Browsing by Author "Kraljic, Katarina"

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    How galaxy properties vary with filament proximity in the SIMBA simulations
    (Oxford University Press, 2024) Bulichi, Teodora-Elena; Davé, Romeel; Kraljic, Katarina
    We explore the dependence of global galaxy properties in the SIMBA simulation as a function of distance from filaments identified using DISPERSE. We exclude haloes with mass Mh > 1013 M to mitigate the impact of group and cluster environments. Galaxies near filaments are more massive and have more satellites, which we control for by examining deviations from best-fitting scaling relations. At z = 0, star formation (SF) is significantly suppressed within 100 kpc of filaments, more strongly for satellites, indicating substantial pre-processing in filaments. By z = 2, the trend is weak and if anything indicates an increase in SF activity close to filaments. The suppression at z 1 is accompanied by lowered H I fractions, and increased metallicities, quenched fractions, and dispersion-dominated systems. H2 fractions are not strongly suppressed when controlling for stellar mass, suggesting that SF efficiency drives the drop in SF. By comparing amongst different SIMBA feedback variant runs, we show that the majority of SF suppression owes to filamentary shock-heating, but there is a non-trivial additional effect from AGN feedback. When looking around massive (Mh > 1013 M) haloes, those galaxies near filaments behave somewhat differently, indicating that filaments provide an additional environmental effect relative to haloes.
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    The impact of quenching on galaxy profiles in the SIMBA simulation
    (Oxford University Press, 2020) Dave, Romeel; Appleby, Sarah; Kraljic, Katarina
    We study specific star formation rate (sSFR) and gas profiles of star-forming (SF) and green valley (GV) galaxies in the SIMBA cosmological hydrodynamic simulation. SF galaxy half-light radii (Rhalf) at z = 0 and their evolution (∝(1 + z)−0.78) agree with observations. Passive galaxy Rhalf agree with observations at high redshift, but by z = 0 are too large, owing to numerical heating. We compare SIMBAz = 0 sSFR radial profiles for SF and GV galaxies to observations. SIMBA shows strong central depressions in star formation rate (SFR), sSFR, and gas fraction in GV galaxies and massive SF systems, qualitatively as observed, owing to black hole X-ray feedback, which pushes central gas outwards.
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    The impact of the connectivity of the cosmic web on the physical properties of galaxies at its nodes
    (Oxford University Press, 2019) Dave, Romeel; Kraljic, Katarina; Pichon, Christophe
    We investigate the impact of the number of filaments connected to the nodes of the cosmic web on the physical properties of their galaxies using the Sloan Digital Sky Survey. We compare these measurements to the cosmological hydrodynamical simulations H ORIZON-(NO)AGN and SIMBA. We find that more massive galaxies are more connected, in qualitative agreement with theoretical predictions and measurements in dark-matter-only simulations. The star formation activity and morphology of observed galaxies both display some dependence on the connectivity of the cosmic web at a fixed stellar mass: Less star forming and less rotation supported galaxies also tend to have higher connectivity.