Kinematic Evidence for Halo Substructure in Spiral Galaxies

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dc.creatorHerrmann, Kimberly A.
dc.creatorCiardullo, Robin
dc.creatorSigurdsson, Steinn
dc.date2009-01-24
dc.date2009-02-17
dc.date.accessioned2026-07-07T12:42:02Z
dc.date.available2026-07-07T12:42:02Z
dc.descriptionWe present the results of a kinematic study of planetary nebulae in the extreme outskirts of two spiral galaxies, M83 (NGC 5236) and M94 (NGC 4736). We find that in the inner regions of the galaxies, the vertical velocity dispersion (sigma_z) falls off exponentially with the light, as expected for a constant mass-to-light ratio, constant thickness disk. However, starting at four optical scale lengths, sigma_z asymptotes out at roughly 20 km/s. Our analysis finds evidence for significant flaring in the outer regions as well, especially in M94. These observations are in excellent agreement with predictions derived from models of disk heating by halo substructure, and demonstrate how kinematic surveys in the outer disks of spirals can be used to test hierarchical models of galaxy formation.
dc.description4 pages, 2 figures, published in ApJ Letters (uses emulateapj.cls); added 1 reference and corrected Fig 2
dc.identifierhttps://arxiv.org/abs/0901.3798
dc.identifierhttp://arxiv.org/abs/0901.3798
dc.identifierAstrophysical Journal Letters 693 (2009) L19-L22
dc.identifierdoi:10.1088/0004-637X/693/1/L19
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/219940
dc.subjectCosmology and Nongalactic Astrophysics
dc.subjectAstrophysics of Galaxies
dc.titleKinematic Evidence for Halo Substructure in Spiral Galaxies
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