Exploring the connection between stellar halo profiles and accretion histories in $L_{\ast }$ galaxies

Abstract

I use a library of controlled minor merger N-body simulations, a particle tagging technique and Monte Carlo generated $\Lambda$CDM accretion histories to study the highly stochastic process of stellar deposition onto the accreted stellar halos (ASHs) of $L_{\ast }$ galaxies. I explore the main physical mechanisms that drive the connection between the accretion history and the density profile of the ASH. I find that: i) through dynamical friction, more massive satellites are more effective at delivering their stars deeper into the host; ii) as a consequence, ASHs feature a negative gradient between radius and the local mass-weighed virial satellite-to-host mass ratio; iii) in $L_{\ast }$ galaxies, most ASHs feature a density profile that steepens towards sharper logarithmic slopes at increasing radii, though with significant halo-to-halo scatter; iv) the ASHs with the largest total ex-situ mass are such because of the chance accretion of a small number of massive satellites (rather than of a large number of low-mass ones).

arXiv commentProceedings of IAU Symposium 321, "Formation and evolution of galaxy outskirts", Eds. A. Gil de Paz, J. C. Lee & J. H. Knapen, Cambridge University Press, Cambridge

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Cited by in corpus (2)

• The Auriga Stellar Haloes: Connecting stellar population properties with accretion and merging history
• The accreted stellar halo as a window on halo assembly in L* galaxies