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Title: MAXIMALLY STAR-FORMING GALACTIC DISKS. II. VERTICALLY RESOLVED HYDRODYNAMIC SIMULATIONS OF STARBURST REGULATION

Abstract

We explore the self-regulation of star formation using a large suite of high-resolution hydrodynamic simulations, focusing on molecule-dominated regions (galactic centers and [U]LIRGS) where feedback from star formation drives highly supersonic turbulence. In equilibrium, the total midplane pressure, dominated by turbulence, must balance the vertical weight of the interstellar medium. Under self-regulation, the momentum flux injected by feedback evolves until it matches the vertical weight. We test this flux balance in simulations spanning a wide range of parameters, including surface density {Sigma}, momentum injected per stellar mass formed (p{sub *}/m{sub *}), and angular velocity. The simulations are two-dimensional radial-vertical slices, and include both self-gravity and an external potential that helps to confine gas to the disk midplane. After the simulations reach a steady state in all relevant quantities, including the star formation rate {Sigma}{sub SFR}, there is remarkably good agreement between the vertical weight, the turbulent pressure, and the momentum injection rate from supernovae. Gas velocity dispersions and disk thicknesses increase with p{sub *}/m{sub *}. The efficiency of star formation per free-fall time at the midplane density, {epsilon}{sub ff}(n{sub 0}), is insensitive to the local conditions and to the star formation prescription in very dense gas. We measure {epsilon}{sub ff}(n{submore » 0}) {approx} 0.004-0.01, consistent with low and approximately constant efficiencies inferred from observations. For {Sigma} in (100-1000) M{sub Sun} pc{sup -2}, we find {Sigma}{sub SFR} in (0.1-4) M{sub Sun} kpc{sup -2} yr{sup -1}, generally following a {Sigma}{sub SFR} {proportional_to} {Sigma}{sup 2} relationship. The measured relationships agree very well with vertical equilibrium and with turbulent energy replenishment by feedback within a vertical crossing time. These results, along with the observed {Sigma}-{Sigma}{sub SFR} relation in high-density environments, provide strong evidence for the self-regulation of star formation.« less

Authors:
 [1]
  1. Zentrum fuer Astronomie der Universitaet Heidelberg, Institut fuer Theoretische Astrophysik, Albert-Ueberle-Str. 2, 69120 Heidelberg (Germany)
Publication Date:
OSTI Identifier:
22039342
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 754; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANGULAR VELOCITY; ASTRONOMY; ASTROPHYSICS; COMPUTERIZED SIMULATION; COSMIC GASES; DENSITY; GALAXIES; GRAVITATION; MASS; MOLECULES; RESOLUTION; STAR EVOLUTION; STEADY-STATE CONDITIONS; SUPERNOVAE; TURBULENCE; TWO-DIMENSIONAL CALCULATIONS

Citation Formats

Shetty, Rahul, and Ostriker, Eve C., E-mail: R.Shetty@.uni-heidelberg.de, E-mail: ostriker@astro.umd.edu. MAXIMALLY STAR-FORMING GALACTIC DISKS. II. VERTICALLY RESOLVED HYDRODYNAMIC SIMULATIONS OF STARBURST REGULATION. United States: N. p., 2012. Web. doi:10.1088/0004-637X/754/1/2.
Shetty, Rahul, & Ostriker, Eve C., E-mail: R.Shetty@.uni-heidelberg.de, E-mail: ostriker@astro.umd.edu. MAXIMALLY STAR-FORMING GALACTIC DISKS. II. VERTICALLY RESOLVED HYDRODYNAMIC SIMULATIONS OF STARBURST REGULATION. United States. https://doi.org/10.1088/0004-637X/754/1/2
Shetty, Rahul, and Ostriker, Eve C., E-mail: R.Shetty@.uni-heidelberg.de, E-mail: ostriker@astro.umd.edu. 2012. "MAXIMALLY STAR-FORMING GALACTIC DISKS. II. VERTICALLY RESOLVED HYDRODYNAMIC SIMULATIONS OF STARBURST REGULATION". United States. https://doi.org/10.1088/0004-637X/754/1/2.
@article{osti_22039342,
title = {MAXIMALLY STAR-FORMING GALACTIC DISKS. II. VERTICALLY RESOLVED HYDRODYNAMIC SIMULATIONS OF STARBURST REGULATION},
author = {Shetty, Rahul and Ostriker, Eve C., E-mail: R.Shetty@.uni-heidelberg.de, E-mail: ostriker@astro.umd.edu},
abstractNote = {We explore the self-regulation of star formation using a large suite of high-resolution hydrodynamic simulations, focusing on molecule-dominated regions (galactic centers and [U]LIRGS) where feedback from star formation drives highly supersonic turbulence. In equilibrium, the total midplane pressure, dominated by turbulence, must balance the vertical weight of the interstellar medium. Under self-regulation, the momentum flux injected by feedback evolves until it matches the vertical weight. We test this flux balance in simulations spanning a wide range of parameters, including surface density {Sigma}, momentum injected per stellar mass formed (p{sub *}/m{sub *}), and angular velocity. The simulations are two-dimensional radial-vertical slices, and include both self-gravity and an external potential that helps to confine gas to the disk midplane. After the simulations reach a steady state in all relevant quantities, including the star formation rate {Sigma}{sub SFR}, there is remarkably good agreement between the vertical weight, the turbulent pressure, and the momentum injection rate from supernovae. Gas velocity dispersions and disk thicknesses increase with p{sub *}/m{sub *}. The efficiency of star formation per free-fall time at the midplane density, {epsilon}{sub ff}(n{sub 0}), is insensitive to the local conditions and to the star formation prescription in very dense gas. We measure {epsilon}{sub ff}(n{sub 0}) {approx} 0.004-0.01, consistent with low and approximately constant efficiencies inferred from observations. For {Sigma} in (100-1000) M{sub Sun} pc{sup -2}, we find {Sigma}{sub SFR} in (0.1-4) M{sub Sun} kpc{sup -2} yr{sup -1}, generally following a {Sigma}{sub SFR} {proportional_to} {Sigma}{sup 2} relationship. The measured relationships agree very well with vertical equilibrium and with turbulent energy replenishment by feedback within a vertical crossing time. These results, along with the observed {Sigma}-{Sigma}{sub SFR} relation in high-density environments, provide strong evidence for the self-regulation of star formation.},
doi = {10.1088/0004-637X/754/1/2},
url = {https://www.osti.gov/biblio/22039342}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 754,
place = {United States},
year = {Fri Jul 20 00:00:00 EDT 2012},
month = {Fri Jul 20 00:00:00 EDT 2012}
}