Dr. Treu will use innovative observational strategies and analysis techniques to map the evolution of the internal structure of spheroids (i.e. elliptical and lenticular galaxies, and bulges of spiral galaxies) over cosmic time, with a focus on the redshift interval z = 0-1, an era when spheroids undergo substantial evolution. This research places its emphasis on dark matter and black holes. Whereas recent studies have made progress on the evolution of their stellar populations, empirical data on the co-evolution of stars, dark halos, and black holes are needed to understand the formation of spheroids in a cosmological context. The new observations made under this award will provide an empirical benchmark for the next generation of theoretical models of galaxy formation.
Dr. Treu will also work on several educational/public outreach components as a part of this award. The general public and K-12 student efforts, based on a collaboration with the Santa Barbara Museum of Natural history (SBMNH) and the Las Cumbres Observatory (LCOGT), will consist of a series of public lectures in the Museum auditorium. In addition, the LCOGT is donating a 32" telescope to the UC-operated Sedgwick Natural Reserve. Dr. Treu will work with K-12 teachers and the SBMNH to establish an astronomy curriculum at Sedgwick. At the undergraduate non-science major level, Dr. Treu is developing, in collaboration with the UCSB Religious Studies (RS) and History (H) departments, a course entitled "Origins", which will be organized around questions such as "What's the Universe made of?". For each question, students will be exposed to the distinct methodologies employed by scientists, philosophers, theologians, so as to appreciate the essence and the importance of the scientific method.
This award is funded by the NSF Division of Astronomical Sciences
Intellectual merit The past few decades have seen the development of a standard cosmological model. Based on dark matter and dark energy, this standard cosmological model successfully reproduces the properties of the universe on large scales. However many open issues remain. In particular, the origin of spheroidal galaxies is currently a point of tension between observation and theory. In order to she light on this tension, this program exploited innovative observational strategies and analysis techniques to map the evolution of the internal structure of spheroidal galaxies over the second half of the age of the life of the universe. The main novelty of this program was the connection between the known components stars and gas, and the invisible components dark matter and black holes. The program produced many results, described in 63 refereed publications. Highlights include the following results. The most advanced study of the distribution of luminous and dark matter in galaxies as a function of cosmic time, using a technique called gravitational lensing. This led to the discovery of a new fundamental relationship for massive galaxies, called the mass plane, to the discovery of the bulge-halo conspiracy, and to the discovery of a double Einstein Ring system. This work was widely covered in the news, including articles in the "The economist". One of the surprises of this work was the discovery that massive galaxies form stars in a different way than galaxies like the Milky Way. This discovery has profound implications in astrophysics and generated intense research on the topic throughout the world. We have also carried out the first direct measurement of how black holes evolve over cosmic time, finding evidence that the assembly of black holes predates that of their host galaxies. Finally, we have developed and demonstrated a new way to measure the mass of a black hole at any arbitrary distance. Broader impact This program included a comprehensive educational/public outreach component. The general public and K-12 students efforts are based on a collaboration with the Santa Barbara Museum of Natural history (SBMNH) and the Las Cumbres Observatory (LCOGT). The first result of this partnership are a series of public lectures in the Museum auditorium, carried out between 2006 and 2013. At the undergraduate non-science major level, the principal investigator has been actively engaged to promote a full understanding of the scientific method. For this purpose he developed a course in collaboration with the UCSB Religious Studies (RS) and History (H) departments. The course entitled ``Origins'' has been very successful. Hundreds of students have been involved into an in depth discussion of the methodology of science and learned to appreciate the diversity of intellectual enterprises, and to distinguish between different approaches. Several undergraduate and graduate students have been involved in the research group, helping to train tomorrow's scientists. Finally, under this the program instrumentation based on adaptive optics (AO) with laser guide stars was used for the study of distant galaxies. The experience gathered during this research program will help optimize future Adaptive Optics facilities and thus maximize benefit to the entire community of astronomers.
