247 research outputs found

    Morphologies of Ultracompact HII Regions in W49A and Sgr B2: Prevalence of Shells and a Modified Classification Scheme

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    We have used Very Large Array (VLA) observations of the massive star forming regions W49A and Sgr B2, obtained with resolutions from 2\farcs0 to 0\farcs04, to classify the morphologies of nearly 100 ultracompact HII regions. These high resolution, multi-frequency, multi-configuration VLA observations motivate several modifications of the existing morphological classification scheme for UC HII regions. In this work, we describe the modified morphology scheme and the criteria used in source classification. In particular, we drop the ``core-halo'' classification, add a ``bipolar'' classification, and change the shell classification to ``shell-like''. We tally the percentage of each morphology found in the Sgr B2 and W49A regions and find broad agreement with the Galactic plane surveys in the distribution of morphologies for most types. However, we find that nearly a third of the sources in these regions are shell-like, which is a higher percentage by nearly a factor of ten than found in the surveys of Galactic plane star forming regions by Wood & Churchwell (1989a) and Kurtz et al. (1994). This difference may be due to physical differences in the environments of these two extreme star forming regions. Alternatively, differences in observational technique may be responsible.Comment: 10 pages, 1 figure, 1 table, to appear in The Astrophysical Journal Letter

    Identification of protein interactions of grapevine fanleaf virus RNA-dependent RNA polymerase during infection of by affinity purification and tandem mass spectrometry.

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    The RNA-dependent RNA polymerase (1E) is involved in replication of grapevine fanleaf virus (GFLV, , ) and causes vein clearing symptoms in . Information on protein 1E interaction with other viral and host proteins is scarce. To study protein 1E biology, three GFLV infectious clones, i.e. GHu (a symptomatic wild-type strain), GHu-1E (an asymptomatic GHu mutant) and F13 (an asymptomatic wild-type strain), were engineered with protein 1E fused to a V5 epitope tag at the C-terminus. Following -mediated delivery of GFLV clones in and protein extraction at seven dpi, when optimal 1E:V5 accumulation was detected, two viral and six plant putative interaction partners of V5-tagged protein 1E were identified for the three GFLV clones by affinity purification and tandem mass spectrometry. This study provides insights into the protein interactome of 1E during GFLV systemic infection in and lays the foundation for validation work

    Nuclear dependence of the transverse single-spin asymmetry in the production of charged hadrons at forward rapidity in polarized p+pp+p, p+p+Al, and p+p+Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV

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    We report on the nuclear dependence of transverse single-spin asymmetries (TSSAs) in the production of positively-charged hadrons in polarized p↑+pp^{\uparrow}+p, p↑+p^{\uparrow}+Al and p↑+p^{\uparrow}+Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV. The measurements have been performed at forward rapidity (1.4<η<2.41.4<\eta<2.4) over the range of 1.8<pT<7.01.8<p_{T}<7.0 GeV/c/c and 0.1<xF<0.20.1<x_{F}<0.2. We observed a positive asymmetry ANA_{N} for positively-charged hadrons in \polpp collisions, and a significantly reduced asymmetry in p↑p^{\uparrow}+AA collisions. These results reveal a nuclear dependence of charged hadron ANA_N in a regime where perturbative techniques are relevant. These results provide new opportunities to use \polpA collisions as a tool to investigate the rich phenomena behind TSSAs in hadronic collisions and to use TSSA as a new handle in studying small-system collisions.Comment: 303 authors from 66 institutions, 9 pages, 2 figures, 1 table. v1 is version accepted for publication in Physical Review Letters. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm
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