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Aug. 25
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Steven Finkelstein
University of Texas at Austin
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Organizational Meeting
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Sep. 1
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11:00 a.m. this week only
Kelly Lockhart
Institute for Astronomy, University of Hawaii - Manoa
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Testing Theories of in situ Star Formation in the Nucleus of M31
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Sep. 8
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No talk scheduled
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Sep. 15
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Steve Finkelstein
The University of Texas at Austin
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A Semi-empirical Model of Reionization
I will present the results of our new analysis of the contribution of both galaxies and AGNs to the reionization of the intergalactic medium (IGM). The time evolution of reionization, and the ionizing sources, are poorly constrained primarily due to the lack of knowledge about the escape fraction of ionizing photons from star-forming galaxies. Using the results of detailed zoom-in hydrodynamical simulations, we parameterize the escape fraction as a function of halo mass and combine this with observations of the evolution of the galaxy luminosity function at high redshift. This fiducial model with fixed assumptions does not complete reionization by z=6. We therefore run a MCMC analysis using the observations of quasars and the electron scattering optical depth to the CMB to constrain a number of free parameters, including a scale factor applied to the simulation escape fraction results, a contribution from AGN, minimum halo mass for star formation, and the Lyman continuum photon production efficiency, finding that star-forming galaxies alone can fully reionize the universe by z~6 with an average escape fraction of only ~5% (dominated by star-bursting galaxies with large escape fractions). This model implies that reionization is more extended than previously thought (with 20-30% of the IGM ionized (by volume) by z~10), and that AGN may dominate the ionizing emissivity at z < 6.
close
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Sep. 22
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No talk scheduled
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Sep. 29
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No talk scheduled
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Oct. 6
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Anson D’Aloisio
University of Washington
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Probing Cosmological Reionization with the High-redshift Lyman-alpha Forest
abstract
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Oct. 13 (Talk #1)
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Jackie Champagne
The University of Texas at Austin
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Title: TBA
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Oct. 13 (Talk #2)
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Rebecca Larson
The University of Texas at Austin
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A Blind Search for Ly-a Emission from Galaxies at z = 6-8 with Deep HST Grism Spectra
abstract
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Oct. 20
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Marcelo Alvarez
Canadian Institute for Theoretical Astrophyics, University of Toronto
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Fundamental Physics with the Next Generation of Large Scale Structure Surveys
abstract
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Oct. 27
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No talk scheduled
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Nov. 3 (Talk #1)
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Kristy McQuinn
The University of Texas at Austin
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JWST Science Case: Resolved Stellar Populations
abstract
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Nov. 3 (Talk #2)
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Patrick Drew
The University of Texas at Austin
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Title: TBA
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Nov. 10
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Irene Shivaei
University of California, Riverside
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A Multi-Wavelength Census of Star Formation and Dust in Galaxies at z ~ 2
abstract
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Nov. 17
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Andreia Carrillo
The University of Texas at Austin
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Characterizing dw1335-29, a dwarf galaxy of M83
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Nov. 24
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Thanksgiving Holiday
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Dec. 1
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Allison Strom
California Institute of Technology
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Star-formation history and chemical enrichment in the early Universe: clues from the rest-UV and rest-optical spectra of high-redshift galaxies
abstract
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