Scope and Outcomes

Introduction

Illustris is a large cosmological simulation suite that has simulated the history of a “universe in a box” over a time frame of 13 Gyr. The primary building block of the simulations is the “dark-matter particle”, which has an initial mass of 6 million solar masses (6x10^6 Msun) and an initial gas mass of 1.3x10^6 Msun (http://www.illustris-project.org/data/ ). Each particle also contains various sub-grid parameters, such as stellar mass, star formation rate, number of black holes, etc.

Todo

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As time progresses in the the simulation, particles group together, and galaxies form in the dense centres of these groups (the so-called Sub-halos. Halos are the larger overarching groups that surround galaxy clusters). The snapshots of this universe-in-a-box allow us to view the evolution history of a certain galaxy all the way back to its beginning.

Simulations are one thing, reality is often different. Hence out main goal of this project is to determine whether the predictions made through this cosmological simulation will actually be testable in real life - i.e. will the next generation of telescopes be able to observe the phenomena seen in the simulations.

The current generation of telescopes, through simple physics, will never be able to resolve galaxies at distances larger than z>3, simply because the galaxies are two small (D<1 kpc), the diffraction limit of an 8m class telescope (VLT) is around 0.05” in K-band (lam/D), and the cosmological angular size scale is ~8kpc/” (0.125”/kpc) at 1<z<3 (http://www.astro.ucla.edu/~wright/CosmoCalc.html ). Even the JWST, with its 6.5m mirror, will struggle to get any spatial information from high-z galaxies.

The ELT however, with a 40m mirror and a corresponding diffraction limit of 0.007” in J (0.012” in K), will have a spatial resolution of ~60pc (100pc) in J (K), and will thus be able to provide information on the spatial variations of star formation in the very first galaxies. Unfortunately the ELT is a ground-based telescope, and consequently suffers from a sensitivity limit due to atmospheric extinction.

The main goals of this project revolve around the central theme:

What will actually be bright enough for the ELT to observe?

Scope and Method

  • We will concentrate on using 3D particle data form the illustris API
  • We will generate realistic 2D on-sky projections of the particle data using the hyperion radiative transfer code
  • We will create simulated observations of particle data using the SimCADO instrument data simulation software
  • We will determine what star formation rates will be visible for a redshift and volume density