Events at Physics |
Events on Thursday, October 7th, 2010
- Astronomy Colloquium
- Casting Shadows on the standard intersteller medium paradign with GALFA-HI
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall Same Location
- Speaker: Josh Peek, Columbia University
- Abstract: Our understanding of the diffuse interstellar medium (ISM) revolves around the balance of pressures between warm and cold phases and the interruption of that balance by the explosion of stars in supernovae. I will show new results enabled by the GALFA-HI survey that throw these standard theoretical underpinnings into disarray. I will discuss our investigation of the nearest cold neutral medium (CNM) to the sun, deep within the boundaries of the local cavity. High spectral resolution observations of this object present interesting constraints to theorists and simulators who propose that CNM clouds are formed by the collision of warmer clouds. Observations of the absorption of soft X-rays by this CNM show that X-rays emanate much nearer to the sun than was thought before, casting doubt on the local hot bubble theory. We have also investigated hundreds of compact HI clouds in our Galaxy, many of which seem to be in extreme force imbalance with the expected ambient ISM. These finding all suggest we have much to learn about the Galactic ISM we call home.
- Host: Snezana Stanimirovic
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Dark matter, under different angles
- Time: 4:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Alberto Vallinoto, Fermilab
- Abstract: Most often, the dark matter puzzle is analyzed along a single perspective, thus trying to answer a single question. Either "what is the dark matter?", focusing on its microscopic nature, or "how is dark matter distributed?" and "how does it cluster?" focusing on the large scale structure of the universe, or still "how does it
affect what we observe in the sky?", focusing on gravitational lensing. Both my scientific interests and some random fluctuations at the beginning of my career have conspired so that I would take on projects in all these fields. Leaving aside the ambition -- and the impossible task -- to be comprehensive, I will review some interesting aspects of these fields and some of my contributions. - Host: Peter Timbie
- Graduate Introductory Seminar
- Condensed Matter Theory
- Time: 5:30 pm - 6:30 pm
- Place: 2223 Chamberlin Hall
- Speaker: Bruch, Chubukov, Coppersmith, Joynt, Perkins, Vavilov