The lifetimes of spiral patterns in disc galaxies

By J. Sellwood. 2010

135 citations recorded by the source corpus.

The rate of internally driven evolution of galaxy discs is strongly affected by the lifetimes of the spiral patterns they support. Evolution is much faster if the spiral patterns are recurrent short-lived transients rather than long-lived, quasi-steady features. As rival theories are still advocated based on these two distinct hypotheses, I review the evidence that bears on the question of the lifetimes of spiral patterns in galaxies. Observational evidence from external galaxies is frustratingly inconclusive, but the velocity distribution in the solar neighbourhood is more consistent with the transient picture. I present simulations of galaxy models that have been proposed to support quasi-steady, two-arm spiral modes that in fact evolve quickly due to multi-arm instabilities. I also show that all simulations to date manifest short-lived patterns, despite claims to the contrary. Thus the transient hypothesis is favoured by both numerical results and the velocity distribution in the solar neighbourhood.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/a428ac06f3bf3d1e260f28e287d624d9dbf5eea8

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Citations in the corpus

Dawes Review 4: Spiral Structures in Disc Galaxies (2014, background): “The main previous review on spiral structure is Toomre (1977), though there have also been a couple of shorter reviews by Sellwood in recent years (Sellwood 2010b, 2011).”
LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) — The survey's science plan (2012, methodology): “These data will allow one to search, e.g., for the local signature of Galactic halo streams (Re Fiorentin et al. 2005, Famaey et al. 2005), for the kinematic signature of the Galactic spiral arms and bulge (Sellwood 2011), or signs of accretion events in the disk (Helmi et al. 2006).”
SELF-PERPETUATING SPIRAL ARMS IN DISK GALAXIES (2012, background): “Simulations of cool, shearing disks always exhibit recurrent transient spiral activity and this situation has not changed over the past several decades as computational power has increased (Sellwood 2000; Fujii et al. 2011; Sellwood 2011).”
Evolution of galactic discs: multiple patterns, radial migration, and disc outskirts (2012, background): “An outer pattern with a roughly constant pattern speed has also been reported from simulationsof non-barred galactic discs (Roškar et al., 2011; Sellwood,2011).”
The dynamics of stars around spiral arms (2011, methodology): “The transient co-rotating spiral arm found in Nbody simulations should be tested by observations of both our Galaxy (Sellwood 2011) and external galaxies (e.g. Meidt et al. 2009; Foyle et al. 2011; Speights & Westpfahl 2011).”