Projects per year
Abstract
© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.We present the Dark-ages Reionization and Galaxy formation Observables from Numerical Simulations (DRAGONS) programme and Tiamat, the collisionless N-body simulation programme upon which DRAGONS is built. The primary trait distinguishing Tiamat from other large simulation programme is its density of outputs at high redshift (100 from z = 35 to z = 5; roughly one every 10 Myr) enabling the construction of very accurate merger trees at an epoch when galaxy formation is rapid and mergers extremely frequent. We find that the friends-of-friends halo mass function agrees well with the prediction of Watson et al. at high masses, but deviates at low masses, perhaps due to our use of a different halo finder or perhaps indicating a break from 'universal' behaviour. We then analyse the dynamical evolution of galaxies during the Epoch of Reionization finding that only a small fraction (~20 per cent) of galactic haloes are relaxed. We illustrate this using standard relaxation metrics to establish two dynamical recovery time-scales: (i) haloes need ~1.5 dynamical times following formation, and (ii) ~2 dynamical times following a major (3:1) or minor (10:1) merger to be relaxed. This is remarkably consistent across a wide mass range. Lastly, we use a phase-space halo finder to illustrate that major mergers drive long-lived massive phase-space structures which take many dynamical times to dissipate. This can yield significant differences in the inferred mass build-up of galactic haloes and we suggest that care must be taken to ensure a physically meaningful match between the galaxy formation physics of semi-analytic models and the halo finders supplying their input.
Original language | English |
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Pages (from-to) | 3025-3039 |
Number of pages | 15 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 459 |
Issue number | 3 |
Early online date | 30 Mar 2016 |
DOIs | |
Publication status | Published - 1 Jul 2016 |
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Dive into the research topics of 'Dark-ages Reionization and Galaxy formation simulation - I: The dynamical lives of high-redshift galaxies'. Together they form a unique fingerprint.Projects
- 3 Finished
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The Orbits and Interactions of Satellite Galaxies: A Fundamental Test of Cosmology
Power, C., Knebe, A., Lewis, G., Robotham, A., Obreschkow, D. & Zucker, D.
1/01/14 → 30/09/17
Project: Research
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Observing the Synthetic Universe - Revealing the Dark Cosmos with Future Telescopes
Power, C., Lewis, G., Poole, G. & Obreschkow, D.
1/01/13 → 31/12/15
Project: Research
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Monstrous Black Holes, Dead Stars and Accretion-Powered Feedback in Galaxy Formation
1/01/13 → 31/12/17
Project: Research