Gravitational Lensing at Millimeter Wavelengths

With today's millimeter and submillimeter instruments observers use gravitational lensing mostly as a tool to boost the sensitivity when observing distant objects. This is evident through the dominance of gravitationally lensed objects among those detected in CO rotational lines at z>1. It is also evident in the use of lensing magnification by galaxy clusters in order to reach faint submm/mm continuum sources. There are, however, a few cases where millimeter lines have been directly involved in understanding lensing configurations. Future mm/submm instruments, such as the ALMA interferometer, will have both the sensitivity and the angular resolution to allow detailed observations of gravitational lenses. The almost constant sensitivity to dust emission over the redshift range z=1-10 means that the likelihood for strong lensing of dust continuum sources is much higher than for optically selected sources. A large number of new strong lenses are therefore likely to be discovered with ALMA, allowing a direct assessment of cosmological parameters through lens statistics. Combined with an angular resolution <0.1", ALMA will also be efficient for probing the gravitational potential of galaxy clusters, where we will be able to study both the sources and the lenses themselves, free of obscuration and extinction corrections, derive rotation curves for the lenses, their orientation and, thus, greatly constrain lens models.Comment: 69 pages, Review on quasar lensing. Part of a LNP Topical Volume on "Dark matter and gravitational lensing", eds. F. Courbin, D. Minniti. To be published by Springer-Verlag 2002. Paper with full resolution figures can be found at ftp://oden.oso.chalmers.se/pub/tommy/mmviews.ps.g

ALMA imaging of the cold molecular and dusty disk in the type 2 active nucleus of the Circinus galaxy

Galaxie

Black hole feeding and star formation in NGC 1808

Galaxie

Physics of ULIRGs with MUSE and ALMA: the PUMA project. IV. No tight relation between cold molecular outflow rates and AGN luminosities

Galaxie

N-body simulations of gravitational dynamics

We describe the astrophysical and numerical basis of N-body simulations, both of collisional stellar systems (dense star clusters and galactic centres) and collisionless stellar dynamics (galaxies and large-scale structure). We explain and discuss the state-of-the-art algorithms used for these quite different regimes, attempt to give a fair critique, and point out possible directions of future improvement and development. We briefly touch upon the history of N-body simulations and their most important results.Comment: invited review (28 pages), to appear in European Physics Journal Plu

Gas and dust cooling along the major axis of M 33 (HerM33es). Herschel/PACS [C II] and [O I] observations

Galaxie

Convergence ou divergence régionale ?

National audienceRevue de la littérature empirique concernant la convergence des régions et ses différentes mesures. Après avoir rappelé les fondements macro-économiques des différentes mesures de la convergence, en particulier les théories de la croissance, les auteurs précisent les différentes mesures de la convergence utilisées, les raffinements économétriques développés ces dernières années dans ce domaine et les principaux résultats qui en découlent. Ils s'intéressent ensuite aux théories de la localisation et leurs prédictions en termes de convergence régionale, avant de faire à nouveau l'état des lieux critique des travaux empiriques issus de ces théories

The spatial sorting and matching of skills and firms

In this paper we make use of a matched employer-employee database for Italy to look at the spatial distribution of wages. Using this rich database we aim to open up the black box of agglomeration economies exploiting the micro dimension of interaction among economic agents, both individuals and firms. We provide evidence that firm size and, especially, skills are sorted across space and account for a large portion of the spatial wage variation. Our data also support the assortative matching hypothesis, which we show not to be driven by co-location of good workers and firms. Finally, we point out that assortative matching is negatively related to local market size