Catalog of observed tangents to the spiral arms in the milky way galaxy

  1. Get@NRC: Catalog of observed tangents to the spiral arms in the milky way galaxy (Opens in a new window)
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Journal titleAstrophysical Journal, Supplement Series
Article number1
Subjectcatalogs; Galaxy: disk; Galaxy: fundamental parameters; Galaxy: structure; ISM: kinematics and dynamics
AbstractFrom the Sun's location in the Galactic disk, one can use different arm tracers (CO, H I, thermal or ionized or relativistic electrons, masers, cold and hot dust, etc.) to locate a tangent to each spiral arm in the disk of the Milky Way. We present a master catalog of the astronomically observed tangents to the Galaxy's spiral arms, using different arm tracers from the literature. Some arm tracers can have slightly divergent results from several papers, so a mean value is taken - see the Appendix for CO, H II, and masers. The catalog of means currently consists of 63 mean tracer entries, spread over many arms (Carina, Crux-Centaurus, Norma, Perseus origin, near 3 kpc, Scutum, Sagittarius), stemming from 107 original arm tracer entries. Additionally, we updated and revised a previous statistical analysis of the angular offset and linear separation from the mid-arm for each different mean arm tracer. Given enough arm tracers, and summing and averaging over all four spiral arms, one could determine if arm tracers have separate and parallel lanes in the Milky Way. This statistical analysis allows a cross-cut of a Galactic spiral arm to be made, confirming a recent discovery of a linear separation between arm tracers. Here, from the mid-arm's CO to the inner edge's hot dust, the arm halfwidth is about 340 pc; doubling would yield a full arm width of 680 pc. We briefly compare these observations with the predictions of many spiral arm theories, notably the density wave theory.
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AffiliationNational Science Infrastructure; National Research Council Canada
Peer reviewedYes
NPARC number21272747
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Record identifier1a3d6600-aaba-49ee-9945-6c516a0033f1
Record created2014-12-03
Record modified2016-05-09
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