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Revisiting the relations: Galactic thin disc age–velocity dispersion relation

Seabroke, G. M. and Gilmore, G. (2007). Revisiting the relations: Galactic thin disc age–velocity dispersion relation. Monthly Notices of the Royal Astronomical Society, 380(4) pp. 1348–1368.

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The velocity dispersion of stars in the solar neighbourhood thin disc increases with time after star formation. Nordström et al. performed the most recent observations to constrain the age–velocity dispersion relation. They fitted the age–velocity dispersion relations of each Galactic cardinal direction space velocity component, U (towards the Galactic Centre), V (in the direction of Galactic rotation) and W (towards the North Galactic Pole), with power laws and interpreted these as evidence for continuous heating of the disc in all directions throughout its lifetime. We revisit these relations with their data and use the results of Famaey et al. to show that structure in the local velocity distribution function distorts the in-plane (U and V) velocity distributions away from Gaussian so that a dispersion is not an adequate parametrization of their functions. The age'? W relation can however be constrained because the sample is well phase-mixed vertically. We do not find any local signature of the stellar warp in the Galactic disc. Vertical disc heating does not saturate at an early stage. Our new result is that a power law is not required by the data: disc heating models that saturate after ?4.5 Gyr are equally consistent with observations.

Item Type: Journal Item
ISSN: 1365-2966
Project Funding Details:
Funded Project NameProject IDFunding Body
Not SetNot SetParticle Physics and Astronomy Research Council
Not SetNot SetGordon Wigan Fund
Not SetNot SetGonville and Caius College
Not SetNot SetCambridge Philosophical Society Research Studentship Fund
Keywords: galaxy: disc; galaxy: evolution; galaxy: kinematics and dynamics; solar neighbourhood; galaxy: stellar content
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 12966
Depositing User: George Seabroke
Date Deposited: 30 Jan 2009 03:23
Last Modified: 10 Dec 2018 03:46
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