57 research outputs found
The moment of truth for WIMP Dark Matter
We know that dark matter constitutes 85% of all the matter in the Universe,
but we do not know of what it is made. Amongst the many Dark Matter candidates
proposed, WIMPs (weakly interacting massive particles) occupy a special place,
as they arise naturally from well motivated extensions of the standard model of
particle physics. With the advent of the Large Hadron Collider at CERN, and a
new generation of astroparticle experiments, the moment of truth has come for
WIMPs: either we will discover them in the next five to ten years, or we will
witness the inevitable decline of WIMP paradigm.Comment: To appear in Nature (Nov 18, 2010
Cluster Lenses
Clusters of galaxies are the most recently assembled, massive, bound
structures in the Universe. As predicted by General Relativity, given their
masses, clusters strongly deform space-time in their vicinity. Clusters act as
some of the most powerful gravitational lenses in the Universe. Light rays
traversing through clusters from distant sources are hence deflected, and the
resulting images of these distant objects therefore appear distorted and
magnified. Lensing by clusters occurs in two regimes, each with unique
observational signatures. The strong lensing regime is characterized by effects
readily seen by eye, namely, the production of giant arcs, multiple-images, and
arclets. The weak lensing regime is characterized by small deformations in the
shapes of background galaxies only detectable statistically. Cluster lenses
have been exploited successfully to address several important current questions
in cosmology: (i) the study of the lens(es) - understanding cluster mass
distributions and issues pertaining to cluster formation and evolution, as well
as constraining the nature of dark matter; (ii) the study of the lensed objects
- probing the properties of the background lensed galaxy population - which is
statistically at higher redshifts and of lower intrinsic luminosity thus
enabling the probing of galaxy formation at the earliest times right up to the
Dark Ages; and (iii) the study of the geometry of the Universe - as the
strength of lensing depends on the ratios of angular diameter distances between
the lens, source and observer, lens deflections are sensitive to the value of
cosmological parameters and offer a powerful geometric tool to probe Dark
Energy. In this review, we present the basics of cluster lensing and provide a
current status report of the field.Comment: About 120 pages - Published in Open Access at:
http://www.springerlink.com/content/j183018170485723/ . arXiv admin note:
text overlap with arXiv:astro-ph/0504478 and arXiv:1003.3674 by other author
On the V-DE Construction in Mandarin Chinese
The paper proposes a novel classification and analysis of the V-DE construction in Mandarin Chinese. On this proposal, the V-DE construction is divided into two types, predicative and non-predicative. The predicative type can be further divided into entity-predicative V-DE constructions and eventuality-predicative V-DE constructions. With respect to the analysis of the V-DE construction, the paper identifies four different structures. It points out that the de-part (i.e. the part after and marked by 得-de) in most V-DE constructions is a clause with or without an overt subject. Moreover, with respect to the cases where the de-part has an overt NP that can be interpreted as the Patient argument of the verb before -de and at the same time is semantically compatible with the VP or AP in the de-part, the paper proposes that the overt NP in such cases is syntactically the subject of the de-clause and syntactically is not the direct object of V-DE or the verb before -de. Finally, when the de-part of an entity-predicative V-DE construction has an overt NP between -de and the predicate of the de-clause, the AP or VP of the de-part generally needs to be predicated of the overt NP in the de-part. This constraint, however, can be occasionally relaxed to allow for a pragmatically-inducted interpretation when both of the following conditions are met: (i) the de-part is a well-formed clause in both form and meaning and (ii) the pragmatically-induced interpretation is pragmatically plausible
Binary systems and their nuclear explosions
Peer ReviewedPreprin
- …