Thermal instabilities in cooling galactic coronae: fuelling star formation in galactic discs

摘要: We investigate the means by which cold gas can accrete onto Milky Way mass galaxies from a hot corona of gas, using new smoothed particle hydrodynamics code, ‘SPHS’. find that ‘cold clumps’ seen in many classic SPH simulations literature are not present our SPHS simulations. Instead, condenses halo along filaments form at intersection supernovae-driven bubbles previous phases star formation. This positive feedback feeds to galactic disc directly, fuelling further The resulting and differ greatly their morphology, phase diagrams, stellar content. show clumps owe numerical thermal instability caused an inability for mix halo. improved treatment mixing suppresses this leading dramatically different physical outcome. In highest resolution simulation, we break up into bound stars. overdense factor 10-100 compared surrounding suggesting fragmentation results non-linear driven overdensity. ‘fragmenting filament’ mode growth has important implications galaxy formation, particular role formation bringing galaxies.