The Supernova Rate-Velocity Dispersion Relation in the Interstellar Medium

By S. Dib, Eric F. Bell, A. Burkert. 2005

173 citations recorded by the source corpus.

We investigate the relationship between the velocity dispersion of the gas and the supernova (SN) rate and feedback efficiency with three-dimensional numerical simulations of SN-driven turbulence in the interstellar medium (ISM). Our simulations aim to explore the constancy of the velocity dispersion profiles in the outer parts of galactic disks at ~6-8 km s-1 and the transition to the starburst regime, i.e., high star formation rates (SFRs) associated with high velocity dispersions. With our fiducial value of the SN feedback efficiency (i.e., ϵ = 0.25, corresponding to an injected energy per SN of 0.25 × 1051 ergs), our results show that (1) SN driving leads to constant velocity dispersions of σ ~ 6 km s-1 for the total gas and σ ~ 3 km s-1 for the H I gas, independent of the SN rate, for values of the rate between 0.01 and 0.5 the Galactic value (ηG); (2) the position of the transition to the starburst regime (i.e., location of sharp increase in the velocity dispersion) at around SFR/area ≃ 5 × 10-3 to 10-2 M☉ yr-1 kpc-2 observed in the simulations is in good agreement with the transition to the starburst regime in the observations (e.g., NGC 628 and NGC 6949); (3) for the high SN rates, no H I gas is present in the simulations box; however, for the total gas velocity dispersion, there is good agreement between the models and the observations; (4) at the intermediate SN rates (η/ηG ~ 0.5-1), taking into account the thermal broadening of the H I line helps reach a good agreement in that regime between the models and the observations; and (5) for η/ηG < 0.5, σ and σ fall below the observed values by a factor of ~2. However, a set of simulations with different values of ϵ indicates that, for larger values of the SN feedback efficiencies, velocity dispersions of the H I gas of the order of 5-6 km s-1 can be obtained, in closer agreement with the observations. The fact that for η/ηG < 0.5, the H I gas velocity dispersions are a factor of ~2 smaller than the observed values could result from the fact that we might have underestimated the SN feedback efficiency. On the other hand, it might also be an indication that other physical processes couple to the stellar feedback in order to produce the observed level of turbulence in galactic disks.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/b7690a0d779b20853b1bab741064a099c7580dd9

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In Astronomy and Astrophysics

1. P. Hopkins
2. L. Hernquist
3. A. Dekel
4. R. Dav'e
5. T. Naab
6. E. Quataert
7. R. Somerville
8. C. Faucher-Giguére

In Nuclear and High Energy Physics

1. E. Quataert
2. P. Hopkins
3. C. Faucher-Giguére
4. C. Steidel
5. D. Erb
6. A. Shapley
7. E. Ostriker
8. T. Naab

Citations in the corpus

• Resolved spectroscopy of gravitationally lensed galaxies: recovering coherent velocity fields in subluminous z ~ 2-3 galaxies (2009, methodology): “In one such model, Dib et al. (2006) simulate the velocity dispersion within the inter-stellar medium of galaxies induced by supernovae energy injection (assuming a 25% feedback efficiency) and predict a correlation between starformation surface density and velocity dispersion.”
• TOWARD A COMPLETE ACCOUNTING OF ENERGY AND MOMENTUM FROM STELLAR FEEDBACK IN GALAXY FORMATION SIMULATIONS (2012, background): “10−3 − 10−2 M yr−1 kpc−2 (Dib et al. 2006), above which stellar feedback becomes the more dominant driver of the observed HI velocity dispersions (as shown numerically by Agertz et al. 2009a).”
• THREE-DIMENSIONAL HYDRODYNAMIC SIMULATIONS OF MULTIPHASE GALACTIC DISKS WITH STAR FORMATION FEEDBACK. I. REGULATION OF STAR FORMATION RATES (2013, background): “Many other recent simulations have also found nearly constant velocity dispersions with respect to the input SFR (e.g., Dib et al. 2006; Shetty & Ostriker 2008; Agertz et al. 2009; Joung et al. 2009; Dobbs et al. 2011; SO12).”
• THE SINS SURVEY OF z ∼ 2 GALAXY KINEMATICS: PROPERTIES OF THE GIANT STAR-FORMING CLUMPS (2010, background): “It is not clear whether the overall trend of the high-z points connects to the region occupied by lower surface star formation density, z ∼ 0 SFGs, as presented by Dib et al. (2006).”
• THE KMOS3D SURVEY: DESIGN, FIRST RESULTS, AND THE EVOLUTION OF GALAXY KINEMATICS FROM 0.7 ⩽ z ⩽ 2.7 (2014, background): “Various origins have been proposed for the high velocity dispersions such as feedback (Dib et al. 2006; Green et al. 2010), gas accretion (Förster Schreiber et al. 2006; Genzel et al. 2006; Elmegreen & Burkert 2010; Genel et al. 2010), conversion of gravitational potential energy into random…”
• Feedback-regulated star formation in molecular clouds and galactic discs (2013, background): “…(z ∼ 2) starforming galaxies have comparably large gas fractions (e.g., Daddi et al. 2010b; Tacconi et al. 2010) and are also inferred to have velocity dispersions that are elevated (Cresci et al. 2009; Genzel et al. 2011) relative to local spirals, which have cT ≈ 10 km s−1 (Dib et al. 2006).”
• The age structure of stellar populations in the solar vicinity Clues of a two-phase formation history of the Milky Way disk (2013, methodology): “…would have a star formation intensity similar to that of nearby starbursts and distant intensely star-forming galaxies at z ∼ 2−3 (e.g. Lehnert & Heckman 1996; Dib et al. 2006; Lehnert et al. 2009, 2013) Above these values, there is a sharp increase in the velocity dispersion of the ISM with ΣSFR.”
• THE KILOPARSEC-SCALE KINEMATICS OF HIGH-REDSHIFT STAR-FORMING GALAXIES (2009, background): “…vshear/σmean = 0.2 − 0.7 is significantly lower than the typical values (vdisk/σint ∼ 10 − 20, i.e., vshear/σmean∼ 2 − 4) appropriate to disk galaxies today (e.g. Dib et al. 2006), in agreement with the general con- clusion that these galaxies must be considerably thicker than traditional disk…”
• Evolution of magnetic fields in galaxies and future observational tests with the Square Kilometre Array (2008, background): “The turbulent velocity (or characteristic velocity dispersion of the gas) and the SFR correlate positively for nearby galaxies (Dib et al. 2006).”
• The CO-H2 Conversion Factor in Disc Galaxies and Mergers (2011, unknown): “…velocity dispersion is calculated from the external pressure from the hot ISM (Robertson et al. 2004) usingσ2 = P/ρcell though we impose a ceiling of 10 km s−1 which comes from average values found in turbulent feedback simulations (e.g Dib et al. 2006; Joung et al. 2009; Ostriker & Shetty 2011).”