278 research outputs found

    Scaling relations of the colour-detected cluster RzCS 052 at z=1.016 and of some other high redshift clusters

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    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

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    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

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    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

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    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

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    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

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    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 δ≈7.5\delta \approx 7.5, in poor superclusters δ≈6.0\delta \approx 6.0. Rich superclusters contain high density cores with densities δ>10\delta > 10 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 (δ>10\delta > 10) 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 UBVRIzJHKUBVRIzJHK Photometry of Galaxies in the Coma Cluster

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    We present a set of UBVRIzJHKsUBVRIzJHK_s photometry for 745 J+HJ+H band selected objects in a 22.5′×29.2′22.5' \times 29.2' 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 H<14.5H < 14.5. 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 (∼0.05\sim 0.05 mag in U−VU-V and less than ∼0.03\sim 0.03 in B−RB-R, V−IV-I or J−KJ-K). 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 ∼100\sim 100 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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