CMU Astrophysics Seminar

Spring 2006/Fall 2006/Winter 2007

Speakers:

Date	Speaker	Title
15 February 2006	K. Simon Krughoff, University of Pittsburgh	The National Virtual Observatory: What Can I Do With It Today?
8 March 2006	Ryan Scranton, University of Pittsburgh	Cosmology in the Era of Large Surveys
12 April 2006	Francesco Shankar, Ohio State University	How much do data constrain SMBH evolution?
26 April 2006	Taotao Fang, University of California, Berkeley	Cosmic Evolution of the Intergalactic Medium
10 May 2006	Robert Smith, University of Pennsylvania	Cosmological structure formation -- beyond linear theory
31 May 2006	Ben Maughan, Harvard-Smithsonian CfA	tba
2 November 2006	Ue-Li Pen, CITA	Cosmic Reionization
1 December 2006	Antonaldo Diaferio, University of Turin	tba
31 January 2007	Carlos Hernandez-Monteagudo, University of Pennsylvania	tba
7 February 2007	Christoph Pfrommer, CITA	tba

15 February 2006

K. Simon Krughoff, University of Pittsburgh

The National Virtual Observatory: What Can I Do With It Today?

"The NVO is reaching the end of the development phase. With the approach of the facilities phase, many astronomers may be asking 'What can I do with the VO right now?' Currently, many previously tedious (or impossible) tasks are being made manageable by tools and services developed during the first five years of NVO operation. Whether you are interested in catalog data or single pointings, the NVO presents opportunities for data discovery as well as data analysis. Tools and services to be discussed include: DataScope, OpenSkyPortal, WCSFixer, WESIX, VO Registries, Cone Search and SIAP."

8 March 2006

Ryan Scranton, University of Pittsburgh

Cosmology in the Era of Large Surveys

"The past decade has seen an enormous increase in both the quantity and quality of cosmological data. The current generation of surveys have largely answered the central cosmological questions of the 1990s: what is the shape of the universe and how old is it? In doing so, however, they found strong and largely unpredicted evidence for dark energy. In my talk, I will outline this basic history of the field and describe some of the unexpected synergies that have come from having large, uniform data sets stretching over vast areas of the sky and different parts of the electromagnetic spectrum. Specifically, a measurement of weak gravitational lensing magnification using galaxies and quasars from the Sloan Digital Sky Survey and the detection of the integrated Sachs-Wolfe effect, a key indicator of the existence of dark energy. Finally, I will discuss the future of the field. The next generation of surveys will be devoted to the task of puzzling out the nature and behavior of dark energy. While that is extremely important science, the central lesson of the current surveys is that we should also bear in mind the fact that the most interesting results from these surveys may not be those that we originally envisioned. Thus, we should plan accordingly."

12 April 2006

Francesco Shankar, Ohio State University

How much do data constrain SMBH evolution? A new quasi-empirical approach to SMBH-galaxy evolution

"Super-Massive Black Holes (SMBH) are very common in all bulged stellar systems and tightly linked with the kinematical, virial and structural properties of the host. Many models have been proposed to solve this issue, but how far can we get just by using simple semi-empirical recipes and matching several different data together? I will present simple techniques to probe the link between SMBH growth and stellar mass, the SMBH-sigma and SMBH-Dark Matter halo relations. I will then discuss and reproduce the statistics of galaxies, SMBH and Optical/Xray Active Galactic Nuclei. Throughout my presentation I will also report and compare with results obtained using the Granato et al. (2004) SAM model."

26 April 2006

Taotao Fang, University of California, Berkeley

Cosmic Evolution of the Intergalactic Medium

"The intergalactic space is a fascinating place to study cosmic structure formation and evolution. Multi-wavelength studies of the intergalactic medium (IGM), the main repository of baryonic matter in the universe, have revealed its complex history and critical role in galaxy formation and evolution. In this talk, I will begin with a brief review our current understanding of the IGM. Details of the cosmic evolution of the IGM are presented through the studies of three outstanding questions at different cosmic epochs, namely, the proximity effect at high redshift, the "missing baryons" problem at low redshift, and the hot gas distribution at the vicinity of our Galaxy. Finally, I will discuss perspectives of the IGM study, including instrumental development."

10 May 2006

Robert Smith, University of Pennsylvania

Cosmological structure formation -- beyond linear theory

"In the modern era of physical cosmology the parameters that define our local world model are rapidly being pinned down, thanks largely to the increasing number of high-fidelity data sets. These data sets are opening our horizons and enabling us to ask many new and interesting questions about the nature and structure of the Universe, and about the way in which galaxies form. Moreover they are also forcing us to re-examine our long cherished theoretical prejudices. In this somewhat outro-introspective talk I will address two important questions: What can we learn from higher order clustering statistics? Is the power spectrum on large scales really linear?"

2 November 2006

Ue-Li Pen, CITA

Cosmic Reionization

"The first luminous objects which reionized the universe are constrained to have formed at redshifts 6 < z < 20. I will report on theoretical and observational constraints, and progress through simulations and observations. Two types of targets may be observable in the near future: the Stromgren spheres around known SDSS quasars, and the more typical reionization bubbles surrounding protogalaxies."