567 Wilson Rd East LansingMI48824 United States McWilliams Center for Cosmology Department of Physics Carnegie Mellon University PittsburghPA15213 United States Department of Astronomy Yale University 266 Whitney Avenue New HavenCT06511 United States CRESST and X-ray Astrophysics Laboratory NASA/GSFC GreenbeltMD20771 United States Columbia Astrophysics Laboratory Columbia University New YorkNY10027 United States Department of Physics Columbia Astrophysics Laboratory Columbia University New YorkNY10027 United States Center for Computational Astrophysics Flatiron Institute 162 5th Ave New YorkNY10010 United States Sternberg Astronomical Institute Moscow State University Universitetskii pr. 13 Moscow119992 Russia Department of Physics and Astronomy Johns Hopkins University BaltimoreMD21218 United States Vihorlat Astronomical Observatory Mierová 4 Humenné066 01 Slovakia CIERA Department of Physics and Astronomy Northwestern University 1800 Sherman Ave EvanstonIL60201 United States University of Maryland Baltimore County BaltimoreMD21250 United States NASA Goddard Space Flight Center GreenbeltMD20771 United States National Radio Astronomy Observatory Domenici Science Operations Center 1003 Lopezville Road SocorroNM87801 United States INAF Astronomical Observatory of Padova VI Asiago36012 Italy Department of Astronomy and Mount Laguna Observatory San Diego State University San DiegoCA92182 United States The University of Tokyo Institutes for Advanced Study The University of Tokyo Chiba Kashiwa277-8583 Japan National Research Council Herzberg Astronomy and Astrophysics 717 White Lake Rd PO Box 248 PentictonBCV2A 6J9 Canada Centre for Extragalactic Astronomy Department of Physics Durham Un

Lightcurves of many classical novae deviate from the canonical "fast rise - smooth decline" pattern and display complex variability behavior. We present the first TESS-space-photometry-based investigation of this phenomenon. We use Sector 41 full-frame images to extract a lightcurve of the slow Galactic nova V606Vul that erupted nine days prior to the start of the TESS observations. The lightcurve covers the first of two major peaks of V606Vul that was reached 19 days after the start of the eruption. The nova reached its brightest visual magnitude V = 9.9 in its second peak 64 days after the eruption onset, following the completion of Sector 41 observations. To increase the confidence level of the extracted lightcurve, we performed the analysis using four different codes implementing the aperture photometry (Lightkurve, VaST) and image subtraction (TESSreduce, tequila_shots) and find good agreement between them. We performed ground-based photometric and spectroscopic monitoring to complement the TESS data. The TESS lightcurve reveals two features: periodic variations (0.12771d, 0.01mag average peak-to-peak amplitude) that disappeared when the source was within 1mag of peak optical brightness and a series of isolated mini-flares (with peak-to-peak amplitudes of up to 0.5mag) appearing at seemingly random times. We interpret the periodic variations as the result of azimuthal asymmetry of the photosphere engulfing the nova-hosting binary that was distorted by and rotating with the binary. Whereas we use spectra to associate the two major peaks in the nova lightcurve with distinct episodes of mass ejection, the origin of mini-flares remains elusive. Copyright © 2023, The Authors. All rights reserved.

关键词： Photometry

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The Early Light Curve of SN 2023bee: Constraining Type Ia Supernova Progenitors the Apian Way

arXiv

引用

arXiv 2023年

作者： Hosseinzadeh, Griffin Sand, David J. Sarbadhicary, Sumit K. Ryder, Stuart D. Jha, Saurabh W. Dong, Yize Bostroem, K. Azalee Andrews, Jennifer E. Hoang, Emily Janzen, Daryl Jencson, Jacob E. Lundquist, Michael Meza Retamal, Nicolas E. Pearson, Jeniveve Shrestha, Manisha Valenti, Stefano Wyatt, Samuel Farah, Joseph Howell, D. Andrew McCully, Curtis Newsome, Megan Gonzalez, Estefania Padilla Pellegrino, Craig Terreran, Giacomo Alzaabi, Muzoun Green, Elizabeth M. Gurney, Jessica L. Milne, Peter A. Ridenhour, Kaycee I. Smith, Nathan Robles, Paulina Soto Kwok, Lindsey A. Schwab, Michaela Gromadzki, Mariusz Buckley, David A.H. Itagaki, Koichi Hiramatsu, Daichi Chomiuk, Laura Lundqvist, Peter Haislip, Joshua Kouprianov, Vladimir Reichart, Daniel E. Steward Observatory University of Arizona 933 North Cherry Avenue TucsonAZ85721-0065 United States Center for Cosmology and AstroParticle Physics Ohio State University 191 West Woodruff Avenue ColumbusOH43210-1117 United States School of Mathematical and Physical Sciences Macquarie University SydneyNSW2109 Australia Astrophysics and Space Technologies Research Centre Macquarie University SydneyNSW2109 Australia Department of Physics and Astronomy Rutgers The State University of New Jersey 136 Frelinghuysen Road PiscatawayNJ08854-8019 United States Department of Physics and Astronomy University of California Davis 1 Shields Avenue DavisCA95616-5270 United States Gemini Observatory 670 North A‘ohoku Place HiloHI96720-2700 United States Department of Physics & Engineering Physics University of Saskatchewan 116 Science Place SaskatoonSKS7N 5E2 Canada W. M. Keck Observatory 65-1120 Māmalahoa Highway KamuelaHI96743-8431 United States Department of Astronomy University of Washington 3910 15th Avenue NE SeattleWA98195-0002 United States Las Cumbres Observatory 6740 Cortona Drive Suite 102 GoletaCA93117-5575 United States Department of Physics University of California Santa BarbaraCA93106-9530 United States Astronomical Observatory University of Warsaw Al. Ujazdowskie 4 Warszawa00-478 Poland South African Astronomical Observatory P.O. Box 9 Observatory7935 South Africa Department of Physics University of the Free State P.O. Box 339 Bloemfontein9300 South Africa Department of Astronomy University of Cape Town Private Bag X3 Rondebosch7701 South Africa Itagaki Astronomical Observatory Yamagata990-2492 Japan Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138-1516 United States The NSF AI Institute for Artificial Intelligence and Fundamental Interactions United States Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University East LansingMI48

We present very early photometric and spectroscopic observations of the Type Ia supernova (SN Ia) 2023bee, starting about 8 hr after the explosion, which reveal a strong excess in the optical and nearest UV (U and UVW1) bands during the first several days of explosion. This data set allows us to probe the nature of the binary companion of the exploding white dwarf and the conditions leading to its ignition. We find a good match to the Kasen model in which a main-sequence companion star stings the ejecta with a shock as they buzz past. Models of double detonations, shells of radioactive nickel near the surface, interaction with circumstellar material, and pulsational delayed detonations do not provide good matches to our light curves. We also observe signatures of unburned material, in the form of carbon absorption, in our earliest spectra. Our radio nondetections place a limit on the mass-loss rate from the putative companion that rules out a red giant but allows a main-sequence star. We discuss our results in the context of other similar SNe Ia in the literature. Copyright © 2023, The Authors. All rights reserved.

关键词： Detonation

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Synapse: Synthetic application profiler and emulator

arXiv

引用

arXiv 2018年

作者： Merzky, Andre Ha, Ming Tai Turilli, Matteo Jha, Shantenu RADICAL Laboratory Electric and Computer Engineering Rutgers University New BrunswickNJ United States Center for Data Driven Discovery Computational Science Initiative Brookhaven National Laboratory NY United States

Motivated by the need to emulate workload execution characteristics on high-performance and distributed heterogeneous resources, we introduce Synapse. Synapse is used as a proxy application (or"representative application") for real workloads, with the advantage that it can be tuned in different ways and dimensions, and also at levels of granularity that are not possible with real applications. Synapse has a platform-independent application profiler, and has the ability to emulate profiled workloads on a variety of resources. Experiments show that the automated profiling performed using Synapse captures an application's characteristics with high fidelity. The emulation of an application using Synapse can reproduce the application's execution behavior in the original runtime environment, and can also reproduce those behaviors on different run-time environments. Copyright © 2018, The Authors. All rights reserved.

关键词： Machine learning

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A model for meme popularity growth in social networking systems based on biological principle and human interest dynamics

arXiv

引用

arXiv 2019年

作者： Wang, Le-Zhi Zhao, Zhi-Dan Jiang, Jun-Jie Guo, Bing-Hui Wang, Xiao Huang, Zi-Gang Lai, Ying-Cheng School of Electrical Computer and Energy Engineering Arizona State University TempeAZ85287 United States Web Sciences Center Big Data Research Center University of Electronic Science and Technology of China Chengdu610054 China School of Mathematics Beihang University Beijing100191 China School of Biological and Health Systems Engineering Arizona State University TempeAZ85287 United States School of Life Science and Technology Xi'An Jiaotong University Xi'an710049 China Institute of Computational Physics and Complex Systems Lanzhou University Lanzhou Gansu730000 China Department of Physics Arizona State University TempeAZ85287 United States

We analyze five big data sets from a variety of online social networking (OSN) systems and find that the growth dynamics of meme popularity exhibit characteristically different behaviors. For example, there is linear growth associated with online recommendation and sharing platforms, a plateaued (or an \S"-shape) type of growth behavior in a web service devoted to helping users to collect bookmarks, and an exponential increase on the largest and most popular microblogging website in China. Does a universal mechanism with a common set of dynamical rules exist, which can explain these empirically observed, distinct growth behaviors? We provide an affirmative answer in this paper. In particular, inspired by biomimicry to take advantage of cell population growth dynamics in microbial ecology, we construct a base growth model for meme popularity in OSNs. We then take into account human factors by incorporating a general model of human interest dynamics into the base model. The final hybrid model contains a small number of free parameters that can be estimated purely from data. We demonstrate that our model is universal in the sense that, with a few parameters estimated from data, it can successfully predict the distinct meme growth dynamics. Our study represents a successful effort to exploit principles in biology to understand online social behaviors by incorporating the traditional microbial growth model into meme popularity. Our model can be used to gain insights into critical issues such as classification, robustness, optimization, and control of OSN systems. Copyright © 2019, The Authors. All rights reserved.

关键词： Social networking (online)

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Revisiting the classics: On the evolutionary origin of the "Fe II" and "He/N" spectral classes of novae

arXiv

引用

arXiv 2023年

作者： Aydi, E. Chomiuk, L. Strader, J. Sokolovsky, K.V. Williams, R.E. Buckley, D.A.H. Ederoclite, A. Izzo, L. Kyer, R. Linford, J.D. Kniazev, A. Metzger, B.D. Mikolajewska, J. Molaro, P. Molina, I. Mukai, K. Munari, U. Orio, M. Panurach, T. Shappee, B.J. Shen, K.J. Sokoloski, J.L. Urquhart, R. Walter, F.M. Center for Data Intensive and Time Domain Astronomy Department of Physics and Astronomy Michigan State University East LansingMI48824 United States Department of Astronomy University of Illinois at Urbana-Champaign 1002 W. Green Street UrbanaIL61801 United States Sternberg Astronomical Institute Moscow State University Universitetskii pr. 13 Moscow119992 Russia Department of Astronomy & Astrophysics University of California Santa Cruz 1156 High Street Santa CruzCA95064 United States Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 United States South African Astronomical Observatory P.O. Box 9 Observatory7935 South Africa Department of Astronomy University of Cape Town Private Bag X3 Rondebosch7701 South Africa Centro de Estudios de Física del Cosmos de Aragón Plaza San Juan 1 Teruel44001 Spain UK Astronomy Technology Centre Royal Observatory Blackford Hill EdinburghEH9 3HJ United Kingdom DARK Niels Bohr Institute University of Copenhagen Jagtvej 128 Copenhagen Ø2200 Denmark National Radio Astronomy Observatory P.O. Box O SocorroNM87801 United States Southern African Large Telescope Foundation PO Box 9 Observatory7935 South Africa Special Astrophysical Observatory Nizhnij Arkhyz Karachai-Circassia 369167 Russia Department of Physics Columbia Astrophysics Laboratory Columbia University New YorkNY10027 United States Center for Computational Astrophysics Flatiron Institute 162 5th Ave New YorkNY10010 United States Nicolaus Copernicus Astronomical Center Polish Academy of Sciences Bartycka 18 WarsawPL 00-716 Poland INAF-Osservatorio Astronomico di Trieste Via G.B. Tiepolo 11 TriesteI-34143 Italy Institute of Fundamental Physics of the Universe Via Beirut 2 Miramare Trieste Italy CRESST and X-ray Astrophysics Laboratory NASA GSFC GreenbeltMD20771 United States Department of Physics University of Maryland Baltimore County 1000 Hilltop Circle BaltimoreMD21250 United States INAF Astronomical Obs

The optical spectra of novae are characterized by emission lines from the hydrogen Balmer series and either Fe II or He/N, leading to their traditional classification into two spectral classes: "Fe II" and "He/N". For decades, the origins of these spectral features were discussed in the literature in the contexts of different bodies of gas or changes in the opacity of the ejecta, particularly associated with studies by R. E. Williams and S. N. Shore. Here, we revisit these major studies with dedicated, modern data sets, covering the evolution of several novae from early rise to peak all the way to the nebular phase. Our data confirm previous suggestions in the literature that the "Fe II" and "He/N" spectral classes are phases in the spectroscopic evolution of novae driven primarily by changes in the opacity, ionization, and density of the ejecta, and most if not all novae go through at least three spectroscopic phases as their eruptions evolve: an early He/N (phase 1;observed during the early rise to visible peak and characterized by P Cygni lines of He I and N II/III), then an Fe II (phase 2;observed near visible peak and characterized by P Cygni lines of Fe II and O I), and then a later He/N (phase 3;observed during the decline and characterized by emission lines of He I/II, N II/III), before entering the nebular phase. This spectral evolution seems to be ubiquitous across novae, regardless of their speed class;however the duration of each of these phases differs based on the speed class of the nova. © 2023, CC BY-NC-ND.

关键词： Opacity

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Brain Tumor Segmentation (BraTS) Challenge 2024: Meningioma Radiotherapy Planning Automated Segmentation

arXiv

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arXiv 2024年

作者： LaBella, Dominic Schumacher, Katherine Mix, Michael Leu, Kevin McBurney-Lin, Shan Nedelec, Pierre Villanueva-Meyer, Javier Shapey, Jonathan Vercauteren, Tom Chia, Kazumi Ivory, Marina Barfoot, Theodore Al-Salihi, Omar Leu, Justin Halasz, Lia Velichko, Yury Wang, Chunhao Kirkpatrick, John Floyd, Scott Reitman, Zachary J. Mullikin, Trey Bagci, Ulas Sachdev, Sean Hattangadi-Gluth, Jona A. Seibert, Tyler M. Farid, Nikdokht Puett, Connor Pease, Matthew W. Shiue, Kevin Anwar, Syed Muhammad Faghani, Shahriar Taylor, Peter Haider, Muhammad Ammar Warman, Pranav Albrecht, Jake Jakab, András Moassefi, Mana Chung, Verena Aristizabal, Alejandro Karargyris, Alexandros Kassem, Hasan Pati, Sarthak Sheller, Micah Coley, Aaron Huang, Christina Ghanta, Siddharth Schneider, Alex Sharp, Conrad Saluja, Rachit Kofler, Florian Lohmann, Philipp Vollmuth, Phillipp Gagnon, Louis Adewole, Maruf Li, Hongwei Bran Kazerooni, Anahita Fathi Tahon, Nourel Hoda Anazodo, Udunna Moawad, Ahmed W. Menze, Bjoern Linguraru, Marius George Aboian, Mariam Wiestler, Benedikt Baid, Ujjwal Conte, Gian-Marco Rauschecker, Andreas M. Nada, Ayman Abayazeed, Aly H. Huang, Raymond de Verdier, Maria Correia Rudie, Jeffrey D. Bakas, Spyridon Calabrese, Evan Department of Radiation Oncology Duke University Medical Center DurhamNC United States Department of Radiation Oncology SUNY Upstate Medical University SyracuseNY United States San FranciscoCA United States Department of Neurosurgery King’s College Hospital London United Kingdom School of Biomedical Engineering and Imaging Sciences King’s College London London United Kingdom Guy’s and St Thomas’ NHS Foundation Trust United Kingdom Department of Radiation Oncology University of Washington SeattleWA United States Department of Radiology Northwestern University EvanstonIL United States Department of Radiation Oncology Northwestern University EvanstonIL United States Department of Radiation Medicine and Applied Sciences University of California San Diego La Jolla CA United States Department of Radiology University of California San Diego La Jolla CA United States Department of Bioengineering University of California San Diego La Jolla CA United States Department of Neurological Surgery Indiana University School of Medicine IndianapolisIN United States Department of Radiation Oncology Indiana University IndianapolisIN United States Children’s National Hospital WashingtonDC United States George Washington University WashingtonDC United States Mayo Clinic RochesterMN United States CMH Lahore Medical College Lahore Pakistan Duke University Medical Center School of Medicine DurhamNC United States Sage Bionetworks United States University of Zürich Zürich Switzerland Artificial Intelligence Lab Department of Radiology Mayo Clinic RochesterMN United States MLCommons United States Factored AI United States Center For Federated Learning in Medicine Indiana University IndianapolisIN United States Division of Computational Pathology Department of Pathology and Laboratory Medicine Indiana University School of Medicine IndianapolisIN United States Medical Working Group MLCommons San FranciscoCA United States Intel United States Duke Universi

The 2024 Brain Tumor Segmentation Meningioma Radiotherapy (BraTS-MEN-RT) challenge aims to advance automated segmentation algorithms using the largest known multi-institutional dataset of 750 radiotherapy planning brain MRIs with expert-annotated target labels for patients with intact or postoperative meningioma that underwent either conventional external beam radiotherapy or stereotactic radiosurgery. Each case includes a defaced 3D post-contrast T1-weighted radiotherapy planning MRI in its native acquisition space, accompanied by a single-label "target volume" representing the gross tumor volume (GTV) and any at-risk postoperative site. Target volume annotations adhere to established radiotherapy planning protocols, ensuring consistency across cases and institutions. For preoperative meningiomas, the target volume encompasses the entire GTV and associated nodular dural tail, while for postoperative cases, it includes at-risk resection cavity margins as determined by the treating institution. Case annotations were reviewed and approved by expert neuroradiologists and radiation oncologists. Participating teams will develop, containerize, and evaluate automated segmentation models using this comprehensive dataset. Model performance will be assessed using an adapted lesion-wise Dice Similarity Coefficient and the 95% Hausdorff distance. The top-performing teams will be recognized at the Medical Image Computing and Computer Assisted Intervention Conference in October 2024. BraTS-MEN-RT is expected to significantly advance automated radiotherapy planning by enabling precise tumor segmentation and facilitating tailored treatment, ultimately improving patient outcomes. © 2024, CC BY.

关键词： Radiotherapy

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Mutual clustering on comparative texts via heterogeneous information networks

arXiv

引用

arXiv 2019年

作者： Cao, Jianping Wang, Senzhang Wen, Danyan Peng, Zhaohui Yu, Philip S. Wang, Fei-yue Research Center for Military Computational Experiments and Parallel Systems Technology National University of Defense Technology Changsha410073 China Ministry of Industry and Information Technology Nanjing211106 China School of Economics & Management Nanjing University of Science and Technology Nanjing210094 China School of Computer Science and Technology Shandong University Qingdao China Department of Computer Science University of Illinois at Chicago Chicago60607 United States Institute for Data Science Tsinghua University Beijing100084 China Beijing China Qingdao Academy of Intelligent Industries Qingdao266000 China Institute of Systems Engineering Macau University of Science and Technology Macau999078 China

Currently, many intelligence systems contain the texts from multi-sources, e.g., bulletin board system (BBS) posts, tweets and news. These texts can be "comparative" since they may be semantically correlated and thus provide us with different perspectives toward the same topics or events. To better organize the multi-sourced texts and obtain more comprehensive knowledge, we propose to study the novel problem of Mutual Clustering on Comparative Texts (MCCT), which aims to cluster the comparative texts simultaneously and collaboratively. The MCCT problem is difficult to address because 1) comparative texts usually present different data formats and structures and thus they are hard to organize, and 2) there lacks an effective method to connect the semantically correlated comparative texts to facilitate clustering them in an unified way. To this aim, in this paper we propose a Heterogeneous Information Network-based Text clustering framework HINT. HINT first models multi-sourced texts (e.g. news and tweets) as heterogeneous information networks by introducing the shared "anchor texts" to connect the comparative texts. Next, two similarity matrices based on HINT as well as a transition matrix for cross-text-source knowledge transfer are constructed. Comparative texts clustering are then conducted by utilizing the constructed matrices. Finally, a mutual clustering algorithm is also proposed to further unify the separate clustering results of the comparative texts by introducing a clustering consistency constraint. We conduct extensive experimental on three tweets-news datasets, and the results demonstrate the effectiveness and robustness of the proposed method in addressing the MCCT problem. Copyright © 2019, The Authors. All rights reserved.

关键词： Clustering algorithms

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