Colloquia Archives

Mark Krumholz (UC Santa Cruz)
Thursday, February 23, 2012
3:45 p.m.
LGRT 1033
Title:
The Origin of the IMF
Abstract:
Star-forming environments vary by orders of magnitude in density, pressure, metallicity, and other properties, yet the initial mass function (IMF) of the stars they produce remains stubbornly unchanged. Explaining the origin and universality of the IMF is one of the oldest problems in theoretical astrophysics, but in the last few years theoretical advances in understanding how gas fragments, together with algorithmic advances that have allowed simulations to include improved physics such as radiative transfer, have produced significant progress. I describe these advances, and lay out the beginnings of a theoretical model capable of explaining the IMF. This model suggests that the IMF is nearly but not perfectly universal, and the subtle variations that it admits provide avenues for future observational tests.
Daniel Wang (UMass, Amherst)
Tuesday, February 21, 2012
3:45 p.m.
LGRT 1033
Title:
Stellar Feedback and Galaxy Evolution
Abstract:
TBA
Alyson Brooks (U. Wisconsin - Madison)
Thursday, February 16, 2012
3:45 p.m.
LGRT 1033
Title:
Toward the Formation of Realistic Galaxies
Abstract:
Much progress has been made in recent years in forming realistic disk galaxies in fully cosmological simulations. Computational advances have allowed for unprecedented resolution, which in turn allows for a more realistic treatment of star formation and energy feedback. These improvements have led to a new examination of gas accretion, consumption, and loss in the formation of galaxy disks. I will show that a more realistic treatment of gas in simulated disk galaxies leads to a better match with observational results as a function of redshift. I will demonstrate that because star formation (i.e., gas consumption) varies with galaxy mass, the structure of dark matter within galaxies varies with mass. This leads to observable scaling relations as a function of galaxy mass, and resolves a number of long standing challenges within the CDM model. Realistic simulated galaxies are the necessary starting point for interpreting observations in light of galaxy formation theory.
Romeel Dave (U. Arizona)
Thursday, February 9, 2012
3:45 p.m.
LGRT 1033
Title:
Baryon Cycling: A Modern View of Galaxy Evolution
Abstract:
Traditionally, galaxy formation theory has been based on connecting observable baryons to dark matter halos and their merger history. But in the past decade, hydrodynamic simulations of galaxy formation have elucidated a somewhat different view, in which galaxy growth is governed by an evolving balance between continual inflow from the intergalactic medium and strong, ubiquitous outflows. In this talk I will discuss the formalism of baryon cycling and the simulations that led to it, and highlight some of the new insights and interpretations that it yields for the stellar, gas, and metal content of galaxies. Of central importance in baryon cycling is the role of circum-galactic gas in regulating galaxy growth, and I will present results from simulations detailing this connection and its observational implications. I will argue that in the coming years, the holistic study of galaxies and their surrounding gas will be the key to understanding galaxy evolution across cosmic time.
Andrew Benson (Caltech)
Thursday, February 2, 2012
3:45 p.m.
LGRT 1033
Title:
Galaxy Formation Theory: The Next Decade
Abstract:
I will present my view of how the field of galaxy formation theory should, and must, progress over the next decade to keep pace with expected observational advances. I will describe my current work aimed at establishing robust modelling techniques that can generate detailed realizations of astronomical datasets, and will discuss the challenges that must be met to reach the primary goal of my research program: inferring the underlying physical mechanisms of galaxy formation from observational measures.
Lars Hernquist (CfA)
Thursday, January 26, 2012
3:45 p.m.
LGRT 1033
Title:
Cosmology on a Moving Mesh
Abstract:
Understanding the formation and evolution of galaxies in a cosmological context using numerical simulations remains an elusive goal. In this talk, I describe a new approach to modeling the hydrodynamics of galaxy formation in which the equations of motion are solved on a moving mesh. The use of a moving mesh makes the scheme fully Lagrangian, unlike popular particle-based codes which are quasi-Lagrangian in nature, and mitigates against advection errors when a spatially fixed grid is used. I present results from an initial study comparing results for a moving mesh with those obtained using a smoothed particle hydrodynamics solver. This preliminary work suggests that the new approach offers promise for resolving the long-standing problems which have plagued this field for nearly two decades.
Els Peeters (University of Western Ontario)
Thursday, December 8, 2011
3:45 p.m.
LGRT 1033
Title:
PAH emission features as astrophysical probes
Jiangtao Li (UMass)
Thursday, December 1, 2011
3:45 p.m.
LGRT 1033
Title:
CHANDRA SURVEY OF GALACTIC CORONAE AROUND NEARBY EDGE-ON DISK GA
Abstract:
CHANDRA SURVEY OF GALACTIC CORONAE AROUND NEARBY EDGE-ON DISK GALAXIES
Pete Schloerb (UMass)
Thursday, November 17, 2011
3:45 p.m.
LGRT 1033
Title:
LMT
Caleb Fassett (Mt. Holyoke)
Thursday, November 10, 2011
3:45 p.m.
LGRT 1033
Title:
TBA
Sugata Kaviraj (Imperial College London)
Thursday, November 3, 2011
3:45 p.m.
LGRT 1033
Title:
Early-type galaxies: the last 8 billion years
Jen Andrews (UMass)
Thursday, October 27, 2011
3:45 p.m.
LGRT 1033
Title:
The Formation of Dust in Core Collapse Supernovae
Lynn Mathews (MIT Haystack Observatory)
Thursday, October 20, 2011
3:45 p.m.
LGRT 1033
Title:
Tails of Stellar Mass Loss: The HI 21-cm Line as a Probe of the
Abstract:
Tails of Stellar Mass Loss: The HI 21-cm Line as a Probe of the Late Stages of Stellar Evolution
Desika Narayanan (University of Arizona)
Thursday, October 13, 2011
3:45 p.m.
LGRT 1033
Title:
The Efficiency of Star Formation in High Redshift Galaxies
Kristen Coppin (McGill University)
Thursday, October 6, 2011
3:45 p.m.
LGRT 1033
Title:
Probing the Evolutionary Sequence of the Formation of Massive Galaxies
Abstract:
Probing the Evolutionary Sequence of the Formation of Massive Galaxies
Jim Geach (McGill University)
Thursday, September 29, 2011
3:45 p.m.
LGRT 1033
Title:
The Evolution of the Molecular Gas Fraction of Star-Forming Galaxies
Abstract:
The Evolution of the Molecular Gas Fraction of Star-Forming Galaxies
Ben Oppenheimer (Leiden Observatory)
Thursday, September 22, 2011
3:45 p.m.
LGRT 1033
Title:
A Full Confrontation of the Low-Redshift Galaxy-Intergalactic Medium Relationship
Abstract:
A Full Confrontation of the Low-Redshift Galaxy-Intergalactic Medium Relationship
Ed Jenkins (Princeton University)
Thursday, September 15, 2011
3:45 p.m.
LGRT 1033
Title:
The Distribution of Thermal Pressures in the Diffuse Interstellar Medium of our Galaxy
Abstract:
The Distribution of Thermal Pressures in the Diffuse Interstellar Medium of our Galaxy
Tereasa Brainerd (Boston University)
Thursday, September 8, 2011
3:45 p.m.
LGRT 1033
Title:
Clues to the Orientations of Bright Galaxies inside their Dark Matter Halos
Adam Frank (Rochester)
Thursday, April 28, 2011
3:45 p.m.
LGRT 1033
Title:
Turbulence and Feedback in Star Forming Clouds: Who Stirs the Pot?
Kevin Covey (Cornell)
Thursday, April 21, 2011
3:45 p.m.
LGRT 1033
Title:
Kevin Covey (Cornell)
Alexandra Pope (U Mass)
Thursday, April 14, 2011
3:45 p.m.
LGRT 1033
Title:
The cosmic history of dust-obscured star formation
Mary Putman (Columbia)
Thursday, April 7, 2011
3:45 p.m.
LGRT 1033
Title:
Galaxy Gas Flows
Danilo Marchesini (Tufts)
Thursday, March 31, 2011
3:45 p.m.
LGRT 1033
Title:
Massive Galaxies at 2<z<4: New Insights into Galaxy Formation and Evolution
Scott Ransom (NRAO)
Thursday, March 24, 2011
3:45 p.m.
LGRT 1033
Title:
Detecting Gravitational Waves (and doing other cool physics) with Millisecond Pulsars
Jennifer Lotz (STScI)
Thursday, March 10, 2011
3:45 p.m.
LGRT 1033
Title:
Galaxy Mergers through Cosmic Time
Joseph Meiring (UMass)
Thursday, March 3, 2011
3:45 p.m.
LGRT 1033
Title:
Shadows of Galaxies: Quasar Absorption Line Observations of Galaxy Evolution
Jacqueline Van Gorkom (Columbia)
Thursday, February 24, 2011
3:45 p.m.
LGRT 1033
Title:
From voids to clusters: HI imaging surveys of galaxies in different environments
Mark Brodwin (CfA)
Thursday, February 17, 2011
3:45 p.m.
LGRT 1033
Title:
The IRAC Shallow Cluster Survey (ISCS): Evolution of Galaxy Clusters Over the Last 10 Gyr
Joe Adams (Cornell University )
Thursday, February 10, 2011
3:45 p.m.
LGRT 1033
Title:
FORCAST: A First Light Facility Instrument for SOFIA

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