I have recently accepted a faculty postion in the University of Washington physics department (woo-hoo!). I am currently a research scientist at the MIT Kavli Institute, and I'm looking forward to moving out to Seattle summer 2008.
My research interests fall into three related areas: observational cosmology, the transient universe, and the development of the advanced hardware and software needed for emerging astrophysics observations. Over the past few years I have developed several new radio cosmology signatures and I’m currently working on the construction of the Mileura Widefield Array (MWA) and GASE arrays.
In particular, much of my recent research has focused on upcoming Epoch of Reionization (EOR) observations. The cosmic microwave background (CMB) shows us that the early universe was very, very smooth, while today matter is clumped into galaxies and clusters separated by enormous voids. The slow accretion of galaxies and the formation of the first stars is known as structure formation, and is what I am interested in. However, just after the picture of the smooth universe we see from the microwave background, the hydrogen filling the universe became neutral. Because neutral hydrogen is very efficient at absorbing the light seen with optical telescopes, we can only see galaxies after the fog of neutral hydrogen was burned off at redshifts smaller than about six. Because of the absorption by neutral hydrogen, the time between the smooth microwave background at a redshift of 1089 and the clumpy galaxies and quasars at a redshift of 6 is largely unexplored, and has become known as the “cosmic dark ages.” The end of the cosmic dark ages is called the Epoch of Reionization, and fortunately, neutral hydrogen has a faint spectral line at radio frequencies. By observing this faint radio signal from the neutral hydrogen we can observe the formation of galaxies and the ignition of the first stars and quasars at the end of the cosmic dark ages.
My EOR work has concentrated on the hardware and analysis advances needed to observe this faint radio emission and remove the foreground contamination. In a paper with Jacqueline Hewitt, we extended the CMB style analyses to utilize the line-of-sight information and the symmetries inherent in the EOR signal. This three-dimensional statistical analysis significantly improves the sensitivity of radio arrays to the EOR structure.
I have the pleasure of leading an extraordinarily talented team of US–Australian scientists observing the Epoch of Reionization power spectrum with the MWA, including Jacqueline Hewitt, Max Tegmark, Angelica de Oliveira-Costa, Matias Zaldarriaga, Frank Briggs, and many others.
My other main science interest is in transient sources. On a much smaller scale than the MWA, I am working with a small team at MIT and the Naval Research Laboratory to build GASE (pronounced “gaze”). This little (less than $50k!) interferometer consists of eight dipole antennas, and will search for the highly dispersed prompt gamma ray burst emission that is predicted to exist near 30 MHz (Judd and Jackie digging out one of the antennas in the picture to the left). In addition to providing unique science observations, GASE also serves as a pathfinder for wide field transient detection techniques with the MWA and the Long Wavelength Array.
The science of EOR and transient observations require new observational capabilities, and as a member of the MIT/Haystack team I have played a significant role in developing wide field radio capabilities and designing the Mileura Widefield Array. The MWA consists of 500 fully cross-correlated antennas in a compact 1.5 km diameter array, and is currently under construction in the western Australian desert. Full cross-correlation provides a very large ~30° field-of-view (survey speed) and excellent instantaneous visibility coverage (PSF quality); both of which are required to achieve the sensitivity and systematic error control needed for the EOR.
The majority of the hits to this web site probably still come from visualizations I did as a graduate student at UC Santa Cruz. The movies of extensive air showers and their interactions with the Milagro detector have become popular in the TeV gamma ray community. Please visit the Milagro Animations web site to see these movies (they're pretty cool to watch).
Email me for any reason that strikes your fancy. My office is in building 37, room 582d at MIT and my phone number is (617) 253-2354 if you would prefer to call or swing by.
-Miguel F. Morales
