Gabriel Altay

I am developing a radiative transfer code called SPHRAY. It ray traces through Smoothed Particle Hydrodynamics (SPH) density fields without griding the particles and so can preserve the symmetries and resolution of an SPH run. I have applied it to reionization simulations using 512³ particles sampled with hundreds of millions of rays. You can learn more about the code at the SPHRAY home page or by reading the SPHRAY code paper which is becoming slightly dated as the code evolves but contains a nice overview of the fundamental solution method.

Many groups (see the observational links below) are preparing to observe the 21 cm signal from neutral hydrogen in the Universe before, during and after reionization. I would like to use SPHRAY (or any other software that proves to be a useful tool) to help connect 21 cm maps to the underlying cosmological density field.

Lyman prefixed objects, namely Lyman-&alpha forests, Lyman limit systems (LLSs), damped Lyman-&alpha systems (DLAs), and Lyman break galaxies (LBGs) give us many ways to gain information about cosmology, the intergalactic medium (IGM), and active galaxies. I'm interested in squeezing more information out of observations of these systems using simulations that track the ionization and temperature state of gas in the presence of a realistic UV field that varies in time and space.

Many galaxies, including our own, are believed to harbor super massive black holes at their center. I am interested in exploring the feedback processes associated with active galactic nuclei and their host galaxies both numerically (by exploring coupling mechanisms using hydrodynamic simulations) and observationally (through SZ and lensing measurements)

I organize the papers I've read or am trying to read using a web service called citeulike. Here is a link to my library.

Links to some movies I've made of my most recent reionization simulations.
grid_032_2fps.mp4
grid_064_3fps.mp4
grid_128_5fps.mp4
grid_256_5fps.mp4
grid_256_10fps.mp4
part_512_10fps.mp4
part_512_20fps.mp4
part_512_30fps.mp4