Conveners
Cosmology
- Martina Gerbino
Cosmology
- Dragan Huterer (University of Michigan)
Cosmology
- Dragan Huterer (University of Michigan)
Cosmology
- Tom Giblin (Kenyon College)
Cosmology
- Tom Giblin (Kenyon College)
Cosmology
- Tom Giblin (Kenyon College)
SPIDER is a balloon-borne telescope designed to characterize the linear polarization of the cosmic microwave background at degree angular scales, and in particular to place constraints on the $B$-mode angular power spectrum arising from primordial gravitational waves. For the inaugural flight in January 2015, SPIDER observed approximately 12% of the sky with nearly 2000 detectors at...
I will present a new upper limit on CMB circular polarization from the 2015 flight of SPIDER, a balloon-borne telescope designed to search for B-mode linear polarization from cosmic inflation. Although the level of circular polarization in the CMB is predicted to be very small, experimental limits provide a valuable test of the underlying models. By exploiting the non-zero circular-to-linear...
The South Pole Telescope is a 10-meter diameter telescope located at the NSF Amundsen-Scott South Pole Station in Antarctica, designed for high-precision measurements of the temperature anisotropy and polarization properties of the cosmic microwave background. The third-generation camera on the telescope, SPT-3G, was deployed in the 2016-2017 austral summer season and represents a significant...
The odd-parity (B-mode) polarization anisotropy of the Cosmic Microwave Background (CMB) provides a unique window into the history and contents of the universe. At sub-degree scales this polarization is primarily created by the gravitational lensing of the CMB due to intervening large scale structure while at degree scales B-mode polarization can indicate the presence of primordial...
I will describe a novel method to measure the absolute orientation of the polarization plane of the CMB with arcsecond accuracy, that will enable unprecedented measurements for cosmology and fundamental physics. Existing and planned CMB polarization instruments looking for primordial B-mode signals need an independent, experimental method for systematics control on the absolute polarization...
Increasingly precise maps of the polarization of the CMB are a unique and powerful tool for understanding new physics, including inflation, the superluminal expansion of the universe during the first moments after the Big Bang. I will discuss constraints on inflation, set using the BICEP series of experiments at the South Pole (BICEP2, The Keck Array, and BICEP3). I will then discuss...
HETDEX (Hobby-Eberly Telescope Dark Energy eXperiment) is a galaxy survey targeting Lyman-alpha emitters (LAEs) at high redshifts (1.9<z<3.5). Starting from late 2017, the survey will observe about a million LAEs over ~400 sq. degrees, which corresponds to ~10Gpc^3 in volume. The main science goal of HETDEX is to measure the angular diameter distance and the Hubble expansion rate at high...
The next frontiers in cosmic microwave background (CMB) science include a detailed mapping of the CMB polarization field, with goals of detecting the inflationary B-mode signal and constructing high-fidelity maps of the matter distribution via CMB lensing reconstruction, as well as a first detection of CMB spectral distortions. At these levels of precision (~nK), Galactic and extragalactic...
Inflation generically predicts a background of primordial gravitational waves, which generate a primordial B-mode component in the polarization of the cosmic microwave background (CMB). The measurement of such a B-mode signature would lend significant support to the paradigm of inflation and be important for development of quantum gravity theories. Observed B modes also contain a component...
The Lyman-alpha forest provides a powerful probe of cosmic structure at z = 2-4, with physics that is relatively straightforward. I will discuss current constraints on dark energy from baryon acoustic oscillation measurements in the 3-d Lya forest and on neutrino masses from the 1-d Lya forest power spectrum, with measurements coming from the Baryon Oscillation Spectrosopic Survey (BOSS). I...
I will present results from the completed Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic Survey (BOSS) and initial results from the SDSS-IV extended BOSS (eBOSS). These experiments have obtained spectroscopic redshifts for nearly 2 million galaxies and quasars, allowing the creation of 3 dimensional maps spanning most of the history of the Universe. In addition to other...
We model galaxy-galaxy lensing and clustering into nonlinear scales with a suite of N-body simulations, and we project significantly tighter cosmological parameter constraints possible within the ΛCDM parameter space and a HOD galaxy biasing model by using small scales. To include possible assembly bias effects, we introduce a two-halo environmental density dependence parameter into our model...
Cosmological perturbation theory is a powerful tool to model observations of large-scale structure in the weakly non-linear regime. However, even at next-to-leading order, it results in computationally expensive mode-coupling integrals. In this talk, I will focus on the physics of our extremely efficient algorithm, FAST-PT. I will show how the algorithm can be applied to calculate 1-loop power...
Cosmological observations represent a powerful tool to constrain neutrino physics, complementary to laboratory experiments. In particular, observations of the cosmic microwave background (CMB) have the potential to constrain the properties of relic neutrinos, as well as of additional light relic particles in the Universe. I will present current constraints on neutrino properties, focusing on...
We study and constrain the impact of non-standard neutrino interactions on the CMB angular power spectrum. Starting from the collisional Boltzmann equation, we derive the Boltzmann hierarchy for neutrinos including interactions with a massive scalar particle.
In contrast to the Boltzmann hierarchy for photons, our interacting neutrino Boltzmann hierarchy is momentum dependent, which reflects...
Light sterile neutrinos with eV mass have been suggested by different anomalies observed in short-baseline neutrino experiments. These particles would have been produced in the Early Universe changing the amount of relativistic energy density by increasing the
effective number of relativistic species ($N_{\rm{eff}}$). This results in a conflict with existing cosmological bounds on primordial...
A number of ground-based CMB surveys are currently in the planning stages that will provide significant new information on properties of physics beyond the standard model. Measurements of the lensing of the CMB are expected to provide evidence for neutrino mass in the case of a minimal mass as expected from neutrino oscillation experiments. Meanwhile measurements of the phase of the acoustic...
The standard $\Lambda$CDM cosmological model has successfully explained large scale cosmological observations. However, there are some discrepancies between the $\Lambda$CDM predictions and measurements at small scales. Even though these discrepancies could be due to unaccounted effects on weak lensing analyses and/or numerical simulations, in this talk, I will explore the possibility of...
Present measurements are not able to firmly single out nature’s choice for the neutrino mass hierarchy. Consequently, in the absence of a robust measurement of the neutrino mass ordering, a desirable bound on the neutrino mass would be one which relies on the less informative possible assumption about the hierarchical distribution of the total mass among the three eigenstates. We will discuss...
In recent years, advances in numerical methods have allowed us to calculate precision observables with fewer assumptions. Here I will discuss two of these observables, Hubble Diagrams and the Weak Lensing Convergence Power Spectrum. I will comment on the role that inhomogeneities, entering at high order, effects cosmological measurements.
I will describe how statistical anisotropies, such as dipole modulations of the cosmic microwave background temperature and polarization fluctuations, are more likely if the primordial fluctuations are non-Gaussian. I will then discuss the implications of this effect for observations in the cosmic microwave background temperature and polarization anisotropies, and how such observations can be...
In this talk we will present the latest development of the CLUMPY code. The first version aimed at the calculation of the astrophysical J-factors from dark matter annihilation/decay in any galaxy or galaxy cluster dark matter halo including substructures. While refining on several aspects of the first version (halo-to-halo concentration scatter, multi-level boost factors, and triaxiality), the...
Particles present in the early Universe can leave observable imprints if they affect dark matter properties after dark matter has gone out of equilibrium with the thermal bath. We will investigate such possibilities and their associated observable signatures in several well-motivated dark matter frameworks.
Milky Way satellite dwarf galaxies are among the oldest, smallest, and most dark matter dominated galaxies in the known Universe. The study of these tiny galaxies can help shed light on the nature of dark matter and the mysteries of galaxy formation. Over the last two years, efforts using the Dark Energy Camera (DECam) have nearly doubled the known population of Milky Way satellite galaxies....
The WFIRST high-latitude survey (HLS) will provide an exciting dataset for constraining dark energy through a variety of measurement methods. In this talk, I will describe the current plans for the WFIRST HLS and the potential for competitive constraints on dark energy with weak lensing. I will also discuss the potential synergies with other surveys during the same time-frame, including the...
I will present a suite of new algorithms for measuring higher-point statistics from large-scale structure surveys. I will begin with a transformatively-fast algorithm that enables computation of the isotropic 3-point correlation function scaling as the number of galaxies squared. This algorithm was applied to BOSS data to make the first high-significance detection of the Baryon Acoustic...
We analyze the Extended Quasi-Dilaton Massive Gravity model around a Friedmann-Lemaitre-Robertson-Walker cosmological background. We present a careful stability analysis of asymptotic fixed points. We find that the traditional fixed point cannot be approached dynamically, except from a perfectly fine-tuned initial condition involving both the quasi-dilaton and the Hubble parameter. A...
In models of early universe cosmology, primordial magnetic fields with helicity can be created during cosmological inflation, and they may play a role in the generation of the matter / antimatter asymmetry of the universe. Such a primordial magnetic field will persist in the universe today as an intergalactic magnetic field, and the discovery of this cosmological relic will open a new window...
Hyper Suprime-Cam (HSC) is an imaging camera mounted at the Prime Focus of the Subaru 8.2-m telescope operated by the National Astronomical Observatory of Japan on the summit of Maunakea in Hawaii. A consortium of astronomers from Japan, Taiwan and Princeton University is carrying out a three-layer, 300-night, multiband survey from 2014-2019 with this instrument. In this talk, I will focus on...
CHIME will use the 21cm emission line of neutral hydrogen to map large-scale structure between redshifts of 0.8 and 2.5. By measuring Baryon Acoustic Oscillations (BAO) we will place constraints on the dark energy equation of state as it begins to dominate the expansion of the Universe, particularly at redshifts poorly probed by current BAO surveys.
In this talk I will introduce CHIME, a...
Type Ia supernovae (SNe Ia) provided the first direct evidence for the accelerated expansion of the universe, leading to the now-standard Lambda-CDM model featuring dark energy. Beyond direct dark energy measurements, these accurate standard candles can be employed in a variety of ways to test the Lambda-CDM model. I will show how an analysis of the peculiar velocities of SNe Ia constitutes a...
The Hubble constant H0 — the expansion rate of the Universe today — has recently been measured to percent-level precision, but two of the key results are in tension. The local measurements using distance ladders have indicated H0 ~ 73 km/s/Mpc, while the global measurements using cosmic microwave background have indicated H0 ~ 67 km/s/Mpc. In this talk, I will first review the methods and...
