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arXiv 2017年

作者： Shvartzvald, Y. Yee, J.C. Calchi, S. Novati Gould, A. Lee, C.-U. Beichman, C. Bryden, G. Carey, S. Gaudi, B.S. Henderson, C.B. Zhu, W. Albrow, M.D. Cha, S.-M. Chung, S.-J. Han, C. Hwang, K.-H. Jung, Y.K. Kim, D.-J. Kim, H.-W. Kim, S.-L. Lee, Y. Park, B.-G. Pogge, R.W. Ryu, Y.-H. Shin, I.-G. Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive PasadenaCA91109 United States Smithsonian Astrophysical Observatory 60 Garden St. CambridgeMA02138 United States IPAC Mail Code 100-22 Caltech 1200 E. California Blvd. PasadenaCA91125 United States 84084 Italy Korea Astronomy and Space Science Institute Daejon305-348 Korea Republic of Max-Planck-Institute for Astronomy Königstuhl 17 Heidelberg69117 Germany Department of Astronomy Ohio State University 140 W. 18th Ave. ColumbusOH43210 United States Korea University of Science and Technology 217 Gajeong-ro Yuseong-gu Daejeon34113 NASA Exoplanet Science Institute California Institute of Technology PasadenaCA91125 United States Spitzer Science Center MS 220-6 California Institute of Technology PasadenaCA United States University of Canterbury Department of Physics and Astronomy Private Bag 4800 Christchurch8020 New Zealand School of Space Research Kyung Hee University Yongin446-701 Department of Physics Chungbuk National University Cheongju361-763 Korea Republic of NASA Postdoctoral Program Fellow

We combine Spitzer and ground-based KMTNet microlensing observations to identify and precisely measure an Earth-mass (1.43+0−0..4532M⊕) planet OGLE-2016BLG-1195Lb at 1.16+0−0..1613AU orbiting a 0.078+0−0..012016M☉ ultracool dwarf. This is the lowest-mass microlensing planet to date. At 3.91+0−0..4246 kpc, it is the third consecutive case among the Spitzer "Galactic distribution" planets toward the Galactic bulge that lies in the Galactic disk as opposed to the bulge itself, hinting at a skewed distribution of planets. Together with previous microlensing discoveries, the seven Earth-size planets orbiting the ultracool dwarf TRAPPIST-1, and the detection of disks around young brown dwarfs, OGLE-2016-BLG-1195Lb suggests that such planets might be common around ultracool dwarfs. It therefore sheds light on the formation of both ultracool dwarfs and planetary systems at the limit of low-mass protoplanetary disks. Copyright © 2017, The Authors. All rights reserved.

关键词： Planets

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Toward a galactic distribution of planets. I. Methodology & planet sensitivities of the 2015 high-cadence spitzer microlens sample

arXiv

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arXiv 2017年

作者： Zhu, Wei Udalski, A. Novati, S. Calchi Chung, S.-J. Jung, Y.K. Ryu, Y.-H. Shin, I.-G. Gould, A. Lee, C.-U. Albrow, M.D. Yee, J.C. Han, C. Hwang, K.-H. Cha, S.-M. Kim, D.-J. Kim, H.-W. Kim, S.-L. Kim, Y.-H. Lee, Y. Park, B.-G. Pogge, R.W. Poleski, R. Skowron, J. Mroz, P. Szymanski, M.K. Soszynski, I. Pietrukowicz, P. KozLowski, S. Ulaczyk, K. Pawlak, M. Beichman, C. Bryden, G. Carey, S. Fausnaugh, M. Gaudi, B.S. Henderson, C.B. Shvartzvald, Y. Wibking, B. Department of Astronomy Ohio State University 140 W. 18th Ave ColumbusOH43210 United States Warsaw University Observatory AI. Ujazdowskie 4 Warszawa00-478 Poland IPAC Caltech 1200 E. California Blvd PasadenaCA91125 United States Dipartimento di Fisica E. R. Caianiello Universita di Salerno Via Giovanni Paolo II Fisciano84084 Italy Korea Astronomy and Space Science Institute 776 Daedeokdae-ro Yuseong-Gu Daejeon34055 Korea University of Science and Technology 217 Gajeong-Ro Yuseong-Gu Daejeon34113 Harvard-Smithsonian Center for Astrophysics 60 Garden St CambridgeMA02138 United States Max-Planck-Institute for Astronomy Konigstuhl 17 Heidelberg69117 Department of Physics and Astronomy University of Canterbury Private Bag Christchurch4800 New Zealand Department of Physics Chungbuk National University Cheongju361-763 Korea Republic of School of Space Research Kyung Hee University Giheung-Gu Yongin Gyeonggi-Go17104 Korea Republic of Department of Physics University of Warwick Gibbet Hill Road CoventryCV47AL United Kingdom NASA Exoplanet Science Institute California Institute of Technology PasadenaCA91125 United States Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive PasadenaCA91109 United States Spitzer Science Center California Institute of Technology PasadenaCA91125 United States Spitzer Team KMTNet Collaboration OGLE Collaboration NASA Postdoctoral Program Fellow

We analyze an ensemble of microlensing events from the 2015 Spitzer microlensing campaign, all of which were densely monitored by ground-based high-cadence survey teams. The simultaneous observations from Spitzer and the ground yield measurements of the microlensing parallax vector π E, from which compact constraints on the microlens properties are derived, including 25% uncertainties on the lens mass and distance. With the current sample, we demonstrate that the majority of microlenses are indeed in the mass range of M dwarfs. The planet sensitivities of all 41 events in the sample are calculated, from which we provide constraints on the planet distribution function. In particular, assuming a planet distribution function that is uniform in log q, where q is the planet-to-star mass ratio, we find a 95% upper limit on the fraction of stars that host typical microlensing planets of 49%, which is consistent with previous studies. Based on this planet-free sample, we develop the methodology to statistically study the Galactic distribution of planets using microlensing parallax measurements. Under the assumption that the planet distributions are the same in the bulge as in the disk, we predict that -1/3 of all planet detections from the microlensing campaigns with Spitzer should be in the bulge. This prediction will be tested with a much larger sample, and deviations from it can be used to constrain the abundance of planets in the bulge relative to the disk. Copyright © 2017, The Authors. All rights reserved.

关键词： Uncertainty analysis

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An ordinary short gamma-ray burst with extraordinary implications: Fermi-GBM detection of GRB 170817A

arXiv

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arXiv 2017年

作者： Goldstein, A. Veres, P. Burns, E. Briggs, M.S. Hamburg, R. Kocevski, D. Wilson-Hodge, C.A. Preece, R.D. Poolakkil, S. Roberts, O.J. Hui, C.M. Connaughton, V. Racusin, J. von Kienlin, A. Dal Canton, T. Christensen, N. Littenberg, T. Siellez, K. Blackburn, L. Broida, J. Bissaldi, E. Cleveland, W.H. Gibby, M.H. Giles, M.M. Kippen, R.M. McBreen, S. McEnery, J. Meegan, C.A. Paciesas, W.S. Stanbro, M. Science and Technology Institute Universities Space Research Association HuntsvilleAL35805 United States Center for Space Plasma and Aeronomic Research University of Alabama in Huntsville 320 Sparkman Drive HuntsvilleAL35899 United States NASA Postdoctoral Program Fellow Goddard Space Flight Center GreenbeltMD20771 United States Space Science Department University of Alabama in Huntsville 320 Sparkman Drive HuntsvilleAL35899 United States ST12 NASA/Marshall Space Flight Center Astrophysics Office HuntsvilleAL35812 United States NASA Goddard Space Flight Center GreenbeltMD20771 United States Max-Planck-Institut für extraterrestrische Physik Giessenbachstrasse 1 Garching85748 Germany Physics and Astronomy Carleton College MN55057 United States Artemis Université Côte d’Azur Observatoire Côte d’Azur CNRS CS 34229 Nice Cedex 4F-06304 France Center for Relativistic Astrophysics School of Physics Georgia Institute of Technology AtlantaGA30332 United States Harvard-Smithsonian Center for Astrophysics 60 Garden St CambridgeMA02138 United States Istituto Nazionale di Fisica Nucleare Sezione di Bari BariI-70126 Italy Jacobs Technology Inc. HuntsvilleAL35805 United States Los Alamos National Laboratory PO Box 1663 Los AlamosNM87545 United States School of Physics University College Dublin Belfield Stillorgan Road Dublin 4 Ireland

On August 17, 2017 at 12:41:06 UTC the Fermi Gamma-ray Burst Monitor (GBM) detected and triggered on the short gamma-ray burst GRB 170817A. Approximately 1.7 s prior to this GRB, the Laser Interferometer Gravitational-Wave Observatory (LIGO) triggered on a binary compact merger candidate associated with the GRB. This is the first unambiguous coincident observation of gravitational waves and electromagnetic radiation from a single astrophysical source and marks the start of gravitational-wave multi-messenger astronomy. We report the GBM observations and Copyright © 2017, The Authors. All rights reserved.

关键词： Stars

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A Measurement of CMB Cluster Lensing with SPT and DES Year 1 Data

arXiv

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arXiv 2017年

作者： Baxter, E.J. Raghunathan, S. Crawford, T.M. Fosalba, P. Hou, Z. Holder, G.P. Omori, Y. Patil, S. Rozo, E. Abbott, T.M.C. Annis, J. Aylor, K. Benoit-Lévy, A. Benson, B.A. Bertin, E. Bleem, L. Buckley-Geer, E. Burke, D.L. Carlstrom, J. Carnero Rosell, A. Carrasco Kind, M. Walker, A.R. Williamson, R. Zhang, Y. Zuntz, J. Carretero, J. Chang, C.L. Cho, H.-M. Crites, A.T. Crocce, M. Cunha, C.E. da Costa, L.N. Marrone, D.P. Marshall, J.L. Martini, P. McMahon, J.J. Melchior, P. Menanteau, F. Meyer, S.S. Miller, C.J. Miquel, R. Mocanu, L.M. Mohr, J.J. Natoli, T. Nord, B. Ogando, R.L.C. Sevilla-Noarbe, I. Shirokoff, E. Smith, M. Smith, R.C. Soares-Santos, M. Sobreira, F. Staniszewski, Z. D’Andrea, C.B. Davis, C. de Haan, T. Desai, S. Dietrich, J.P. Dobbs, M.A. Dodelson, S. Doel, P. Drlica-Wagner, A. Estrada, J. Everett, W.B. Fausti Neto, A. Flaugher, B. Frieman, J. García-Bellido, J. George, E.M. Gaztanaga, E. Giannantonio, T. Gruen, D. Gruendl, R.A. Gschwend, J. Gutierrez, G. Halverson, N.W. Harrington, N.L. Hartley, W.G. Holzapfel, W.L. Honscheid, K. Hrubes, J.D. Jain, B. James, D.J. Jarvis, M. Jeltema, T. Knox, L. Krause, E. Kuehn, K. Kuhlmann, S. Kuropatkin, N. Lahav, O. Lee, A.T. Leitch, E.M. Li, T.S. Lima, M. Luong-Van, D. Manzotti, A. March, M. Padin, S. Plazas, A.A. Pryke, C. Rapetti, D. Reichardt, C.L. Romer, A.K. Roodman, A. Ruhl, J.E. Rykoff, E. Sako, M. Sanchez, E. Sayre, J.T. Scarpine, V. Schaffer, K.K. Schindler, R. Schubnell, M. Stark, A. Story, K. Suchyta, E. Tarle, G. Thomas, D. Troxel, M.A. Vanderlinde, K. Vieira, J.D. Department of Physics and Astronomy University of Pennsylvania PhiladelphiaPA19104 United States School of Physics University of Melbourne ParkvilleVIC3010 Australia Kavli Institute for Cosmological Physics University of Chicago ChicagoIL60637 United States Department of Astronomy and Astrophysics University of Chicago ChicagoIL60637 United States Institute of Space Sciences IEEC-CSIC Campus UAB Carrer de Can Magrans s/n Barcelona08193 Spain Canadian Institute for Advanced Research CIFAR Program on Gravity and the Extreme Universe TorontoONM5G 1Z8 Canada Astronomy Department University of Illinois at Urbana Champaign 1002 W. Green Street UrbanaIL61801 United States Department of Physics University of Illinois Urbana Champaign 1110 W. Green Street UrbanaIL61801 United States Department of Physics McGill University 3600 rue University MontrealQCH3A 2T8 Canada Department of Physics University of Arizona TucsonAZ85721 United States Cerro Tololo Inter-American Observatory National Optical Astronomy Observatory Casilla 603 La Serena Chile Fermi National Accelerator Laboratory P. O. Box 500 BataviaIL60510 United States Department of Physics University of California DavisCA95616 United States CNRS UMR 7095 Institut d’Astrophysique de Paris ParisF-75014 France Department of Physics & Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom Sorbonne Universités UPMC Univ Paris 06 UMR 7095 Institut d’Astrophysique de Paris ParisF-75014 France Department of Physics University of Chicago 5640 South Ellis Avenue ChicagoIL60637 United States Argonne National Laboratory 9700 South Cass Avenue LemontIL60439 United States Kavli Institute for Particle Astrophysics and Cosmology Stanford University 452 Lomita Mall StanfordCA94305 United States SLAC National Accelerator Laboratory Menlo ParkCA94025 United States Enrico Fermi Institute University of Chicago ChicagoIL60637 United States Laboratório Interi

Clusters of galaxies gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint in the CMB on arcminute scales. Measurement of this effect offers a promising way to constrain the masses of galaxy clusters, particularly those at high redshift. We use CMB maps from the South Pole Telescope Sunyaev-Zel’dovich (SZ) survey to measure the CMB lensing signal around galaxy clusters identified in optical imaging from first year observations of the Dark Energy Survey. The cluster catalog used in this analysis contains 3697 members with mean redshift of z¯ = 0.45. We detect lensing of the CMB by the galaxy clusters at 8.1σ significance. Using the measured lensing signal, we constrain the amplitude of the relation between cluster mass and optical richness to roughly 17% precision, finding good agreement with recent constraints obtained with galaxy lensing. The error budget is dominated by statistical noise but includes significant contributions from systematic biases due to the thermal SZ effect and cluster miscentering. Copyright © 2017, The Authors. All rights reserved.

关键词： Cosmology

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OGLE-2016-BLG-1045: A test of cheap space-based microlens parallaxes

arXiv

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arXiv 2017年

作者： Shin, I.-G. Udalski, A. Yee, J.C. Calchi Novati, S. Christie, G. Poleski, R. Mróz, P. Skowron, J. Szymanski, M.K. Soszynski, I. Pietrukowicz, P. Kozlowski, S. Ulaczyk, K. Pawlak, M. Natusch, T. Pogge, R.W. Gould, A. Han, C. Albrow, M.D. Chung, S.-J. Hwang, K.-H. Ryu, Y.-H. Jung, Y.K. Zhu, W. Lee, C.-U. Cha, S.-M. Kim, D.-J. Kim, H.-W. Kim, S.-L. Lee, Y. Lee, D.-J. Park, B.-G. Beichman, C. Bryden, G. Carey, S. Gaudi, B.S. Henderson, C.B. Shvartzvald, Y. Harvard-Smithsonian Center for Astrophysics 60 Garden St. CambridgeMA02138 United States Warsaw University Observatory Al. Ujazdowskie 4 Warszawa00-478 Poland Department of Physics University of Warwick Gibbet Hill Road CoventryCV4 7AL United Kingdom Auckland Observatory Auckland New Zealand AUT University Auckland New Zealand Korea Astronomy and Space Science Institute 776 Daedeokdae-ro Yuseong-Gu Daejeon34055 Korea Republic of Korea University of Science and Technology 217 Gajeong-ro Yuseong-gu Daejeon34113 Korea Republic of University of Canterbury Department of Physics and Astronomy Private Bag 4800 Christchurch8020 New Zealand School of Space Research Kyung Hee University Giheung-gu Yongin Gyeonggi-do17104 Korea Republic of Department of Physics Chungbuk National University Cheongju28644 Korea Republic of IPAC Mail Code 100-22 California Institute of Technology 1200 E. California Boulevard PasadenaCA91125 United States NASA Exoplanet Science Institute California Institute of Technology PasadenaCA91125 United States Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive PasadenaCA91109 United States Spitzer Science Center MS 220-6 California Institute of Technology PasadenaCA United States Department of Astronomy Ohio State University 140 W. 18th Ave. ColumbusOH43210 United States Max-Planck-Institute for Astronomy Königstuhl 17 Heidelberg69117 Germany OGLE Collaboration µFUN Collaboration KMTNet Group Spitzer Team NASA Postdoctoral Program Fellow

Microlensing is a powerful and unique technique to probe isolated objects in the Galaxy. To study the characteristics of these interesting objects based on the microlensing method, measurement of the microlens parallax is required to determine the properties of the lens. Of the various methods to measure microlens parallax, the most routine way is to make simultaneous ground- and space-based observations, i.e., by measuring the space-based microlens parallax. However, space-based campaigns usually require "expensive" resources. Gould & Yee (2012) proposed an idea called the "cheap space-based microlens parallax" that can measure the lens-parallax using only two or three space-based observations of high-magnification events (as seen from Earth). This cost-effective observation strategy to measure microlens parallaxes could be used by space-borne telescopes to build a complete sample for studying isolated objects. This would enable a direct measurement of the mass function including both extremely low-mass objects and high-mass stellar remnants. However, to adopt this idea requires a test to check how it would work in actual situations. Thus, we present the first practical test of this idea using the high-magnification microlensing event OGLE-2016-BLG-1045, for which a subset of Spitzer observations fortuitously duplicate the prescription of Gould & Yee (2012). From the test, we confirm that the measurement of the lens-parallax adopting this idea has sufficient accuracy to determine the physical properties of the isolated lens. Copyright © 2017, The Authors. All rights reserved.

关键词： Geometrical optics

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From Dissemination to Propagation: A New Paradigm for Education Developers

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Change 2017年第4期49卷 35-42页

作者： Froyd, Jeffrey E. Henderson, Charles Cole, Renée S. Friedrichsen, Debra Khatri, Raina Stanford, Courtney Jeffrey E. Froyd is a Research Professor at Texas A&M University. His research interests include sustained adoption of improvements in learning and teaching systematic reviews in engineering education evaluation of faculty campus climates and assessment of complex learning outcomes. Charles Henderson is a Professor at Western Michigan University with a joint appointment between the Department of Physics and the Mallinson Institute for Science Education. His research focuses on promoting productive changes in higher education at the individual department institution and national levels. Renée S. Cole is an Associate Professor of Chemistry at the University of Iowa. She teaches introductory and advanced courses in chemistry and runs a research program focused on the design and assessment of instructional materials and teaching strategies and faculty professional development. Debra Friedrichsen founded and operates a small consulting company. She received her Ph.D. from Oregon State University in Chemical Engineering with a dissertation focused on engineering education. Debra also has a MBA a MS and a patent for sensor development. Raina Khatri is a doctoral student in the Mallinson Institute for Science Education at Western Michigan University. Her research focus is understanding how education developers in STEM can promote sustained adoption of their innovations. Courtney Stanford is a postdoctoral researcher in the Department of Chemistry at Virginia Commonwealth University. Her current research focuses on the identification development and assessment of process skills (also known as professional skills) in active learning undergraduate STEM classrooms.

Scholarly studies and national reports document failure of current efforts to achieve broad, sustained adoption of research-based instructional practices, despite compelling bodies of evidence supporting efficacy of many of these practices. The authors of this paper argue that many change agents who are working to promote systemic adoption of these teaching practices use approaches that are characterized by what the authors call the "dissemination paradigm." A dissemination paradigm characterizes patterns of these current, failing efforts. Change agents, working within the dissemination paradigm, try to convince adopters that their innovations can help their students. Efforts within the dissemination paradigm have not led, and are unlikely to lead, to systemic adoption. The authors offer the "propagation paradigm" as an alternative with the potential to produce improved results. Change agents, working within the propagation paradigm, engage with adopters early and often to understand their instructional systems and interactively develop a strong product adaptable to specific contexts.

关键词： Models Change Agents Teaching Methods Information Dissemination Educational Innovation Instructional Systems STEM Education Comparative Analysis

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Exploring the Environment of the most powerful Explosions

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Proceedings of the International Astronomical Union 2016年第A29B期11卷 261-262页

作者： Antonino Cucchiara Mark Rafelski Michele Fumagalli Daniel Kocevski Jason X. Prochaska Ryan J. Cooke G. D. Becker NASA Postdoctoral Program Fellow Goddard Space Flight Center Greenbelt MD 20771 USA email: antonino.cucchiara@nasa.gov Institute for Computational Cosmology Department of Physics Durham University South Road Durham DH1 3LE UK Carnegie Observatories 813 Santa Barbara Street Pasadena CA 91101 USA Department of Astronomy and Astrophysics UCO/Lick Observatory University of California 1156 High Street Santa Cruz CA 95064 USA Kavli Institute for Cosmology and Institute of Astronomy University of Cambridge Madingley Road Cambridge CB3 0HA UK

More than 60 GRBs at z ≳ 1.5 reside in the vicinity of dense, cold gas as probed by the measured neutral hydrogen via afterglow absorption spectroscopy. We present the largest sample of GRB-DLAs to date in comparison with a sample of DLAs along quasars: the metallicity of the GRB hosts represents a unique tool to understand if this particular subset of galaxies can be the key ingredient for GRB formation (and massive stars) at any redshift as well as the overall cosmic star-formation rate. We show that GRB-DLAs live in a metal enriched environment, especially at z ≳ 4, likely the result of recent intense star formation and/or SNe episodes. We also derive that our metallicity measurements are broadly consistent with a mild metallicity bias for the GRB formation.

关键词： gamma rays: bursts galaxies: ISM ISM: abundances

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Baryon content in a sample of 91 galaxy clusters selected by the south pole telescope at 0.2 < z < 1.25

arXiv

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arXiv 2017年

作者： Chiu, I. Mohr, J.J. McDonald, M. Bocquet, S. Desai, S. Klein, M. Israel, H. Ashby, M.L.N. Stanford, A. Benson, B.A. Brodwin, M. Abbott, T.M.C. Abdalla, F.B. Allam, S. Annis, J. Bayliss, M. Benoit-Lévy, A. Bertin, E. Bleem, L. Brooks, D. Buckley-Geer, E. Bulbul, E. Capasso, R. Carlstrom, J.E. Carnero Rosell, A. Carretero, J. Castander, F.J. Cunha, C.E. D'Andrea, C.B. da Costa, L.N. Davis, C. Diehl, H.T. Dietrich, J.P. Doel, P. Drlica-Wagner, A. Eifler, T.F. Evrard, A.E. Flaugher, B. García-Bellido, J. Garmire, G. Gaztanaga, E. Gerdes, D.W. Gonzalez, A. Gruen, D. Gruendl, R.A. Gschwend, J. Gupta, N. Gutierrez, G. Hlavacek, J.-L. Honscheid, K. James, D.J. Jeltema, T. Kraft, R. Krause, E. Kuehn, K. Kuhlmann, S. Kuropatkin, N. Lahav, O. Lima, M. Maia, M.A.G. Marshall, J.L. Melchior, P. Menanteau, F. Miquel, R. Murray, S. Nord, B. Ogando, R.L.C. Plazas, A.A. Rapetti, D. Reichardt, C.L. Romer, A.K. Roodman, A. Sanchez, E. Saro, A. Scarpine, V. Schindler, R. Schubnell, M. Sharon, K. Smith, R.C. Smith, M. Soares-Santos, M. Sobreira, F. Stalder, B. Stern, C. Strazzullo, V. Suchyta, E. Swanson, M.E.C. Tarle, G. Vikram, V. Walker, A.R. Weller, J. Zhang, Y. 11F of AS/NTU Astronomy-Mathematics Building No.1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan Faculty of Physics Ludwig-Maximilians-Universität Scheinerstr. 1 Munich81679 Germany Excellence Cluster Universe Boltzmannstr. 2 Garching85748 Germany Max Planck Institute for Extraterrestrial Physics Giessenbachstrasse Garching85748 Germany Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology 77 Massachusetts Avenue CambridgeMA02139 United States Argonne National Laboratory High-Energy Physics Division 9700 S. Cass Avenue ArgonneIL60439 United States Department of Physics IIT Hyderabad Kandi Telangana502285 India Harvard-Smithsonian Center for Astrophysics 60 Garden Street CambridgeMA02138 United States Physics Department University of California DavisCA95616 United States Fermi National Accelerator Laboratory BataviaIL60510-0500 United States Department of Astronomy and Astrophysics University of Chicago 5640 South Ellis Avenue ChicagoIL60637 United States Kavli Institute for Cosmological Physics University of Chicago 5640 South Ellis Avenue ChicagoIL60637 United States Department of Physics and Astronomy University of Missouri 5110 Rockhill Road Kansas CityMO64110 United States Cerro Tololo Inter-American Observatory National Optical Astronomy Observatory Casilla 603 La Serena Chile Department of Physics and Electronics Rhodes University PO Box 94 Grahamstown6140 South Africa Department of Physics & Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom Fermi National Accelerator Laboratory P. O. Box 500 BataviaIL60510 United States Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology 77 Massachusetts Avenue CambridgeMA02139 United States Sorbonne Universités UPMC Univ Paris 06 UMR 7095 Institut d'Astrophysique de Paris ParisF-75014 France CNRS UMR 7095 Institut d'Astrophysique de Paris ParisF-75014 France Argonne National

We estimate total mass (M500), intracluster medium (ICM) mass (MICM) and stellar mass (M*) in a Sunyaev-Zel'dovich effect (SZE) selected sample of 91 galaxy clusters with masses M500 2.5 × 1014M☉ and redshift 0.2 2 South Pole Telescope SPT-SZ survey. The total masses M500 are estimated from the SZE observable, the ICM masses MICM are obtained from the analysis of Chandra X-ray observations, and the stellar masses M* are derived by fitting spectral energy distribution templates to Dark Energy Survey (DES) griz optical photometry and WISE or Spitzer near-infrared photometry. We study trends in the stellar mass, the ICM mass, the total baryonic mass and the cold baryonic fraction with cluster halo mass and redshift. We find significant departures from self-similarity in the mass scaling for all quantities, while the redshift trends are all statistically consistent with zero, indicating that the baryon content of clusters at fixed mass has changed remarkably little over the past ≈ 9 Gyr. We compare our results to the mean baryon fraction (and the stellar mass fraction) in the field, finding that these values lie above (below) those in cluster virial regions in all but the most massive clusters at low redshift. Using a simple model of the matter assembly of clusters from infalling groups with lower masses and from infalling material from the low density environment or field surrounding the parent halos, we show that the measured mass trends without strong redshift trends in the stellar mass scaling relation could be explained by a mass and redshift dependent fractional contribution from field material. Similar analyses of the ICM and baryon mass scaling relations provide evidence for the so-called "missing baryons" outside cluster virial regions. Copyright © 2017, The Authors. All rights reserved.

关键词： Hadrons

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A survey of eight hot Jupiters in secondary eclipse using WIRCam at CFHT

arXiv

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arXiv 2017年

作者： Stassun, Keivan G. Eastman, Jason D. Pepper, Joshua Angerhausen, Daniel Stevens, Daniel J. James, David J. Gaudi, B. Scott Bayliss, Daniel Tata, Ramarao Zhou, George Colón, Knicole D. Martioli, Eder Rodriguez, Joseph E. Beatty, Thomas G. Wilson, Paul Anthony Rua Estados Unidos 154 ItajubáMG Brazil NASA Ames Research Center M/S 244-30 Moffett FieldCA94035 United States Bay Area Environmental Research Institute 625 2nd St. Ste 209 PetalumaCA94952 United States USRA NASA Postdoctoral Program Fellow NASA Goddard Space Flight Center 8800 Greenbelt Road GreenbeltMD20771 United States Department of Physics and Astronomy Vanderbilt University 6301 Stevenson Center NashvilleTN37235 United States Department of Physics Fisk University NashvilleTN37208 United States Harvard-Smithsonian Center for Astrophysics 60 Garden St CambridgeMA02138 United States Department of Astronomy Ohio State University 140 West 18th Avenue ColumbusOH43210 United States Department of Physics Lehigh University 16 Memorial Drive East BethlehemPA18015 United States Department of Astronomy & Astrophysics Pennsylvania State University 525 Davey Lab University ParkPA16802 United States Center for Exoplanets and Habitable Worlds Pennsylvania State University 525 Davey Lab University ParkPA16802 United States Ohio University AthensOH45701 United States Department of Astronomy University of Washington Box 351580 SeattleWA98195 United States CNRS UMR 7095 Institut d’Astrophysique de Paris 98bis Boulevard Arago ParisF-75014 France Observatoire Astronomique de l’Université de Geève Chemin des Maillettes 51 Sauverny1290 Switzerland Center for Space and Habitability University of Bern Sidlerstrasse 5 Bern3012 Switzerland GreenbeltMD20771 United States

We present near infrared high-precision photometry for eight transiting hot Jupiters observed during their predicted secondary eclipses. Our observations were carried out using the staring mode of the WIRCam instrument on the Canada-France-Hawaii Telescope (CFHT). We present the observing strategies and data reduction methods which delivered time series photometry with statistical photometric precision as low as 0.11%. We performed a Bayesian analysis to model the eclipse parameters and systematics simultaneously. The measured planet-to-star flux ratios allowed us to constrain the thermal emission from the day side of these hot Jupiters, as we derived the planet brightness temperatures. Our results combined with previously observed eclipses reveal an excess in the brightness temperatures relative to the blackbody prediction for the equilibrium temperatures of the planets for a wide range of heat redistribution factors. We find a trend that this excess appears to be larger for planets with lower equilibrium temperatures. This may imply some additional sources of radiation, such as reflected light from the host star and/or thermal emission from residual internal heat from the formation of the planet. Copyright © 2017, The Authors. All rights reserved.

关键词： Photometry

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OGLE-2015-BLG-1482L: THE FIRST ISOLATED LOW-MASS MICROLENS IN THE GALACTIC BULGE

arXiv

引用

arXiv 2017年

作者： Chung, S.-J. Zhu, W. Udalski, A. Lee, C.-U. Ryu, Y.-H. Jung, Y.K. Shin, I.-G. Yee, J.C. Hwang, K.-H. Gould, A. Albrow, M. Cha, S.-M. Han, C. Kim, D.-J. Kim, H.-W. Kim, S.-L. Kim, Y.-H. Lee, Y. Park, B.-G. Pogge, R.W. Poleski, R. Mróz, P. Pietrukowicz, P. Skowron, J. Szymanski, M.K. Soszynski, I. Kozlowski, S. Ulaczyk, K. Pawlak, M. Beichman, C. Bryden, G. Novati, S. Calchi Carey, S. Fausnaugh, M. Gaudi, B.S. Henderson, Calen B. Shvartzvald, Y. Wibking, B. Korea Astronomy and Space Science Institute 776 Daedeokdae-ro Yuseong-Gu Daejeon34055 Korea Republic of Korea Universit of Science and Technolo 217 Gajeon -ro Yuseon Daejeon34113 Department of Astronomy Ohio State University 140 W 18th Ave ColumbusOH43210 United States Warsaw University Observatory AI Ujazdowskie 4 Warszawa00-478 Poland Harvard-Smithsonian Center for Astrophysics 60 Garden St. CambridgeMA02138 United States Max-Planck-Institute for Astronomy Königstuhl 17 Heidelberg69117 Germany Department of Physics and Astronomy University of Canterbury Private Bag 4800 Christchurch New Zealand School of Space Research Kyung Hee University Giheung-gu Yongin Gyeonggi-do17104 Korea Republic of Department of Physics Chungbuk National University Cheongju361-763 Korea Republic of De artment of Ph sics Uni ersit of War ick Gibbet Hill Road Co entrCV4 7AL United Kingdom NASA Exoplanet Science Institute MS 100-22 California Institute of Technology PasadenaCA91125 United States Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive PasadenaCA91109 United States IPAC Mail Code 100-22 Caltech 1200 E California Blvd PasadenaCA91125 United States 84084 Italy Spitzer Science Center MS 220-6 California Institute of Technology PasadenaCA United States NASA Postdoctoral Program Fellow KMTNet Collaboration The OGLE Collaboration Spitzer Team

We analyze the single microlensing event OGLE-2015-BLG-1482 simultaneously observed from two ground-based surveys and from Spitzer. The Spitzer data exhibit finite-source effects due to the passage of the lens close to or directly over the surface of the source star as seen from Spitzer. Such finite-source effects generally yield measurements of the angular Einstein radius, which when combined with the microlens parallax derived from a comparison between the ground-based and the Spitzer light curves, yields the lens mass and lens-source relative parallax. From this analysis, we find that the lens of OGLE-2015-BLG-1482 is a very low-mass star with the mass 0.10±0.02 M or a brown dwarf with the mass 55±9 MJ, which are respectively located at DLS = 0.80±0.19 kpc and DLS = 0.54±0.08 kpc, where DLS is the distance between the lens and the source, and thus it is the first isolated low-mass microlens that has been decisively located in the Galactic bulge. The degeneracy between the two solutions is severe (∆χ2 = 0.3). The fundamental reason for the degeneracy is that the finite-source effect is seen only in a single data point from Spitzer and this single data point gives rise to two solutions for ρ, the angular size of the source in units of the angular Einstein ring radius. Because the ρ degeneracy can be resolved only by relatively high cadence observations around the peak, while the Spitzer cadence is typically ∼ 1 day−1, we expect that events for which the finite-source effect is seen only in the Spitzer data may frequently exhibit this ρ degeneracy. For OGLE-2015-BLG-1482, the relative proper motion of the lens and source for the low-mass star is µrel = 9.0 ±1.9 mas yr−1, while for the brown dwarf it is µrel = 5.5 ± 0.5 mas yr−1. Hence, the degeneracy can be resolved within ∼ 10 yrs from direct lens imaging by using next-generation instruments with high spatial resolution. Keywords: brown dwarfs - gravitational lensing: micro - stars: fundamental parameters Copyright

关键词： Geometrical optics

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