Talks & Events
KICP Wednesday Colloquia - Usually Wednesdays, 3 PM, BSLC 115, unless otherwise specified. Reception starts at 4 PM in LASR conference room. For more information visit the KICP website.
Current & Future KICP Colloquia
Past KICP Colloquia
Dark Energy Survey: Early Results
The expansion of the universe is accelerating, a discovery that earned the 2011 Nobel Prize in physics. Is cosmic acceleration due to "dark energy," or do we need to modify Einstein's General Relativity? If it is a new form of energy, is it constant or changing in time? Addressing these questions is the primary goal of the Dark Energy Survey (DES). After achieving first light in 2012, followed by months of commissioning and science verification, DES has just completed its first season of science observations at the Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory in Chile. The DES Collaboration built a new 570-megapixel digital imager, the Dark Energy Camera (DECam), to carry out a deep, wide survey over the course of five (5) years---observing thousands of Type-Ia supernovae and hundreds of millions of galaxies. The thick, red-sensitive imager will allow us to see more supernovae and galaxies at higher redshift than previous surveys, like the Sloan Digital Sky Survey (SDSS). These observations will provide a suite of cosmological signatures: the Supernova Hubble diagram, galaxy cluster number counts, large-scale galaxy clustering and weak gravitational lensing. With this data, we will probe both the cosmic expansion history and the growth of large-scale structures, and thus explore the nature of dark energy. I will discuss the motivation for DES, the first years of operation and early results.
News from the Extreme Energy Cliff
Thanks to giant extensive air-showers observatories, such as the Pierre Auger Observatory and the Telescope Array, we now know that the sources of ultrahigh energy cosmic rays (UHECRs) are extragalactic. We also know that either they interact with the CMB as predicted or they run out of energy at the same energy scale of the CMB interactions! Their composition is either surprising (dominated by heavier nuclei at the highest energies) or the hadronic interactions at 100 TeV are not a standard extrapolation of LHC interaction energies. Hints of anisotropies begin to appear as energies reach 60 EeV, just when statistics become very limited. Basic questions remain unanswered: What generates such extremely energetic particles that reach above 10^20 eV (100 EeV)? Where do they come from? How do they reach these energies? What are they? How do they interact on their way to Earth and with the Earth's atmosphere? To answer these questions larger statistics at the highest energies is necessary. Space-based observatories can significantly improve the exposure to these extremely energetic particles. The first step to answer these questions is to place a wide field UV telescope at the International State Station to monitor the Earth's atmosphere from above. This is the goal of the JEM-EUSO mission: the Extreme Universe Space Observatory (EUSO) at the Japanese Experiment Module (JEM).