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Dark Energy Survey year 3 results: Constraints on cosmological parameters and galaxy-bias models from galaxy clustering and galaxy-galaxy lensing using the redMaGiC sample

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Physical Review D 2022年第4期106卷 043520-043520页

作者： S. Pandey E. Krause J. DeRose N. MacCrann B. Jain M. Crocce J. Blazek A. Choi H. Huang C. To X. Fang J. Elvin-Poole J. Prat A. Porredon L. F. Secco M. Rodriguez-Monroy N. Weaverdyck Y. Park M. Raveri E. Rozo E. S. Rykoff G. M. Bernstein C. Sánchez M. Jarvis M. A. Troxel G. Zacharegkas C. Chang A. Alarcon O. Alves A. Amon F. Andrade-Oliveira E. Baxter K. Bechtol M. R. Becker H. Camacho A. Campos A. Carnero Rosell M. Carrasco Kind R. Cawthon R. Chen P. Chintalapati C. Davis E. Di Valentino H. T. Diehl S. Dodelson C. Doux A. Drlica-Wagner K. Eckert T. F. Eifler F. Elsner S. Everett A. Farahi A. Ferté P. Fosalba O. Friedrich M. Gatti G. Giannini D. Gruen R. A. Gruendl I. Harrison W. G. Hartley E. M. Huff D. Huterer A. Kovacs P. F. Leget J. McCullough J. Muir J. Myles A. Navarro-Alsina Y. Omori R. P. Rollins A. Roodman R. Rosenfeld I. Sevilla-Noarbe E. Sheldon T. Shin A. Troja I. Tutusaus T. N. Varga R. H. Wechsler B. Yanny B. Yin Y. Zhang J. Zuntz T. M. C. Abbott M. Aguena S. Allam J. Annis D. Bacon E. Bertin D. Brooks D. L. Burke J. Carretero C. Conselice M. Costanzi L. N. da Costa M. E. S. Pereira J. De Vicente J. P. Dietrich P. Doel A. E. Evrard I. Ferrero B. Flaugher J. Frieman J. García-Bellido E. Gaztanaga D. W. Gerdes T. Giannantonio J. Gschwend G. Gutierrez S. R. Hinton D. L. Hollowood K. Honscheid D. J. James T. Jeltema K. Kuehn N. Kuropatkin O. Lahav M. Lima H. Lin M. A. G. Maia J. L. Marshall P. Melchior F. Menanteau C. J. Miller R. Miquel J. J. Mohr R. Morgan A. Palmese F. Paz-Chinchón D. Petravick A. Pieres A. A. Plazas Malagón E. Sanchez V. Scarpine S. Serrano M. Smith M. Soares-Santos E. Suchyta G. Tarle D. Thomas J. Weller Department of Physics and Astronomy University of Pennsylvania Philadelphia Pennsylvania 19104 USA Department of Astronomy/Steward Observatory University of Arizona 933 North Cherry Avenue Tucson Arizona 85721-0065 USA Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley California 94720 USA Department of Applied Mathematics and Theoretical Physics University of Cambridge Cambridge CB3 0WA United Kingdom Institut d’Estudis Espacials de Catalunya (IEEC) 08034 Barcelona Spain Institute of Space Sciences (ICE CSIC) Campus UAB Carrer de Can Magrans s/n 08193 Barcelona Spain Department of Physics Northeastern University Boston Massachusetts 02115 USA Laboratory of Astrophysics École Polytechnique Fédérale de Lausanne (EPFL) Observatoire de Sauverny 1290 Versoix Switzerland Center for Cosmology and Astro-Particle Physics The Ohio State University Columbus Ohio 43210 USA Department of Physics University of Arizona Tucson Arizona 85721 USA Department of Physics Stanford University 382 Via Pueblo Mall Stanford California 94305 USA Kavli Institute for Particle Astrophysics and Cosmology P.O. Box 2450 Stanford University Stanford California 94305 USA SLAC National Accelerator Laboratory Menlo Park California 94025 USA Department of Physics The Ohio State University Columbus Ohio 43210 USA Department of Astronomy and Astrophysics University of Chicago Chicago Illinois 60637 USA Kavli Institute for Cosmological Physics University of Chicago Chicago Illinois 60637 USA Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT) Madrid Spain Department of Physics University of Michigan Ann Arbor Michigan 48109 USA Kavli Institute for the Physics and Mathematics of the Universe (WPI) UTIAS The University of Tokyo Kashiwa Chiba 277-8583 Japan Department of Physics Duke University Durham North Carolina 27708 USA Argonne National Laboratory 9700 South Cass Avenue Lemont Illinois 60439 USA Instituto de Física Teórica Uni

We constrain cosmological parameters and galaxy-bias parameters using the combination of galaxy clustering and galaxy-galaxy lensing measurements from the Dark Energy Survey (DES) year-3 data. We describe our modeling framework and choice of scales analyzed, validating their robustness to theoretical uncertainties in small-scale clustering by analyzing simulated data. Using a linear galaxy-bias model and redMaGiC galaxy sample, we obtain 10% constraints on the matter density of the Universe. We also implement a nonlinear galaxy-bias model to probe smaller scales that includes parametrization based on hybrid perturbation theory and find that it leads to a 17% gain in cosmological constraining power. We perform robustness tests of our methodology pipeline and demonstrate stability of the constraints to changes in the theory model. Using the redMaGiC galaxy sample as foreground lens galaxies and adopting the best-fitting cosmological parameters from DES year-1 data, we find the galaxy clustering and galaxy-galaxy lensing measurements to exhibit significant signals akin to decorrelation between galaxies and mass on large scales, which is not expected in any current models. This likely systematic measurement error biases our constraints on galaxy bias and the S8 parameter. We find that a scale-, redshift- and sky-area-independent phenomenological decorrelation parameter can effectively capture this inconsistency between the galaxy clustering and galaxy-galaxy lensing. We trace the source of this correlation to a color-dependent photometric issue and minimize its impact on our result by changing the selection criteria of redMaGiC galaxies. Using this new sample, our constraints on the S8 parameter are consistent with previous studies and we find a small shift in the Ωm constraints compared to the fiducial redMaGiC sample. We infer the constraints on the mean host-halo mass of the redMaGiC galaxies in this new sample from the large-scale bias constraints, finding the galax

关键词： Cosmological constant Cosmological parameters Dark energy Dark matter Evolution of the Universe General relativity Gravitational lenses Large scale structure of the Universe Optical, UV, & IR astronomy

DeepZipper: A Novel Deep Learning Architecture for Lensed Supernovae Identification

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arXiv 2021年

作者： Morgan, Robert Nord, B. Bechtol, K. González, S.J. Buckley-Geer, E. Möller, A. Park, J.W. Kim, A.G. Birrer, S. Aguena, M. Annis, J. Bocquet, S. Brooks, D. Rosell, A. Carnero Kind, M. Carrasco Carretero, J. Cawthon, R. da Costa, L.N. Davis, T.M. De Vicente, J. Doel, P. Ferrero, I. Friedel, D. Frieman, J. García-Bellido, J. Gatti, M. Gaztanaga, E. Giannini, G. Gruen, D. Gruendl, R.A. Gutierrez, G. Hollowood, D.L. Honscheid, K. James, D.J. Kuehn, K. Kuropatkin, N. Maia, M.A.G. Miquel, R. Palmese, A. Paz-Chinchón, F. Pereira, M.E.S. Pieres, A. Plazas Malagón, A.A. Reil, K. Roodman, A. Sanchez, E. Smith, M. Suchyta, E. Swanson, M.E.C. Tarle, G. To, C. Physics Department University of Wisconsin-Madison 1150 University Avenue MadisonWI53706 United States Fermi National Accelerator Laboratory P. O. Box 500 BataviaIL60510 United States Legacy Survey of Space and Time Corporation Data Science Fellowship Program United States Department of Astronomy and Astrophysics University of Chicago ChicagoIL60637 United States Kavli Institute for Cosmological Physics University of Chicago ChicagoIL60637 United States Legacy Survey of Space and Time 933 North Cherry Avenue TucsonAZ85721 United States Centre for Astrophysics & Supercomputing Swinburne University of Technology VIC3122 Australia Kavli Institute for Particle Astrophysics and Cosmology Department of Physics Stanford University StanfordCA94305 United States SLAC National Accelerator Laboratory Menlo ParkCA94025 United States Lawrence Berkeley National Laboratory 1 Cyclotron Road BerkeleyCA94720 United States Laboratório Interinstitucional de e-Astronomia - LIneA Rua Gal. José Cristino 77 RJ Rio de Janeiro20921-400 Brazil Faculty of Physics Ludwig-Maximilians-Universität Scheinerstr. 1 Munich81679 Germany Department of Physics & Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom Center for Astrophysical Surveys National Center for Supercomputing Applications 1205 West Clark St. UrbanaIL61801 United States Department of Astronomy University of Illinois at Urbana-Champaign 1002 W. Green Street UrbanaIL61801 United States The Barcelona Institute of Science and Technology Campus UAB Bellaterra Barcelona08193 Spain Physics Department William Jewell College LibertyMO64068 United States Observatório Nacional Rua Gal. José Cristino 77 RJ Rio de Janeiro20921-400 Brazil School of Mathematics and Physics University of Queensland BrisbaneQLD4072 Australia Madrid Spain Institute of Theoretical Astrophysics University of Oslo P.O. Box 1029 Blindern OsloNO-0315 Norway Instituto de Fisica Teorica UAM/CSIC

Large-scale astronomical surveys have the potential to capture data on large numbers of strongly gravitationally lensed supernovae (LSNe). To facilitate timely analysis and spectroscopic follow-up before the supernova fades, an LSN needs to be identified soon after it begins. To quickly identify LSNe in optical survey datasets, we designed ZipperNet, a multi-branch deep neural network that combines convolutional layers (traditionally used for images) with long short-term memory (LSTM) layers (traditionally used for time series). We tested ZipperNet on the task of classifying objects from four categories – no lens, galaxy-galaxy lens, lensed type Ia supernova, lensed core-collapse supernova – within high-fidelity simulations of three cosmic survey data sets – the Dark Energy Survey (DES), Rubin Observatory’s Legacy Survey of Space and Time (LSST), and a Dark Energy Spectroscopic Instrument (DESI) imaging survey. Among our results, we find that for the LSST-like dataset, ZipperNet classifies LSNe with a receiver operating characteristic area under the curve of 0.97, predicts the spectroscopic type of the lensed supernovae with 79% accuracy, and demonstrates similarly high performance for LSNe 1-2 epochs after first detection. We anticipate that a model like ZipperNet, which simultaneously incorporates spatial and temporal information, can play a significant role in the rapid identification of lensed transient systems in cosmic survey experiments. Copyright © 2021, The Authors. All rights reserved.

关键词： Supernovae

Dark Energy Survey Year 3 results: Cosmological constraints from galaxy clustering and weak lensing

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Physical Review D 2022年第2期105卷 023520-023520页

作者： T. M. C. Abbott M. Aguena A. Alarcon S. Allam O. Alves A. Amon F. Andrade-Oliveira J. Annis S. Avila D. Bacon E. Baxter K. Bechtol M. R. Becker G. M. Bernstein S. Bhargava S. Birrer J. Blazek A. Brandao-Souza S. L. Bridle D. Brooks E. Buckley-Geer D. L. Burke H. Camacho A. Campos A. Carnero Rosell M. Carrasco Kind J. Carretero F. J. Castander R. Cawthon C. Chang A. Chen R. Chen A. Choi C. Conselice J. Cordero M. Costanzi M. Crocce L. N. da Costa M. E. da Silva Pereira C. Davis T. M. Davis J. De Vicente J. DeRose S. Desai E. Di Valentino H. T. Diehl J. P. Dietrich S. Dodelson P. Doel C. Doux A. Drlica-Wagner K. Eckert T. F. Eifler F. Elsner J. Elvin-Poole S. Everett A. E. Evrard X. Fang A. Farahi E. Fernandez I. Ferrero A. Ferté P. Fosalba O. Friedrich J. Frieman J. García-Bellido M. Gatti E. Gaztanaga D. W. Gerdes T. Giannantonio G. Giannini D. Gruen R. A. Gruendl J. Gschwend G. Gutierrez I. Harrison W. G. Hartley K. Herner S. R. Hinton D. L. Hollowood K. Honscheid B. Hoyle E. M. Huff D. Huterer B. Jain D. J. James M. Jarvis N. Jeffrey T. Jeltema A. Kovacs E. Krause R. Kron K. Kuehn N. Kuropatkin O. Lahav P.-F. Leget P. Lemos A. R. Liddle C. Lidman M. Lima H. Lin N. MacCrann M. A. G. Maia J. L. Marshall P. Martini J. McCullough P. Melchior J. Mena-Fernández F. Menanteau R. Miquel J. J. Mohr R. Morgan J. Muir J. Myles S. Nadathur A. Navarro-Alsina R. C. Nichol R. L. C. Ogando Y. Omori A. Palmese S. Pandey Y. Park F. Paz-Chinchón D. Petravick A. Pieres A. A. Plazas Malagón A. Porredon J. Prat M. Raveri M. Rodriguez-Monroy R. P. Rollins A. K. Romer A. Roodman R. Rosenfeld A. J. Ross E. S. Rykoff S. Samuroff C. Sánchez E. Sanchez J. Sanchez D. Sanchez Cid V. Scarpine M. Schubnell D. Scolnic L. F. Secco S. Serrano I. Sevilla-Noarbe E. Sheldon T. Shin M. Smith M. Soares-Santos E. Suchyta M. E. C. Swanson M. Tabbutt G. Tarle D. Thomas C. To A. Troja M. A. Troxel D. L. Tucker I. Tutusaus T. N. Varga A. R. Walker N. Weaverdyck R. Wechsler J. Weller B. Yanny B. Yin Y. Zhang J. Zuntz Cerro Tololo Inter-American Observatory NSF’s National Optical-Infrared Astronomy Research Laboratory Casilla 603 La Serena Chile Laboratório Interinstitucional de e-Astronomia—LIneA Rua Gal. José Cristino 77 Rio de Janeiro RJ—20921-400 Brazil Argonne National Laboratory 9700 South Cass Avenue Lemont Illinois 60439 USA Fermi National Accelerator Laboratory P. O. Box 500 Batavia Illinois 60510 USA Department of Physics University of Michigan Ann Arbor Michigan 48109 USA Instituto de Física Teórica Universidade Estadual Paulista São Paulo 01140-070 Brazil Kavli Institute for Particle Astrophysics and Cosmology P. O. Box 2450 Stanford University Stanford California 94305 USA Instituto de Fisica Teorica UAM/CSIC Universidad Autonoma de Madrid 28049 Madrid Spain Institute of Cosmology and Gravitation University of Portsmouth Portsmouth PO1 3FX United Kingdom Institute for Astronomy University of Hawai’i 2680 Woodlawn Drive Honolulu Hawaii 96822 USA Physics Department 2320 Chamberlin Hall University of Wisconsin-Madison 1150 University Avenue Madison Wisconsin 53706-1390 USA Department of Physics and Astronomy University of Pennsylvania Philadelphia Pennsylvania 19104 USA Department of Physics and Astronomy Pevensey Building University of Sussex Brighton BN1 9QH United Kingdom Graduate School of Education Stanford University 160 450 Serra Mall Stanford California 94305 USA Department of Physics Northeastern University Boston Massachusetts 02115 USA Laboratory of Astrophysics École Polytechnique Fédérale de Lausanne (EPFL) Observatoire de Sauverny 1290 Versoix Switzerland Instituto de Física Gleb Wataghin Universidade Estadual de Campinas 13083-859 Campinas SP Brazil Jodrell Bank Center for Astrophysics School of Physics and Astronomy University of Manchester Oxford Road Manchester M13 9PL United Kingdom Department of Physics and Astronomy University College London Gower Street London WC1E 6BT United Kingdom Department of Astronomy and Astroph

We present the first cosmology results from large-scale structure using the full 5000 deg2 of imaging data from the Dark Energy Survey (DES) data Release 1. We perform an analysis of large-scale structure combining three two-point correlation functions (3×2pt): (i) cosmic shear using 100 million source galaxies, (ii) galaxy clustering, and (iii) the cross-correlation of source galaxy shear with lens galaxy positions, galaxy–galaxy lensing. To achieve the cosmological precision enabled by these measurements has required updates to nearly every part of the analysis from DES Year 1, including the use of two independent galaxy clustering samples, modeling advances, and several novel improvements in the calibration of gravitational shear and photometric redshift inference. The analysis was performed under strict conditions to mitigate confirmation or observer bias; we describe specific changes made to the lens galaxy sample following unblinding of the results and tests of the robustness of our results to this decision. We model the data within the flat ΛCDM and wCDM cosmological models, marginalizing over 25 nuisance parameters. We find consistent cosmological results between the three two-point correlation functions; their combination yields clustering amplitude S8=0.776−0.017+0.017 and matter density Ωm=0.339−0.031+0.032 in ΛCDM, mean with 68% confidence limits; S8=0.775−0.024+0.026, Ωm=0.352−0.041+0.035, and dark energy equation-of-state parameter w=−0.98−0.20+0.32 in wCDM. These constraints correspond to an improvement in signal-to-noise of the DES Year 3 3×2pt data relative to DES Year 1 by a factor of 2.1, about 20% more than expected from the increase in observing area alone. This combination of DES data is consistent with the prediction of the model favored by the Planck 2018 cosmic microwave background (CMB) primary anisotropy data, which is quantified with a probability-to-exceed p=0.13–0.48. We find better agreement between DES 3×2pt and Planck than in DES Y1

关键词： Cosmological parameters Cosmology Dark energy Dark matter Large scale structure of the Universe

SN 2018agk: A prototypical Type Ia Supernova with a smooth power-law rise in Kepler (K2)

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arXiv 2021年

作者： Wang, Qinan Rest, Armin Zenati, Yossef Ridden-Harper, Ryan Dimitriadis, Georgios Narayan, Gautham Villar, V. Ashley Magee, Mark R. Foley, Ryan J. Shaya, Edward J. Garnavich, Peter Wang, Lifan Hu, Lei Bódi, Attila Armstrong, Patrick Auchettl, Katie Barclay, Thomas Barentsen, Geert Bognár, Zsófia Brimacombe, Joseph Bulger, Joanna Burke, Jamison Challis, Peter Chambers, Kenneth Coulter, David A. Csörnyei, Géza Cseh, Borbála Deckers, Maxime Dotson, Jessie L. Galbany, Lluís González-Gaitán, Santiago Gromadzki, Mariusz Gully-Santiago, Michael Hanyecz, Ottó Hedges, Christina Hiramatsu, Daichi Hosseinzadeh, Griffin Howell, D. Andrew Howell, Steve B. Huber, Mark E. Jha, Saurabh W. Jones, David O. Könyves-Tóth, Réka Kalup, Csilla Kilpatrick, Charles D. Kriskovics, Levente Li, Wenxiong Lowe, Thomas B. Margheim, Steven McCully, Curtis Mitra, Ayan Muñoz, Jose A. Nicholl, Matt Nordin, Jakob Pál, András Pan, Yen-Chen Piro, Anthony L. Rest, Sofia Rino-Silvestre, João Rojas-Bravo, César Sárneczky, Krisztián Siebert, Matthew R. Smartt, Stephen J. Smith, Ken Sódor, Ádám Stritzinger, Maximilian D. Szabó, Róbert Szakáts, Róbert Tucker, Brad E. Vinkó, József Wang, Xiaofeng Wheeler, J. Craig Young, David R. Zenteno, Alfredo Zhang, Kaicheng Zsidi, Gabriella Department of Physics and Astronomy The Johns Hopkins University BaltimoreMD21218 United States Space Telescope Science Institute BaltimoreMD21218 United States Israel Excellence Fellowship Department of Astronomy and Astrophysics University of California Santa CruzCA95064 United States School of Physics Trinity College Dublin The University of Dublin Dublin 2 Ireland Department of Astronomy University of Illinois 1002 W. Green St. Urbana-ChampaignIL61801 United States Center for Astrophysical Surveys National Center for Supercomputing Applications UrbanaIL61801 United States Department of Astronomy & Astrophysics The Pennsylvania State University University ParkPA16802 United States Institute for Computational & Data Sciences The Pennsylvania State University University ParkPA16802 United States Institute for Gravitation and the Cosmos The Pennsylvania State University University ParkPA16802 United States Astronomy Department University of Maryland College ParkMD20742 United States University of Notre Dame Notre DameIN46556 United States Mitchell Institute for Fundamental Physics Department of Physics and Astronomy Texas A&M University College StationTX77843 United States Purple Mountain Observatory Chinese Academy of Sciences 10 Yuanhua Road Nanjing210033 China Konkoly Observatory CSFK Konkoly-Thege M. ut 15-17 Budapest1121 Hungary MTA CSFK Lendület Near-Field Cosmology Research Group Konkoly Thege Miklós út 15-17 Budapest1121 Hungary Mt Stromlo Observatory The Research School of Astronomy and Astrophysics Australian National University ACT2601 Australia School of Physics The University of Melbourne VIC3010 Australia University of Maryland Baltimore County 1000 Hilltop Circle BaltimoreMD21250 United States Bay Area Environmental Research Institute P.O. Box 25 Moffett Field CA94035 United States Coral Towers Observatory Cairns Australia Institute for Astronomy University of Hawai'i 2680 Woodlawn Drive HonoluluHI96

We present the 30-min cadence Kepler/K2 light curve of the Type Ia supernova (SN Ia) SN 2018agk, covering approximately one week before explosion, the full rise phase and the decline until 40 days after peak. We additionally present ground-based observations in multiple bands within the same time range, including the 1-day cadence DECam observations within the first ~5 days after the first light. The Kepler early light curve is fully consistent with a single power-law rise, without evidence of any bump feature. We compare SN 2018agk with a sample of other SNe Ia without early excess flux from the literature. We find that SNe Ia without excess flux have slowly-evolving early colors in a narrow range (g - i ≈ -0.20±0.20 mag) within the first ~ 10 days. On the other hand, among SNe Ia detected with excess, SN 2017cbv and SN 2018oh tend to be bluer, while iPTF16abc's evolution is similar to normal SNe Ia without excess in g - i. We further compare the Kepler light curve of SN 2018agk with companion-interaction models, and rule out the existence of a typical non-degenerate companion undergoing Roche-lobe overflow at viewing angles smaller than 45°. © 2021, CC BY.

关键词： Supernovae

Multi-wavelength optical and NIR variability analysis of the Blazar PKS 0027-426

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arXiv 2021年

作者： Guise, Ella Hönig, S.F. Almeyda, T. Horne, K. Kishimoto, M. Aguena, M. Allam, S. Andrade-Oliveira, F. Asorey, J. Banerji, M. Bertin, E. Boulderstone, B. Brooks, D. Burke, D.L. Carnero Rosell, A. Carollo, D. Carrasco Kind, M. Carretero, J. Costanzi, M. da Costa, L.N. Davis, T.M. de Vicente, J. Doel, P. Everett, S. Ferrero, I. Flaugher, B. Frieman, J. Gandhi, P. Goad, M. Gruen, D. Gruendl, R.A. Gschwend, J. Gutierrez, G. Hinton, S.R. Hollowood, D.L. Honscheid, K. James, D.J. Johnson, M.A.C. Kuehn, K. Lewis, G.F. Lidman, C. Lima, M. Maia, M.A.G. Malik, U. Menanteau, F. Miquel, R. Morgan, R. Ogando, R.L.C. Palmese, A. Paz-Chinchón, F. Pereira, M.E.S. Pieres, A. Plazas Malagón, A.A. Sanchez, E. Scarpine, V. Serrano, S. Sevilla-Noarbe, I. Seymour, N. Smith, M. Soares-Santos, M. Suchyta, E. Swanson, M.E.C. Tarle, G. To, C. Tucker, B.E. School of Physics and Astronomy University of Southampton SouthamptonSO17 1BJ United Kingdom Department of Biological and Physical Sciences South Carolina State University OrangeburgSC29117 United States SUPA School of Physics and Astronomy University of St. Andrews North Haugh KY16 9SS United Kingdom Department of Physics Faculty of Science Kyoto Sangyo University Kamigamo-motoyama Kita-ku Kyoto603-8555 Japan Laboratório Interinstitucional de e-Astronomia - LIneA Rua Gal.José Cristino 77 RJ Rio de Janeiro20921-400 Brazil Fermi National Accelerator Laboratory P. O. Box 500 BataviaIL60510 United States Instituto de Física Teórica Universidade Estadual Paulista São Paulo Brazil Madrid Spain Institute of Astronomy University of Cambridge Madingley Road CambridgeCB3 0HA United Kingdom Kavli Institute for Cosmology University of Cambridge Madingley Road CambridgeCB3 0HA United Kingdom CNRS UMR 7095 Institut d’Astrophysique de Paris ParisF-75014 France Sorbonne Universités UPMC Univ Paris 06 UMR 7095 Institut d’Astrophysique de Paris ParisF-75014 France Department of Physics & Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom Kavli Institute for Particle Astrophysics & Cosmology Stanford University P. O. Box 2450 StanfordCA94305 United States SLAC National Accelerator Laboratory Menlo ParkCA94025 United States Instituto de Astrofisica de Canarias Tenerife La LagunaE-38205 Spain Universidad de La Laguna Dpto. Astrofísica Tenerife La LagunaE-38206 Spain INAF Astrophysical Observatory of Turin Pino TorineseI-10025 Italy Center for Astrophysical Surveys National Center for Supercomputing Applications 1205 West Clark St. UrbanaIL61801 United States Department of Astronomy University of Illinois at Urbana-Champaign 1002 W. Green Street UrbanaIL61801 United States 08193 Spain Astronomy Unit Department of Physics University of Trieste via Tiepolo 11 TriesteI-34131 Italy INAF-Osservatorio Astrono

We present multi-wavelength spectral and temporal variability analysis of PKS 0027-426 using optical griz observations from DES (Dark Energy Survey) between 2013-2018 and VOILETTE (VEILS Optical Light curves of Extragalactic TransienT Events) between 2018-2019 and near infrared (NIR) JKs observations from VEILS (VISTA Extragalactic Infrared Legacy Survey) between 2017-2019. Multiple methods of cross-correlation of each combination of light curve provides measurements of possible lags between optical-optical, optical-NIR, and NIR-NIR emission, for each observation season and for the entire observational period. Inter-band time lag measurements consistently suggest either simultaneous emission or delays between emission regions on timescales smaller than the cadences of observations. The colour-magnitude relation between each combination of filters was also studied to determine the spectral behaviour of PKS 0027-426. Our results demonstrate complex colour behaviour that changes between bluer when brighter (BWB), stable when brighter (SWB) and redder when brighter (RWB) trends over different timescales and using different combinations of optical filters. Additional analysis of the optical spectra is performed to provide further understanding of this complex spectral behaviour. © 2021, CC BY.

关键词： Infrared devices

An Integrated Tone Mapping for High Dynamic Range Image Visualization

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An Integrated Tone Mapping for High Dynamic Range Image Visu...

作者： Lei Liang Jeng-Shyang Pan Yongjun Zhuang Department of Computer Science and Technology Shenzhen Graduate School Harbin Institute of Technology Qihan Research Qihan Technology Co. LTD Fujian Provincial Key Lab of Big Data Mining and Applications Fujian University of Techology

There are two type tone mapping operators for high dynamic range(HDR) image visualization. HDR image mapped by perceptual operators have strong sense of reality, but will lose local details. Empirical operators can maximize local detail information of HDR image, but realism is not strong. A common tone mapping operator suitable for all applications is not available. This paper proposes a novel integrated tone mapping framework which can achieve conversion between empirical operators and perceptual operators. In this framework, the empirical operator is rendered based on improved saliency map, which simulates the visual attention mechanism of the human eye to the natural scene. The results of objective evaluation prove the effectiveness of the proposed solution.

关键词： image An Integrated Tone Mapping for High Dynamic Range Image Visualization HDR Mapping

C/2014 UN271(Bernardinelli-Bernstein): The nearly spherical cow of comets

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arXiv 2021年

作者： Bernardinelli, Pedro H. Bernstein, Gary M. Montet, Benjamin T. Weryk, Robert Wainscoat, Richard Aguena, M. Allam, S. Andrade-Oliveira, F. Annis, J. Avila, S. Bertin, E. Brooks, D. Burke, D.L. Rosell, A. Carnero Kind, M. Carrasco Carretero, J. Cawthon, R. Conselice, C. Costanzi, M. Da Costa, L.N. Pereira, M.E.S. De Vicente, J. Diehl, H.T. Everett, S. Ferrero, I. Flaugher, B. Frieman, J. García-Bellido, J. Gaztanaga, E. Gerdes, D.W. Gruen, D. Gruendl, R.A. Gschwend, J. Gutierrez, G. Hinton, S.R. Hollowood, D.L. Honscheid, K. James, D.J. Kuehn, K. Kuropatkin, N. Lahav, O. Maia, M.A.G. Marshall, J.L. Menanteau, F. Miquel, R. Morgan, R. Ogando, R.L.C. Paz-Chinchón, F. Pieres, A. Plazas Malagón, A.A. Rodriguez-Monroy, M. Romer, A.K. Roodman, A. Sanchez, E. Schubnell, M. Serrano, S. Sevilla-Noarbe, I. Smith, M. Soares-Santos, M. Suchyta, E. Swanson, M.E.C. Tarle, G. To, C. Troxel, M.A. Varga, T.N. Walker, A.R. Zhang, Y. Department of Physics and Astronomy University of Pennsylvania PhiladelphiaPA19104 United States School of Physics University of New South Wales SydneyNSW2052 Australia UNSW Data Science Hub University of New South Wales SydneyNSW2052 Australia Dept. of Physics & Astronomy University of Western Ontario 1151 Richmond Street LondonONN6A 3K7 Canada Institute for Astronomy University of Hawaii 2680 Woodlawn Drive HonoluluHI96822 United States Laboratório Interinstitucional de e-Astronomia - LIneA Rua Gal. José Cristino 77 RJ Rio de Janeiro20921-400 Brazil Fermi National Accelerator Laboratory P. O. Box 500 BataviaIL60510 United States Instituto de Física Teórica Universidade Estadual Paulista São Paulo Brazil Instituto de Fisica Teorica CSIC Universidad Autonoma de Madrid Madrid28049 Spain CNRS UMR 7095 Institut d'Astrophysique de Paris ParisF-75014 France Sorbonne Universités UPMC Univ Paris 06 UMR 7095 Institut d'Astrophysique de Paris ParisF-75014 France Department of Physics & Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom Kavli Institute for Particle Astrophysics & Cosmology Stanford University P. O. Box 2450 StanfordCA94305 United States SLAC National Accelerator Laboratory Menlo ParkCA94025 United States Center for Astrophysical Surveys National Center for Supercomputing Applications 1205 West Clark St. UrbanaIL61801 United States Department of Astronomy University of Illinois at Urbana-Champaign 1002 W. Green Street UrbanaIL61801 United States The Barcelona Institute of Science and Technology Campus UAB Bellaterra Barcelona08193 Spain Physics Department University of Wisconsin-Madison 2320 Chamberlin Hall 1150 University Avenue MadisonWI53706-1390 United States Jodrell Bank Center for Astrophysics School of Physics and Astronomy University of Manchester Oxford Road ManchesterM13 9PL United Kingdom University of Nottingham School of Physics and Astronomy NottinghamNG7 2RD U

C/2014 UN271(Bernardinelli-Bernstein) is a comet incoming from the Oort cloud which is remarkable in having the brightest (and presumably largest) nucleus of any well-measured comet, and having been discovered at heliocentric distance rh≈29 au farther than any Oort-cloud member. We describe the properties that can be inferred from images recorded until the first reports of activity in June 2021. The orbit has i=95°, with perihelion of 10.97 au to be reached in 2031, and previous aphelion at 40,400±260 au. Backwards integration of the orbit under a standard Galactic tidal model and known stellar encounters suggests this is a pristine new comet, with a perihelion of q≈18 au on its previous perihelion passage 3.5 Myr ago. The photometric data show an unresolved nucleus with absolute magnitude Hr=8.0, colors that are typical of comet nuclei or Damocloids, and no secular trend as it traversed the range 34-23 au. For r-band geometric albedo pr, this implies a diameter of 150 (pr/0.04)-0.5km. There is strong evidence of brightness fluctuations at ±0.2 mag level, but no rotation period can be discerned. A coma consistent with a "stationary" 1/ρ surface-brightness distribution grew in scattering cross-section at an exponential rate from Afρ ≈ 1 m to ≈ 150 m as the comet approached from 28 to 20 au. The activity is consistent with a simple model of sublimation of a surface species in radiative equilibrium with the Sun. The inferred enthalpy of sublimation matches those of CO2and NH3. More-volatile species - N2, CH4, and CO - must be far less abundant on the sublimating surfaces. © 2021, CC BY-NC-ND.

关键词： Comets

Robust frequent directions with application in online learning

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arXiv 2017年

作者： Luo, Luo Chen, Cheng Zhang, Zhihua Li, Wu-Jun Zhang, Tong Department of Computer Science and Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai200240 China National Engineering Lab for Big Data Analysis and Applications School of Mathematical Sciences Peking University 5 Yiheyuan Road Beijing100871 China National Key Laboratory for Novel Software Technology Collaborative Innovation Center of Novel Software Technology and Industrialization Department of Computer Science and Technology Nanjing University 163 Xianlin Avenue Nanjing210023 China Computer Science & Mathematics Hong Kong University of Science and Technology Hong Kong

The frequent directions (FD) technique is a deterministic approach for online sketching that has many applications in machine learning. The conventional FD is a heuristic procedure that often outputs rank deficient matrices. To overcome the rank deficiency problem, we propose a new sketching strategy called robust frequent directions (RFD) by introducing a regularization term. RFD can be derived from an optimization problem. It updates the sketch matrix and the regularization term adaptively and jointly. RFD reduces the approximation error of FD without increasing the computational cost. We also apply RFD to online learning and propose an effective hyperparameter-free online Newton algorithm. We derive a regret bound for our online Newton algorithm based on RFD, which guarantees the robustness of the algorithm. The experimental studies demonstrate that the proposed method outperforms state-of-the-art second order online learning algorithms. Copyright © 2017, The Authors. All rights reserved.

关键词： Heuristic methods

An Integrated Tone Mapping for High Dynamic Range Image Visualization

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Journal of Physics: Conference Series 2018年第1期960卷

作者： Lei Liang Jeng-Shyang Pan Yongjun Zhuang Department of Computer Science and Technology Shenzhen Graduate School Harbin Institute of Technology Shenzhen China Qihan Research Qihan Technology Co. LTD Shenzhen China Fujian Provincial Key Lab of Big Data Mining and Applications Fujian University of Techology Fujian China

There are two type tone mapping operators for high dynamic range (HDR) image visualization. HDR image mapped by perceptual operators have strong sense of reality, but will lose local details. Empirical operators can maximize local detail information of HDR image, but realism is not strong. A common tone mapping operator suitable for all applications is not available. This paper proposes a novel integrated tone mapping framework which can achieve conversion between empirical operators and perceptual operators. In this framework, the empirical operator is rendered based on improved saliency map, which simulates the visual attention mechanism of the human eye to the natural scene. The results of objective evaluation prove the effectiveness of the proposed solution.

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