Search results for "Jets [Galaxies]"

3D simulations of wind-jet interaction in massive X-ray binaries

2010

High-mass microquasars may produce jets that will strongly interact with surrounding stellar winds on binary system spatial scales. We study the dynamics of the collision between a mildly relativistic hydrodynamical jet of supersonic nature and the wind of an OB star. We performed numerical 3D simulations of jets that cross the stellar wind with the code Ratpenat. The jet head generates a strong shock in the wind, and strong recollimation shocks occur due to the initial overpressure of the jet with its environment. These shocks can accelerate particles up to TeV energies and produce gamma-rays. The recollimation shock also strengthens jet asymmetric Kelvin-Helmholtz instabilities produced i…

Tracking the evolution of the accretion flow in MAXI J1820+070 during its hard state with the JED-SAD model

2021

X-ray binaries in outburst typically show two canonical X-ray spectral states, i.e. hard and soft states, in which the physical properties of the accretion flow and of the jet are known to change. Recently, the JED-SAD paradigm has been proposed for black hole X-ray binaries, aimed to address the accretion-ejection interplay in these systems. According to this model, the accretion flow is composed by an outer standard Shakura-Sunyaev disk (SAD) and an inner hot Jet Emitting Disk (JED). The JED produces both the hard X-ray emission, effectively playing the role of the hot corona, and the radio jets. In this paper, we use the JED-SAD model to describe the evolution of the accretion flow in th…

High-energy monitoring of NGC 4593 II. Broad-band spectral analysis: testing the two-corona model

2019

It is widely believed that the primary X-ray emission of AGN is due to the Comptonisation of optical-UV photons from a hot electron corona, while the origin of the 'soft-excess' is still uncertain and matter of debate. A second Comptonisation component, called warm corona, was therefore proposed to account for the soft-excess, and found in agreement with the optical-UV to X-ray emission of a sample of Seyfert galaxies. In this context, we exploit the broadband XMM-Newton and NuSTAR simultaneous observations of the Seyfert galaxy NGC 4593 to further test the so called "two corona model". The NGC 4593 spectra are well reproduced by the model, from the optical/UV to the hard X-rays. Moreover, …

Traduction de : Jimenez, Jimi et Herrasti, Lourdes, "Objets associés des fosses de la guerre civile en Espagne"

2017

International audience

X-ray and optical emission in protostellar jets: model predictions and comparison with observations

2007

Modeling the X-ray emission from the nearest jets: HH 154 and DG Tau

2010

X-ray Emission in protostellar jets

2005

Prompted by the recent detection of X-ray emission from Herbig-Haro objects, we studied the interaction between a supersonic jet originating from a young stellar object and the ambient medium; our aim is to investigate the mechanisms causing the X-ray emission. Our model takes into account the radiative losses from optically in plasmas and Spitzer's thermal conduction including saturation effects. We explored the parameter space defined by the density contrast between the ambient medium and the jet and by the Mach number, to infer the configurations which can give rise to X-ray emission. From the models, we derived the X-ray emission as it would be observed with Chandra/ACIS-I and XMM-Newto…

X-ray emission in protostellar jets: comparison between model predictions and observations

2007

Herbig-Haro objects: model prediction and comparison with X-ray and optical observations

2007

X-ray emission from fast moving shocks in the protostellar jet HH 154: a binding diagnostic of the emission mechanism

2004

We propose to determine the proper motion of the X-ray source associated with HH 154, the only known protostellar jet in which the X-ray emission mechanism can be studied in detail. Our numerical simulations indicate that the X-rays are produced in a fast-moving (500 km/s) post-shock region, and our HST observations show high proper motion shocked material moving at similar speed. Detection (or lack of) of proper motion of the X-ray source will strongly confirm (or falsify) our model, and constitute the basis for a general theory of X-ray emission in protostellar jets. Understanding and modeling the emission mechanism is key to assess the lifetime of the X-ray emission and thus the influenc…