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Free keywords:
STAR-FORMING GALAXIES; HALO MASS RELATION; FAST ALPHA SURVEY; COSMIC
WEB; ATOMIC-HYDROGEN; NEUTRAL HYDROGEN; GAS DEFICIENCY; ASSEMBLY GAMA;
RAM PRESSURE; I GASAstronomy & Astrophysics; galaxies; formation; emission lines; cosmology : large-scale structure
of Universe;
Abstract:
We present the first measurement of H I mass of star-forming galaxies in different large scale structure environments from a blind survey at z similar to 0.37. In particular, we carry out a spectral line stacking analysis considering 2875 spectra of colour-selected star-forming galaxies undetected in H I at 0.23 < z < 0.49 in the COSMOS field, extracted from the MIGHTEE-H I Early Science data cubes, acquired with the MeerKAT radio telescope. We stack galaxies belonging to different subsamples depending on three different definitions of large-scale structure environment: local galaxy overdensity, position inside the host dark matter halo (central, satellite, or isolated), and cosmic web type (field, filament, or knot). We first stack the full star-forming galaxy sample and find a robust H I detection yielding an average galaxy H I mass of M-HI=(8.12 +/- 0.75)x10(9 )M(circle dot) at similar to 11.8 sigma. Next, we investigate the different subsamples finding a negligible difference in M-H I as a function of the galaxy overdensity. We report an H I excess compared to the full sample in satellite galaxies (M-H I = (11.31 +/- 1.22) x 10(9), at similar to 10.2 sigma) and in filaments (M-H I = (11.62 +/- 0.90) x 10(9). Conversely, we report non-detections for the central and knot galaxies subsamples, which appear to be H I-deficient. We find the same qualitative results also when stacking in units of H I fraction (f(H I)). We conclude that the H I amount in star-forming galaxies at the studied redshifts correlates with the large-scale structure environment.
