I am a junior faculty member at the University of Washington in the physics department. The above photo is of my RadCos (radio cosmology) research group (left to right):  Amy Kimball, David Wright, myself, Adam Beardsley, Ken Odenberger, Adrienne Stilp, Bryna Hazelton, Patti Carroll, Christian Boutan, Brynn MacCoy, and Alex Bastidas Fry.

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 Murchison Widefield Array (MWA) and GASE array, and the design of the CARPE.

Much of my research concentrates on 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 process of galaxies and stars coallescing out of the smooth early universe is called structure formation, and we would like to study the first stars and galaxies as they form to help us understand how the structure we see around us formed. Unfortunately, seeing the first galaxies and stars as they turn on is very hard. Just after the image of the smooth early universe we see in the microwave background, the hydrogen filling the universe becomes neutral. Since neutral hydrogen absorbs the light we can detect with optical telescopes, we can only see galaxies after this fog of neutral hydrogen has 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.

Observing the EoR requires new observational capabilities, and I am one of the principal designers of the Murchison Widefield Array. The MWA will consist of 512 fully cross-correlated antennas in a compact 1.5 km diameter array, and is currently under construction at the very remote Murchison Radio Observatory in the western Australian desert. Full cross-correlation of all antenna pairs 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 photo above is from a November 2008 trip to commission the prototype (I'm next to one of the 32 antennas of the prototype, and others can be seen in the distance, more photos from the trip). The images below are from data taken during the November trip. The left one shows many sources surrounding the bright radio galaxy Pictor A (note the image is 30° across!), and the right image shows the extended emission from the Puppis A super nova remnant.

(click on photos for larger versions, 5 min. integration, 25 antennas, 1.3 MHz bandwidth @ 159 MHz, images courtesy Randall Wayth)

Extracting the faint EoR signal from the strong astrophysical signals (like galaxies and super nova remnants) will require advances in data analysis and foreground removal techniques. We have 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 recently wrote a review article with Stuart Wyithe for Annual Review of Astronomy and Astrophyscis on 21 cm Epoch of Reionization and dark energy observations that can be found here. I am also leading the effort to subtract the foreground emission and reveal the EoR power spectrum signal with MWA observations, and have the pleasure of working with an extraordinarily talented team of US, Australian, and Indian scientists including Jacqueline Hewitt, Judd Bowman, Max Tegmark, Bryan Gaensler, Frank Briggs, Stuart Wyithe, Matias Zaldarriaga, Angelica de Oliveira-Costa, and many others.

It turns out that approximately 3% of the hydrogen in the universe remains neutral after reionization (principally in small DLA galaxies). This might enable the efficient measurement of the expansion history of the universe and dark energy with specially designed interferometers. I am working with Maura McLaughlin, David Kaplan, Rich Bradley, and Judd Bowman to design the CARPE telescope which focuses on measuring the size of the universe from redshift 1–3.5 via baryon acoustic oscillations and gravity waves via precision pulsar timing.

On a much smaller scale than the MWA or CARPE, 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.

Many of the hits to this web site probably still come from visualizations I did as a graduate student at UC Santa Cruz back when I worked in particle astrophysics. 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 the Physics Astronomy Building C525 if you would prefer to swing by.

-Miguel F. Morales