Durham University

About: Durham University is a education organization based out in Durham, United Kingdom. It is known for research contribution in the topics: Population & Galaxy. The organization has 39385 authors who have published 82311 publications receiving 3110994 citations. The organization is also known as: University of Durham & Gallery of Durham University.

The 60-μ and far-infrared luminosity functions of IRAS galaxies

Abstract: Une etude d'un echantillon de 2818 galaxies IRAS est realisee. La fonction de luminosite a 60 μm independante des variations de flux, et la distribution de densite radiale, independante de la fonction de luminosite, sont determinees avec une methode du maximum de vraisemblance

The spin and shape of dark matter haloes in the Millennium simulation of a Λ cold dark matter universe

Abstract: We investigate the spins and shapes of over a million dark matter haloes identified at z = 0 in the Millennium simulation. Our sample spans halo masses ranging from dwarf galaxies to rich galaxy clusters. The very large dynamic range of this A cold dark matter cosmological simulation enables the distribution of spins and shapes and their variation with halo mass and environment to be characterized with unprecedented precision. We compare results for haloes identified using three different algorithms, and investigate (and remove) biases in the estimate of angular momentum introduced both by the algorithm itself and by numerical effects. We introduce a novel halo definition called the TREE halo, based on the branches of the halo merger trees, which is more appropriate for comparison with real astronomical objects than the traditional 'friends-of-friends' and 'spherical overdensity' (SO) algorithms. We find that for this many objects, the traditional lognormal function is no longer an adequate description of the distribution, P(λ), of the dimensionless spin parameter λ, and we provide a different function that gives a better fit for TREE and SO haloes. The variation in spin with halo mass is weak but detectable, although the trend depends strongly on the halo definition used. For the entire population of haloes, we find median values of λ med = 0.0367-0.0429, depending on the definition of a halo. The haloes exhibit a range of shapes, with a preference for prolateness over oblateness. More-massive haloes tend to be less spherical and more prolate. We find that the more-spherical haloes have less coherent rotation in the median, and those closest to being spherical have a spin independent of mass (λ med ≈0.033). The most-massive haloes have a spin independent of shape (λ med ≈0.032). The majority of haloes have their angular momentum vector aligned with their minor axis and perpendicular to their major axis. We find a general trend for higher spin haloes to be more clustered, with a stronger effect for more-massive haloes. For galaxy cluster haloes, this can be larger than a factor of∼2.

Revisiting the urban politics of climate change

Abstract: In our 2005 paper, Rethinking Sustainable Cities, we made a case for the increasing significance of climate change in the urban politics of sustainability. Taking a multilevel governance perspective, we argued that the ‘urban’ governance of climate protection was not confined to a local arena or to the actions of the state, but rather was orchestrated through the interrelations between global, national and local actors across state/non-state boundaries. We revisit these arguments and examine their validity in the light of the rapidly changing landscape of urban responses to climate change and the growing academic literature in this field. We consider in turn: the ways in which climate change is shaping urban agendas; the utility of multilevel governance perspectives for understanding this phenomenon; and the extent to which we can identify a ‘new’ politics of urban climate change governance and its consequent implications for the development of theory and practice in this field.