The connection between the peaks in velocity dispersion and star-forming clumps of turbulent galaxies

P. Oliva-Altamirano, D. B. Fisher, K. Glazebrook, E. Wisnioski, G. Bekiaris, R. Bassett, D. Obreschkow, R. Abraham

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Abstract

We present Keck/OSIRIS (OH Suppressing Infrared Imaging Spectrograph) adaptive optics observations with 150-400 pc spatial sampling of seven turbulent, clumpy disc galaxies from the DYnamics of Newly-Assembled Massive Objects (DYNAMO) sample (0.07 < z < 0.2). DYNAMO galaxies have previously been shown to be well matched in properties to mainsequence galaxies at z ~ 1.5. Integral field spectroscopy observations using adaptive optics are subject to a number of systematics including a variable point spread function and spatial sampling, which we account for in our analysis. We present gas velocity dispersion maps corrected for these effects, and confirm that DYNAMO galaxies do have high gas velocity dispersion (σ = 40-80 km s-1), even at high spatial sampling. We find statistically significant structure in six out of seven galaxies. The most common distance between the peaks in velocity dispersion (σpeaks) and emission line peaks is ~0.5 kpc; we note this is very similar to the average size of a clump measured with Hubble Space Telescope Ha maps. This could suggest that σpeaks in clumpy galaxies likely arise due to some interaction between the clump and the surrounding interstellar medium of the galaxy, though our observations cannot distinguish between outflows, inflows or velocity shear. Observations covering a wider area of the galaxies will be needed to confirm this result.

Original languageEnglish
Pages (from-to)522-535
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume474
Issue number1
DOIs
Publication statusPublished - 11 Feb 2018

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Oliva-Altamirano, P., Fisher, D. B., Glazebrook, K., Wisnioski, E., Bekiaris, G., Bassett, R., ... Abraham, R. (2018). The connection between the peaks in velocity dispersion and star-forming clumps of turbulent galaxies. Monthly Notices of the Royal Astronomical Society, 474(1), 522-535. https://doi.org/10.1093/mnras/stx2797