31 research outputs found

    VizieR Online Data Catalog: The 2009 multiwavelength campaign on Mrk421 (Aleksic+, 2015)

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    Light Curves of Mrk 421 as shown in Figure 1 of the paper are presented for following instruments/observatories and bands (radio to very high energy gamma rays): Effelsberg (2.6, 4.6, 7.9, 10.3, 13.6, 21.7, 31GHz), Medicina (8.4GHz), Metsahovi (37GHz), OVRO (15GHz), Noto (8, 22GHz), OAGH (J, H, K bands), WIRO (J, K bands), MITSuME (g, Rc, Ic bands), ROVOR (B band), GRT (V, R, B, I bands), GASP (R band), Steward (V band), Swift/UVOT (UVW1, UVM2, UVW2), Swift/XRT (0.3-2 and 2-10keV), RXTE/PCA (2-10keV). RXTE/ASM (2-10keV), Swift/BAT (15-50keV), Fermi-LAT (>0.3keV), Whipple (>300GeV), MAGIC (>300GeV). The observation period is from 2009 January 19 (MJD 54850) to 2009 June 1st (MJD 54983), where Mrk 421 was observed approximately once every two days. The Fermi-LAT photon fluxes are integrated over a three-day-long time interval, the RXTE/ASM and Swift/BAT photon fluxes over a seven-day long time interval. The Whipple 10-meter data (with an energy threshold of 400GeV) were converted into fluxes above 300GeV using a power-law spectrum with index of 2.5. Host galaxy fluxes are given where a good estimate is available, which is the case for some optical bands only. In the infrared, e.g., the host galaxy flux is larger than in the R band, however, we do not have a good estimate of the galaxy flux and therefore it is not given in the table. (1 data file)

    Insights into the high-energy Îł-ray emission of Markarian 501 from extensive multifrequency observations in the Fermi era

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    We report on the Îł-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation. We find that the average Large Area Telescope (LAT) Îł-ray spectrum of Mrk 501 can be well described by a single power-law function with a photon index of 1.78 ± 0.03. While we observe relatively mild flux variations with the Fermi-LAT (within less than a factor of two), we detect remarkable spectral variability where the hardest observed spectral index within the LAT energy range is 1.52 ± 0.14, and the softest one is 2.51 ± 0.20. These unexpected spectral changes do not correlate with the measured flux variations above 0.3 GeV. In this paper, we also present the first results from the 4.5 month long multifrequency campaign (2009 March 15-August 1) on Mrk 501, which included the Very Long Baseline Array (VLBA), Swift, RXTE, MAGIC, and VERITAS, the F-GAMMA, GASP-WEBT, and other collaborations and instruments which provided excellent temporal and energy coverage of the source throughout the entire campaign. The extensive radio to TeV data set from this campaign provides us with the most detailed spectral energy distribution yet collected for this source during its relatively low activity. The average spectral energy distribution of Mrk 501 is well described by the standard one-zone synchrotron self-Compton (SSC) model. In the framework of this model, we find that the dominant emission region is characterized by a size â‰Č0.1 pc (comparable within a factor of few to the size of the partially resolved VLBA core at 15-43 GHz), and that the total jet power (≃1044 erg s-1) constitutes only a small fraction (∌10-3) of the Eddington luminosity. The energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3 GeV-10 TeV, with spectral indices 2.2 and 2.7 below and above the break energy of 20 GeV. We argue that such a form is consistent with a scenario in which the bulk of the energy dissipation within the dominant emission zone of Mrk 501 is due to relativistic, proton-mediated shocks. We find that the ultrarelativistic electrons and mildly relativistic protons within the blazar zone, if comparable in number, are in approximate energy equipartition, with their energy dominating the jet magnetic field energy by about two orders of magnitude. © 2011. The American Astronomical Society

    Thermodynamics: fundamental principles and applications

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    This book offers a comprehensive overview of thermodynamics. It is divided into four parts, the first of which equips readers with a deeper understanding of the fundamental principles of thermodynamics of equilibrium states and of their evolution. The second part applies these principles to a series of generalized situations, presenting applications that are of interest both in their own right and in terms of demonstrating how thermodynamics, as a theory of principle, relates to different fields. In turn, the third part focuses on non-equilibrium configurations and the dynamics of natural processes. It discusses both discontinuous and continuous systems, highlighting the interference among non-equilibrium processes, and the nature of stationary states and of fluctuations in isolated systems. Lastly, part four introduces the relation between physics and information theory, which constitutes a new frontier in fundamental research. The book includes step-by-step exercises, with solutions, to help readers to gain a fuller understanding of the subjects, and also features a series of appendices providing useful mathematical formulae. Reflecting the content of modern university courses on thermodynamics, it is a valuable resource for students and young scientists in the fields of physics, chemistry, and engineering

    Explicating the notion of 'causation': the role of the extensive quantities

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    We propose an empirical explication of the notion of ‘causation’, which we call a generalized explication of ‘causation’ (GEC), based on the numerical balance between instantiations of extensive quantities. In this way, it will be shown that both the conserved and the non-conserved quantities have a role. It follows that the Salmon– Dowe approach should be considered valid only in particular cases

    An AGN Observation Catalogue For The MAGIC Cherenkov Telescope

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    Abstract The 17m diameter MAGIC telescope will become operational in mid-2003. Active Galactic Nuclei (AGN) known to be T eV Îł-ray emitters will be observed by the telescope in its initial phase. But, due to the high sensitivity measuring fluxes and low Energy Threshold, MAGIC will be able to observe very high redshifted AGNs which have remained undetected by the present Cherenkov Telescopes. The EGRET AGNs and Constamante-Ghisellini T eV BL Lacs candidates are taken as a reference to perform a study of source observability by evaluating their fluxes at the MAGIC energy detection range

    An AGN observation catalogue for the MAGIC Cherenkov telescope

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    The 17m diameter MAGIC telescope will become operational in mid-2003. Active Galactic Nuclei (AGN) known to be TeV \u3b3\u2013ray emitters will be observed by the telescope in its initial phase. But, due to the high sensitivity measur- ing fluxes and low Energy Threshold, MAGIC will be able to observe very high redshifted AGNs which have remained undetected by the present Cherenkov Tele- scopes. The EGRET AGNs and Constamante-Ghisellini T eV BL Lacs candidates are taken as a reference to perform a study of source observability by evaluating their fluxes at the MAGIC energy detection range

    Development and Performances of the MAGIC Telescope

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    The MAGIC Collaboration is building an imaging Čerenkov telescope at La Palma site (2200 m a.s.l.), in the Canary Islands, to observe gamma rays in the hundred-GeV region. The MAGIC telescope, with its reflecting parabolic dish, 17 m in diameter, and a two-level pattern trigger designed to cope with severe trigger rates, is the Čerenkov telescope with the lowest envisaged energy threshold. Due to its lightweight alto-azimuthal mounting, MAGIC can be repositioned in less than 30 seconds, becoming the only detector, with an adequate effective area, capable to observe GRB phenomena above 30 GeV. MAGIC telescope is characterised by a 30 GeV energy threshold and a sensitivity of 6×l0-11 cm-2s-1 for a 5σ-detection in 50-hours of observation. In this report, some future scientific goals for MAGIC will be highlighted and the technical development for the main elements of the telescope will be detailed. Special emphasis will be given to the construction of the individual metallic mirrors which form the reflecting surface and the development of the fast pattern-recognition trigger
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