701 research outputs found
Jet evolution in steep spectrum radio quasars: A multiwavelength study
No full textThanks to the Fermi γ-ray satellite, it is now confirmed that Misaligned Active Galactic Nuclei (MAGN), i.e. radio galaxies and steep spectrum radio quasars, are a new class of GeV emitters. In this work we present the first γ-ray and multiwavelength study of the two steep spectrum radio quasars, i.e. 3C 207 and 3C 380, belonging to the MAGN sample. From the γ -ray variability study we estimate the physical size of the zone where high-energy photons are dissipated: for both sources this region should be very compact, not larger than 0.05 pc. As a successive step, we build multiwavelength light curves of 3C 207 and 3C 380 to search for possible simultaneous outbursts in different wavebands with the aim of localizing the compact emitting region. This is an important issue with strong impact on theoretical models: indeed, knowing where highenergy photons are dissipated (at sub-pc or pc-scale) provides information on the nature of the seed photons involved in the production of the GeV radiation. © Owned by the authors, published by EDP Sciences, 2013
The high energy view of FR0 radio galaxies
No full textA new class of low-power compact radio sources with limited jet structures, named FR 0, is emerging from recent radio-optical surveys. This abundant population of radio galaxies, five times more numerous than FR Is in the local Universe (z < 0.05), represent a potentially interesting target at high and very-high energies (greater than 100 GeV), as demonstrated by a single case of Fermi detection. Furthermore, these radio galaxies have been recently claimed to contribute non-negligibly to the extra-galactic γ-ray background and to be possible cosmic neutrino emitters. Here, we review the radio through X-ray properties of FR 0s to predict their high-energy emission (from MeV to TeV), in light of the near-future facilities operating in this band.</p
JETS AND OUTFLOWS IN RADIO GALAXIES: IMPLICATIONS FOR AGN FEEDBACK
No full textOne of the main debated astrophysical problems is the role of the AGN
feedback in galaxy formation. It is known that massive black holes have a
profound effect on the formation and evolution of galaxies, but how black holes
and galaxies communicate is still an unsolved problem. For Radio Galaxies,
feedback studies have mainly focused on jet/cavity systems in the most massive
and X-ray luminous galaxy clusters. The recent high-resolution detection of
warm absorbers in some Broad Line Radio Galaxies allow us to investigate the
interplay between the nuclear engine and the surrounding medium from a
different perspective. We report on the detection of warm absorbers in two
Broad Line Radio Galaxies, 3C 382 and 3C 390.3, and discuss the physical and
energetic properties of the absorbing gas. Finally, we attempt a comparison
between radio-loud and radio-quiet outflows
The γ-ray emission region in the Fanaroff-Riley II radio galaxy 3C111
No full textThe broad-line radio galaxy 3C111, characterized by a Fanaroff-Riley II (FRII) radio morphology, is one of the sources of the misaligned active galactic nucleus sample, consisting of radio galaxies and steep spectrum radio quasars, recently detected by the Fermi Large Area Telescope (LAT). Our analysis of the 24 month γ-ray light curve shows that 3C111 was only occasionally detected at high energies. It was bright at the end of 2008 and faint, below the Fermi-LAT sensitivity threshold, for the rest of the time. A multifrequency campaign of 3C111, ongoing in the same period, revealed an increase of the millimeter, optical, and X-ray fluxes in 2008 September-November, interpreted by Chatterjee etal. as due to the passage of a superluminal knot through the jet core. The temporal coincidence of the millimeter-optical-X-ray outburst with the GeV activity suggests a cospatiality of the events, allowing, for the first time, the localization of the γ-ray dissipative zone in an FRII jet. We argue that the GeV photons of 3C111 are produced in a compact region confined within 0.1 pc and at a distance of about 0.3 pc from the black hole. © 2012. The American Astronomical Society. All rights reserved.
“but I am also influenced by no such thing”-The Radical Pietist and Theological Author Johanna Eleonora Petersen
No full textJohanna Eleonora von und zu Merlau, verheiratete Petersen, von jeher tief gläubig, veränderte die religiöse Welt des 17. Jahrhunderts. Sie bekannte sich zur Bewegung des Pietismus und vertrat radikale Ansichten, nicht nur im privaten Kreis, sondern als anerkannte und heftig kritisierte theologische Autorin. Ihrem Werk ist eine Studie gewidmet, in der neue Forschungsergebnisse vorgestellt und Leben und Werk dieser bedeutenden Autorin in zeitgenössische Diskurse eingebunden werden.The deeply devout Johanna Eleonora Petersen, whose maiden name was „von und zu Merlau,” changed the religious world of the seventeenth century. She avowed herself to Pietism and held radical views, not only in private but also as an acknowledged and sharply criticized theological author. This study attends to her work. It presents new research results and weaves the life and work of this important author into contemporary discourses
La notion de défectuosité du produit dans les jurisprudences des pays européens
No full textThis work analyses the notion of defective product originally developed by US Courts, then ambiguously defined by the European directive n. 374 of 1985 and differently interpreted and applied by the respective domestic Courts. In particular, some European jurisdictions apply the risk / utility test introduced by the US Courts for design defects cases, although this test is not mentioned by the European Directive. The author, having highlighted the inconsistences of the risk / utility test, proposes an alternative model of classification of defective products according to the elements actually used by judges in order to allocate the liability, as emerging from the text of their decisions. This classification leads to held the manufacturer strictly liable not only for manufacturing defects, but also for those design defects which he was aware of (as in some cases of defective vaccine).Cette étude examine la notion de défectuosité du produit initialement élaborée par les Cours américaines, définie de manière ambigüe par le législateur européen avec la directive n° 374 de 1985, puis différemment interprétée et appliquée par les Cours respectives des pays membres. Notamment certains systèmes juridiques européens appliquent le risk/ utility test élaboré par les Cours américaines pour les cas de défaut de conception du produit, bien que ce test ne soit pas mentionné par la directive européenne. L’auteur, après avoir mis en évidence les incongruences du risk/ utility test, propose un modèle alternatif de classification des cas de produits défectueux sur la base des critères d’imputation de la responsabilité qui sont concrètement utilisés par les juges et tels qu’imagés dans les textes de leurs décisions. Cette reconstruction amène à imputer au fabricant une responsabilité objective non seulement pour les cas de défaut de production, mais aussi pour les cas de défaut de conception dont il était averti (tel que certain cas de vaccin défectueux).Rajneri Karageorgevitch Eleonora. La notion de défectuosité du produit dans les jurisprudences des pays européens. In: Revue internationale de droit comparé. Vol. 67 N°1,2015. pp. 185-205
Detection of a radio-filled X-ray cavity within the interstellar medium of NGC 5141
No full textWe present the first Chandra detection of a single X-ray cavity within the interstellar medium of the small Fanaroff-Riley type I radio galaxy NGC 5141. The X-ray surface brightness depression, located ≈4 kpc away from the galaxy center, is projected on the northern radio lobe, which is completely contained within the galaxy. The thermal gas surrounding the cavity, which extends to ≃20 kpc, has a bolometric X-ray luminosity (0.1–100 keV) of LX ≈ 2 × 1040 erg s−1 and a temperature of kT ≈ 0.8 keV. We calculated the total energy (Ecav = 4PV ≈ 1055 erg) required to inflate the cavity and its age (tcav ≈ 9 Myrs), assuming that it is filled with relativistic particles and rises buoyantly. The inferred total cavity power is as low as Pcav = Ecav/tcav ≈ 6 × 1040 erg s−1, which is the lowest one among the radio-filled systems. Comparing Pcav to the bolometric X-ray luminosity (i.e., the cooling luminosity), we conclude that NGC 5141’s central active galactic nucleus can heat the interstellar medium and balance its cooling luminosity, confirming that the Pcav − Lcool relation, mainly tested on groups and clusters, also works for such a low-power system
TO THE JUBILEE OF PROFESSOR STEPANOVA ELEONORA FEDOROVNA
No full textThe article is devoted to the anniversary of Professor Eleonora Fedorovna Stepanova – a bright representative of the Russian intelligentsia: a talented lecturer, an inventor, an author of numerous books, an internationally recognized scholar
Author response
No full textHebb's idea of a cell assembly as the fundamental unit of neural information processing has dominated neuroscience like no other theoretical concept within the past 60 years. A range of different physiological phenomena, from precisely synchronized spiking to broadly simultaneous rate increases, has been subsumed under this term. Yet progress in this area is hampered by the lack of statistical tools that would enable to extract assemblies with arbitrary constellations of time lags, and at multiple temporal scales, partly due to the severe computational burden. Here we present such a unifying methodological and conceptual framework which detects assembly structure at many different time scales, levels of precision, and with arbitrary internal organization. Applying this methodology to multiple single unit recordings from various cortical areas, we find that there is no universal cortical coding scheme, but that assembly structure and precision significantly depends on the brain area recorded and ongoing task demands
Rescate y conservación del Acervo Histórico del Palacio de Minería: Informe de las labores de conservación preventiva e intervenciones menores en material Bibliohemerográfico y actividades en apoyo al Acervo Histórico : octubre 2011 - febrero 2012
No full textEl presente informe tiene como finalidad dar constancia de los trabajos realizados en el Acervo Histórico del Palacio de Minería, por los restauradores Roderick Palacios, Isabel Ritter y Eleonora Cruz, pasantes de la Licenciatura en Restauración de Bienes Culturales como prestación de su servicio social.</p
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