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The diverse evolutionary paths of simulated high-z massive, compact galaxies to z= 0

Wellons, Sarah and Torrey, Paul and Ma, Chung-Pei and Rodriguez-Gomez, Vicente and Pillepich, Annalisa and Nelson, Dylan and Genel, Shy and Vogelsberger, Mark and Hernquist, Lars (2016) The diverse evolutionary paths of simulated high-z massive, compact galaxies to z= 0. Monthly Notices of the Royal Astronomical Society, 456 (1). pp. 1030-1048. ISSN 0035-8711.

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Massive quiescent galaxies have much smaller physical sizes at high redshift than today. The strong evolution of galaxy size may be caused by progenitor bias, major and minor mergers, adiabatic expansion, and/or renewed star formation, but it is difficult to test these theories observationally. Herein, we select a sample of 35 massive, compact galaxies (M_* = 1–3 × 10^(11) M_⊙, M_*/R^(1.5) > 10^(10.5) M_⊙/kpc^(1.5)) at z = 2 in the cosmological hydrodynamical simulation Illustris and trace them forwards to z = 0 to uncover their evolution and identify their descendants. By z = 0, the original factor of 3 difference in stellar mass spreads to a factor of 20. The dark matter halo masses similarly spread from a factor of 5 to 40. The galaxies’ evolutionary paths are diverse: about half acquire an ex situ envelope and are the core of a more massive descendant, a third survive undisturbed and gain very little mass, 15 per cent are consumed in a merger with a more massive galaxy, and a small remainder are thoroughly mixed by major mergers. The galaxies grow in size as well as mass, and only ∼10 per cent remain compact by z = 0. The majority of the size growth is driven by the acquisition of ex situ mass. The most massive galaxies at z = 0 are the most likely to have compact progenitors, but this trend possesses significant dispersion which precludes a direct linkage to compact galaxies at z = 2. The compact galaxies’ merger rates are influenced by their z = 2 environments, so that isolated or satellite compact galaxies (which are protected from mergers) are the most likely to survive to the present day.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Torrey, Paul0000-0002-5653-0786
Rodriguez-Gomez, Vicente0000-0002-9495-0079
Pillepich, Annalisa0000-0003-1065-9274
Genel, Shy0000-0002-3185-1540
Vogelsberger, Mark0000-0001-8593-7692
Hernquist, Lars0000-0001-6950-1629
Additional Information:© 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2015 November 19. Received 2015 November 4; in original form 2015 July 8. First published online December 18, 2015. W is supported by the National Science Foundation Graduate Research Fellowship under grant number DGE1144152. PT acknowledges support from NASA ATP Grant NNX14AH35G. CPM acknowledges support from NASA grant NNX11AI97G and NSF grant AST-1411945. AP acknowledges support from the HST grant HST-AR-13897. SG acknowledges support provided by NASA through Hubble Fellowship grant HST-HF2-51341.001-A awarded by the STScI, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. LH acknowledges support from NASA grant NNX12AC67G and NSF grant AST-1312095.
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE1144152
NASA Hubble FellowshipHST-HF2-51341.001-A
Subject Keywords:galaxies: evolution – galaxies: high-redshift
Issue or Number:1
Record Number:CaltechAUTHORS:20160204-143736101
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Official Citation:Sarah Wellons, Paul Torrey, Chung-Pei Ma, Vicente Rodriguez-Gomez, Annalisa Pillepich, Dylan Nelson, Shy Genel, Mark Vogelsberger, and Lars Hernquist The diverse evolutionary paths of simulated high-z massive, compact galaxies to z = 0 MNRAS (February 11, 2016) Vol. 456 1030-1048 doi:10.1093/mnras/stv2738 First published online December 18, 2015
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64240
Deposited By: Ruth Sustaita
Deposited On:05 Feb 2016 17:35
Last Modified:09 Mar 2020 13:19

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