450 research outputs found

    H2_2 Emission Nebulosity Associated with KH 15D

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    An H2_2 emission filament is found in close proximity to the unique object KH 15D using the adaptive optics system of the Subaru Telescope. The morphology of the filament, the presence of spectroscopic outflow signatures observed by Hamilton et al., and the detection of extended H2_2 emission from KH 15D by Deming, Charbonneau, & Harrington suggest that this filament arises from shocked H2_2 in an outflow. The filament extends about 15" to the north of KH 15D.Comment: 11 pages, 3 figures, 1 table. Astrophysical Journal Letters, in pres

    First Detection of NaI D lines in High-Redshift Damped Lyman-alpha Systems

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    A Near-infrared (1.18-1.35 micron) high-resolution spectrum of the gravitationally-lensed QSO APM 08279+5255 was obtained with the IRCS mounted on the Subaru Telescope using the AO system. We detected strong NaI D 5891,5897 doublet absorption in high-redshift DLAs at z=1.062 and 1.181, confirming the presence of NaI, which was first reported for the rest-frame UV NaI 3303.3,3303.9 doublet by Petitjean et al. This is the first detection of NaI D absorption in a high-redshift (z>1) DLA. In addition, we detected a new NaI component in the z=1.062 DLA and four new components in the z=1.181 DLA. Using an empirical relationship between NaI and HI column density, we found that all "components" have large HI column density, so that each component is classified as DLA absorption. We also detected strong NaI D absorption associated with a MgII system at z=1.173. Because no other metal absorption lines were detected in this system at the velocity of the NaI absorption in previously reported optical spectra (observed 3.6 years ago), we interpret this NaI absorption cloud probably appeared in the line of sight toward the QSO after the optical observation. This newly found cloud is likely to be a DLA based upon its large estimated HI column density. We found that the N(NaI)/N(CaII) ratios in these DLAs are systematically smaller than those observed in the Galaxy; they are more consistent with the ratios seen in the Large Magellanic Cloud. This is consistent with dust depletion generally being smaller in lower metallicity environments. However, all five clouds of the z=1.181 system have a high N(NaI)/N(CaII) ratio, which is characteristic of cold dense gas. We tentatively suggest that the host galaxy of this system may be the most significant contributor to the gravitational-lens toward APM 08279+5255.Comment: 22 pages, 6 Postscript figures, 3 tables, ApJ in press (Vol.643, 2 June 2006

    A Subarcsecond Companion to the T Tauri Star AS 353B

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    Adaptive optics imaging of the bright visual T Tauri binary AS 353 with the Subaru Telescope shows that it is a hierarchical triple system. The secondary component, located 5.6" south of AS 353A, is resolved into a subarcsecond binary, AS 353Ba and Bb, separated by 0.24". Resolved spectroscopy of the two close components shows that both have nearly identical spectral types of about M1.5. Whereas AS 353A and Ba show clear evidence for an infrared excess, AS 353Bb does not. We discuss the possible role of multiplicity in launching the large Herbig-Haro flow associated with AS 353A.Comment: AASTeXv5.0, 21 pages, 5 figures, Astronomical Journal, in pres

    Near-Infrared Adaptive Optics Spectroscopy of Binary Brown Dwarf HD 130948B and C

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    We present near-infrared spectroscopy of low-mass companions in a nearby triple system HD 130948 (Gliese 564, HR 5534). Adaptive optics on the Subaru Telescope allowed spectroscopy of the individual components of the 0".13 binary system. Based on a direct comparison with a series of template spectra, we determined the spectral types of HD 130948B and C to be L4 +- 1. If we take the young age of the primary star into account (0.3-0.8 Gyr), HD 130948B and C most likely are a binary brown dwarf system.Comment: 6 pages, 3 figures, accepted for publication in ApJ Letter

    Etude morphostructurale de la zone sud des rides Nouvelle-Calédonie et Loyauté (Zone Economique Exclusive de Nouvelle-Calédonie, Pacifique Sud-Ouest)

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    Les données de la campagne ZoNéCo 1 permettent de préciser la morphostructure du Sud des rides calédonienne et Loyauté qui s'avèrent plus complexes que les cartes précédentes ne le montraient, mais on retrouve les principales structures de la région Calédonie-Loyauté. L'imagerie met en évidence les zones de roches nues ou encroûtées, la présence d'écoulements gravitaires du Sud du bassin des Loyauté vers le bassin Sud-Fidjien. (Résumé d'auteur

    Search for CP Violation in the Decay Z -> b (b bar) g

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    About three million hadronic decays of the Z collected by ALEPH in the years 1991-1994 are used to search for anomalous CP violation beyond the Standard Model in the decay Z -> b \bar{b} g. The study is performed by analyzing angular correlations between the two quarks and the gluon in three-jet events and by measuring the differential two-jet rate. No signal of CP violation is found. For the combinations of anomalous CP violating couplings, h^b=h^AbgVbh^VbgAb{\hat{h}}_b = {\hat{h}}_{Ab}g_{Vb}-{\hat{h}}_{Vb}g_{Ab} and hb=h^Vb2+h^Ab2h^{\ast}_b = \sqrt{\hat{h}_{Vb}^{2}+\hat{h}_{Ab}^{2}}, limits of \hat{h}_b < 0.59and and h^{\ast}_{b} < 3.02$ are given at 95\% CL.Comment: 8 pages, 1 postscript figure, uses here.sty, epsfig.st

    Improved tau polarisation measurement

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    Wait times for breast cancer care

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    Measurement of care time intervals is complex, being influenced by many factors. The definition of the care interval monitored can also bias the detection of changes in waits. The implications of using different care interval definitions to report wait times and identify delays in care provision were examined using a retrospective chart review of 637 women with surgically treated breast cancer who were referred to a cancer centre between September 1999 and 2000 or September 2003 and 2004. Overall waits between detection and adjuvant treatment increased by 12 days over the two periods, but their exact location and cause(s) could not be determined at such a low-resolution interval. At higher resolutions of care intervals, reporting the comprehensive sequence of care events, the prolongation was mainly associated with delayed access to surgery (4 days) and delivery of adjuvant chemotherapy (4 days). The latter went unnoticed when waits were reported at intermediate (referral to adjuvant treatment) and low (detection to adjuvant treatment) resolutions. Disease stage and type of first adjuvant treatment consistently and significantly influenced the length of waits. Comprehensive monitoring of the entire care path is essential to effectively prioritize interventions, assess their outcomes and optimise access to cancer care

    Production of excited beauty states in Z decays

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    A data sample of about 3.0 million hadronic Z decays collected by the ALEPH experiment at LEP in the years 1991 through 1994, is used to make an inclusive selection of B~hadron events. In this event sample 4227 \pm 140 \pm 252 B^* mesons in the decay B^* \to B \gamma and 1944 \pm 108 \pm 161 B^{**} mesons decaying into a B~meson and a charged pion are reconstructed. For the well established B^* meson the following quantities areobtained: \Delta M = M_{B^*} - M_{B} = (45.30\pm 0.35\pm 0.87)~\mathrm{MeV}/c^2 and N_{B^*}/(N_B+N_{B^*}) = (77.1 \pm 2.6 \pm 7.0)\%. The angular distribution of the photons in the B^* rest frame is used to measure the relative contribution of longitudinal B^* polarization states to be \sigma_L/(\sigma_L + \sigma_T)= (33 \pm 6 \pm 5)\%. \\ Resonance structure in the M(B\pi)-M(B) mass difference is observed at (424 \pm 4 \pm 10)~\mathrm{MeV}/c^2. Its shape and position is in agreement with the expectation for B^{**}_{u,d} states decaying into B_{u,d}^{(*)} \pi^\pm. The signal is therefore interpreted as arising from them. The relative production rate is determined to be \frac{BR(Z \to b \to B_{u,d}^{**})}{BR(Z \to b \to B_{u,d})} = [27.9 \pm 1.6(stat) \pm 5.9(syst) \phantom{a}^{+3.9}_{-5.6}(model)]\%. where the third error reflects the uncertainty due to different production and decay models for the broad B_{u,d}^{**} states
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