3,904 research outputs found
A Case-Study Survey of an Eight-year Cluster of Motor Neurone Disease (MND) Referrals in a Rural English Village: Exploring Possible Aetiological Influences in a Hypothesis Stimulating Study
Cosmic Feedback from AGN
Accretion onto the massive black hole at the centre of a galaxy can feed
energy and momentum into its surroundings via radiation, winds and jets.
Feedback due to radiation pressure can lock the mass of the black hole onto the
M-sigma relation, and shape the final stellar bulge of the galaxy. Feedback due
to the kinetic power of jets can prevent massive galaxies greatly increasing
their stellar mass, by heating gas which would otherwise cool radiatively. The
mechanisms involved in cosmic feedback are discussed and illustrated with
observations.Comment: 9 pages, 13 figures, Proceedings IAU Symposium 267, Co-Evolution of
Central Black Holes and Galaxie
Can the WIMP annihilation boost factor be boosted by the Sommerfeld enhancement?
We demonstrate that the Sommerfeld correction to CDM annihilations can be
appreciable if even a small component of the dark matter is extremely cold.
Subhalo substructure provides such a possibility given that the smallest clumps
are relatively cold and contain even colder substructure due to incomplete
phase space mixing. Leptonic channels can be enhanced for plausible models and
the solar neighbourhood boost required to account for PAMELA/ATIC data is
plausibly obtained, especially in the case of a few TeV mass neutralino for
which the Sommerfeld-corrected boost is found to be Saturation
of the Sommerfeld effect is shown to occur below thereby
constraining the range of contributing substructures to be above We find that the associated diffuse gamma ray signal from
annihilations would exceed EGRET constraints unless the channels annihilating
to heavy quarks or to gauge bosons are suppressed. The lepton channel gamma
rays are potentially detectable by the FERMI satellite, not from the inner
galaxy where substructures are tidally disrupted, but rather as a
quasi-isotropic background from the outer halo, unless the outer substructures
are much less concentrated than the inner substructures and/or the CDM density
profile out to the virial radius steepens significantly.Comment: 8 pages, 5 figures. References added. Replaced to match published
versio
Cosmological Constraints from a Combined Analysis of the Cluster Mass Function and Microwave Background Anisotropies
We present constraints on several cosmological parameters from a combined
analysis of the most recent Cosmic Microwave Background anisotropy data and the
Sloan Digital Sky Survey cluster mass function. We find that the combination of
the two data sets breaks several degeneracies among the parameters and provides
the following constraints: ,
, , ,
.Comment: 7 pages, 1 figur
A late-time transition in the equation of state versus Lambda-CDM
We study a model of the dark energy which exhibits a rapid change in its
equation of state w(z), such as occurs in vacuum metamorphosis. We compare the
model predictions with CMB, large scale structure and supernova data and show
that a late-time transition is marginally preferred over standard Lambda-CDM.Comment: 4 pages, 1 figure, to appear in the proceedings of XXXVIIth
Rencontres de Moriond, "The Cosmological Model", March 200
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