%0 Generic %1 guszejnov2017testing %A Guszejnov, David %A Hopkins, Philip F. %A Ma, Xiangcheng %D 2017 %K imf simulation variation %T Testing Models for IMF Variation in Milky Way-like Galaxies %U http://arxiv.org/abs/1702.04431 %X One of the key observations regarding the stellar initial mass function (IMF) is its near-universality in the Milky Way (MW), which provides a powerful way to test different star formation models that predict the IMF. However, those models are almost universally "cloud-scale" or smaller -- they take as input or simulate single molecular clouds (GMCs), clumps, or cores, and predict the resulting IMF as a function of the cloud properties. Without a model for the progenitor properties of all clouds which formed the stars at different locations in the MW (including ancient stellar populations formed in high-redshift, likely gas-rich dwarf progenitor galaxies that looked little like the Galaxy today), the predictions cannot be explored. We therefore utilize a high-resolution fully-cosmological simulation (from the Feedback In Realistic Environments project), which forms a MW-like galaxy with reasonable mass, morphology, abundances, and star formation history, and explicitly resolves massive GMCs; we combine this with several cloud-scale IMF models applied independently to every star-forming resolution element in the simulation to synthesize the predicted IMF variations in the present-day galaxy. We specifically explore broad classes of models where the IMF depends on the Jeans mass, the sonic or "turbulent Bonner-Ebert" mass, fragmentation with some polytropic equation-of-state, or where it is self-regulated by proto-stellar feedback. We show that all of these models, except the feedback-regulated models, predict far more variation ($0.6-1$ dex $1\,\sigma$ scatter in the IMF turnover mass) than is observed in the MW. This strongly constraints the parameters that can drive IMF variation in nearby galaxies, as well.

@misc{guszejnov2017testing, abstract = {One of the key observations regarding the stellar initial mass function (IMF) is its near-universality in the Milky Way (MW), which provides a powerful way to test different star formation models that predict the IMF. However, those models are almost universally "cloud-scale" or smaller -- they take as input or simulate single molecular clouds (GMCs), clumps, or cores, and predict the resulting IMF as a function of the cloud properties. Without a model for the progenitor properties of all clouds which formed the stars at different locations in the MW (including ancient stellar populations formed in high-redshift, likely gas-rich dwarf progenitor galaxies that looked little like the Galaxy today), the predictions cannot be explored. We therefore utilize a high-resolution fully-cosmological simulation (from the Feedback In Realistic Environments project), which forms a MW-like galaxy with reasonable mass, morphology, abundances, and star formation history, and explicitly resolves massive GMCs; we combine this with several cloud-scale IMF models applied independently to {\em every star-forming resolution element} in the simulation to synthesize the predicted IMF variations in the present-day galaxy. We specifically explore broad classes of models where the IMF depends on the Jeans mass, the sonic or "turbulent Bonner-Ebert" mass, fragmentation with some polytropic equation-of-state, or where it is self-regulated by proto-stellar feedback. We show that all of these models, except the feedback-regulated models, predict far more variation ($\sim 0.6-1$ dex $1\,\sigma$ scatter in the IMF turnover mass) than is observed in the MW. This strongly constraints the parameters that can drive IMF variation in nearby galaxies, as well.}, added-at = {2017-02-16T10:12:04.000+0100}, author = {Guszejnov, David and Hopkins, Philip F. and Ma, Xiangcheng}, biburl = {https://www.bibsonomy.org/bibtex/2cb2c843332a2637e3cf1cca96d914414/miki}, description = {[1702.04431] Testing Models for IMF Variation in Milky Way-like Galaxies}, interhash = {3cb3cf7813a2c02f8301aa9ad30cb714}, intrahash = {cb2c843332a2637e3cf1cca96d914414}, keywords = {imf simulation variation}, note = {cite arxiv:1702.04431Comment: 5 pages, 4 figures Submitted to MNRAS}, timestamp = {2017-02-16T10:12:04.000+0100}, title = {Testing Models for IMF Variation in Milky Way-like Galaxies}, url = {http://arxiv.org/abs/1702.04431}, year = 2017 }