Events at Physics |
Events on Tuesday, December 1st, 2009
- Chaos & Complex Systems Seminar
- Health Care Reform: what are we reforming?
- Time: 12:05 pm
- Place: 5310 Chamberlin (Refreshments will be served)
- Speaker: Linda Reivitz, UW School of Nursing
- Abstract: Health care reform, and ideas for national health insurance, have been part of our national dialogue at least since 1912, when the idea was proposed by Theodore Roosevelt . We're still talking about health care reform today. But what is health care reform. And what are we 'reforming' anyway. Is 'reform' going to happen. What would change if it did. Of all the reform ideas now being discussed, which one is 'best'? And how many people are really uninsured? The answers to these questions will be discussed by Linda Reivitz, an instructor of health policy in the UW School of Nursing and former legislation aide on Capitol Hill. Says Reivitz: as I write this in late September, two things are clear: first, the world of 'health care reform' will surely be a lot different in December, 2009 than it is today; and second, questions about public policy are rarely answered using the scientific method. Talking about health care and health reform to a seminar on Chaos and Complex Systems is totally apropos. For those who have an interest in comparing, across a number of characteristics and plan components, the leading comprehensive reform proposals being considered by the Congress, you can find this information at http://www.kff.org/healthreform/upload/healthreform_sbs_full.pdf
- Astronomy Colloquium
- The Invisibles: Revealing dark matter and the lower limit on galaxy Formation
- Time: 3:30 pm - 5:00 pm
- Place: 3425 Sterling Hall
- Speaker: Beth Willman, Haverford College
- Abstract: Tracking the growth of stellar mass in galaxies is a fundamental characterization of the galaxy population. Recent observations have shown that the total mass in L>L* red galaxies has increased by a factor of ~2 at z<1, although at different rates as a function of galaxy mass. Despite the advance made by these studies of the whole galaxy population, until recently it has not been clear if the growth of the red sequence depended on environment. Galaxy clusters are a useful probe of this as they sample the most extreme environments. However, progress toward answering this question has been hampered by a lack of deep multi-band imaging of a large sample of clusters that can be well linked to those in the local universe. To address this I will present the evolution of the red sequence as measured in 16 intermediate redshift clusters drawn from the ESO Distant Cluster Survey (EDisCS). Unlike massive x-ray selected clusters, these clusters have velocity dispersions that make them likely progenitors of clusters that populate the local Universe. I will show how the luminosity function (LF) of red-sequence galaxies in these clusters has evolved over 50% of cosmic time, highlighting the rapid buildup of the faint cluster galaxy population. I will also compare the evolution of the red sequence in clusters to the evolution of the field red sequence population and show that they evolve at different rates. Finally I will address how the total mass on the red sequence evolves in clusters and will use this to constrain the mechanisms of how red galaxies can be added to clusters. From this analysis it appears likely that some fraction of the light in recently added cluster red sequence galaxies is currently in the in the form of intracluster stars.