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Title: THE THICK DISKS OF SPIRAL GALAXIES AS RELICS FROM GAS-RICH, TURBULENT, CLUMPY DISKS AT HIGH REDSHIFT

Abstract

The formation of thick stellar disks in spiral galaxies is studied. Simulations of gas-rich young galaxies show formation of internal clumps by gravitational instabilities, clump coalescence into a bulge, and disk thickening by strong stellar scattering. The bulge and thick disks of modern galaxies may form this way. Simulations of minor mergers make thick disks too, but there is an important difference. Thick disks made by internal processes have a constant scale height with galactocentric radius, but thick disks made by mergers flare. The difference arises because in the first case, perpendicular forcing and disk-gravity resistance are both proportional to the disk column density, so the resulting scale height is independent of this density. In the case of mergers, perpendicular forcing is independent of the column density and the low-density regions get thicker; the resulting flaring is inconsistent with observations. Late-stage gas accretion and thin-disk growth are shown to preserve the constant scale heights of thick disks formed by internal evolution. These results reinforce the idea that disk galaxies accrete most of their mass smoothly and acquire their structure by internal processes, in particular through turbulent and clumpy phases at high redshift.

Authors:
;  [1];  [2]
  1. CEA, IRFU, SAp, 91191 Gif-sur-Yvette (France)
  2. IBM Research Division, T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598 (United States)
Publication Date:
OSTI Identifier:
21389343
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal (Online)
Additional Journal Information:
Journal Volume: 707; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/707/1/L1; Journal ID: ISSN 1538-4357
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COALESCENCE; FLARING; GALAXIES; GRAVITATION; GRAVITATIONAL INSTABILITY; MASS; RED SHIFT; SCALE HEIGHT; SCATTERING; SIMULATION; DIMENSIONS; HEIGHT; INSTABILITY; PLASMA INSTABILITY

Citation Formats

Bournaud, Frederic, Martig, Marie, and Elmegreen, Bruce G. THE THICK DISKS OF SPIRAL GALAXIES AS RELICS FROM GAS-RICH, TURBULENT, CLUMPY DISKS AT HIGH REDSHIFT. United States: N. p., 2009. Web. doi:10.1088/0004-637X/707/1/L1.
Bournaud, Frederic, Martig, Marie, & Elmegreen, Bruce G. THE THICK DISKS OF SPIRAL GALAXIES AS RELICS FROM GAS-RICH, TURBULENT, CLUMPY DISKS AT HIGH REDSHIFT. United States. https://doi.org/10.1088/0004-637X/707/1/L1
Bournaud, Frederic, Martig, Marie, and Elmegreen, Bruce G. 2009. "THE THICK DISKS OF SPIRAL GALAXIES AS RELICS FROM GAS-RICH, TURBULENT, CLUMPY DISKS AT HIGH REDSHIFT". United States. https://doi.org/10.1088/0004-637X/707/1/L1.
@article{osti_21389343,
title = {THE THICK DISKS OF SPIRAL GALAXIES AS RELICS FROM GAS-RICH, TURBULENT, CLUMPY DISKS AT HIGH REDSHIFT},
author = {Bournaud, Frederic and Martig, Marie and Elmegreen, Bruce G},
abstractNote = {The formation of thick stellar disks in spiral galaxies is studied. Simulations of gas-rich young galaxies show formation of internal clumps by gravitational instabilities, clump coalescence into a bulge, and disk thickening by strong stellar scattering. The bulge and thick disks of modern galaxies may form this way. Simulations of minor mergers make thick disks too, but there is an important difference. Thick disks made by internal processes have a constant scale height with galactocentric radius, but thick disks made by mergers flare. The difference arises because in the first case, perpendicular forcing and disk-gravity resistance are both proportional to the disk column density, so the resulting scale height is independent of this density. In the case of mergers, perpendicular forcing is independent of the column density and the low-density regions get thicker; the resulting flaring is inconsistent with observations. Late-stage gas accretion and thin-disk growth are shown to preserve the constant scale heights of thick disks formed by internal evolution. These results reinforce the idea that disk galaxies accrete most of their mass smoothly and acquire their structure by internal processes, in particular through turbulent and clumpy phases at high redshift.},
doi = {10.1088/0004-637X/707/1/L1},
url = {https://www.osti.gov/biblio/21389343}, journal = {Astrophysical Journal (Online)},
issn = {1538-4357},
number = 1,
volume = 707,
place = {United States},
year = {Thu Dec 10 00:00:00 EST 2009},
month = {Thu Dec 10 00:00:00 EST 2009}
}