128 research outputs found

    Spatially resolved observations of outflows in the radio loud AGN of UGC 8782

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    We use optical Integral Field Spectroscopy (IFU) to study the gas emission structure and kinematics in the inner 3.4×\times4.9 kpc2^2 region of the galaxy UGC 8782 (3C 293), host of a radio loud Active Galactic Nucleus (AGN). The observations were performed with the GMOS-IFU on the Gemini North telescope, resulting in a spatial resolution of 725\sim725 pc at the distance of the galaxy. While the stars present ordered rotation following the orientation of the large scale disc, the gas shows a disturbed kinematics. The emission-line profiles present two kinematic components: a narrow (σ200\sigma\lesssim200 km s1^{-1}) component associated with the gas in the disc of the galaxy and a broad (σ200\sigma\gtrsim200 km s1^{-1}) component produced by gas outflows. Emission-line ratio diagrams indicate that the gas in the disc is excited by the AGN radiation field, while the emission of the outflow includes additional contribution of shock excitation due to the interaction of the radio jet with the environment gas. Deviations from pure rotation, of up to 30 km s1^{-1}, are observed in the disc component and likely produced by a previous merger event. The broad component is blueshifted by 150500\sim150-500 km s1^{-1} relative to the systemic velocity of the galaxy in all locations. We construct radial profiles of the mass outflow rate and kinetic power of the ionized gas outflows, which have the maximum values at 1\sim1 kpc from the nucleus with peak values of M˙out,ΔR=0.5±0.1\dot{M}_{\rm out,\Delta R}=0.5\pm0.1 M_\odot yr1^{-1} and K˙out,ΔR=\dot{K}_{\rm out,\Delta R} =(6.8±\pm1.1)×\times1041^{41} erg s1^{-1}. The kinetic coupling efficiency of these outflows is in the range of 1-3 per cent, indicating that they could be powerful enough to affect the star formation in the host galaxy as predicted by theoretical simulations.Comment: Accepted for publication by MNRA

    A epidemiologia da cardiomiopatia de Takotsubo no Brasil e os principais fatores de risco da cardiomiopatia de Takotsubo: The epidemiology of Takotsubo cardiomyopathy in Brazil and the main risk factors for takotsubo cardiomyopathy

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    A Cardiomiopatia de Takotsubo (CTT) é uma disfunção cardíaca reversível, a qual está relacionada, diretamente, ao estresse físico ou emocional. Objetiva-se através dessa pesquisa evidenciar os principais fatores de risco da CT. Trata-se de uma revisão sistemática realizada no motor de busca Biblioteca Virtual em Saúde (BVS) na base de dados das “Ciências em Saúde em Geral” (Scielo, Medline, Lilacs). Percebeu-se que que a CT apresenta uma ocorrência maior em mulheres na fase de pós-menopausa, onde são atingidas pelo estresse emocional, bem como a inserção de marcapasso também pode desencadear a doença. Entretanto, a etiologia da CT ainda é marcada por controvérsias, mas há concordância acerca do surgimento da CT estar relacionado com a abundância de catecolaminas circulantes

    The second knee in the cosmic ray spectrum observed with the surface detector of the Pierre Auger Observatory

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    Studies of the mass composition of cosmic rays and proton-proton interaction cross-sections at ultra-high energies with the Pierre Auger Observatory

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    In this work, we present an estimate of the cosmic-ray mass composition from the distributions of the depth of the shower maximum (Xmax) measured by the fluorescence detector of the Pierre Auger Observatory. We discuss the sensitivity of the mass composition measurements to the uncertainties in the properties of the hadronic interactions, particularly in the predictions of the particle interaction cross-sections. For this purpose, we adjust the fractions of cosmic-ray mass groups to fit the data with Xmax distributions from air shower simulations. We modify the proton-proton cross-sections at ultra-high energies, and the corresponding air shower simulations with rescaled nucleus-air cross-sections are obtained via Glauber theory. We compare the energy-dependent composition of ultra-high-energy cosmic rays obtained for the different extrapolations of the proton-proton cross-sections from low-energy accelerator data

    Study of downward Terrestrial Gamma-ray Flashes with the surface detector of the Pierre Auger Observatory

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    The surface detector (SD) of the Pierre Auger Observatory, consisting of 1660 water-Cherenkov detectors (WCDs), covers 3000 km2 in the Argentinian pampa. Thanks to the high efficiency of WCDs in detecting gamma rays, it represents a unique instrument for studying downward Terrestrial Gamma-ray Flashes (TGFs) over a large area. Peculiar events, likely related to downward TGFs, were detected at the Auger Observatory. Their experimental signature and time evolution are very different from those of a shower produced by an ultrahigh-energy cosmic ray. They happen in coincidence with low thunderclouds and lightning, and their large deposited energy at the ground is compatible with that of a standard downward TGF with the source a few kilometers above the ground. A new trigger algorithm to increase the TGF-like event statistics was installed in the whole array. The study of the performance of the new trigger system during the lightning season is ongoing and will provide a handle to develop improved algorithms to implement in the Auger upgraded electronic boards. The available data sample, even if small, can give important clues about the TGF production models, in particular, the shape of WCD signals. Moreover, the SD allows us to observe more than one point in the TGF beam, providing information on the emission angle

    Measuring the muon content of inclined air showers using AERA and the water-Cherenkov detector array of the Pierre Auger Observatory

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    Investigating multiple elves and halos above strong lightning with the fluorescence detectors of the Pierre Auger Observatory

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    ELVES are being studied since 2013 with the twenty-four FD Telescopes of the Pierre Auger Observatory, in the province of Mendoza (Argentina), the world’s largest facility for the study of ultra-high energy cosmic rays. This study exploits a dedicated trigger and extended readout. Since December 2020, this trigger has been extended to the three High levation Auger Telescopes (HEAT), which observe the night sky at elevation angles between 30 and 60 degrees, allowing a study of ELVES from closer lightning. The high time resolution of the Auger telescopes allows us to upgrade reconstruction algorithms and to do detailed studies on multiple ELVES. The origin of multiple elves can be studied by analyzing the time difference and the amplitude ratio between flashes and comparing them with the properties of radio signals detected by the ENTLN lightning network since 2018. A fraction of multi-ELVES can also be interpreted as halos following ELVES. Halos are disc-shaped light transients emitted at 70-80 km altitudes, appearing at the center of the ELVES rings, due to the rearrangement of electric charges at the base of the ionosphere after a strong lightning event

    Status and expected performance of the AugerPrime Radio Detector

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    AugerPrime implementation in the DAQ systems of the Pierre Auger Observatory

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    Radio Interferometry applied to air showers recorded by the Auger Engineering Radio Array

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    A new radio interferometric technique was recently developed that takes into account time lags caused by the three-dimensional dependency of the refractive index in the atmosphere. It enables us to track the extensive air shower while it propagates through the atmosphere. Using this technique, properties of the air shower can be estimated, like the depth of maximum and the axis of propagation. In order to apply this method, strict constraints on the time-synchronisation between radio antennas in an array must be satisfied. In this contribution, we show that the Auger Engineering Radio Array can meet these timing criteria by operating a time reference beacon. We will show how this enables us to reconstruct air shower properties using the radio interferometric technique
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