Spatial metallicity distribution statistics at ≲100 pc scales in the AMUSING++ nearby galaxy sample
Abstract
We analyse the spatial statistics of the 2D gasphase oxygen abundance distributions in a sample of 219 local galaxies. We introduce a new adaptive binning technique to enhance the signaltonoise ratio of weak lines, which we use to produce wellfilled metallicity maps for these galaxies. We show that the twopoint correlation functions computed from the metallicity distributions after removing radial gradients are in most cases welldescribed by a simple injectiondiffusion model. Fitting the data to this model yields the correlation length l_{corr}, which describes the characteristic interstellar medium (ISM) mixing lengthscale. We find typical correlation lengths l_{corr} ~ 1 kpc, with a strong correlation between l_{corr} and stellar mass, star formation rate (SFR), and effective radius, and a weak correlation with Hubble type. Two galaxies in the sample show significantly larger l_{corr}, and both prove to be interacting or merging systems. We show that the trend of l_{corr} with SFR can be reproduced by a simple transport + feedback model of ISM turbulence at high SFR, and plausibly also at low SFR if dwarf galaxy winds have large massloading factors. We also report the first measurements of the injection width that describes the initial radii over which supernova remnants deposit metals. Inside this radius the metallicity correlation function is not purely the product of a competition between injection and diffusion. We show that this size scale is generally smaller than 60 pc.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 January 2023
 DOI:
 10.1093/mnras/stac3028
 arXiv:
 arXiv:2206.08072
 Bibcode:
 2023MNRAS.518..286L
 Keywords:

 galaxies: abundances;
 galaxies: ISM;
 Astrophysics  Astrophysics of Galaxies
 EPrint:
 18 pages, 18 figures, 1 table, submitted to MNRAS. Comments are welcome