Noon: Solar, Stellar, and Planetary Sciences Division Seminar. "A New High-Resolution Imaging View of Exoplanet Host Stars," Steve Howell, NASA Ames Research Center. Pratt Conference Room.

Abstract: Based on our past two years of speckle imaging at Gemini-N and our past 5 years of related observations at other observatories, this talk will summarize what we have learned about exoplanet host stars. I will discuss our recent findings on eccentric giant planets, the binary fraction of exoplanet host stars, and how we can observationally validate Earth-size exoplanets. Finally, a summary of these new results and their impact on our understanding of exoplanets, in particular their radius and their location in the habitable zone, will be discussed.


1:00 pm: Institute for Theory and Computation (ITC) Seminar. "Orbital Architectures of Complex Exoplanet Systems," Benjamin Nelson, Penn State; and, "Stability of Force-Free Magnetospheres of Black Holes," Huan Yang, Perimeter Institute. Pratt Conference Room.


12:30 pm: High Energy Astrophysics Division Lunch Talk. "Observing Galaxy Buildup with SMART-X," Alexey Vikhlinin, CfA; "Fully Successful, Failed or Barely Failed: The Fate of Jets Trying to Break Through Their Stellar Progenitors," Rafaella Margutti, CfA; and, "Boosting the Sensitivity of RXTE," Javier Garcia-Martinez, CfA. Pratt Conference Room.


11:00 am: Institute for Theory and Computation (ITC) Colloquium. Speaker: Anze Slosar, Brookhaven National Laboratory. Topic: To be announced. Pratt Conference Room.

4:00 pm: Colloquium. "The Large Reservoirs of Gas Around Galaxies," Jessica Werk, University of California, Santa Cruz. Preceded by tea at 3:30 pm. Phillips Auditorium.

Abstract: The Circumgalactic Medium (CGM) is where infalling gas that feeds star formation meets outflowing, feedback-enriched materials. It is where satellites are stripped and disrupted, and where gas ejected from galaxies may eventually be recycled. This medium is seen primarily in absorption, taking the form of diffuse, ionized gas bound to the dark matter halo of its host galaxy and extending to at least 300 kpc. In this talk I will present two observationally-motivated puzzles requiring theoretical investigation. First, I will review the evidence that the CGM of quenched galaxies contains as much cold gas as their star-forming counterparts. This observation implies that galaxies are transformed from star-forming disks to quiescent spheroids while retaining a significant store of cold gas in their halos. Then, I will show that the cool and warm phases of the CGM (T less than 10^6 K) account for most of the baryons purported to be missing from dark matter halos of both star-forming and passive galaxies with M_halo ~ 10^12. Yet, surprisingly, the cool (10^4 K) gas in the CGM is far from pressure equilibrium with a hot medium that could provide hydrostatic support.