![]() ![]() Using a Bayesian analysis, we constrain the parameters of the model and estimate the spectral indices of the non-thermal radio emission, the intensity of the magnetic field, and its degree of turbulence. We then apply our model to the star-forming region OMC-2 FIR 3/FIR 4. These fluxes are used to compute the ionisation rate and the non-thermal emission at centimetre wavelengths. We assume that relativistic protons and electrons are accelerated according to the first-order Fermi acceleration mechanism, and we calculate their emerging fluxes at the shock surface. The aim of this article is to show that when synchrotron emission and a high ionisation rate are measured in the same spatial region, a locally shock-accelerated cosmic-ray flux is sufficient to explain both phenomena. The high ionisation rate observed in some protostellar sources is generally attributed to shock-generated UV photons. These locally accelerated cosmic rays offer an attractive explanation for the high levels of non-thermal emission and ionisation rates observed close to these sources.Īims. Recently, there has been an increased interest in the study of the generation of low-energy cosmic rays (< 1 TeV) in shocks situated on the surface of a protostar or along protostellar jets. Bataillon, cc072, 34095 Montpellier, FranceĬontext. Fermi 5, 50125 Firenze, ItalyĮ-mail: Univers et Particules de Montpellier, UMR 5299 du CNRS, Université de Montpellier, Place E. INAF–Osservatorio Astrofisico di Arcetri, Largo E. Marco Padovani 1, Alexandre Marcowith 2, Daniele Galli 1, Leslie K. ![]() Astronomical objects: linking to databases.Including author names using non-Roman alphabets.Suggested resources for more tips on language editing in the sciences ![]() Punctuation and style concerns regarding equations, figures, tables, and footnotes “All our thinking since the Renaissance has been working against that idea,” says Seshadri Nadathur, a cosmologist at the University of Portsmouth in the UK. The concept of favoured regions in the universe is anathema to modern cosmology. If he is right, and these behemoths don’t exist as physical objects within our universe, then the cosmological principle might still be safe. One researcher claims these massive structures are illusions projected from another dimension, the first tantalising evidence of realities beyond our own. But the solution could prove equally controversial. Small wonder that the spate of recent findings has got cosmologists hot under the collar. No vast galactic walls or bald spots, and no huge structures. You’re allowed to have patches of individuality on the level of solar systems, galaxies and galaxy clusters, of course, but zoom out far enough and the universe should exhibit a drab homogeneity. The cosmological principle it has evolved into goes a step further, stating that nowhere in the universe is special. There’s only one problem: none of them should be there.Įver since Copernicus proposed his revolutionary idea that Earth’s place among the stars is nothing special, astronomers have regarded it as fundamental. As our observations of the cosmos come into ever sharper focus, astronomers are beginning to identify structures bigger than any seen before. ![]() A ring made out of hugely energetic bursts of radiation that spans 6 per cent of the visible universe. A colossal string of quasars billions of light years across. A GIANT hole in the web of galaxies that fills the cosmos. ![]()
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