Systematic study of outflows in the Local Universe using CALIFA: I. Sample selection and main properties

Carlos Lopez Coba; Sebastian F. Sanchez; Joss Bland-Hawthorn; Alexei V. Moiseev; Irene Cruz-Gonzalez; Ruben Garcia-Benito; Jorge K. Barrera-Ballesteros; Lluis Galbany

doi:10.1093/mnras/sty2960

paper

Systematic study of outflows in the Local Universe using CALIFA: I. Sample selection and main properties

arXiv:1811.01253 · doi:10.1093/mnras/sty2960

Abstract

We present a sample of 17 objects from the CALIFA survey where we find initial evidence of galactic winds based on their off-axis ionization properties. We identify the presence of outflows using various optical diagnostic diagrams (e.g., EW(H $α$ ), [Nii]/H $α$ , [Sii]/H $α$ , [Oi]/H $α$ line-ratio maps). We find that all 17 candidate outflow galaxies lie along the sequence of active star formation in the M $_{⋆}$ vs. star-formation rate diagram, without a clear excess in the integrated SFR. The location of galaxies along the star-formation main sequence (SFMS) does not influence strongly the presence or not of outflows. The analysis of the star-formation rate density ( $Σ_{SFR}$ ) reveals that the CALIFA sources present higher values when compared with normal star-forming galaxies. The strength of this relation depends on the calibrator used to estimate the SFR. This excess in $Σ_{SFR}$ is significant within the first effective radius supporting the idea that most outflows are driven by processes in the inner regions of a galaxy. We find that the molecular gas mass density ( $Σ_{gas}$ ) is a key parameter that plays an important role in the generation of outflows through its association with the local SFR. The canonical threshold reported for the generation of outflows -- $Σ_{SFR} > 0.1$ $M_{⊙} yr^{- 1} kpc^{- 2}$ -- is only marginally exceeded in our sample. Within the Kennicutt-Schmidt diagram we propose a domain for galaxies hosting starburst-driven outflows defined by $Σ_{SFR} > 1 0^{- 2} M_{⊙} yr^{- 1} kpc^{- 2}$ and $Σ_{gas} > 1 0^{1.2} M_{⊙} pc^{- 2}$ within a central kiloparcec region.

25 pages, 16 figues, accepted for publishing in MNRAS

Systematic study of outflows in the Local Universe using CALIFA: I. Sample selection and main properties

Abstract

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