Publications by authors named "Giovanni Peres"

Background:  Coronavirus disease 2019 (COVID-19), a disease caused by the SARS-CoV-2 coronavirus, was declared a pandemic in March 2020, posing significant challenges globally. Homeopathy has historical relevance in epidemic management. In response, the government of the state of Santa Catarina, Brazil, distributed 1M as a potential prophylactic intervention for COVID-19.

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Article Synopsis
  • The origin of cosmic rays remains a significant mystery in high-energy astrophysics, with supernova remnants being strong candidates for their production due to their powerful blast waves.
  • Evidence is lacking that supernova remnants can efficiently convert their kinetic energy into cosmic rays; this study explores the relationship between shock energy and post-shock density in this context.
  • By analyzing X-ray observations of the SN 1006 remnant and comparing results with models, the study concludes that SN 1006 is an effective source of cosmic rays, supporting the quasi-parallel acceleration mechanism.
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Impacts of falling fragments observed after the eruption of a filament in a solar flare on 7 June 2011 are similar to those inferred for accretion flows on young stellar objects. As imaged in the ultraviolet (UV)-extreme UV range by the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory, many impacts of dark, dense matter display uncommonly intense, compact brightenings. High-resolution hydrodynamic simulations show that such bright spots, with plasma temperatures increasing from ~10(4) to ~10(6) kelvin, occur when high-density plasma (>>10(10) particles per cubic centimeter) hits the solar surface at several hundred kilometers per second, producing high-energy emission as in stellar accretion.

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The determination of the fine thermal structure of the solar corona is fundamental to constraining the coronal heating mechanisms. The Hinode X-ray Telescope collected images of the solar corona in different passbands, thus providing temperature diagnostics through energy ratios. By combining different filters to optimize the signal-to-noise ratio, we observed a coronal active region in five filters, revealing a highly thermally structured corona: very fine structures in the core of the region and on a larger scale further away.

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