Christopher Martin

Galaxy Evolution, Intergalactic Medium, and Experimental Astrophysics

Our laboratory is engaged in an experimental and observation program to image emission from the intergalactic medium (IGM), the location of most of the baryons in the Universe. Ultimately, our goal is to understand how gas from the IGM flows into the halos of galaxies, the "Circum-Galactic Medium" (CGM), and how it flows out of galaxies back into the CGM and IGM. The cosmic evolution of galaxies is driven by the flow of gas into and out of them. Our long-term goals are: 

1. To understand the history of cosmic gas accretion into galaxies; 
2. The feedback of energy, gas, and heavy elements into the IGM from galactic scale and black hole winds; 
3. To locate galaxies within the baryonic cosmic web; and 
4. Using these observations combined with numerical simulations, to assemble a predictive theory for baryonic structure formation.

We are developing new instruments that are designed to image the very low surface brightness emission from the IGM and CGM, "Dim Matter". These instruments include the Palomar Cosmic Web Imager, the Keck Cosmic Web Imager and its red arm the Keck Cosmic Reionization Mapper, and the FIREBALL-2 and HALO balloon and explorer. Using these instruments we will be able to detect and map CGM and IGM emission from the epoch of Reionization (z=8) to the local Universe (z=0). For the space UV, we need to develop new, high efficiency photon counting detectors and wide field imaging spectrometers to enable detecting the local cosmic web in emission.

We are developing techniques for interpreting the data from these instruments, and observational techniques to unravel the star formation history in galaxies. One of our principal goals is to relate the star formation history of galaxies with the properties of their halos (CGM).

Credit: NASA/JPL-Caltech/C. Martin (Caltech)/M. Seibert (OCIW)

[Image credits: Bob Paz; NASA/JPL-Caltech/C. Martin (Caltech)/M. Seibert (OCIW)]