278 research outputs found
Scaling relations of the colour-detected cluster RzCS 052 at z=1.016 and of some other high redshift clusters
We report on the discovery of the z=1.016 cluster RzCS 052 using a modified
red sequence method, followup spectroscopy and X-ray imaging. This cluster has
a velocity dispersion of 710+-150 km/s, a virial mass of 4.0e14 Msol (based on
21 spectroscopically confirmed members) and an X-ray luminosity of (0.68+-
0.47)e44 ergs/s in the [1-4] keV band. This optically selected cluster appears
to be of richness class 3 and to follow the known L_X-sigma_v relation for high
redshift X-ray selected clusters. Using these data, we find that the halo
occupation number for this cluster is only marginally consistent with what
expected assuming a self-similar evolution of cluster scaling relations,
suggesting perhaps a break of them at z~1. We also rule out a strong galaxy
merging activity between z=1 and today. Finally, we present a Bayesian approach
to measuring cluster velocity dispersions and X-ray luminosities in the
presence of a background: we critically reanalyze recent claims for X-ray
underluminous clusters using these techniques and find that the clusters can be
accommodated within the existing L_X -sigma_v relation.Comment: MNRAS, in pres
Manufacturing reshoring and its limits:the UK automotive case
This paper explores the meaning of reshoring and its drivers in the case of UK manufacturing and in particular its automotive sector. Drawing on interviews, policy reviews and a range of recent surveys, the paper finds that while reshoring is a discernable trend in UK manufacturing, it is less pronounced than many have claimed and that – in the UK case at least - there are severe limits as to how far this reshoring trend can go, particularly in relation to the availability of skills and finance in the supply chain. This is in turn raises questions over the stance of British policy and whether more could be done, with comparisons made to US experience
Galaxy Orientations in the Coma Cluster
We have examined the orientations of early-type galaxies in the Coma cluster
to see whether the well-established tendency for brightest cluster galaxies to
share the same major axis orientation as their host cluster also extends to the
rest of the galaxy population. We find no evidence of any preferential
orientations of galaxies within Coma or its surroundings. The implications of
this result for theories of the formation of clusters and galaxies
(particularly the first-ranked members) are discussed.Comment: Accepted for publication in the Astrophysical Journal Letters. 4
pages, 4 figure
Local industrial systems and the location of FDI in Italy
This article investigates the determinants of foreign direct investment (FDI)location across Italian provinces. Specifically it examines the relationship between industry- specific local industrial systems and the location of inward FDI. This extends previous analysis beyond the mere density of activity, to illustrate the importance of the specific nature of agglomerations in attracting inward investment. The article develops a model of FDI location choice using a unique FDI database stratified by industry and province. The results also suggest that the importance of agglomeration differs between industries, and offers some explanation for this
Faint dwarf spheroidals in the Fornax Cluster: A flat luminosity function
We have discovered about 70 very faint dwarf galaxies in the Fornax Cluster.
These dSphs candidates follow the same magnitude-surface brightness relation as
their counterparts in the Local Group, and even extend it to fainter limits.
The faintest dSph candidate in our sample has an absolute magnitude of M_V =
-8.8 mag and a central surface brightness of mu_V = 27 mag/arcsec^2. There
exists a tight color-magnitude relation for the early-type galaxies in Fornax
that extends from the giant to the dwarf regime. The faint-end slope of the
luminosity function of the early-type dwarfs is flat (alpha = -1.1+/-0.1),
contrary to the results obtained by Kambas et al. (2000).Comment: 4 pages, 3 figures, accepted for publication in Astronomy &
Astrophysics (Letters
Superclusters of galaxies in the 2dF redshift survey. III. The properties of galaxies in superclusters
We use catalogues of superclusters of galaxies from the 2dF Galaxy Redshift
Survey to study the properties of galaxies in superclusters. We compare the
properties of galaxies in high and low density regions of rich superclusters,
in poor superclusters and in the field, as well as in groups, and of isolated
galaxies in superclusters of various richness. We show that in rich
superclusters the values of the luminosity density smoothed on a scale of 8
\Mpc are higher than in poor superclusters: the median density in rich
superclusters is , in poor superclusters . Rich superclusters contain high density cores with densities while in poor superclusters such high density cores are absent. The
properties of galaxies in rich and poor superclusters and in the field are
different: the fraction of early type, passive galaxies in rich superclusters
is slightly larger than in poor superclusters, and is the smallest among the
field galaxies. Most importantly, in high density cores of rich superclusters
() there is an excess of early type, passive galaxies in groups
and clusters, as well as among those which do not belong to groups or clusters.
The main galaxies of superclusters have a rather limited range of absolute
magnitudes. The main galaxies of rich superclusters have larger luminosities
than those of poor superclusters and of groups in the field. Our results show
that both the local (group/cluster) environments and global (supercluster)
environments influence galaxy morphologies and their star formation activity.Comment: 13 pages, 10 figures, submitted to Astronomy and Astrophysic
Multiaperture Photometry of Galaxies in the Coma Cluster
We present a set of photometry for 745 band selected
objects in a region centered on the core of the Coma
cluster. This includes 516 galaxies and is at least 80% complete to H=16, with
a spectroscopically complete sample of 111 cluster members (nearly all with
morphological classification) for . For each object we present total
\cite{kron80} magnitudes and aperture photometry. As an example, we use these
data to derive color-magnitude relations for Coma early-type galaxies, measure
the intrinsic scatter of these relations and its dependence on galaxy mass, and
address the issue of color gradients. We find that the color gradients are mild
and that the intrinsic scatter about the color-magnitude relation is small
( mag in and less than in , or ).
There is no evidence that the intrinsic scatter varies with galaxy luminosity,
suggesting that the cluster red sequence is established at early epochs over a
range of in stellar mass.Comment: 41 pages, 5 figures, 18 data tables attached to source files or
available on request from R. De propris. Accepted for publication in
Astrophysical Journal Supplement Serie
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