Science & Technology


Witnessing the Formation and Evolution of Galaxies

We live in a Universe of remarkable structure. From super-clusters of galaxies, tens of millions of light years across, to grand-design spiral galaxies and  small rocky planets like Earth,  structure exists on all scales.   It wasn’t always this way: through the extraordinary advancements of observational cosmology of the last several decades,   we now know the Universe was homogeneous at its beginning.   While the physics which links the young and smooth Universe to its underlying Dark Matter skeleton is well-established, perhaps paradoxically we know very little about how the objects composed of regular matter – the stuff you and I are made of – assembled.   In a general sense, cosmological structure grows hierarchically; small systems collapse first then merge to form progressively more massive objects. But this is a violent and energetic process, triggering bursts of star formation, feeding matter onto super-massive black holes,  stripping galaxies of their interstellar medium, and fundamentally shaping the complex structure we see around us today.

Dr. Webb’s research centers on the growth of structure in the universe, and galaxies in particular. Her approach is to use data at many different wavelengths of light; each wavelength probes a different physical process and tells us something unique about galaxy formation. Because a lot of the physics in galaxies happens behind thick veils of dust, she focusses much of her research on submillimeter (~400-1200µm) and mid/far-infrared (~3-400µm) observations, which directly detect the dust and provide clues to what’s happening behind it. She primarily studies galaxies in the very distant and young universe (i.e., high-redshift); because of the finite speed of light we are seeing these systems as they existed 5-12 billion years ago and can literally watch them form! However, she is also beginning programs to study near-by galaxies since these systems can be studied in much more detail and will provide insight into the processes which formed the galaxies of today.

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    April 24, 2013 at 11:15 am