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Fading features found in the kinematics of the far-reaching Milky Way stellar halo




TekijätSarah A. Bird, Chris Flynn

KustantajaOxford University Press

Julkaisuvuosi2015

JournalMonthly Notices of the Royal Astronomical Society

Tietokannassa oleva lehden nimiMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Lehden akronyymiMON NOT R ASTRON SOC

Vuosikerta452

Numero3

Aloitussivu2675

Lopetussivu2679

Sivujen määrä5

ISSN0035-8711

eISSN1365-2966

DOIhttps://doi.org/10.1093/mnras/stv1448


Tiivistelmä

We test the long-term kinematical stability of a Galactic stellar halo model, due to Kafle et al. (2012), who study the kinematics of approximately 5000 blue horizontal branch stars in the Sloan Digital Sky Survey. The velocity dispersion sigma and anisotropy parameter beta of the stars have been determined as functions of Galactocentric radius, over the range 6 < R-GC < 25 kpc, and show a strong dip in the anisotropy profile at R-GC similar to 17 kpc. By directly integrating orbits of particles in a 3D model of the Galactic potential with these characteristics, we show that the sigma and beta profiles quickly evolve on a time-scale of a few x 10 Myr whereas the density rho profile remains largely unaffected. We suggest that the feature is therefore transient. The origin of such features in the Galactic halo remains unclear.




Last updated on 2024-26-11 at 22:59