HESS Observations of Pulsar Wind Nebulae

Jager, O. C. de

doi:10.1063/1.2141885

Cited by 11 publications

(9 citation statements)

References 34 publications

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“…These leptons are able to power a bright inverse Compton nebula with a nondetectable X-ray counterpart. This phenomenon could explain a significant fraction of unidentified VHE γ-ray sources and has already been proposed [8]. To visualize this effect, we simulated the long-term evolution of a generic PWN system over a time span of 200 kyr (Fig.…”

Section: The Modelmentioning

confidence: 99%

Unidentified VHE γ-ray sources and evolved pulsar wind nebulae - A possible connection?

Mayer¹,

Brucker²,

Holler³

et al. 2012

AIP Conference Proceedings

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Abstract. Among Galactic VHE (very high energy, E > 100 GeV) γ-ray sources, pulsar wind nebulae (PWNe) form the most abundant class. At the same time, there are numerous sources of VHE γ-rays which are still unidentified. A firm identification of such objects requires a counterpart at other wavelengths. Middle-aged PWNe may account for many of these unidentified sources. While leptons that have been injected into a PWN a long time ago can still cause the observed VHE γ-ray flux, the present energy output of the pulsar is significantly reduced with respect to former times and powers only a faint synchrotron nebula which is difficult to detect with current X-ray observatories. We present a time-dependent model to study the spectral evolution of PWNe. With this model it is possible to roughly predict the X-ray emission of PWNe based on the VHE γ-ray observations only. These predictions allow to select those unidentified VHE γ-ray sources for which, assuming an evolved PWN scenario, a detection of an X-ray counterpart seems to be feasible.

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Section: The Modelmentioning

confidence: 99%

Unidentified VHE γ-ray sources and evolved pulsar wind nebulae - A possible connection?

Mayer¹,

Brucker²,

Holler³

et al. 2012

AIP Conference Proceedings

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“…In the scaling equations below we will focus on the contribution from the CMBR alone, but refer the reader to [24,28] for first order analytical KleinNishina corrections when including the dust component (also based on [15].…”

Section: Energy Scales and Lifetimes Of X-ray Synchrotron And Vhe Ic mentioning

confidence: 99%

Implications of HESS Observations of Pulsar

Jager

Djannati‐Ataï

2009

Neutron Stars and Pulsars

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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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“…and VERITAS) does not allow us to detect TeV emission from the same particles that produce bright and compact X-ray nebulae in the vicinity of the pulsar. Instead, TeV images reveal much larger structures filled with the aged particles that may have accumulated over substantial part of pulsar's lifetime (see de Jager and Djannati-Ataï 2009). The TeV emission is usually attributed to inverse Compton (IC) scattering of background optical/IR photons off aged electrons, although, in denser environments, the contribution of neutral pion decay to the γ-rays emission could play an important role (if the pulsar winds indeed contain the so far elusive relativistic protons).…”

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confidence: 99%