[Emeriti-faculty] DEPARTMENT EVENTS FOE WEEK OF MARCH 1, 2010

[Gayle Grant <gayle grant tufts edu>]

Good morning:

Events for this week:

*Monday, March 1, 2010*

3:00 pm
Monday, March 1, 2010
TUFTS UNIVERSITY
SPECIAL PHYSICS AND ASTRONOMY COLLOQUIUM
Robinson 253
“The Most Distant Clusters of Galaxies”
Adam Muzzin
Yale University
Clusters of galaxies are spectacular cosmic structures. They are the 
largest dark matter reservoirs in the universe and contain thousands of 
galaxies plunging through hot 10^7K gas at speeds in excess of 1000 
km/s. Because clusters form at the intersection points of the cosmic web 
of galaxies, measurements of their number density and mass function 
provide strong constraints on our cosmological model. Furthermore, as 
the densest locations in the universe they illustrate the effect of 
local environment on the growth of galaxies. The most distant, and 
therefore youngest clusters are potential Rosetta Stones for cosmology 
and galaxy evolution; however, at present, the majority of distant 
clusters known are at a redshift (z) ~ 1.0, with only a handful at 
higher redshift. I will present results from the SpARCS cluster survey 
which has discovered hundreds of new clusters at z > 1 using wide-field 
infrared imaging from the Spitzer Space telescope. We have found strong 
radial gradients in the stellar populations of galaxies in these young 
clusters indicating that environment may be a driving factor in the 
early formation and evolution of galaxies. I will conclude by discussing 
current efforts to measure cosmological parameters such as the equation 
of state of dark energy using the SpARCS cluster catalogs.
Refreshments served in Robinson 251 at 2:30 pm

*Tuesday, March 2, 2010*

12:00 pm (noon)
March 2, 2010
Physics and Astronomy
Graduate & Undergraduate Students Lunchtime Meeting
Robinson Hall, Room 251
Dr. Adam Muzzin
Yale University
Pizza served at Noon in Knipp Library
Students are encouraged to attend

*Friday, March 5, 2010*

12:00 pm (Noon)
Friday, March 5, 2010
Physics and Astronomy
Graduate & Undergraduate Students Lunchtime Meeting
Knipp Library, Robinson Hall, Room 251
Dr. Eric Murphy
Caltech
Friday, March 5, 2010
Pizza served at Noon
Students are encouraged to attend

3:00 pm
Friday, March 5, 2010
TUFTS UNIVERSITY
SPECIAL PHYSICS AND ASTRONOMY COLLOQUIUM
Nelson Auditorium, Anderson Hall
“Studying Galaxy Evolution at Far-Infrared and Radio Wavelengths”
Eric Murphy
Caltech
One of the strongest, and least understood, empirical correlations in 
astrophysics is that between the globally integrated far-infrared (FIR) 
and radio continuum emission from star-forming galaxies. While the 
common link between these observed quantities lies in the process of 
massive star formation - massive stars (>8 M_sun) dominate the dust 
heating in galaxies and end their lives as supernovae whose remnants are 
thought to accelerate cosmic-ray (CR) electrons producing synchrotron 
emission - the relative importance of the various underlying physics 
(e.g. dust grain sizes distribution/chemistry, CR diffusion and decay, 
magnetic field distribution and strength) is still not well known. Due 
to the increased spatial resolution and sensitivity at FIR wavelengths 
achieved by NASA's last great observatory, the Spitzer Space Telescope, 
we have made tremendous advancements towards a better understanding of 
the physical underpinnings that drive this correlation by studying it at 
sub-kiloparsec scales within nearby galaxies. In discussing these 
advancements, I will highlight a number of other physical processes 
which we have been able to get a better handle on through an improved 
understanding of the FIR-radio correlation including: (1) empirical 
estimates for the diffusion length of CR electrons in a number of 
external galaxies and its dependence on star formation activity; (2) a 
method to measure the direction and strength of ongoing ram pressure 
affecting the evolution of galaxies residing in cluster environments; 
and (3) a means to test for the existence of magnetic fields at early 
epochs while also providing reliable ionizing photon rates (a measure of 
the star formation activity) for galaxies at high (z > 5) redshifts 
using future radio telescopes.
Refreshments served in Robinson 251 at 2:30 pm