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The observed age gradient in the Milky Way—as a test for theories of spiral arm structure.

Authors :
Vallée, Jacques P.
Source :
Astrophysics & Space Science; Mar2022, Vol. 367 Issue 3, p1-10, 10p
Publication Year :
2022

Abstract

Some important predictions from 4 main models of spiral arm formation are tested here, using observational data acquired for the Milky Way galaxy. Many spiral arm models (density wave, tidal wave, nuclear Lyapunov tube, or dynamic transient wave) have some consistencies with some of the observations, and some inconsistencies. Our 4 tests consist of the relative locations and relative speeds of different arm tracers away from the dust lane, and the global arm pitch angle as obtained over two Galactic quadrants and several Galactic radii, as well as the arm's continuity of shape from Galactic quadrant IV to Galactic quadrant I. In the Milky Way, an age gradient is observed from different arm tracers, amounting to 12.9 ± 1.1 Myrs/kpc, or a relative speed from the dust lane of 76 ± 10 km/s. The presence of an age gradient is predicted by the density waves, but is not consistent with the predictions of the tidal waves, of the nuclear Lyapunov tubes, nor of the dynamic transient recurrent waves. [ABSTRACT FROM AUTHOR]

Subjects

Subjects :
TSUNAMIS
SPIRAL galaxies
MILKY Way

Details

Language :
English
ISSN :
0004640X
Volume :
367
Issue :
3
Database :
Complementary Index
Journal :
Astrophysics & Space Science
Publication Type :
Academic Journal
Accession number :
156342658
Full Text :
https://doi.org/10.1007/s10509-022-04057-2