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Published February 11, 2017 | Published + Submitted
Journal Article Open

Giant clumps in the FIRE simulations: a case study of a massive high-redshift galaxy

Abstract

The morphology of massive star-forming galaxies at high redshift is often dominated by giant clumps of mass ~ 10^8 - 10^9 M_☉ and size ~ 100 - 1000 pc. Previous studies have proposed that giant clumps might have an important role in the evolution of their host galaxy, particularly in building the central bulge. However, this depends on whether clumps live long enough to migrate from their original location in the disc or whether they get disrupted by their own stellar feedback before reaching the centre of the galaxy. We use cosmological hydrodynamical simulations from the FIRE (Feedback in Realistic Environments) project that implement explicit treatments of stellar feedback and ISM physics to study the properties of these clumps. We follow the evolution of giant clumps in a massive (M_* ~ 10^(10.8) M_☉ at z = 1), discy, gas-rich galaxy from redshift z ≳ 2 to z = 1. Even though the clumpy phase of this galaxy lasts over a gigayear, individual gas clumps are short-lived, with mean lifetime of massive clumps of ~ 20 Myr. During that time, they turn between 0.1% and 20% of their gas into stars before being disrupted, similar to local GMCs. Clumps with M ≳ 10^7 M_☉ account for ~ 20 % of the total star formation in the galaxy during the clumpy phase, producing ~ 10^(10) M_☉ of stars. We do not find evidence for net inward migration of clumps within the galaxy. The number of giant clumps and their mass decrease at lower redshifts, following the decrease in the overall gas fraction and star-formation rate.

Additional Information

© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 October 23. Received 2016 October 23; in original form 2016 March 10. We would like to thank the anonymous referee for their comments which helped to improve the quality of the paper. This research made use of astrodendro, a python package to compute dendrograms of astronomical data (http://www.dendrograms.org/). AO thanks Stella Offner for recommending the use of astrodendro for this work. AO is supported by the US Department of Energy, the David & Lucile Packard Foundation and the Simons Foundation. Support for PFH was provided by an Alfred P. Sloan Research Fellowship, NASA ATP Grant NNX14AH35G, and NSF Collaborative Research Grant #1411920 and CAREER grant #1455342. Numerical calculations were run on the Caltech compute cluster 'Zwicky' (NSF MRI award #PHY-0960291) and allocation TG-AST130039 granted by the Extreme Science and Engineering Discovery Environment (XSEDE) supported by the NSF. Additional computing support was provided by HECC (NASA) allocations SMD-14-5492, SMD-14-5189, SMD-15-5950 and XSEDE (NSF) allocations AST120025, AST150045. DK was supported by NSF grant AST-1412153 and a Cottrell Scholar award from the Research Corporation for Science Advancement. CAFG was supported by NSF through grants AST-1412836 and AST-1517491, by NASA through grant NNX15AB22G and by STScI through grant HST-AR-14293.001-A.

Attached Files

Published - stw2754.pdf

Submitted - 1603.03778v2.pdf

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Additional details

Created:
August 19, 2023
Modified:
October 23, 2023