28,167 research outputs found

    The non-segregated population of blue straggler stars in the remote globular cluster Palomar 14

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    We used deep wide-field observations obtained with the Canada-France-Hawaii Telescope to study the blue straggler star (BSS) population in the innermost five arcminutes of the remote Galactic globular cluster Palomar 14. The BSS radial distribution is found to be consistent with that of the normal cluster stars, showing no evidence of central segregation. Palomar 14 is the third system in the Galaxy (in addition to OmegaCentauri and NGC 2419) showing a population of BSS not centrally segregated. This is the most direct evidence that in Palomar 14 two-body relaxation has not fully established energy equipartition yet, even in the central regions (in agreement with the estimated half-mass relaxation time, which is significantly larger than the cluster age). These observational facts have important implications for the interpretation of the shape of the mass function and the existence of the tidal tails recently discovered in this cluster.Comment: 5 pages, 4 figures, accepted for publication in ApJ Letter

    The Unimodal Distribution Of Blue Straggler Stars in M75 (NGC 6864)

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    We have used a combination of multiband high-resolution and wide-field ground-based observations to image the Galactic globular cluster M75 (NGC 6864). The extensive photometric sample covers the entire cluster extension, from the very central regions out to the tidal radius, allowing us to determine the center of gravity and to construct the most extended star density profile ever published for this cluster. We also present the first detailed star counts in the very inner regions. The star density profile is well re-produced by a standard King model with core radius r_c ~ 5.4" and intermediate-high concentration c ~ 1.75. The present paper presents a detailed study of the BSS population and its radial distribution. A total number of 62 bright BSSs (with m_F255W < 21, corresponding to m_F555W < 20) has been identified, and they have been found to be highly segregated in the cluster core. No significant upturn in the BSS frequency has been observed in the outskirts of M75, in contrast to several other clusters studied with the same technique. This observational fact is quite similar to what has been found in M79 (NGC 1904) by Lanzoni et al. (2007a). Indeed the BSS radial distributions in the two clusters is qualitatively very similar, even if in M75 the relative BSS frequency seems to decrease significantly faster than in M79: indeed it decreases by a factor of 5 (from 3.4 to 0.7) within 1 r_c. Such evidence indicate that the vast majority of the cluster heavy stars (binaries) have already sunk to the core.Comment: ApJ accepted, 10 pages, 11 figures, 2 table

    Operator ordering for generally covariant systems

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    The constraint operators belonging to a generally covariant system are found out within the framework of the BRST formalism. The result embraces quadratic Hamiltonian constraints whose potential can be factorized as a never null function times a gauge invariant function. The building of the inner product between physical states is analyzed for systems featuring either intrinsic or extrinsic time.Comment: 4 pages. Talk given at the Third Conference on "Constrained Dynamics and Quantum Gravity" held in Sardinia (Italy), September 1999. Journal reference:Nucl. Phys. B (Proc. Suppl.) 88 (2000) 322-32

    Card from a Supporter in Cyprus to Geraldine Ferraro

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    Card from a supporter in Cyprus to Geraldine Ferraro.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_international/1297/thumbnail.jp

    Letter from a New York Supporter to Geraldine Ferraro

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    Letter from a Queens supporter to Geraldine Ferraro. Includes data entry sheet.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_new_york/1176/thumbnail.jp

    Letter from a Connecticut Supporter to Geraldine Ferraro

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    Greeting card from a Connecticut supporter to Geraldine Ferraro. Includes data entry sheet.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_connecticut/1040/thumbnail.jp

    Telegram from a New York Supporter to Geraldine Ferraro

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    Telegram from a Queens supporter to Geraldine Ferraro. Author is a Catholic priest. Includes data entry sheet.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_new_york/1205/thumbnail.jp

    Letter from an Indian Supporter to Geraldine Ferraro

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    Letter from an Indian supporter to Geraldine Ferraro. Author requests a signed photograph. Letter has handwritten notes.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_international/1305/thumbnail.jp

    Letter from a New York Supporter to Geraldine Ferraro

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    Letter from a Queens supporter to Geraldine Ferraro. Includes data entry sheet.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_new_york/1185/thumbnail.jp

    Letter from a New Jersey Supporter to Geraldine Ferraro

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    Letter from a young New Jersey supporter to Geraldine Ferraro. Includes data entry sheet.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_new_jersey/1181/thumbnail.jp
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