Is a top-heavy initial mass function needed to reproduce the submillimetre galaxy number counts?. Safarzadeh, M., Lu, Y., & Hayward, C. C. Monthly Notices of the Royal Astronomical Society, 472:2462–2467, December, 2017. ![Is a top-heavy initial mass function needed to reproduce the submillimetre galaxy number counts? [link]](https://bibbase.org/img/filetypes/link.svg "link")
Paper doi abstract bibtex Matching the number counts and redshift distribution of submillimetre galaxies (SMGs) without invoking modifications to the initial mass ffunction (IMF) has proved challenging for semi-analytic models (SAMs) of galaxy formation. We adopt a previously developed SAM that is constrained to match the z = 0 galaxy stellar mass function and makes various predictions which agree well with observational constraints; we do not recalibrate the SAM for this work. We implement three prescriptions to predict the submillimetre flux densities of the model galaxies; two depend solely on star formation rate, whereas the other also depends on the dust mass. By comparing the predictions of the models, we find that taking into account the dust mass, which affects the dust temperature and thus influences the far-infrared spectral energy distribution, is crucial for matching the number counts and redshift distribution of SMGs. Moreover, despite using a standard IMF, our model can match the observed SMG number counts and redshift distribution reasonably well, which contradicts the conclusions of some previous studies that a top-heavy IMF, in addition to taking into account the effect of dust mass, is needed to match these observations. Although we have not identified the key ingredient that is responsible for our model matching the observed SMG number counts and redshift distribution without IMF variation - which is challenging given the different prescriptions for physical processes employed in the SAMs of interest - our results demonstrate that in SAMs, IMF variation is degenerate with other physical processes, such as stellar feedback.
@article{safarzadeh_is_2017,
title = {Is a top-heavy initial mass function needed to reproduce the submillimetre galaxy number counts?},
volume = {472},
issn = {0035-8711},
url = {http://adsabs.harvard.edu/abs/2017MNRAS.472.2462S},
doi = {10.1093/mnras/stx2172},
abstract = {Matching the number counts and redshift distribution of submillimetre
galaxies (SMGs) without invoking modifications to the initial mass
ffunction (IMF) has proved challenging for semi-analytic models (SAMs)
of galaxy formation. We adopt a previously developed SAM that is
constrained to match the z = 0 galaxy stellar mass function and makes
various predictions which agree well with observational constraints; we
do not recalibrate the SAM for this work. We implement three
prescriptions to predict the submillimetre flux densities of the model
galaxies; two depend solely on star formation rate, whereas the other
also depends on the dust mass. By comparing the predictions of the
models, we find that taking into account the dust mass, which affects
the dust temperature and thus influences the far-infrared spectral
energy distribution, is crucial for matching the number counts and
redshift distribution of SMGs. Moreover, despite using a standard IMF,
our model can match the observed SMG number counts and redshift
distribution reasonably well, which contradicts the conclusions of some
previous studies that a top-heavy IMF, in addition to taking into
account the effect of dust mass, is needed to match these observations.
Although we have not identified the key ingredient that is responsible
for our model matching the observed SMG number counts and redshift
distribution without IMF variation - which is challenging given the
different prescriptions for physical processes employed in the SAMs of
interest - our results demonstrate that in SAMs, IMF variation is
degenerate with other physical processes, such as stellar feedback.},
urldate = {2020-03-16},
journal = {Monthly Notices of the Royal Astronomical Society},
author = {Safarzadeh, Mohammadtaher and Lu, Yu and Hayward, Christopher C.},
month = dec,
year = {2017},
keywords = {galaxies: high-redshift - galaxies: starburst, infrared: galaxies, mass function, stars: luminosity function, submillimetre: galaxies},
pages = {2462--2467},
}
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We implement three prescriptions to predict the submillimetre flux densities of the model galaxies; two depend solely on star formation rate, whereas the other also depends on the dust mass. By comparing the predictions of the models, we find that taking into account the dust mass, which affects the dust temperature and thus influences the far-infrared spectral energy distribution, is crucial for matching the number counts and redshift distribution of SMGs. Moreover, despite using a standard IMF, our model can match the observed SMG number counts and redshift distribution reasonably well, which contradicts the conclusions of some previous studies that a top-heavy IMF, in addition to taking into account the effect of dust mass, is needed to match these observations. Although we have not identified the key ingredient that is responsible for our model matching the observed SMG number counts and redshift distribution without IMF variation - which is challenging given the different prescriptions for physical processes employed in the SAMs of interest - our results demonstrate that in SAMs, IMF variation is degenerate with other physical processes, such as stellar feedback.","urldate":"2020-03-16","journal":"Monthly Notices of the Royal Astronomical Society","author":[{"propositions":[],"lastnames":["Safarzadeh"],"firstnames":["Mohammadtaher"],"suffixes":[]},{"propositions":[],"lastnames":["Lu"],"firstnames":["Yu"],"suffixes":[]},{"propositions":[],"lastnames":["Hayward"],"firstnames":["Christopher","C."],"suffixes":[]}],"month":"December","year":"2017","keywords":"galaxies: high-redshift - galaxies: starburst, infrared: galaxies, mass function, stars: luminosity function, submillimetre: galaxies","pages":"2462–2467","bibtex":"@article{safarzadeh_is_2017,\n\ttitle = {Is a top-heavy initial mass function needed to reproduce the submillimetre galaxy number counts?},\n\tvolume = {472},\n\tissn = {0035-8711},\n\turl = {http://adsabs.harvard.edu/abs/2017MNRAS.472.2462S},\n\tdoi = {10.1093/mnras/stx2172},\n\tabstract = {Matching the number counts and redshift distribution of submillimetre \ngalaxies (SMGs) without invoking modifications to the initial mass\nffunction (IMF) has proved challenging for semi-analytic models (SAMs)\nof galaxy formation. We adopt a previously developed SAM that is\nconstrained to match the z = 0 galaxy stellar mass function and makes\nvarious predictions which agree well with observational constraints; we\ndo not recalibrate the SAM for this work. We implement three\nprescriptions to predict the submillimetre flux densities of the model\ngalaxies; two depend solely on star formation rate, whereas the other\nalso depends on the dust mass. By comparing the predictions of the\nmodels, we find that taking into account the dust mass, which affects\nthe dust temperature and thus influences the far-infrared spectral\nenergy distribution, is crucial for matching the number counts and\nredshift distribution of SMGs. 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