The Supersonic Project
At the time of recombination baryons and radiation decoupled. In standard cold dark matter cosmology, the baryons proceeded to hierarchically form within dark matter halos. Tseliakhovich 2010 showed that there is a second order term in the governing equations which should represent a supersonic relative velocity between the baryons and the dark matter. Naoz (2014) showed that one of the effects of this supersonic relative motion is that the Baryons should be able to collapse outside dark matter halos. These collapsing baryons could be progenitors of some old globular clusters. I’m currently looking at the turbulent properties of these baryons, also known as SIGO (Supersonically Induced Gas Objeted). I’m analyzing their two-point statistics such as the Velocity Power Spectrum, and second order Structure Functions to see, among other things, whether they follow any known universal scaling laws. Quantifying the turbulent properties of these objects should help us better understand their evolution and their capacity to undergo gravitational collapse.
Measuring Magnetic Fields
Over the past 20 years we learned that magnetized turbulence pervades the ISM from AU to kpc length scales. This turbulence influences almost all of the properties of the ISM. My research focused on better understanding the properties of this turbulence, and how it can reveal underlying magnetic fields. There are multiple techniques for measuring the magnetic fields. These include Faraday Rotation (polarization of EM waves when interacting with a magnetic field), Zeeman Effect (shifting of spectral lines in the presence of a magnetic field), and dust grain alignment (tiny filings aligning perpendicular to a magnet field). I work on a novel technique to measure the magnetic field called "The Velocity Gradient Technique" (VGT) developed by Diego F. Gonzalez-Casanova and
Alaxander Lazarian from the University of Wisconsin, Madison. This technique analyzes the turbulent flow to predict the orientation and strength of the magnetic field using scaling laws and the statistics of the density and velocity fluctuations. One can find these turbulent flows hidden in the intensity fluctuations of channel and caustic maps of spectroscopic PPV data cubes of different chemical species. I worked on implementing these techniques in both grid based simulations and HI observations. Below is a figure illustrating the magnetic field using the VGT in both the channel and caustic map of a large filament on the outskirts of the Milky Way called Cattail.
