SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Walter M) "

Sökning: WFRF:(Walter M)

  • Resultat 1-10 av 1158
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Niemi, MEK, et al. (författare)
  • 2021
  • swepub:Mat__t
  •  
2.
  • Kanai, M, et al. (författare)
  • 2023
  • swepub:Mat__t
  •  
3.
  •  
4.
  • Acharya, B. S., et al. (författare)
  • Introducing the CTA concept
  • 2013
  • Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 43, s. 3-18
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. (C) 2013 Elsevier B.V. All rights reserved.
  •  
5.
  • Algaba, Juan-Carlos, et al. (författare)
  • Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
  • 2021
  • Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 911:1
  • Forskningsöversikt (refereegranskat)abstract
    • In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M o˙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87's spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded.
  •  
6.
  • Actis, M., et al. (författare)
  • Design concepts for the Cherenkov Telescope Array CTA : an advanced facility for ground-based high-energy gamma-ray astronomy
  • 2011
  • Ingår i: Experimental astronomy. - : Springer. - 0922-6435 .- 1572-9508. ; 32:3, s. 193-316
  • Tidskriftsartikel (refereegranskat)abstract
    • Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
  •  
7.
  • Abdalla, H., et al. (författare)
  • Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation
  • 2021
  • Ingår i: Journal of Cosmology and Astroparticle Physics. - : Institute of Physics Publishing (IOPP). - 1475-7516. ; :2
  • Tidskriftsartikel (refereegranskat)abstract
    • The Cherenkov Telescope Array (CTA), the new-generation ground-based observatory for gamma-ray astronomy, provides unique capabilities to address significant open questions in astrophysics, cosmology, and fundamental physics. We study some of the salient areas of gamma-ray cosmology that can be explored as part of the Key Science Projects of CTA, through simulated observations of active galactic nuclei (AGN) and of their relativistic jets. Observations of AGN with CTA will enable a measurement of gamma-ray absorption on the extragalactic background light with a statistical uncertainty below 15% up to a redshift z = 2 and to constrain or detect gamma-ray halos up to intergalactic-magnetic-field strengths of at least 0.3 pG. Extragalactic observations with CTA also show promising potential to probe physics beyond the Standard Model. The best limits on Lorentz invariance violation from gamma-ray astronomy will be improved by a factor of at least two to three. CTA will also probe the parameter space in which axion-like particles could constitute a significant fraction, if not all, of dark matter. We conclude on the synergies between CTA and other upcoming facilities that will foster the growth of gamma-ray cosmology.
  •  
8.
  • van Leeuwen, F., et al. (författare)
  • Gaia Data Release 1 : Open cluster astrometry: Performance, limitations, and future prospects
  • 2017
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 601
  • Tidskriftsartikel (refereegranskat)abstract
    • Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are calculated using Hipparcos and Tycho-2 positions in 1991.25 as prior information. Aims. We investigate the scientific potential and limitations of the TGAS component by means of the astrometric data for open clusters. Methods. Mean cluster parallax and proper motion values are derived taking into account the error correlations within the astrometric solutions for individual stars, an estimate of the internal velocity dispersion in the cluster, and, where relevant, the effects of the depth of the cluster along the line of sight. Internal consistency of the TGAS data is assessed. Results. Values given for standard uncertainties are still inaccurate and may lead to unrealistic unit-weight standard deviations of least squares solutions for cluster parameters. Reconstructed mean cluster parallax and proper motion values are generally in very good agreement with earlier Hipparcos-based determination, although the Gaia mean parallax for the Pleiades is a significant exception. We have no current explanation for that discrepancy. Most clusters are observed to extend to nearly 15 pc from the cluster centre, and it will be up to future Gaia releases to establish whether those potential cluster-member stars are still dynamically bound to the clusters. Conclusions. The Gaia DR1 provides the means to examine open clusters far beyond their more easily visible cores, and can provide membership assessments based on proper motions and parallaxes. A combined HR diagram shows the same features as observed before using the Hipparcos data, with clearly increased luminosities for older A and F dwarfs.
  •  
9.
  • Singh, B., et al. (författare)
  • Feasibility study for the measurement of pi N transition distribution amplitudes at (P)over-barANDA in (P)over-barp -> J/psi pi(0)
  • 2017
  • Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The exclusive charmonium production process in (P) over barp annihilation with an associated pi 0 meson (p) over barp -> J/psi pi(0) is studied in the framework of QCD collinear factorization. The feasibility of measuring this reaction through the J/psi -> e(+) e(-) decay channel with the AntiProton ANnihilation at DArmstadt ((P) over bar ANDA) experiment is investigated. Simulations on signal reconstruction efficiency as well as the background rejection from various sources including the (P) over barp -> pi(+)pi(-)pi(0) and (p) over barp -> J/psi pi(0)pi(0) reactions are performed with PANDAROOT, the simulation and analysis software framework of the (P) over bar ANDA experiment. It is shown that the measurement can be done at (P) over bar ANDA with significant constraining power under the assumption of an integrated luminosity attainable in four to five months of data taking at the maximum design luminosity.
  •  
10.
  • Singh, B., et al. (författare)
  • Study of doubly strange systems using stored antiprotons
  • 2016
  • Ingår i: Nuclear Physics A. - : Elsevier. - 0375-9474 .- 1873-1554. ; 954, s. 323-340
  • Tidskriftsartikel (refereegranskat)abstract
    • Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the PANDA experiment at FAIR. For the first time, high resolution gamma-spectroscopy of doubly strange Lambda Lambda-hypernuclei will be performed, thus complementing measurements of ground state decays of Lambda Lambda-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Xi(-) -atoms will be feasible and even the production of Omega(-) -atoms will be within reach. The latter might open the door to the vertical bar S vertical bar = 3 world in strangeness nuclear physics, by the study of the hadronic Omega(-) -nucleus interaction. For the first time it will be possible to study the behavior of Xi(+) in nuclear systems under well controlled conditions.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 1158
Typ av publikation
tidskriftsartikel (1027)
konferensbidrag (74)
forskningsöversikt (35)
bokkapitel (11)
annan publikation (5)
doktorsavhandling (2)
visa fler...
rapport (1)
licentiatavhandling (1)
visa färre...
Typ av innehåll
refereegranskat (1089)
övrigt vetenskapligt/konstnärligt (66)
populärvet., debatt m.m. (1)
Författare/redaktör
Wolke, Magnus (254)
Kupsc, Andrzej (250)
Johansson, Tord (250)
Ablikim, M. (244)
Zou, J. H. (242)
Schönning, Karin, 19 ... (233)
visa fler...
Pettersson, Joachim (232)
Ikegami Andersson, W ... (165)
Thorén, Viktor (146)
Papenbrock, Michael (144)
Adlarson, Patrik (143)
Li, Cui, 1984- (127)
Biernat, Jacek (79)
Walter, M. (77)
Montaruli, T. (71)
Hanson, K. (70)
Liu, B. (63)
Peters, K. (63)
..., Wiedner U. (63)
Albrecht, M. (63)
Dbeyssi, A. (63)
Denig, A. (63)
Fritsch, M. (63)
Held, T. (63)
Kavatsyuk, M. (63)
Kliemt, R. (63)
Kopf, B. (63)
Spataro, S. (63)
Weber, T. (63)
Gao, Y. (62)
Bettoni, D. (62)
Feldbauer, F. (62)
Felici, G. (62)
Lange, J. S. (62)
Nerling, F. (62)
Wang, B. (62)
Liu, X (61)
Zhang, J. (61)
Sarkar, S. (61)
Wang, Z. (61)
Ahmed, S. (61)
Amoroso, A. (61)
Destefanis, M. (61)
Fava, L. (61)
Greco, M. (61)
Li, Cheng (61)
Marcello, S. (61)
Sosio, S. (61)
Tiemens, M. (61)
Zhou, X. (61)
visa färre...
Lärosäte
Uppsala universitet (460)
Karolinska Institutet (211)
Lunds universitet (138)
Stockholms universitet (123)
Chalmers tekniska högskola (110)
Umeå universitet (93)
visa fler...
Göteborgs universitet (83)
Kungliga Tekniska Högskolan (54)
Linköpings universitet (41)
Örebro universitet (38)
Linnéuniversitetet (38)
RISE (14)
Sveriges Lantbruksuniversitet (10)
Luleå tekniska universitet (9)
Malmö universitet (8)
Södertörns högskola (8)
Mittuniversitetet (7)
Högskolan Kristianstad (4)
Jönköping University (4)
Högskolan Dalarna (4)
Naturhistoriska riksmuseet (4)
Handelshögskolan i Stockholm (2)
IVL Svenska Miljöinstitutet (2)
Högskolan i Gävle (1)
Karlstads universitet (1)
Blekinge Tekniska Högskola (1)
Marie Cederschiöld högskola (1)
visa färre...
Språk
Engelska (1157)
Odefinierat språk (1)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (619)
Medicin och hälsovetenskap (314)
Teknik (54)
Samhällsvetenskap (36)
Lantbruksvetenskap (9)
Humaniora (1)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy