The specific star formation rate function at different mass scales and quenching: A comparison between cosmological models and SDSS. (arXiv:2010.08173v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Katsianis_A/0/1/0/all/0/1">Antonios Katsianis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_H/0/1/0/all/0/1">Haojie Xu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_X/0/1/0/all/0/1">Xiaohu Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Luo_Y/0/1/0/all/0/1">Yu Luo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cui_W/0/1/0/all/0/1">Weiguang Cui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dave_R/0/1/0/all/0/1">Romeel Davé</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lagos_C/0/1/0/all/0/1">Claudia Del P. Lagos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zheng_X/0/1/0/all/0/1">Xianzhong Zheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhao_P/0/1/0/all/0/1">Ping Zhao</a>
We present the eddington bias corrected Specific Star Formation Rate Function
(sSFRF) at different stellar mass scales from a sub-sample of the Sloan Digital
Sky Survey Data Release DR7 (SDSS), which is considered complete both in terms
of stellar mass (${rm M_{star}}$) and star formation rate (SFR). The above
enable us to study qualitatively and quantitatively quenching, the distribution
of passive/star-forming galaxies and perform comparisons with the predictions
from state-of-the-art cosmological models, within the same ${rm M_{star}}$
and SFR limits. We find that at the low mass end (${rm M_{star}} = 10^{9.5} –
10^{10} , {rm M_{odot}}$) the sSFRF is mostly dominated by star-forming
objects. However, moving to the two more massive bins (${rm M_{star}} =
10^{10} – 10^{10.5} , {rm M_{odot}}$ and ${rm M_{star}} = 10^{10.5} –
10^{11} , {rm M_{odot}}$) a bi-modality with two peaks emerges. One peak
represents the star-forming population, while the other describes a rising
passive population. The bi-modal form of the sSFRFs is not reproduced by a
range of cosmological simulations (e.g. Illustris, EAGLE, Mufasa, IllustrisTNG)
which instead generate mostly the star-forming population, while a bi-modality
emerges in others (e.g. L-Galaxies, Shark, Simba). Our findings reflect the
need for the employed quenching schemes in state-of-the-art models to be
reconsidered, involving prescriptions that allow “quenched galaxies” to retain
a small level of SF activity (sSFR $=$ ${rm 10^{-11} {rm yr^{-1}}}$-${rm
10^{-12} {rm yr^{-1}}}$) and generate an adequate passive
population/bi-modality even at intermediate masses (${rm M_{star}} = 10^{10}
– 10^{10.5} , {rm M_{odot}}$).
We present the eddington bias corrected Specific Star Formation Rate Function
(sSFRF) at different stellar mass scales from a sub-sample of the Sloan Digital
Sky Survey Data Release DR7 (SDSS), which is considered complete both in terms
of stellar mass (${rm M_{star}}$) and star formation rate (SFR). The above
enable us to study qualitatively and quantitatively quenching, the distribution
of passive/star-forming galaxies and perform comparisons with the predictions
from state-of-the-art cosmological models, within the same ${rm M_{star}}$
and SFR limits. We find that at the low mass end (${rm M_{star}} = 10^{9.5} –
10^{10} , {rm M_{odot}}$) the sSFRF is mostly dominated by star-forming
objects. However, moving to the two more massive bins (${rm M_{star}} =
10^{10} – 10^{10.5} , {rm M_{odot}}$ and ${rm M_{star}} = 10^{10.5} –
10^{11} , {rm M_{odot}}$) a bi-modality with two peaks emerges. One peak
represents the star-forming population, while the other describes a rising
passive population. The bi-modal form of the sSFRFs is not reproduced by a
range of cosmological simulations (e.g. Illustris, EAGLE, Mufasa, IllustrisTNG)
which instead generate mostly the star-forming population, while a bi-modality
emerges in others (e.g. L-Galaxies, Shark, Simba). Our findings reflect the
need for the employed quenching schemes in state-of-the-art models to be
reconsidered, involving prescriptions that allow “quenched galaxies” to retain
a small level of SF activity (sSFR $=$ ${rm 10^{-11} {rm yr^{-1}}}$-${rm
10^{-12} {rm yr^{-1}}}$) and generate an adequate passive
population/bi-modality even at intermediate masses (${rm M_{star}} = 10^{10}
– 10^{10.5} , {rm M_{odot}}$).
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