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Theses

Approche multi-diagnostique des émissions de haute énergie des microquasars à trous noirs

Abstract : Accretion-ejection phenomena are seen across the whole Universe, in all wavelenghts and size scales; from the formation of young stars, to active galactic nuclei. Typical timescales are also very different; a few seconds for γ-ray bursts to several billion years for stellar formation. In our galaxy, accreting black holes, usually called microquasars, have the advantage of evolving on human timescales: from one day to several weeks. However, the link between accretion and ejection is misundurstanding. The connection between these mechanisms is the aim of my thesis work. In the first part, I study the spectro-temporal changes observed during outbursts. I compare the fast temporal variabilities observed during four outbursts of GX 339–4 to physical parameters from an accretion-ejection model. In this model, the spectral evolution is due to an interplay between two accretion flows: a standard accretion disk in the outer parts and a jet-emitting disk in the inner parts. I highlight the link between the observed variability and the transitional radius between the two accretion flows. In the second part, I use the INTEGRAL satellite which is an ideal instrument to probe the behaviour of these sources at higher energies, typically between 100 keV and 1000 keV. Here, I research a non-thermal emission signature for several sources which have very dis- tinct spectral behaviour. This emission is, hitherto, unconstrained and its origin is widely debated. I detect and characterize this component for several sources and spectral states. I then present results of a polarimetric study performed on the same sources. Polarization from this emission brings crucial and decisive insights into the emission mechanism from this component. I finally discuss about the implication of these results and the potential origin of this emission while comparing properties of the different sources.
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https://tel.archives-ouvertes.fr/tel-03114988
Contributor : Floriane Cangemi <>
Submitted on : Friday, January 29, 2021 - 4:38:44 PM
Last modification on : Thursday, April 15, 2021 - 3:08:18 PM

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  • HAL Id : tel-03114988, version 3

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Floriane Cangemi. Approche multi-diagnostique des émissions de haute énergie des microquasars à trous noirs. Astrophysique [astro-ph]. Université de Paris / Université Paris Diderot (Paris 7), 2020. Français. ⟨tel-03114988v3⟩

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