%0 Generic %1 luo2015direct %A Luo, Yang %A Nagamine, Kentaro %A Shlosman, Isaac %D 2015 %K black collapse holes seeds %T Direct Collapse to Supermassive Black Hole Seeds: Comparing the AMR and SPH Approaches %U http://arxiv.org/abs/1512.03822 %X We provide detailed comparison between the AMR code Enzo-2.4 and the SPH code GADGET-3 in the context of direct baryonic collapse within DM halos to form supermassive black hole (SMBH) seeds, in isolated and cosmological frameworks, at z ~ 10-20. We find that both codes show an overall agreement in the general features of the collapse, however, many subtle differences exist. For isolated models, we find that the codes increase their spatial and mass resolutions at different pace, leading to substantially earlier collapse times in SPH due to higher gravitational resolution in GADGET-3. In fully cosmological runs, starting from z = 200, the AMR develops a slightly higher baryonic resolution than SPH during DM halo growth via cold accretion permeated by mergers. Still, both numerical schemes agree in the buildup of DM and baryonic structures. However, with the onset of direct collapse, this difference in mass and spatial resolution is amplified, so the evolution of SPH models begins to lag behind the AMR by ~10-20 Myr, especially in the central regions of halos. Such a delay can, in principle, have an effect on formation/destruction rate of molecular hydrogen in the presence of UV background, and on basic properties of host DM halos. Finally, the isolated models in spinning DM halos, with cosmological spin parameter lambda ~ 0.01 - 0.07, show delayed collapse times for greater lambda, but the pace of this increase is faster for the AMR. This conclusion does not stand for cosmological models. Within our simulation setup, GADGET-3 requires significantly larger computational resources than Enzo-2.4 during the collapse stage, cosmological or isolated, and needs similar resources, within factor ~2, during the pre-collapse, cosmological structure formation phase. Yet it benefits from substantially higher force and hydrodynamic resolution, except near the end of the collapse.

@misc{luo2015direct, abstract = {We provide detailed comparison between the AMR code Enzo-2.4 and the SPH code GADGET-3 in the context of direct baryonic collapse within DM halos to form supermassive black hole (SMBH) seeds, in isolated and cosmological frameworks, at z ~ 10-20. We find that both codes show an overall agreement in the general features of the collapse, however, many subtle differences exist. For isolated models, we find that the codes increase their spatial and mass resolutions at different pace, leading to substantially earlier collapse times in SPH due to higher gravitational resolution in GADGET-3. In fully cosmological runs, starting from z = 200, the AMR develops a slightly higher baryonic resolution than SPH during DM halo growth via cold accretion permeated by mergers. Still, both numerical schemes agree in the buildup of DM and baryonic structures. However, with the onset of direct collapse, this difference in mass and spatial resolution is amplified, so the evolution of SPH models begins to lag behind the AMR by ~10-20 Myr, especially in the central regions of halos. Such a delay can, in principle, have an effect on formation/destruction rate of molecular hydrogen in the presence of UV background, and on basic properties of host DM halos. Finally, the isolated models in spinning DM halos, with cosmological spin parameter lambda ~ 0.01 - 0.07, show delayed collapse times for greater lambda, but the pace of this increase is faster for the AMR. This conclusion does not stand for cosmological models. Within our simulation setup, GADGET-3 requires significantly larger computational resources than Enzo-2.4 during the collapse stage, cosmological or isolated, and needs similar resources, within factor ~2, during the pre-collapse, cosmological structure formation phase. Yet it benefits from substantially higher force and hydrodynamic resolution, except near the end of the collapse.}, added-at = {2015-12-15T11:27:41.000+0100}, author = {Luo, Yang and Nagamine, Kentaro and Shlosman, Isaac}, biburl = {https://www.bibsonomy.org/bibtex/246d22752729674abee4c3116157e24cc/miki}, description = {[1512.03822] Direct Collapse to Supermassive Black Hole Seeds: Comparing the AMR and SPH Approaches}, interhash = {adba42209ffdf793776f4491893b204e}, intrahash = {46d22752729674abee4c3116157e24cc}, keywords = {black collapse holes seeds}, note = {cite arxiv:1512.03822Comment: 18 pages, 14 figures, Submitted to MNRAS}, timestamp = {2015-12-15T11:27:41.000+0100}, title = {Direct Collapse to Supermassive Black Hole Seeds: Comparing the AMR and SPH Approaches}, url = {http://arxiv.org/abs/1512.03822}, year = 2015 }