59 research outputs found

    Neutron-capture element deficiency of the Hercules dwarf spheroidal galaxy

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    We present an assessment of the barium abundance ratios for red giant member stars in the faint Hercules dwarf spheroidal (dSph) galaxy. Our results are drawn from intermediate-resolution FLAMES/GIRAFFE spectra around the Ba II 6141.71 AA absorption line at low signal-to-noise ratios. For three brighter stars we were able to gain estimates from direct equivalent-width measurements, while for the remaining eight stars only upper limits could be obtained. These results are investigated in a statistical manner and indicate very low Ba abundances of log epsilon (Ba) < 0.7 dex (3 sigma). We discuss various possible systematic biasses, first and foremost, a blend with the Fe I 6141.73 AA-line, but most of those would only lead to even lower abundances. A better match with metal-poor halo and dSph stars can only be reached by including a large uncertainty in the continuum placement. This contrasts with the high dispersions in iron and calcium (in excess of 1 dex) in this galaxy. While the latter spreads are typical of the very low luminosity, dark-matter dominated dSphs, a high level of depletion in heavy elements suggests that chemical enrichment in Hercules was governed by very massive stars, coupled with a very low star formation efficiency. While very low abundances of some heavy elements are also found in individual stars of other dwarf galaxies, this is the first time that a very low Ba abundance is found within an entire dSph over a broad metallicity range.Comment: 10 pages, 6 figures, accepted for publication in Astronomy & Astrophysic

    Petition for a Writ of Certiorari

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    Petition for a Writ of Certiorari submitted by Public Patent Foundation and ACLU attorney

    Supplemental Brief for Appellees

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    Supplemental brief for appellees, written by appellees in support of plaintiffs-appellees in AMP v. Myriad Genetics (No. 2010-1406)

    Plaintiffs-Appellees' Petition for Panel Rehearing

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    Petitioners-appelles' petition for panel rehearing, submitted after the CAFC's July 29, 2011 ruling

    Brief for Petitioners

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    Petitioners Brief written by ACLU and Public Patent Foundation in support of petitioners in AMP v. Myriad Genetics (Supreme Court Case Docket No. 12-398)

    Petition for a Writ of Certiorari

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    Petition for a Writ of Certiorari submitted by petitioners Public Patent Foundation and American Civil Liberties Union (No. 11-725

    Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars: IV. Two bulge populations

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    Based on high-resolution (R ≈ 42 000 to 48 000) and high signal-to-noise (S/N ≈ 50 to 150) spectra obtained with UVES/VLT, we present detailed elemental abundances (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, Y, and Ba) and stellar ages for 12 new mic

    Brief for the Appellees

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    Brief written by appellees (Public Patent Foundation and American Civil Liberties Union) supporting affirmance in AMP v. Myriad Genetics (No. 2010-1406)
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