Showing posts with label Pulsar Wind Nebulae. Show all posts
Showing posts with label Pulsar Wind Nebulae. Show all posts
Friday, July 18, 2008
Benjamin Owen: How LIGO can follow up high-energy observations of young neutron stars
Ben discussed LIGO's attempts to do searches for gravitational wave emission from isolated spinning neutron stars, where the position is known but where you have to search over an unknown spin frequency. The poster child source for this type of search is Cas A. LIGO are interested in targeting (a) isolated non-pulsing neutron stars (like some of the CCOs), (b) as yet unseen neutron stars in pulsar wind nebulae/small supernova remnants, (c) massive star-forming regions in which a lot of neutron stars might be born, and (d) globular cluster cores. He also advertised the upcoming LIGO/Neutron Star astronomer meeting to be held in January 2009.
Patrick Slane: Observations of pulsar wind nebulae
Pat discussed the geometry of pulsar wind nebulae (PWN), such as their jet and torus structure. The jets, for example, are due to the the fact that the wind termination shock is farther from the pulsar at equator than along the axis. The pulsar dumps energetic particles into the PWN. Where the synchrotron lifetime of the particles is comparable to the age of the supernova, a break appears in the spectrum. Energetic electrons produce both the synchrotron and inverse Compton (IC) emission observed in PWN. By measuring both emission mechanisms, using gamma-ray and X-ray observations, one can constrain the magnetic field of the nebula. The interaction between the PWN and its surrounding supernova remnant may explain why PWN seem distorted. Because PWN evolve within a supernova remnant a reverse shock "slams" into the PWN. Turbulent and asymmetric structures are due to this reverse shock. This may explain why TeV sources are offset from pulsars.
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