%0 Generic %1 trujillogomez2013lowmass %A Trujillo-Gomez, Sebastian %A Klypin, Anatoly %A Colin, Pedro %A Ceverino, Daniel %A Arraki, Kenza %A Primack, Joel %D 2013 %K feedback radiation simulation %T Low-mass galaxy assembly in simulations: regulation of early star formation by radiation from massive stars %U http://arxiv.org/abs/1311.2910 %X Despite recent success in forming realistic disc galaxies at redshift zero, simulations still form the bulk of their stars prematurely. We investigate the process of stellar mass assembly in low-mass simulated galaxies, a dwarf and a typical spiral, focusing on the effects of radiation from young stellar clusters. We employ a novel model of star formation in which stars form deterministically with a small efficiency per free-fall time, as observed in molecular clouds. Stellar feedback includes radiation pressure from massive stars and energy from supernova explosions and stellar winds. In galaxies with masses up to those of typical spirals, radiation efficiently suppresses star formation by dispersing and heating high density gas, mostly in the central regions, preventing the formation of a massive bulge. Once the galaxies reach this radiation-regulated growth regime, their global properties are robust to the specific choice of model parameters. Only when radiative feedback is included, do galaxies exhibit constant or even rising star formation histories, forming more than 50% of their stars at z<1, an observed phenomenon that has so far eluded analytical and numerical models. Low-mass galaxies with radiation pressure have a factor of ~100 reduction in the star formation rate at z = 2, and a factor of ~10 at z = 0.5. We conclude that radiation feedback is the main mechanism that effectively decouples the growth of the galaxy from that of the DM halo. Radiation does not affect the total baryon content of galaxies, but instead maintains gas in a warm, low density phase where it cannot fuel star formation. We find that the fraction of cold baryons within the simulated dwarf galaxy is 20-30%, in agreement with THINGS. Lastly, unlike SN energy, radiation from massive stars reduces the central density of the dark matter halo of a galaxy with M_* ~10^8 M_sun, in support of recent observations.

@misc{trujillogomez2013lowmass, abstract = {Despite recent success in forming realistic disc galaxies at redshift zero, simulations still form the bulk of their stars prematurely. We investigate the process of stellar mass assembly in low-mass simulated galaxies, a dwarf and a typical spiral, focusing on the effects of radiation from young stellar clusters. We employ a novel model of star formation in which stars form deterministically with a small efficiency per free-fall time, as observed in molecular clouds. Stellar feedback includes radiation pressure from massive stars and energy from supernova explosions and stellar winds. In galaxies with masses up to those of typical spirals, radiation efficiently suppresses star formation by dispersing and heating high density gas, mostly in the central regions, preventing the formation of a massive bulge. Once the galaxies reach this radiation-regulated growth regime, their global properties are robust to the specific choice of model parameters. Only when radiative feedback is included, do galaxies exhibit constant or even rising star formation histories, forming more than 50% of their stars at z<1, an observed phenomenon that has so far eluded analytical and numerical models. Low-mass galaxies with radiation pressure have a factor of ~100 reduction in the star formation rate at z = 2, and a factor of ~10 at z = 0.5. We conclude that radiation feedback is the main mechanism that effectively decouples the growth of the galaxy from that of the DM halo. Radiation does not affect the total baryon content of galaxies, but instead maintains gas in a warm, low density phase where it cannot fuel star formation. We find that the fraction of cold baryons within the simulated dwarf galaxy is 20-30%, in agreement with THINGS. Lastly, unlike SN energy, radiation from massive stars reduces the central density of the dark matter halo of a galaxy with M_* ~10^8 M_sun, in support of recent observations.}, added-at = {2013-11-13T17:06:37.000+0100}, author = {Trujillo-Gomez, Sebastian and Klypin, Anatoly and Colin, Pedro and Ceverino, Daniel and Arraki, Kenza and Primack, Joel}, biburl = {https://www.bibsonomy.org/bibtex/265d26185b5f81858cfc8bcfcd0fa0c68/miki}, description = {[1311.2910] Low-mass galaxy assembly in simulations: regulation of early star formation by radiation from massive stars}, interhash = {046716d3d3215847d3b66995114072c0}, intrahash = {65d26185b5f81858cfc8bcfcd0fa0c68}, keywords = {feedback radiation simulation}, note = {cite arxiv:1311.2910Comment: 20 pages, 14 figures. Submitted to MNRAS, November 2013}, timestamp = {2013-11-13T17:06:37.000+0100}, title = {Low-mass galaxy assembly in simulations: regulation of early star formation by radiation from massive stars}, url = {http://arxiv.org/abs/1311.2910}, year = 2013 }