L’expectoration induite, outil de diagnostic de l’asthme professionnel

Lemière, Catherine; Malo, Jean‐Luc

doi:10.1051/medsci/20062267595

“…By extending a line from this shifted VHE center of gravity through the pulsar, [47] discovered a molecular cloud in CO at a distance from earth, which is consistent with the dispersion based distance to the pulsar. This means that the SNR forward shock most likely struck this cloud, resulting in a reverse shock returning first to the expanding PWN of PSR B1823-13, which then resulted in a predictable offset direction for the VHE center of gravity.…”

Section: The Offset Pwn In X-rays and Vhe γ-Rayssupporting

confidence: 64%

“…a T = 20 kyr age), the required field strength would be 3.9µG. Whereas [47] found the abovementioned break energy from broad band modelling of HESS J1825-137, GLAST should be able to measure the uncooled spectral index at γ-ray energies E γ ≪ E b , which will allow us to constrain E b more accurately in future.…”

Section: Energy Dependent Morphology and The Cooling Break (A) Spectrmentioning

confidence: 97%

“…This cloud also has the correct orientation relative to the pulsar and γ-ray center of gravity to explain the observed offset in terms of an early reverse shock from the cloud location. A more detailed study on this topic was performed in the thesis of Lemière [47] whose study have revealed this new class of offset, filled center VHE PWN.…”

Section: The Evolving Definition Of Pulsar Wind Nebulae (Pwn)mentioning

confidence: 99%

“…Therefore, most likely the electron spectral index for this domain is around 2. spectra with increasing photon energy as described by [24] for such PWN. A more accurate procedure would then be either through direct modelling as done by [47] for HESS J1825-137, or, simply through fitting a two component electron spectrum scattering the CMBR and dust IR photons and rewriting the expressions for the cooling break directly in terms of the electron spectral break energy. Fortunately the estimate for the nebular field strength depends weakly on E b as discussed below:…”

Section: Energy Dependent Morphology and The Cooling Break (A) Spectrmentioning

confidence: 99%

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Implications of HESS Observations of Pulsar

Jager

¹

,

Djannati‐Ataï

²

2009

Astrophysics and Space Science Library

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Summary. In this review paper on pulsar wind nebulae (PWN) we discuss the properties of such nebulae within the context of containment against cross-field diffusion (versus normal advection), the effect of reverse shocks on the evolution of offset "Vela-like" PWN, constraints on maximum particle energetics, magnetic field strength estimates based on spectral and spatial properties, and the implication of such field estimates on the composition of the wind. A significant part of the discussion is based on the High Energy Stereoscopic System (H.E.S.S. or HESS) detection of the two evolved pulsar wind nebulae Vela X (cocoon) and HESS J1825-137. In the case of Vela X (cocoon) we also review evidence of a hadronic versus a leptonic interpretation, showing that a leptonic interpretation is favored for the HESS signal. The constraints discussed in this review paper sets a general framework for the interpretation of a number of offset, filled-center nebulae seen by HESS. These sources are found along the galactic plane with galactic latitudes |b| ∼ 0, where significant amounts of molecular gas is found. In these regions, we find that the interstellar medium is inhomogeneous, which has an effect on the morphology of supernova shock expansion. One consequence of this effect is the formation of offset pulsar wind nebulae as observed.

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“…range [9]. By setting the spindown age equal to the total radiation lifetime of VHE γ-ray emitting electrons, we can write the electron energy in terms of the VHE γ-ray energy (Eqn 2) to give the observed spectral break energy of E b ∼ 2.5 TeV [47], which is observed as a steepening in Figure (6):…”

Section: Energy Dependent Morphology and The Cooling Break (A) Spectrmentioning

confidence: 99%

HESS Observations of Pulsar Wind Nebulae

Jager¹

2005

AIP Conference Proceedings

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Summary. In this review paper on pulsar wind nebulae (PWN) we discuss the properties of such nebulae within the context of containment against cross-field diffusion (versus normal advection), the effect of reverse shocks on the evolution of offset "Vela-like" PWN, constraints on maximum particle energetics, magnetic field strength estimates based on spectral and spatial properties, and the implication of such field estimates on the composition of the wind. A significant part of the discussion is based on the High Energy Stereoscopic System (H.E.S.S. or HESS) detection of the two evolved pulsar wind nebulae Vela X (cocoon) and HESS J1825-137. In the case of Vela X (cocoon) we also review evidence of a hadronic versus a leptonic interpretation, showing that a leptonic interpretation is favored for the HESS signal. The constraints discussed in this review paper sets a general framework for the interpretation of a number of offset, filled-center nebulae seen by HESS. These sources are found along the galactic plane with galactic latitudes |b| ∼ 0, where significant amounts of molecular gas is found. In these regions, we find that the interstellar medium is inhomogeneous, which has an effect on the morphology of supernova shock expansion. One consequence of this effect is the formation of offset pulsar wind nebulae as observed.

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Status of very high energy -ray Astronomy as of early 2008

Djannati‐Ataï¹

2009

Nuclear Instruments and Methods in Physics Research Section A:

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Data obtained in the very high energy γ-ray band with the new generation of imaging telescopes, in particular through the galactic plane survey undertaken by H.E.S.S., low threshold observations with MAGIC and more recently by operation of VERITAS, have revealed dozens of galactic and extragalactic sources, providing a wealth of information on a variety of high energy acceleration sites in our universe. Also, the water Cherenkov instrument Milagro has provided several extended sources after seven years of data integration. An overview of these results with focus on some of the most recent highlights is given.

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L’expectoration induite, outil de diagnostic de l’asthme professionnel

Cited by 4 publications

References 37 publications

Implications of HESS Observations of Pulsar

Implications of HESS Observations of Pulsar

HESS Observations of Pulsar Wind Nebulae

Status of very high energy -ray Astronomy as of early 2008

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