Browsing by Author "Elson, Ed"

Now showing 1 - 3 of 3
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    MIGHTEE-H I: H I galaxy properties in the large-scale structure environment at z ∼ 0.37 from a stacking experiment
    (Oxford University Press, 2024) Sinigaglia, Francesco; Elson, Ed; Vaccari, Mattia
    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 ∼ 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 MH I = (8.12 ± 0.75) × 109 M⊙ at ∼11.8σ. Next, we investigate the different subsamples finding a negligible difference in MH I as a function of the galaxy overdensity. We report an H I excess compared to the full sample in satellite galaxies (MH I = (11.31 ± 1.22) × 109, at ∼10.2σ) and in filaments (MH I = (11.62 ± 0.90) × 109. Conversely, we report non-detections for the central and knot galaxies subsamples, which appear to be H I-deficient.
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    Mock HI spectral line stacking experiments for large galaxy surveys
    (University of Western Cape, 2019) Tladi, Modisha; Elson, Ed; Maartens, Roy
    The study of neutral atomic hydrogen (HI) plays a vital role in improving the knowledge about galaxy evolution since HI serves as the raw fuel for star formation. However, the current knowledge about it is limited to the nearby Universe due to its intrinsic faintness and the inadequate sensitivities of the current radio telescopes.
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    A study of the nearby interacting galaxy pair NGC 1512/1510
    (University of Western Cape, 2020) Ndaliso, Xola; Elson, Ed; Glowacki, M.; Maartens, R.
    This work focuses on generating a new dynamical model of the nearby (9.5 Mpc) interacting galaxy system NGC 1512/1510. Neutral hydrogen (H i ) observations from the Australia Telescope Compact Array (ATCA) are used to model the dynamics of the main H i disk using two routines, the two and three-dimensional modeling techniques. For the two-dimensional modeling technique, we adopt ROTCUR which is based on fitting a tilted ring model onto the 2D velocity field of the galaxy. The three-dimensional modeling routine used is 3DBarolo, which is a recently developed algorithm of fitting 3D tilted ring model to the full data cube. We note that the 2D approach fails to model the inclination profile of NGC 1512. Thus, a new rotation curve is generated using the three-dimensional modeling routine only i.e. by fitting a 3D tilted ring model to the H i line data cube of NGC 1512/1510.