Scientific Movies


Helium Reionization MOvie


Movie of the reionization of the second electron of helium by quasars, an important phase transition in the history of the Universe.  It is composed of snapshots from a numerical simulation of this process that was run with my ray tracing code.  The scale of each panel represents 430 comoving megaparsec (300 million light years) and would subtend 3.5 degrees on the sky.  The left panel is the fraction of helium that is doubly ionized, and the right is the temperature (note that black regions represent < 104 K and white represent > 2.5x104 K).  The movie starts at z=6 and ends at z=3, and it assumes isotropic emission and that the quasars have lifetimes of ~100 million years.  See this paper for more details.

HYdrogen Reionization MOvie

Top: Movie of the reionization of hydrogen in a 100x100 comoving megaparsec slice of the Universe.  These movies were made from snapshots from a simulation in which photons from dwarf galaxies within >109 solar mass halos sourced the ionizations.  The colored regions in the left panel show ionized hydrogen, with the yellow/green (light/dark blue) regions representing ionized overdense (underdense) regions.  The black regions represent neutral hydrogen.  The right panel shows the evolution of the 21cm dimensionless power spectrum during this process.   Efforts to detect high-redshift 21cm emission will not be able to make images of the signal like seen on the left and instead will attempt to constrain reionization by measuring the shape and evolution of the power spectrum.

Left: The same but only snapshots of the ionized hydrogen in the simulation.

Click here for more information.

Lyman-alpha emitters during Hydrogen Reionization

Movie of the effect of reionization on the statistics of Lyman-alpha emitting galaxies.  Each panel is 100 comoving Mpc across and 40 comoving Mpc in depth and is calculated from the above reionization simulation.  The left panel is the projected ionized fraction, the middle is the spatial distribution of Lyman-alpha emitting galaxies above a Lyman-alpha luminosity threshold and ignoring scattering from neutral gas in the IGM, and the right is the distribution that would actually be observed above this luminosity threshold during reionization.  An emitter must be in an ionize region of size >1 proper Mpc for the photons to be not scattered by intergalactic neutral gas.  As reionization proceeds in the movie and the ionized regions grow larger, more Lyman-alpha emitters are observed.  This modulation can be used to study reionization.  For example, the distribution during reionization (right) is more clustered than the intrinsic distribution (center).