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arXiv 2017年

作者： Zhu, Wei Udalski, A. Huang, C.X. Novati, S. Calchi Sumi, T. Poleski, R. Skowron, J. Mróz, P. Szymanski, M.K. Soszynski, I. Pietrukowicz, P. Koz lowski, S. Ulaczyk, K. Pawlak, M. Beichman, C. Bryden, G. Carey, S. Gaudi, B.S. Gould, A. Henderson, C.B. Shvartzvald, Y. Yee, J.C. Bond, I.A. Bennett, D.P. Suzuki, D. Rattenbury, N.J. Koshimoto, N. Abe, F. Asakura, Y. Barry, R.K. Bhattacharya, A. Donachie, M. Evans, P. Fukui, A. Hirao, Y. Itow, Y. Kawasaki, K. Li, M.C.A. Ling, C.H. Masuda, K. Matsubara, Y. Miyazaki, S. Munakata, H. Muraki, Y. Nagakane, M. Ohnishi, K. Ranc, C. Saito, To. Sharan, A. Sullivan, D.J. Tristram, P.J. Yamada, T. Yonehara, A. Department of Astronomy Ohio State University 140 W. 18th Ave. ColumbusOH43210 United States Canadian Institute for Theoretical Astrophysics University of Toronto 60 St George Street TorontoONM5S 3H8 Canada Warsaw University Observatory Al. Ujazdowskie 4 Warszawa00-478 Poland Department of Physics Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology CambridgeMA02139 United States IPAC Mail Code 100-22 Caltech 1200 E. California Blvd. PasadenaCA91125 United States 84084 Italy Department of Earth and Space Science Graduate School of Science Osaka University 1-1 Machikaneyama Toyonake Osaka560-0043 Japan Department of Physics University of Warwick Gibbert Hill Road CoventryCV4 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 Spitzer Science Center MS 220-6 California Institute of Technology PasadenaCA United States Korea Astronomy and Space Science Institute 776 Daedeokdae-ro Yuseong-Gu Daejeon34055 Korea Republic of Max-Planck-Institute for Astronomy Königstuhl 17 Heidelberg69117 Germany NASA Postdoctoral Program Smithsonian Astrophysical Observatory 60 Garden St. CambridgeMA02138 United States Institute for Natural and Mathematical Sciences Massey University North Shore Mail Centre Private Bag 102904 Auckland0745 New Zealand Laboratory for Exoplanets and Stellar Astrophysics NASA/Goddard Space Flight Center GreenbeltMD20771 United States Institute of Space and Astronautical Science Japan Aerospace Exploration Agency 3-1-1 Yoshinodai Chuo Sagamihara Kanagawa252-5210 Japan Department of Physics University of Auckland Private Bag 92019 Auckland New Zealand Institute of Space-Earth Environmental Research Nagoya University Furo-cho Chikusa Nagoya Aichi464-8601 Japan Department of Physics Unive

We present the result of microlensing event MOA-2016-BLG-290, which received observations from the two-wheel Kepler (K2), Spitzer, as well as ground-based observatories. A joint analysis of data from K2 and the ground leads to two degenerate solutions of the lens mass and distance. This degeneracy is effectively broken once the (partial) Spitzer light curve is included. Altogether, the lens is found to be an extremely low-mass star located in the Galactic bulge. MOA-2016-BLG-290 is the first microlensing event for which we have signals from three well-separated (∼ 1 AU) locations. It demonstrates the power of two-satellite microlensing experiment in reducing the ambiguity of lens properties, as pointed out independently by S. Refsdal and A. Gould several decades ago. Copyright © 2017, The Authors. All rights reserved.

关键词： Geometrical optics

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Combining spitzer parallax and Keck II adaptive optics imaging to measure the mass of a solar-like star orbited by a cold gaseous planet discovered by microlensing

arXiv

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arXiv 2017年

作者： Beaulieu, J.-P. Batista, V. Bennett, D.P. Marquette, J.-B. Blackman, J.W. Cole, A.A. Coutures, C. Danielski, C. Dominis-Prester, D. Donatowicz, J. Fukui, A. Koshimoto, N. Lončaric, C. Morales, J.C. Sumi, T. Suzuki, D. Henderson, C. Shvartzvald, Y. Beichman, C. School of Physical Sciences University of Tasmania Private Bag 37 HobartTAS7001 Australia Sorbonne Universités UPMC Université Paris 6 CNRS UMR 7095 Institut dAstrophysique de Paris 98 bis bd Arago Paris75014 France Laboratory for Exoplanets and Stellar Astrophysics NASA/Goddard Space Flight Center GreenbeltMD20771 United States Laboratoire d’Astrophysique de Bordeaux Univ. Bordeaux CNRS B18N allée Geoffroy Saint-Hilaire Pessac33615 France GEPI Observatoire de Paris Section de Meudon 5 place Jules Janssen Meudon92195 France Department of Physics University of Rijeka Radmile Matejčić 2 Rijeka51000 Croatia Technische Universitt Wien Karlsplatz 13 Wien1040 Austria Okayama Astrophysical Observatory National Astronomical Observatory of Japan Asakuchi Okayama719-0232 Japan Department of Earth and Space Science Graduate School of Science Osaka University 1-1 Machikaneyama Toyonaka Osaka560-0043 Japan Campus UAB Carrer de Can Magrans s/n Cerdanyola del VallsE-08193 Spain Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive PasadenaCA91109 United States NASA Exoplanet Science Institute California Institute of Technology Jet Propulsion Laboratory PasadenaCA91125 United States PAC/NExScI Mail Code 100-22 Caltech 1200 East California Boulevard PasadenaCA91125 NASA Postdoctoral Program

To obtain accurate mass measurements for cold planets discovered by microlensing, it is usually necessary to combine light curve modeling with at least two lens mass-distance relations. Often, a constraint on the Einstein ring radius measurement is obtained from the caustic crossing time: This is supplemented by secondary constraints such as precise parallax measurements and/or measures of the lens luminosity using high angular resolution observations. In the discovery paper of the planetary system OGLE-2014-BLG-0124Lb, the OGLE ground-based observations were combined with simultaneous Spitzer observations, providing good measurements of the mass ratio and projeced separation of the planetary system. The parallax was also well-measured, but the photometric data failed to tightly constrain the Einstein ring radius, ΘE. As a consequence, the physical parameters are therefore poorly constrained in the original study. We resolved the source+lens star from subarcsecond blends in H band using adaptive optics (AO) observations with NIRC2 mounted on Keck II telescope. We identify additional flux, coincident with the source to within 160 mas. We estimate the potential contributions to this blended light (chance-aligned star, additional companion to the lens or to the source) and find that 85% of of the NIR flux is due to the lens star at HL = 16.63 ± 0.06 and KL = 16.46 ±0.06. We combined the parallax constraint and the AO constraint to derive the physical parameters of the system. The lensing system is composed of a mid-late type G main sequence star of ML = 0.89 ± 0.05 Mo located at DL = 3.6 ± 0.3 kpc in the Galactic disk. Taking the mass ratio and projected separation from the original study leads to a planet of Mp = 0.64 ± 0.044 MJupiter at 3.48 ± 0.22 AU. Excellent parallax measurement from simultaneous ground-space observations have been obtained on the microlensing event OGLE-2014-BLG-0124, but it is only when they are combined with ∼ 30 min of Keck II AO observations

关键词： Geometrical optics

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GAMMA-RAY BLAZARS WITHIN THE FIRST 2 BILLION YEARS

arXiv

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arXiv 2017年

作者： Ackermann, M. Ajello, M. Baldini, L. Ballet, J. Barbiellini, G. Bastieri, D. Becerra Gonzalez, J. Bellazzini, R. Bissaldi, E. Blandford, R.D. Bloom, E.D. Bonino, R. Bottacini, E. Bregeon, J. Bruel, P. Buehler, R. Buson, S. Cameron, R.A. Caragiulo, M. Caraveo, P.A. Cavazzuti, E. Cecchi, C. Cheung, C.C. Chiang, J. Chiaro, G. Ciprini, S. Conrad, J. Costantin, D. Costanza, F. Cutini, S. D’Ammando, F. Palma, F.D.E. Desiante, R. Digel, S.W. Lalla, N.D.I. Mauro, M.D.I. Venere, L.D.I. Domínguez, A. Drell, P.S. Favuzzi, C. Fegan, S.J. Ferrara, E.C. Finke, J. Focke, W.B. Fukazawa, Y. Funk, S. Fusco, P. Gargano, F. Gasparrini, D. Giglietto, N. Giordano, F. Giroletti, M. Green, D. Grenier, I.A. Guillemot, L. Guiriec, S. Hartmann, D.H. Hays, E. Horan, D. Jogler, T. Jóhannesson, G. Johnson, A.S. Kuss, M. Mura, G.L.A. Larsson, S. Latronico, L. Li, J. Longo, F. Loparco, F. Lovellette, M.N. Lubrano, P. Magill, J.D. Maldera, S. Manfreda, A. Marcotulli, L. Mazziotta, M.N. Michelson, P.F. Mirabal, N. Mitthumsiri, W. Mizuno, T. Monzani, M.E. Morselli, A. Moskalenko, I.V. Negro, M. Nuss, E. Ohsugi, T. Ojha, R. Omodei, N. Orienti, M. Orlando, E. Ormes, J.F. Paliya, V.S. Paneque, D. Perkins, J.S. Persic, M. Pesce-Rollins, M. Piron, F. Porter, T.A. Principe, G. Rainò, S. Rando, R. Rani, B. Razzano, M. Razzaque, S. Reimer, A. Torres, D.F. Torresi, E. Tosti, G. Troja, E. Vianello, G. Wood, K.S. Reimer, O. Romani, R.W. Sgrò, C. Simone, D. Siskind, E.J. Spada, F. Spandre, G. Spinelli, P. Stalin, C.S. Stawarz, L. Suson, D.J. Takahashi, M. Tanaka, K. Thayer, J.B. Thompson, D.J. Deutsches Elektronen Synchrotron DESY ZeuthenD-15738 Germany Department of Physics and Astronomy Clemson University Kinard Lab of Physics ClemsonSC29634-0978 United States Università di Pisa Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy Laboratoire AIM CEA-IRFU CNRS Université Paris Diderot Service d’Astrophysique CEA Saclay Gif sur YvetteF-91191 France Istituto Nazionale di Fisica Nucleare Sezione di Trieste TriesteI-34127 Italy Dipartimento di Fisica Università di Trieste TriesteI-34127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Padova PadovaI-35131 Italy Dipartimento di Fisica e Astronomia "G. Galilei" Università di Padova PadovaI-35131 Italy NASA Goddard Space Flight Center GreenbeltMD20771 United States Department of Physics Department of Astronomy University of Maryland College ParkMD20742 United States Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Bari BariI-70126 Italy W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics SLAC National Accelerator Laboratory Stanford University StanfordCA94305 United States Istituto Nazionale di Fisica Nucleare Sezione di Torino TorinoI-10125 Italy Dipartimento di Fisica Università degli Studi di Torino TorinoI-10125 Italy Laboratoire Univers et Particules de Montpellier Université Montpellier CNRS/IN2P3 MontpellierF-34095 France Laboratoire Leprince-Ringuet École polytechnique CNRS/IN2P3 PalaiseauF-91128 France NASA Postdoctoral Program Fellow United States Dipartimento di Fisica "M. Merlin" dell’Università e del Politecnico di Bari BariI-70126 Italy INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano via E. Bassini 15 MilanoI-20133 Italy Science Data Center RomaI-00133 Italy Istituto Nazionale di Fisica Nucleare Sezione di Perugia PerugiaI-06123 Italy Dipartimento di Fisica Università

The detection of high-redshift (z >3) blazars enables the study of the evolution of the most luminous relativistic jets over cosmic time. More importantly, high-redshift blazars tend to host massive black holes and can be used to constrain the space density of heavy black holes in the early Universe. Here, we report the first detection with the Fermi-Large Area Telescope of five γ-ray emitting blazars beyond z = 3.1, more distant than any blazars previously detected in γ-rays. Among these five objects, NVSS J151002+570243 is now the most distant known γ-ray emitting blazar at z = 4.31. These objects have steeply falling γ-ray spectral energy distributions (SEDs) and, those that have been observed in X-rays, a very hard X-ray spectrum, both typical of powerful blazars. Their Compton dominance (ratio of the inverse Compton to synchrotron peak luminosities) is also very large (> 20). All of these properties place these objects among the most extreme members of the blazar population. Their optical spectra and the modeling of their optical-UV SEDs confirm that these objects harbor massive black holes (MBH ∼ 108−10M.). We find that, at z ≈ 4, the space density of > 109M. black holes hosted in radio-loud and radio-quiet active galactic nuclei are similar, implying that radio-loudness may play a key role in rapid black hole growth in the early Universe. Copyright © 2017, The Authors. All rights reserved.

关键词： Cosmology

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Characterizing the population of pulsars in the inner galaxy with the fermi large area telescope

arXiv

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arXiv 2017年

作者： Ajello, M. Baldini, L. Ballet, J. Barbiellini, G. Bastieri, D. Bellazzini, R. Bissaldi, E. Blandford, R.D. Bloom, E.D. Bottacini, E. Bregeon, J. Bruel, P. Buehler, R. Cameron, R.A. Caputo, R. Caragiulo, M. Caraveo, P.A. Cavazzuti, E. Cecchi, C. Charles, E. Chekhtman, A. Chiaro, G. Ciprini, S. Costantin, D. Costanza, F. D’Ammando, F. Palma, F.D.E. Desiante, R. Digel, S.W. Lalla, N.D.I. Mauro, M.D.I. Venere, L.D.I. Favuzzi, C. Ferrara, E.C. Franckowiak, A. Fukazawa, Y. Funk, S. Fusco, P. Gargano, F. Gasparrini, D. Giglietto, N. Giordano, F. Giroletti, M. Green, D. Guillemot, L. Guiriec, S. Harding, A.K. Horan, D. Jóhannesson, G. Kuss, M. Mura, G.L.A. Larsson, S. Latronico, L. Li, J. Longo, F. Loparco, F. Lovellette, M.N. Lubrano, P. Maldera, S. Malyshev, D. Marcotulli, L. Martin, P. Mazziotta, M.N. Meyer, M. Michelson, P.F. Mirabal, N. Mizuno, T. Monzani, M.E. Morselli, A. Moskalenko, I.V. Nuss, E. Omodei, N. Orienti, M. Orlando, E. Palatiello, M. Paliya, V.S. Paneque, D. Perkins, J.S. Persic, M. Pesce-Rollins, M. Piron, F. Principe, G. Rainò, S. Rando, R. Razzano, M. Reimer, A. Reimer, O. Parkinson, P.M. Saz Sgrò, C. Siskind, E.J. Smith, D.A. Spada, F. Spandre, G. Spinelli, P. Tajima, H. Thayer, J.B. Thompson, D.J. Tibaldo, L. Torres, D.F. Troja, E. Vianello, G. Wood, K. Wood, M. Zaharijas, G. Department of Physics and Astronomy Clemson University Kinard Lab of Physics ClemsonSC29634-0978 United States Università di Pisa Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy Laboratoire AIM CEA-IRFU CNRS Université Paris Diderot Service d’Astrophysique CEA Saclay Gif sur YvetteF-91191 France Istituto Nazionale di Fisica Nucleare Sezione di Trieste TriesteI-34127 Italy Dipartimento di Fisica Università di Trieste TriesteI-34127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Padova PadovaI-35131 Italy Dipartimento di Fisica e Astronomia "G. Galilei" Università di Padova PadovaI-35131 Italy Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy Dipartimento di Fisica "M. Merlin" dell’Università e del Politecnico di Bari BariI-70126 Italy Istituto Nazionale di Fisica Nucleare Sezione di Bari BariI-70126 Italy W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics SLAC National Accelerator Laboratory Stanford University StanfordCA94305 United States Laboratoire Univers et Particules de Montpellier Université Montpellier CNRS/IN2P3 MontpellierF-34095 France Laboratoire Leprince-Ringuet École polytechnique CNRS/IN2P3 PalaiseauF-91128 France Deutsches Elektronen Synchrotron DESY ZeuthenD-15738 Germany NASA Goddard Space Flight Center GreenbeltMD20771 United States INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano via E. Bassini 15 MilanoI-20133 Italy Italian Space Agency Via del Politecnico snc Roma00133 Italy Istituto Nazionale di Fisica Nucleare Sezione di Perugia PerugiaI-06123 Italy Dipartimento di Fisica Università degli Studi di Perugia PerugiaI-06123 Italy College of Science George Mason University Fairfax Naval Research DC20375 United States ASI Space Science Data Center Via del Politecnico snc Roma00133 Italy INAF Istituto di Radioastronomia BolognaI-40129 Italy Dipartimento di Ast

An excess of γ-ray emission from the Galactic Center (GC) region with respect to predictions based on a variety of interstellar emission models and γ-ray source catalogs has been found by many groups using data from the Fermi Large Area Telescope (LAT). Several interpretations of this excess have been invoked. In this paper we search for members of an unresolved population of γ-ray pulsars located in the inner Galaxy that are predicted by the interpretation of the GC excess as being due to a population of such sources. We use cataloged LAT sources to derive criteria that efficiently select pulsars with very small contamination from blazars. We search for point sources in the inner 40◦ × 40◦ region of the Galaxy, derive a list of approximately 400 sources, and apply pulsar selection criteria to extract pulsar candidates among our source list. We performed the entire data analysis chain with two different interstellar emission models (IEMs), and found a total of 135 pulsar candidates, of which 66 were selected with both IEMs. Copyright © 2017, The Authors. All rights reserved.

关键词： Pulsars

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Exoplanet biosignatures: A review of remotely detectable signs of life

arXiv

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arXiv 2017年

作者： Schwieterman, Edward W. Kiang, Nancy Y. Parenteau, Mary N. Harman, Chester E. DasSarma, Shiladitya Fisher, Theresa M. Arney, Giada N. Hartnett, Hilairy E. Reinhard, Christopher T. Olson, Stephanie L. Meadows, Victoria S. Cockell, Charles S. Walker, Sara I. Grenfell, John Lee Hegde, Siddharth Rugheimer, Sarah Hu, Renyu Lyons, Timothy W. Department of Earth Sciences University of California RiversideCA United States NASA Postdoctoral Program Universities Space Research Association ColumbiaMD United States NASA Astrobiology Institute Virtual Planetary Laboratory Team SeattleWA United States NASA Astrobiology Institute Alternative Earths Team RiversideCA United States Blue Marble Space Institute of Science SeattleWA United States NASA Goddard Institute for Space Studies New YorkNY United States NASA Ames Research Center Exobiology Branch Mountain ViewCA United States Department of Applied Physics and Applied Mathematics Columbia University New YorkNY United States Department of Microbiology and Immunology University of Maryland School of Medicine BaltimoreMD United States Institute of Marine and Environmental Technology University System of Maryland BaltimoreMD United States School of Earth and Space Exploration Arizona State University TempeAZ United States Planetary Systems Laboratory NASA Goddard Space Flight Center GreenbeltMD United States School of Molecular Sciences Arizona State University TempeAZ United States School of Earth and Atmospheric Sciences Georgia Institute of Technology AtlantaGA United States Astronomy Department University of Washington SeattleWA United States University of Edinburgh School of Physics and Astronomy Edinburgh United Kingdom UK Centre for Astrobiology Edinburgh United Kingdom Beyond Center for Fundamental Concepts in Science Arizona State University TempeAZ United States ASU-Santa Fe Institute Center for Biosocial Complex Systems Arizona State University TempeAZ United States Berlin Germany Carl Sagan Institute Cornell University IthacaNY United States Cornell Center for Astrophysics and Planetary Science Cornell University IthacaNY United States Department of Earth and Environmental Sciences University of St. Andrews St. Andrews United Kingdom Jet Propulsion Laboratory California Institute of Technology PasadenaCA United St

In the coming years and decades, advanced space- and ground-based observatories will allow an unprecedented opportunity to probe the atmospheres and surfaces of potentially habitable exoplanets for signatures of life. Life on Earth, through its gaseous products and reflectance and scattering properties, has left its fingerprint on the spectrum of our planet. Aided by the universality of the laws of physics and chemistry, we turn to Earth’s biosphere, both in the present and through geologic time, for analog signatures that will aid in the search for life elsewhere. Considering the insights gained from modern and ancient Earth, and the broader array of hypothetical exoplanet possibilities, we have compiled a comprehensive overview of our current understanding of potential exoplanet biosignatures, including gaseous, surface, and temporal biosignatures. We additionally survey biogenic spectral features that are well known in the specialist literature but have not yet been robustly vetted in the context of exoplanet biosignatures. We briefly review advances in assessing biosignature plausibility, including novel methods for determining chemical disequilibrium from remotely obtainable data and assessment tools for determining the minimum biomass required to maintain short-lived biogenic gases as atmospheric signatures. We focus particularly on advances made since the seminal review by Des Marais et al. The purpose of this work is not to propose new biosignature strategies, a goal left to companion articles in this series, but to review the current literature, draw meaningful connections between seemingly disparate areas, and clear the way for a path forward. Copyright © 2017, The Authors. All rights reserved.

关键词： Extrasolar planets

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Fermi-lat observations of high-energy behind-the-limb solar flares

arXiv

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arXiv 2017年

作者： Ackermann, M. Allafort, A. Baldini, L. Barbiellini, G. Bastieri, D. Bellazzini, R. Bissaldi, E. Bonino, R. Bottacini, E. Bregeon, J. Bruel, P. Buehler, R. Cameron, R.A. Caragiulo, M. Caraveo, P.A. Cavazzuti, E. Cecchi, C. Charles, E. Ciprini, S. Costanza, F. Cutini, S. D'Ammando, F. de Palma, F. Desiante, R. Digel, S.W. Di Lalla, N. Di Mauro, M. Di Venere, L. Drell, P.S. Favuzzi, C. Fukazawa, Y. Fusco, P. Gargano, F. Giglietto, N. Giordano, F. Giroletti, M. Grenier, I.A. Guillemot, L. Guiriec, S. Jogler, T. Jóhannesson, G. Kashapova, L. Krucker, S. Kuss, M. la Mura, G. Larsson, S. Latronico, L. Li, J. Liu, W. Longo, F. Loparco, F. Lubrano, P. Magill, J.D. Maldera, S. Manfreda, A. Mazziotta, M.N. Mitthumsiri, W. Mizuno, T. Monzani, M.E. Morselli, A. Moskalenko, I.V. Negro, M. Nuss, E. Ohsugi, T. Omodei, N. Orlando, E. Pal'shin, V. Paneque, D. Perkins, J.S. Pesce-Rollins, M. Petrosian, V. Piron, F. Principe, G. Rainò, S. Rando, R. Razzano, M. Reimer, O. Rubio da Costa, F. Sgrò, C. Simone, D. Siskind, E.J. Spada, F. Spandre, G. Spinelli, P. Tajima, H. Thayer, J.B. Torres, D.F. Troja, E. Vianello, G. Deutsches Elektronen Synchrotron DESY ZeuthenD-15738 Germany W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics SLAC National Accelerator Laboratory Stanford University StanfordCA94305 United States Università di Pisa Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Trieste TriesteI-34127 Italy Dipartimento di Fisica Università di Trieste TriesteI-34127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Padova PadovaI-35131 Italy Dipartimento di Fisica e Astronomia "G. Galilei" Università di Padova PadovaI-35131 Italy Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Bari BariI-70126 Italy Istituto Nazionale di Fisica Nucleare Sezione di Torino TorinoI-10125 Italy Dipartimento di Fisica Università degli Studi di Torino TorinoI-10125 Italy Laboratoire Univers et Particules de Montpellier Université Montpellier CNRS IN2P3 MontpellierF-34095 France Laboratoire Leprince-Ringuet École polytechnique CNRS IN2P3 PalaiseauF-91128 France Dipartimento di Fisica "M. Merlin" dell'Università e del Politecnico di Bari BariI-70126 Italy INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano via E. Bassini 15 MilanoI-20133 Italy Science Data Center RomaI-00133 Italy Istituto Nazionale di Fisica Nucleare Sezione di Perugia PerugiaI-06123 Italy Dipartimento di Fisica Università degli Studi di Perugia PerugiaI-06123 Italy INAF Istituto di Radioastronomia BolognaI-40129 Italy Dipartimento di Astronomia Università di Bologna BolognaI-40127 Italy Università Telematica Pegaso Piazza Trieste e Trento 48 NapoliI-80132 Italy Università di Udine UdineI-33100 Italy Department of Physical Sciences Hiroshima University Higashi-Hiroshima Hiroshima739-8526 Japan Laboratoire AIM CEA IRFU CNRS Université Paris Diderot Servic

We report on the Fermi-LAT detection of high-energy emission from the behind-the-limb solar flares that occurred on 2013 October 11, 2014 January 6 and 2014 September 1. The Fermi-LAT observations are associated with flares from active regions originating behind both the eastern and western limbs, as determined by STEREO. All three flares are associated with very fast Coronal Mass Ejections (CMEs) and strong Solar Energetic Particle events. We present updated localizations of the > 100 MeV photon emission, hard X-ray (HXR) and EUV images and broad-band spectra from 10 keV to 10 GeV as well as microwave spectra. We also provide a comparison of the behind-the-limb flares detected by the Fermi-LAT with three on-disk flares and present a study of some of the significant quantities of these flares as an attempt to better understand the acceleration mechanisms at work during these occulted flares. We interpret the HXR emission to be due to electron bremsstrahlung from a coronal thin-target loop-top with the accelerated electron spectra steepening at semirelativistic energies. The > 100 MeV gamma-rays are best described by a pion decay model resulting from interaction of protons (and other ions) in a thick target photospheric source. The protons are believed to have been accelerated (to energies > 10 GeV) in the CME environment and precipitate down to the photosphere from the down-stream side of the CME shock and landed on the front side of the Sun, away from the original flare site and the HXR emission. Copyright © 2017, The Authors. All rights reserved.

关键词： Gamma rays

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Resolving the Extragalactic γ-Ray Background above 50 GeV with the Fermi Large Area Telescope

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Physical Review Letters 2016年第15期116卷 151105-151105页

作者： M. Ackermann M. Ajello A. Albert W. B. Atwood L. Baldini J. Ballet G. Barbiellini D. Bastieri K. Bechtol R. Bellazzini E. Bissaldi R. D. Blandford E. D. Bloom R. Bonino J. Bregeon R. J. Britto P. Bruel R. Buehler G. A. Caliandro R. A. Cameron M. Caragiulo P. A. Caraveo E. Cavazzuti C. Cecchi E. Charles A. Chekhtman J. Chiang G. Chiaro S. Ciprini J. Cohen-Tanugi L. R. Cominsky F. Costanza S. Cutini F. D’Ammando A. de Angelis F. de Palma R. Desiante S. W. Digel M. Di Mauro L. Di Venere A. Domínguez P. S. Drell C. Favuzzi S. J. Fegan E. C. Ferrara A. Franckowiak Y. Fukazawa S. Funk P. Fusco F. Gargano D. Gasparrini N. Giglietto P. Giommi F. Giordano M. Giroletti G. Godfrey D. Green I. A. Grenier S. Guiriec E. Hays D. Horan G. Iafrate T. Jogler G. Jóhannesson M. Kuss G. La Mura S. Larsson L. Latronico J. Li L. Li F. Longo F. Loparco B. Lott M. N. Lovellette P. Lubrano G. M. Madejski J. Magill S. Maldera A. Manfreda M. Mayer M. N. Mazziotta P. F. Michelson W. Mitthumsiri T. Mizuno A. A. Moiseev M. E. Monzani A. Morselli I. V. Moskalenko S. Murgia M. Negro E. Nuss T. Ohsugi C. Okada N. Omodei E. Orlando J. F. Ormes D. Paneque J. S. Perkins M. Pesce-Rollins V. Petrosian F. Piron G. Pivato T. A. Porter S. Rainò R. Rando M. Razzano S. Razzaque A. Reimer O. Reimer T. Reposeur R. W. Romani M. Sánchez-Conde J. Schmid A. Schulz C. Sgrò D. Simone E. J. Siskind F. Spada G. Spandre P. Spinelli D. J. Suson H. Takahashi J. B. Thayer L. Tibaldo D. F. Torres E. Troja G. Vianello M. Yassine S. Zimmer Deutsches Elektronen Synchrotron DESY D-15738 Zeuthen Germany Department of Physics and Astronomy Clemson University Kinard Lab of Physics Clemson SC 29634-0978 USA W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics and SLAC National Accelerator Laboratory Stanford University Stanford CA 94305 USA Santa Cruz Institute for Particle Physics Department of Physics and Department of Astronomy and Astrophysics University of California at Santa Cruz Santa Cruz CA 95064 USA Università di Pisa and Istituto Nazionale di Fisica Nucleare Sezione di Pisa I-56127 Pisa Italy Laboratoire AIM CEA-IRFU/CNRS/Université Paris Diderot Service d’Astrophysique CEA Saclay F-91191 Gif sur Yvette France Istituto Nazionale di Fisica Nucleare Sezione di Trieste I-34127 Trieste Italy Dipartimento di Fisica Università di Trieste I-34127 Trieste Italy Istituto Nazionale di Fisica Nucleare Sezione di Padova I-35131 Padova Italy Dipartimento di Fisica e Astronomia “G. Galilei” Università di Padova I-35131 Padova Italy Dept. of Physics and Wisconsin IceCube Particle Astrophysics Center University of Wisconsin Madison WI 53706 USA Istituto Nazionale di Fisica Nucleare Sezione di Pisa I-56127 Pisa Italy Istituto Nazionale di Fisica Nucleare Sezione di Bari I-70126 Bari Italy Istituto Nazionale di Fisica Nucleare Sezione di Torino I-10125 Torino Italy Dipartimento di Fisica Generale “Amadeo Avogadro” Università degli Studi di Torino I-10125 Torino Italy Laboratoire Univers et Particules de Montpellier Université Montpellier CNRS/IN2P3 Montpellier France Department of Physics University of Johannesburg PO Box 524 Auckland Park 2006 South Africa Laboratoire Leprince-Ringuet École polytechnique CNRS/IN2P3 Palaiseau France Consorzio Interuniversitario per la Fisica Spaziale (CIFS) I-10133 Torino Italy Dipartimento di Fisica “M. Merlin” dell’Università e del Politecnico di Bari I-70126 Bari Italy INAF-Istituto di As

The Fermi Large Area Telescope (LAT) Collaboration has recently released a catalog of 360 sources detected above 50 GeV (2FHL). This catalog was obtained using 80 months of data re-processed with Pass 8, the newest event-level analysis, which significantly improves the acceptance and angular resolution of the instrument. Most of the 2FHL sources at high Galactic latitude are blazars. Using detailed Monte Carlo simulations, we measure, for the first time, the source count distribution, dN/dS, of extragalactic γ-ray sources at E>50 GeV and find that it is compatible with a Euclidean distribution down to the lowest measured source flux in the 2FHL (∼8×10−12 ph cm−2 s−1). We employ a one-point photon fluctuation analysis to constrain the behavior of dN/dS below the source detection threshold. Overall, the source count distribution is constrained over three decades in flux and found compatible with a broken power law with a break flux, Sb, in the range [8×10−12,1.5×10−11] ph cm−2 s−1 and power-law indices below and above the break of α2∈[1.60,1.75] and α1=2.49±0.12, respectively. Integration of dN/dS shows that point sources account for at least 86−14+16% of the total extragalactic γ-ray background. The simple form of the derived source count distribution is consistent with a single population (i.e., blazars) dominating the source counts to the minimum flux explored by this analysis. We estimate the density of sources detectable in blind surveys that will be performed in the coming years by the Cherenkov Telescope Array.

关键词： Gamma ray astronomy Galactic nuclei & quasars

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Measurement of the high-energy gamma-ray emission from the Moon with the Fermi Large Area Telescope

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Physical Review D 2016年第8期93卷 082001-082001页

作者： M. Ackermann M. Ajello A. Albert W. B. Atwood L. Baldini G. Barbiellini D. Bastieri R. Bellazzini E. Bissaldi R. D. Blandford R. Bonino E. Bottacini J. Bregeon P. Bruel R. Buehler G. A. Caliandro R. A. Cameron M. Caragiulo P. A. Caraveo E. Cavazzuti C. Cecchi A. Chekhtman J. Chiang G. Chiaro S. Ciprini R. Claus J. Cohen-Tanugi F. Costanza A. Cuoco S. Cutini F. D’Ammando A. de Angelis F. de Palma R. Desiante S. W. Digel L. Di Venere P. S. Drell C. Favuzzi S. J. Fegan W. B. Focke A. Franckowiak S. Funk P. Fusco F. Gargano D. Gasparrini N. Giglietto F. Giordano M. Giroletti T. Glanzman G. Godfrey I. A. Grenier J. E. Grove S. Guiriec A. K. Harding J. W. Hewitt D. Horan X. Hou G. Iafrate G. Jóhannesson T. Kamae M. Kuss S. Larsson L. Latronico J. Li L. Li F. Longo F. Loparco M. N. Lovellette P. Lubrano J. Magill S. Maldera A. Manfreda M. Mayer M. N. Mazziotta P. F. Michelson W. Mitthumsiri T. Mizuno M. E. Monzani A. Morselli S. Murgia E. Nuss N. Omodei E. Orlando J. F. Ormes D. Paneque J. S. Perkins M. Pesce-Rollins V. Petrosian F. Piron G. Pivato S. Rainò R. Rando M. Razzano A. Reimer O. Reimer T. Reposeur C. Sgrò E. J. Siskind F. Spada G. Spandre P. Spinelli H. Takahashi J. B. Thayer D. J. Thompson L. Tibaldo D. F. Torres G. Tosti E. Troja G. Vianello B. L. Winer K. S. Wood M. Yassine F. Cerutti A. Ferrari P. R. Sala Deutsches Elektronen Synchrotron DESY D-15738 Zeuthen Germany Department of Physics and Astronomy Clemson University Kinard Lab of Physics Clemson South Carolina 29634-0978 USA W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics and SLAC National Accelerator Laboratory Stanford University Stanford California 94305 USA Santa Cruz Institute for Particle Physics Department of Physics and Department of Astronomy and Astrophysics University of California at Santa Cruz Santa Cruz California 95064 USA Università di Pisa and Istituto Nazionale di Fisica Nucleare Sezione di Pisa I-56127 Pisa Italy Istituto Nazionale di Fisica Nucleare Sezione di Trieste I-34127 Trieste Italy Dipartimento di Fisica Università di Trieste I-34127 Trieste Italy Istituto Nazionale di Fisica Nucleare Sezione di Padova I-35131 Padova Italy Dipartimento di Fisica e Astronomia “G. Galilei” Università di Padova I-35131 Padova Italy Istituto Nazionale di Fisica Nucleare Sezione di Pisa I-56127 Pisa Italy Istituto Nazionale di Fisica Nucleare Sezione di Bari I-70126 Bari Italy Istituto Nazionale di Fisica Nucleare Sezione di Torino I-10125 Torino Italy Dipartimento di Fisica Generale “Amadeo Avogadro” Università degli Studi di Torino I-10125 Torino Italy Laboratoire Univers et Particules de Montpellier Université Montpellier CNRS/IN2P3 F-34095 Montpellier France Laboratoire Leprince-Ringuet École polytechnique CNRS/IN2P3 F-91128 Palaiseau Cedex France Consorzio Interuniversitario per la Fisica Spaziale (CIFS) I-10133 Torino Italy Dipartimento di Fisica “M. Merlin” dell’Università e del Politecnico di Bari I-70126 Bari Italy INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica I-20133 Milano Italy Agenzia Spaziale Italiana (ASI) Science Data Center I-00133 Roma Italy Istituto Nazionale di Fisica Nucleare Sezione di Perugia I-06123 Perugia Italy Dipartimento di Fisica Università degli Studi di Perugia I-06123 Perugia

We have measured the gamma-ray emission spectrum of the Moon using the data collected by the Large Area Telescope onboard the Fermi satellite during its first seven years of operation, in the energy range from 30 MeV up to a few GeV. We have also studied the time evolution of the flux, finding a correlation with the solar activity. We have developed a full Monte Carlo simulation describing the interactions of cosmic rays with the lunar surface. The results of the present analysis can be explained in the framework of this model, where the production of gamma rays is due to the interactions of cosmic-ray proton and helium nuclei with the surface of the Moon. Finally, we have used our simulation to derive the cosmic-ray proton and helium spectra near Earth from the Moon gamma-ray data.

关键词： Cosmic ray sources Cosmic rays & astroparticles Gamma ray astronomy Solar cycles

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Large area transition edge sensor x-ray microcalorimeters for diffuse x-ray background studies

Large area transition edge sensor x-ray microcalorimeters fo...

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作者： Morgan, K.M. Busch, S.E. Eckart, M.E. Kilbourne, C.A. McCammon, D. Department of Physics University of Wisconsin-Madison Madison WI 53706 United States X-ray Astrophysics Lab NASA Goddard Space Flight Center Greenbelt MD 20771 United States NASA Postdoctoral Program at Goddard Space Flight Center Greenbelt MD 20771 United States CRESST and University of Maryland Baltimore County MD 21250 United States

We are developing transition edge sensor (TES) mirocalorimeters with large area (0.72 mm2) absorbers to study the keV diffuse X-ray background. The goal is to develop a 2 cm2 array of 256 pixels for a sounding rocket payload. We present a pixel design which includes a Mo/Au bilayer TES coupled to a large (850 x 850 x 0.2 μ m3) gold absorber. Our simulations indicate that such a design can achieve energy resolution as good as 1.6 eV FWHM in our target bandpass of 0.05-1 keV. Additionally, thermal modelling shows that for typical gold layers, the position-dependent variation of the pulse shape over the large area of the absorber is not expected to significantly degrade this energy resolution. An array of devices will be fabricated in late 2013 to test this design. © 2013 Springer Science+Business Media New York.

关键词： Pixels

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Searching for Dark Matter Annihilation from Milky Way Dwarf Spheroidal Galaxies with Six Years of Fermi Large Area Telescope Data

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Physical Review Letters 2015年第23期115卷 231301-231301页

作者： M. Ackermann A. Albert B. Anderson W. B. Atwood L. Baldini G. Barbiellini D. Bastieri K. Bechtol R. Bellazzini E. Bissaldi R. D. Blandford E. D. Bloom R. Bonino E. Bottacini T. J. Brandt J. Bregeon P. Bruel R. Buehler G. A. Caliandro R. A. Cameron R. Caputo M. Caragiulo P. A. Caraveo C. Cecchi E. Charles A. Chekhtman J. Chiang G. Chiaro S. Ciprini R. Claus J. Cohen-Tanugi J. Conrad A. Cuoco S. Cutini F. D’Ammando A. de Angelis F. de Palma R. Desiante S. W. Digel L. Di Venere P. S. Drell A. Drlica-Wagner R. Essig C. Favuzzi S. J. Fegan E. C. Ferrara W. B. Focke A. Franckowiak Y. Fukazawa S. Funk P. Fusco F. Gargano D. Gasparrini N. Giglietto F. Giordano M. Giroletti T. Glanzman G. Godfrey G. A. Gomez-Vargas I. A. Grenier S. Guiriec M. Gustafsson E. Hays J. W. Hewitt D. Horan T. Jogler G. Jóhannesson M. Kuss S. Larsson L. Latronico J. Li L. Li M. Llena Garde F. Longo F. Loparco P. Lubrano D. Malyshev M. Mayer M. N. Mazziotta J. E. McEnery M. Meyer P. F. Michelson T. Mizuno A. A. Moiseev M. E. Monzani A. Morselli S. Murgia E. Nuss T. Ohsugi M. Orienti E. Orlando J. F. Ormes D. Paneque J. S. Perkins M. Pesce-Rollins F. Piron G. Pivato T. A. Porter S. Rainò R. Rando M. Razzano A. Reimer O. Reimer S. Ritz M. Sánchez-Conde A. Schulz N. Sehgal C. Sgrò E. J. Siskind F. Spada G. Spandre P. Spinelli L. Strigari H. Tajima H. Takahashi J. B. Thayer L. Tibaldo D. F. Torres E. Troja G. Vianello M. Werner B. L. Winer K. S. Wood M. Wood G. Zaharijas S. Zimmer Deutsches Elektronen Synchrotron DESY D-15738 Zeuthen Germany W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics and SLAC National Accelerator Laboratory Stanford University Stanford California 94305 USA Department of Physics Stockholm University AlbaNova SE-106 91 Stockholm Sweden The Oskar Klein Centre for Cosmoparticle Physics AlbaNova SE-106 91 Stockholm Sweden Santa Cruz Institute for Particle Physics Department of Physics and Department of Astronomy and Astrophysics University of California at Santa Cruz Santa Cruz California 95064 USA Università di Pisa and Istituto Nazionale di Fisica Nucleare Sezione di Pisa I-56127 Pisa Italy Istituto Nazionale di Fisica Nucleare Sezione di Trieste I-34127 Trieste Italy Dipartimento di Fisica Università di Trieste I-34127 Trieste Italy Istituto Nazionale di Fisica Nucleare Sezione di Padova I-35131 Padova Italy Dipartimento di Fisica e Astronomia “G. Galilei” Università di Padova I-35131 Padova Italy Dept. of Physics and Wisconsin IceCube Particle Astrophysics Center University of Wisconsin Madison Wisconsin 53706 USA Istituto Nazionale di Fisica Nucleare Sezione di Pisa I-56127 Pisa Italy Istituto Nazionale di Fisica Nucleare Sezione di Bari I-70126 Bari Italy Istituto Nazionale di Fisica Nucleare Sezione di Torino I-10125 Torino Italy Dipartimento di Fisica Generale “Amadeo Avogadro” Università degli Studi di Torino I-10125 Torino Italy NASA Goddard Space Flight Center Greenbelt Maryland 20771 USA Laboratoire Univers et Particules de Montpellier Université Montpellier CNRS/IN2P3 Montpellier France Laboratoire Leprince-Ringuet École polytechnique CNRS/IN2P3 Palaiseau France Consorzio Interuniversitario per la Fisica Spaziale (CIFS) I-10133 Torino Italy INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica I-20133 Milano Italy Istituto Nazionale di Fisica Nucleare Sezione di Perugia I-06123 Perugia Italy Dipartimento di Fisica Uni

The dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are some of the most dark matter (DM) dominated objects known. We report on γ-ray observations of Milky Way dSphs based on six years of Fermi Large Area Telescope data processed with the new Pass8 event-level analysis. None of the dSphs are significantly detected in γ rays, and we present upper limits on the DM annihilation cross section from a combined analysis of 15 dSphs. These constraints are among the strongest and most robust to date and lie below the canonical thermal relic cross section for DM of mass ≲100 GeV annihilating via quark and τ-lepton channels.

关键词： Gamma ray astronomy Particle dark matter Normal galaxies

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