2020A&A...641A..70B


C.D.S. - SIMBAD4 rel 1.7 - 2020.12.05CET00:57:54

2020A&A...641A..70B - Astronomy and Astrophysics, volume 641A, 70-70 (2020/9-1)

Evidence for supernova feedback sustaining gas turbulence in nearby star-forming galaxies.

BACCHINI C., FRATERNALI F., IORIO G., PEZZULLI G., MARASCO A. and NIPOTI C.

Abstract (from CDS):

It is widely known that the gas in galaxy discs is highly turbulent, but there is much debate on which mechanism can energetically maintain this turbulence. Among the possible candidates, supernova (SN) explosions are likely the primary drivers but doubts remain on whether they can be sufficient in regions of moderate star formation activity, in particular in the outer parts of discs. Thus, a number of alternative mechanisms have been proposed. In this paper, we measure the SN efficiency η, namely the fraction of the total SN energy needed to sustain turbulence in galaxies, and verify that SNe can indeed be the sole driving mechanism. The key novelty of our approach is that we take into account the increased turbulence dissipation timescale associated with the flaring in outer regions of gaseous discs. We analyse the distribution and kinematics of HI and CO in ten nearby star-forming galaxies to obtain the radial profiles of the kinetic energy per unit area for both the atomic gas and the molecular gas. We use a theoretical model to reproduce the observed energy with the sum of turbulent energy from SNe, as inferred from the observed star formation rate (SFR) surface density, and the gas thermal energy. For the atomic gas, we explore two extreme cases in which the atomic gas is made either of cold neutral medium or warm neutral medium, and the more realistic scenario with a mixture of the two phases. We find that the observed kinetic energy is remarkably well reproduced by our model across the whole extent of the galactic discs, assuming η constant with the galactocentric radius. Taking into account the uncertainties on the SFR surface density and on the atomic gas phase, we obtain that the median SN efficiencies for our sample of galaxies are <ηatom≥0.015–0.008+0.018 for the atomic gas and <ηmol≥0.003–0.002+0.006 for the molecular gas. We conclude that SNe alone can sustain gas turbulence in nearby galaxies with only few percent of their energy and that there is essentially no need for any further source of energy.

Abstract Copyright: © ESO 2020

Journal keyword(s): galaxies: kinematics and dynamics - galaxies: structure - ISM: kinematics and dynamics - ISM: structure - galaxies: star formation

Simbad objects: 19

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Number of rows : 19

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 11108 1
2 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9613 1
3 M 33 GiG 01 33 50.904 +30 39 35.79 6.17 6.27 5.72     ~ 5219 1
4 NGC 891 H2G 02 22 32.907 +42 20 53.95 11.08 10.81 9.93 7.86   ~ 1542 2
5 NGC 925 H2G 02 27 16.913 +33 34 43.97   10.69 10.12 9.55   ~ 701 1
6 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5799 1
7 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15069 1
8 NGC 2403 AGN 07 36 51.396 +65 36 09.17 9.31 8.84 8.38 8.19   ~ 1630 1
9 NGC 2841 LIN 09 22 02.655 +50 58 35.32 10.43 10.09 9.22     ~ 998 1
10 NGC 2976 GiP 09 47 15.458 +67 54 58.97 11.77 11.03 10.16 9.51   ~ 593 1
11 IC 2547 G 10 10 04.4794033616 +36 30 08.705016828   15.7       ~ 13 0
12 NGC 3198 EmG 10 19 54.990 +45 32 58.88 10.83 10.87 10.33     ~ 827 1
13 IC 2574 G 10 28 23.6204574649 +68 24 43.441365350 11.70 11.07 10.87 10.74   ~ 611 1
14 M 94 SyG 12 50 53.148 +41 07 12.55 9.15 8.96 8.24 7.78   ~ 1236 3
15 UGC 8024 GiC 12 54 05.248 +27 08 58.67 14.37 14.23 13.95 13.84   ~ 543 1
16 M 63 LIN 13 15 49.2738527699 +42 01 45.726078017   9.34 8.59 8.35   ~ 1082 2
17 NGC 6946 H2G 20 34 52.332 +60 09 13.24   10.5       ~ 2269 2
18 NGC 7331 LIN 22 37 04.102 +34 24 57.31 10.65 10.35 9.48     ~ 1123 2
19 NGC 7793 GiG 23 57 49.7533807411 -32 35 27.708304655 10.26 9.74 9.28 9.06 9.7 ~ 940 2

    Equat.    Gal    SGal    Ecl

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2020.12.05-00:57:54

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