New Time!
CCAPP Cosmology Lunch meets on Wednesdays at 1:00 pm in the Price Place (PRB M2005).


April, 5  2017

March, 29  2017
  • Speaker: Alex Mead
  • "Is the spherical-collapse model of halo formation useful?"
  • Abstract: I will discuss differences in non-linear structure formation between cosmological models that are designed so as to share a linear-theory power spectrum at redshift zero, but that differ in their growth histories. Simulations of these cosmologies are seen to share a large-scale structure skeleton, but differ in the details of their halo populations. I will demonstrate that these differences can be largely understood via the cosmology dependence of spherical-collapse-model predictions for the formation times and average densities of the haloes. This fact can then be used to generate per-cent level accurate non-linear matter power spectra for a range of dark energy models.

March, 22  2017

March, 8  2017
March, 1  2017
  • Dvorkin & Barausse, 2017,, "The nightmare scenario: measuring the stochastic gravitational-wave background from stalling massive black-hole binaries with pulsar-timing arrays"
  • Masui et al., 2017,, "Two- and Three-dimensional Probes of Parity in Primordial Gravity Waves"
  • Hopkins et al., 2017,, "FIRE-2 Simulations: Physics versus Numerics in Galaxy Formation"
  • Inayoshi et al. 2017,, "Identifying stellar binary black hole formation channels from the imprint of their center-of-mass acceleration in their gravitational wave signal"
  • Shirasaki et al. 2017,, "Large-Scale Clustering as a Probe of the Origin and the Host Environment of Fast Radio Bursts"
  • Bao et al, 2017,, "Quantum Circuit Cosmology: The Expansion of the Universe Since the First Qubit"
  • Dai & Venumadhav, 2017,, "On the waveforms of gravitationally lensed gravitational waves"
  • Our Ami Choi will discuss ways in which overlapping wide-area surveys can be leveraged to investigate photometric redshift bias and shear multiplicative measurement bias based on various combinations of lensing and clustering cross-correlations from spectroscopic, photometric and CMB surveys such as CFHTLenS, RCSLenS, KiDS, BOSS, WiggleZ, and Planck.
February, 22  2017

February, 15  2017
February, 08  2017
  • Guest speaker: David Cinabro, "Search For Type Ia Supernova NUV-Optical Subclasses"
February, 01  2017
  • Local speaker: Ashely Ross, "Things to consider when planning a large-scale structure survey and how this relates to BOSS, eBOSS, DESI, and DES”
  • Abbott et al., 2017,, "First Search for Gravitational Waves from Known Pulsars with Advanced LIGO"
  • Klypin et al., 2017,, "Dark Matter Statistics for Large Galaxy Catalogs: Power Spectra and Covariance Matrices"
January, 25  2017
  • Speaker: Susmita Adhikari, "Outskirts of Dark Matter Halos"
  • Speaker: Kaze Wong, "Advanced LIGO lensing rate predictions"
January, 11  2017

December, 14  2016

December, 1  2016

November, 17 2016

    Special talk: 
    Michael Wilson
    University of Edinburgh
    "Geometric and growth rate tests of gravity with the linearised galaxy distribution"

    This talk will outline the consistency of the VIPERS PDR-2 census of the galaxy distribution at z=0.8 with the expansion history and linear growth rate predicted by General Relativity and a Planck (2015) cosmology.  These may be inferred from the observed anisotropy of the galaxy power spectrum, which is sensitive to both the coherent infall of galaxies towards clusters (outflow from voids) and the assumption of an expansion history differing from the true one.
    I will then present the results of including a simple density transform prior to the analysis; this tackles the principal cause of non-linearity by down-weighting the most massive structures and extends the validity of theoretical models.  Moreover, this weighting would amplify signatures of modified gravity in ‘shielded’ models and represents a higher-order statistic, which contains information beyond that available to the power spectrum.
    Finally, the final data release of the VIPERS spectroscopic survey will be on Nov 18th (  I will detail the characteristics of the survey and describe the breadth of the accompanying clustering analyses.

November, 10  2016

November, 3  2016

October, 27 2016

    Special talk: 
    Patrick Breysse
    John Hopkins University
    "High-Redshift Astrophysics Using Every Photon"

    Large galaxy surveys have dramatically improved our understanding of the complex processes which govern gas dynamics and star formation in the nearby universe. However, we know far less about the most distant galaxies, as existing high-redshift observations can only detect the very brightest sources. Intensity mapping surveys provide a promising tool to access this poorly-studied population. By observing emission lines with low angular resolution, these surveys can make use of every photon in a target line to study faint emitters which are inaccessible using traditional techniques. With upcoming carbon monoxide experiments in mind, I will demonstrate how an intensity map can be used to measure the luminosity function of a galaxy population, and in turn how these measurements will allow us to place robust constraints on the cosmic star formation history. I will then show how cross-correlating CO isotopologue lines will make it possible to study gas dynamics within the earliest galaxies in unprecedented detail.

October, 20  2016

October, 6  2016

September, 29  2016

September, 22  2016

September, 15  2016

September, 8  2016

September, 1  2016