Terapixel Imaging of Cosmological Simulations

Feng, Yu; Croft, Rupert A. C.; Matteo, Tiziana Di; Khandai, Nishikanta; Sargent, Randy; Nourbakhsh, Illah; Dille, Paul; Bartley, Chris; Springel, Volker; Jana, Anirban; Gardner, J. P.

doi:10.1088/0067-0049/197/2/18

Cited by 12 publications

(11 citation statements)

References 27 publications

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“…The cosmological gas density distribution in the full volume of the MassiveBlack is shown in the large scale image of Figure 1. The panel shows the whole of the three-dimensional simulation volume "unwrapped" into a two-dimensional image slice (Feng et al 2011) at z = 5. At these large scales the density distribution of the universe appears fairly uniform.…”

Section: Resultsmentioning

confidence: 99%

Cold Flows and the First Quasars

Matteo

Khandai

DeGraf

et al. 2012

ApJ

283

269

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Observations of the most distant bright quasars imply that billion solar mass supermassive black holes (SMBHs) have to be assembled within the first 800 million years. Under our standard galaxy formation scenario such fast growth implies large gas densities providing sustained accretion at critical or supercritical rates onto an initial black hole seed. It has been a long standing question whether and how such high black hole accretion rates can be achieved and sustained at the centers of early galaxies. Here we use our new MassiveBlack cosmological hydrodynamic simulation covering a volume (0.75 Gpc) 3 appropriate for studying the rare first quasars to show that steady high density cold gas flows responsible for assembling the first galaxies produce the high gas densities that lead to sustained critical accretion rates and hence rapid growth commensurate with the existence of ∼10 9 M black holes as early as z ∼ 7. We find that under these conditions quasar feedback is not effective at stopping the cold gas from penetrating the central regions and hence cannot quench the accretion until the host galaxy reaches M halo 10 12 M . This cold-flow-driven scenario for the formation of quasars implies that they should be ubiquitous in galaxies in the early universe and that major (proto)galaxy mergers are not a requirement for efficient fuel supply and growth, particularly for the earliest SMBHs.

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Section: Resultsmentioning

confidence: 99%

Cold Flows and the First Quasars

Matteo

Khandai

DeGraf

et al. 2012

ApJ

283

269

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“…Halo 2 is located at the confluence of 3 filaments (second panel in Figure 2). From a general visualization of the MB simulation (Feng et al 2011) we can infer that this is one of the typical configurations for massive halo growth by accretion from filaments. The blackhole went though a rapid growth phase between z = 7 and z = 6, likely due to an incoming gas rich merger.…”

Section: Selection Of Halosmentioning

confidence: 94%

High-redshift supermassive black holes: accretion through cold flows

Feng¹,

Matteo²,

Croft³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We use zoom-in techniques to re-simulate three high-redshift (z ≥ 5.5) halos which host 10 9 solar mass blackholes from the ∼ Gpc volume, MassiveBlack cosmological hydrodynamic simulation. We examine a number of factors potentially affecting supermassive blackhole growth at high redshift in cosmological simulations. These include numerical resolution, feedback prescriptions and formulation of smoothed particle hydrodynamics. We find that varying the size of the region over which feedback energy is deposited directly, either for fixed number of neighbours or fixed volume makes very little difference to the accretion history of blackholes. Changing mass resolution by factors of up to 64 also does not change the blackhole growth history significantly. We find that switching from the density-entropy formulation to the pressure-entropy formulation of smoothed particle hydrodynamics slightly increases the accretion rate onto blackholes. In general numerical details appear to have small effects on the main fueling mechanism for blackholes at these high redshifts. We examine the fashion by which this occurs, finding that the insensitivity to simulation technique seems to be a hallmark of the cold flow feeding picture of these high-z supermassive blackholes. We show that the gas that participates in critical accretion phases, in these massive objects at z > 6 ∼ 7 is in all cases colder, denser, and forms more coherent streams than the average gas in the halo. This is also mostly the case when the blackhole accretion is feedback regulated (z < 6), however the distinction is less prominent. For our resimulated halos, cold flows appear to be a viable mechanism for forming the most massive blackholes in the early universe, occurring naturally in ΛCDM models of structure formation. Not requiring fine tuning of numerical parameters, they seem to be physically inevitable in these objects.

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“…Terapixel images have been previously used to visualize astronomical observations [10] while multiple gigapixel images have been used for visualizing cosmology simulation outputs [11]. We aim to apply terapixel imaging to look towards, instead of away from, Earth and to present observations about one region on Earth in detail.…”

Section: Urban Data Visualizationmentioning

confidence: 99%

Petascale Cloud Supercomputing for Terapixel Visualization of a Digital Twin

Holliman

Antony

Charlton

et al. 2022

IEEE Trans. Cloud Comput.

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Background-Photo-realistic terapixel visualization is computationally intensive and to date there have been no such visualizations of urban digital twins, the few terapixel visualizations that exist have looked towards space rather than earth. Objective-our aims are: creating a scalable cloud supercomputer software architecture for visualization; a photo-realistic terapixel 3D visualization of urban IoT data supporting daily updates; a rigorous evaluation of cloud supercomputing for our application. Method-We migrated the Blender Cycles path tracer to the public cloud within a new software framework designed to scale to petaFLOP performance. Results-we demonstrate we can compute a terapixel visualization in under one hour, the system scaling at 98% efficiency to use 1024 public cloud GPU nodes delivering 14 petaFLOPS. The resulting terapixel image supports interactive browsing of the city and its data at a wide range of sensing scales. Conclusion-The GPU compute resource available in the cloud is greater than anything available on our national supercomputers providing access to globally competitive resources. The direct financial cost of access, compared to procuring and running these systems, was low. The indirect cost, in overcoming teething issues with cloud software development, should reduce significantly over time.

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Terapixel Imaging of Cosmological Simulations

Cited by 12 publications

References 27 publications

Cold Flows and the First Quasars

Cold Flows and the First Quasars

High-redshift supermassive black holes: accretion through cold flows

Petascale Cloud Supercomputing for Terapixel Visualization of a Digital Twin

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