Date(s) - 22/09/2003
4:00 pm - 5:00 pm
Title: The Hidden Phases of Galaxy Formation
Speaker: Dr. Tracy Webb
Institute: Sterrewacht Leiden,
One of the most fundamental physical questions remaining to be answered is, how did the complex and rich structure we observe in the Universe form? This talk will focus on a piece of this puzzle, the origin and evolution of galaxies. In the standard picture of structure formation there is no single epoch of galaxy assembly but rather galaxies form and evolve continuously through the historical evolution of the Universe by the merging of smaller clumps, and forming progressively more massive structures with time. However, while this broad outline is well established, many of the important details of the physical mechanisms involved in galaxy formation remain unknown. Recently, it has become abundantly clear that the origin and evolution of galaxies can only be understood through studying their radiation at multiple wavelengths, and in particular through far-infrared and submillimeter (submm) observations. The commissioning of the SCUBA detector array in 1996 on the James Clerk Maxwell Telescope made it possible for the first time to obtain deep and detailed observations over the submm waveband and has literally opened a new window on the early Universe. I will present the results of a large-scale deep submm survey with SCUBA which has uncovered a unique population of young galaxies which, previous to SCUBA, was unknown and unstudied. These systems represent some of the most extreme objects in the early universe and yet are so deeply enshrouded in dust that they were absent or unrecognized in earlier work at optical and ultraviolet wavelengths. It is now clear that they play crucial role in the formation of galaxies and may represent an important evolutionary phase of the most massive galaxies of today. After outlining the methods by which we study these systems I will discuss their place in galaxy formation theory, and summarize the key questions which Premain. Given the upcoming new national and international facilities and continuing advances in technology, the future holds great promise for our understanding of galaxy formation.