%0 Generic %1 mcalpine2019nature %A McAlpine, Stuart %A Smail, Ian %A Bower, Richard G. %A Swinbank, Mark A. %A Trayford, James W. %A Theuns, Tom %A Baes, Maarten %A Camps, Peter %A Crain, Robert A. %A Schaye, Joop %D 2019 %K fraction merger simulation %T The nature of sub-millimeter and highly star-forming galaxies in the EAGLE simulation %U http://arxiv.org/abs/1901.05467 %X We exploit EAGLE, a cosmological hydrodynamical simulation, to reproduce the selection of the observed sub-millimeter (submm) galaxy population by selecting the model galaxies at $z 1$ with mock submm fluxes $S_850 1$ mJy. There is a reasonable agreement between the galaxies within this sample and the properties of the observed submm population, such as their star formation rates (SFRs) at $z<3$, redshift distribution and many integrated galaxy properties. We find that the bulk of the $S_850 1$ mJy model population is at $z = 2.5$, and that they are massive galaxies ($M_* 10^11$ Msol) with high dust masses ($M_dust 10^8$ Msol), gas fractions ($f_gas 50$%) and SFRs ($M_* 100$ Msol/yr). They have major and minor merger fractions similar to the general population, suggesting that mergers are not the primary driver of the model submm galaxies. Instead, the $S_850 1$ mJy model galaxies yield high SFRs primarily because they maintain a significant gas reservoir as a result of hosting an undermassive black hole. In addition, we find that not all highly star-forming EAGLE galaxies have submm fluxes $S_850 > 1$ mJy. Thus, we investigate the nature of $z 1$ highly star-forming Submm-Faint galaxies (i.e., $M_* 80$ Msol/yr but $S_850< 1$ mJy). We find they are similar to the model submm galaxies; being gas rich and hosting undermassive black holes, however they are typically lower mass ($M_* 10^10$ Msol) and are at higher redshifts ($z>4$). These typically higher-$z$ galaxies show stronger evidence for having been triggered by major mergers, and critically, they are likely missed by current submm surveys due to their higher dust temperatures. This suggests a potentially even larger contribution to the SFR density at $z > 3$ from dust-obscured systems than implied by current observations.

@misc{mcalpine2019nature, abstract = {We exploit EAGLE, a cosmological hydrodynamical simulation, to reproduce the selection of the observed sub-millimeter (submm) galaxy population by selecting the model galaxies at $z \geq 1$ with mock submm fluxes $S_{850} \geq 1$ mJy. There is a reasonable agreement between the galaxies within this sample and the properties of the observed submm population, such as their star formation rates (SFRs) at $z<3$, redshift distribution and many integrated galaxy properties. We find that the bulk of the $S_{850} \geq 1$ mJy model population is at $z = 2.5$, and that they are massive galaxies ($M_* \sim 10^{11}$ Msol) with high dust masses ($M_{\mathrm{dust}} \sim 10^{8}$ Msol), gas fractions ($f_{\mathrm{gas}} \approx 50$%) and SFRs ($\dot M_* \approx 100$ Msol/yr). They have major and minor merger fractions similar to the general population, suggesting that mergers are not the primary driver of the model submm galaxies. Instead, the $S_{850} \geq 1$ mJy model galaxies yield high SFRs primarily because they maintain a significant gas reservoir as a result of hosting an undermassive black hole. In addition, we find that not all highly star-forming EAGLE galaxies have submm fluxes $S_{850} > 1$ mJy. Thus, we investigate the nature of $z \geq 1$ highly star-forming Submm-Faint galaxies (i.e., $\dot M_* \geq 80$ Msol/yr but $S_{850}< 1$ mJy). We find they are similar to the model submm galaxies; being gas rich and hosting undermassive black holes, however they are typically lower mass ($M_* \sim 10^{10}$ Msol) and are at higher redshifts ($z>4$). These typically higher-$z$ galaxies show stronger evidence for having been triggered by major mergers, and critically, they are likely missed by current submm surveys due to their higher dust temperatures. This suggests a potentially even larger contribution to the SFR density at $z > 3$ from dust-obscured systems than implied by current observations.}, added-at = {2019-01-18T15:37:01.000+0100}, author = {McAlpine, Stuart and Smail, Ian and Bower, Richard G. and Swinbank, Mark A. and Trayford, James W. and Theuns, Tom and Baes, Maarten and Camps, Peter and Crain, Robert A. and Schaye, Joop}, biburl = {https://www.bibsonomy.org/bibtex/2b4f8af63d6f3241a32f457a55b8ce0fa/heh15}, description = {The nature of sub-millimeter and highly star-forming galaxies in the EAGLE simulation}, interhash = {c161c02247648e56817e803d69028c81}, intrahash = {b4f8af63d6f3241a32f457a55b8ce0fa}, keywords = {fraction merger simulation}, note = {cite arxiv:1901.05467Comment: 15 pages, 9 figures, submitted to MNRAS}, timestamp = {2019-01-18T15:37:01.000+0100}, title = {The nature of sub-millimeter and highly star-forming galaxies in the EAGLE simulation}, url = {http://arxiv.org/abs/1901.05467}, year = 2019 }