Time: 12:30 - 1:30 pm
Place: 131 Campbell
Speakers: Christina Hedges, Geert Barentsen, Michael Gully-Santiago, Ann-Marie Cody
Title: Data products and science from NASA Ames
Summary: This seminar will consist of a series of "lightning talks" lasting ~10 min each, with time for questions and discussion afterward. The speakers are all from NASA Ames and will be sharing new data products and/or science that is relevant to CIPS.
Location: 131 Campbell Hall
Time: 12:30 - 1:30pm
Speaker: Robert Lillis (SSL/Berkeley)
Talk title/abstract: MAVEN and the mysterious disappearance of Mars' atmosphere
Why is the surface of Mars no longer habitable? Sounds like a straightforward question, right? However, those nine words comprise one of the most vexing questions in planetary science. There is now overwhelming evidence from orbiters and rovers that Mars was once a place where liquid water flowed on the surface and, thus, life as we know it could have thrived, at least episodically. However, such stable surface water requires an atmospheric surface pressure much higher than today’s ~7 millibars (<1% of Earth’s pressure) to prevent evaporation and cause greenhouse warming. Where did this ancient atmosphere go? If it had all been absorbed back into the crust, abundant carbonate minerals should exist on or near the surface. However, extensive surveys from orbit have revealed not nearly enough carbonate to account for all the carbon dioxide that has been lost. The only other explanation: The atmosphere escaped out to space over billions of years. But how did this happen? What physical processes drove the escape? How did they vary over time as solar radiation and the solar wind buffeted Mars’ atmosphere, which lacked the protection of a global magnetic field? And, most importantly, how much total atmosphere escaped over Mars’ history? These are the questions that motivate the MAVEN team’s scientific efforts—day in and day out—as we analyze and interpret data from our nine science instruments. Our overarching strategy is to use MAVEN’s observations to understand the processes that cause atmosphere to escape out into space, as they operate under the conditions experienced by present-day Mars. We will then combine that with knowledge of how those conditions have varied over time to estimate the total loss of atmosphere. Sounds simple, right? But as always, and as you probably guessed, the devil is in the details. I will present an overview of scientific results from the first three years of the MAVEN mission to Mars, with an emphasis on atmospheric loss processes and how these have transformed the Martian climate over time.
1:10 pm (Cosmology/ BCCP)
Alex Drlica-Wagner, FNAL
Small Galaxies, Big Science: The Booming Industry of Milky Way Satellite Galaxies
The satellite galaxies of the Milky Way are some of the most ancient, most chemically pristine, and most dark-matter-dominated galaxies known. These extreme objects provide a unique opportunity to test the standard cosmological model in the near-field limit. In addition, the relative proximity and large dark matter content of dwarf galaxies make them excellent systems for probing the fundamental properties of dark matter. Over the past several years, the unprecedented sensitivity of large CCD cameras have allowed us to double the known population of Milky Way satellites. These discoveries help address the "missing satellites problem” and can be used to test the particle nature of dark matter. I will summarize recent results, outstanding questions, and exciting prospect in near-field cosmology.
Note two talks, two locations:
1:10 pm (Cosmology/ BCCP)
Chihway Chang, Chicago
Mapping the Cosmos with the Dark Energy Survey
The first year data from the Dark Energy Survey (DES Y1) provides the most powerful optical survey dataset to date. In this talk I will first give an overall summary of the cosmology results from the DES Y1 dataset combining galaxy clustering and weak gravitational lensing. Next, I will describe our work in generating and testing the wide-field weak lensing mass maps from the galaxy shape measurements and some exciting applications for the maps. I will end with thoughts on how weak lensing could also inform us on various topics of galaxy formation, which is essential for completing the story behind the Universe we see today.
4:00 pm (RPM)
Chihway Chang, Chicago
Cosmic Surveys in the Next Decade: Mapping the Landscape of the Universe
Cosmology in the next decade will be driven by data. Exploiting the information one can extract from the ongoing and upcoming large surveys will give us the power to stress-test the LCDM model with unprecedented precision and open up windows for new physics. In this talk I will present some of our work in the Dark Energy Survey Collaboration and the Large Synoptics Survey Telescope Dark Energy Science Collaboration, to analyse state-of-the-art galaxy survey data as well as getting ready for the next generation of data. I will focus on topics surrounding weak lensing analyses, including cosmology from 2-point functions, generating weak lensing mass maps, and measuring the mass profiles at the outskirts of galaxy clusters.