Seminar archive 2015 | Fermilab Cosmic Physics Center

Event date	Title	Summary
Jan. 5, 2015, 2:00 pm US/Central	Measuring ultra-large cosmological scales with radio telescopes	Surveys of large-scale structure using the next generation of radio telescopes will be capable of probing unprecedentedly large volumes of the Universe. This will make it possible to detect effects that occur on length scales on the order of the cosmological horizon size, including primordial non-Gaussianity, general relativistic corrections, and possible signatures of modified gravity.... More »
Jan. 12, 2015, 2:00 pm US/Central	Formulation of the First Galaxies under Stellar Feedback	The first galaxies, which formed a few hundred million years after the big bang, are related to important cosmological questions. Given that they are thought to be the basic building blocks of large galaxies seen today, understanding their formation and properties is essential to studying galaxy formation as a whole. In this talk, I will... More »
Jan. 20, 2015, 2:00 pm US/Central	Towards precision cosmology: the halo model and necessary modifications	There are several approaches to account for clustering of matter and its evolution in the Universe. One of the more successful frameworks is the halo model. In this approach, all the matter in the Universe is assumed to be in isolated haloes with mass defined by a threshold density. Despite its success over a decade... More »
Feb. 2, 2015, 2:00 pm US/Central	Status of DAMIC at SNOLAB	I will present the recent progress achieved by the DAMIC Collaboration in the installation of charge-coupled devices (CCDs) as dark matter detectors in the low background environment of SNOLAB. I will give an overview of the CCD performance, in particular the continuous, low noise (7 eV RMS) operation of the devices under the conditions for... More »
Feb. 9, 2015, 2:00 pm US/Central	Baryon Acoustic Oscillations and Redshift Space Distortions	The talk will present results about measuring the Baryon Acoustic Oscillation signal in redshift surveys. The impacts of various effects like survey geometries, redshift space distortions, and nonlinear corrections will be discussed. In particular, we will show that redshift-space distortions can substantially sharpen the BAO peak in directions close to the line of sight. We... More »
Feb. 16, 2015, 2:00 pm US/Central	Building tomorrow's submm-wavelength instruments with kinetic inductance detectors and on-chip band-defining circuits	Recent advances in detector technology have enabled precision studies of the Cosmic Microwave Background and of the dusty high-redshift galaxies that played host to the first generations of star formation. However, there remain significant scientific questions which can only be addressed with massive 100-kilopixel scale cameras, wide-band multichroaic pixels, and compact multi-object spectrometers. I’ll discuss... More »
Feb. 23, 2015, 12:30 pm US/Central	Probing the Ultra-High Energy Universe with the Greenland Neutrino Observatory	Ultra-high energy neutrino astronomy sits at the boundary between particle physics and astrophysics. Through neutrino astrophysics, we can probe the nature of the ultra-high energy universe in a unique way and test our understanding of particle physics at energies much greater than those achievable at particle colliders. The best limit to date on the flux... More »
March 2, 2015, 2:00 pm US/Central	Modeling the Evolution of Galaxy Properties with the Illustris Simulation	Cosmological simulations are among the most powerful tools available to probe the non-linear regime of cosmic structure formation. They also provide one of the most powerful testbeds for understanding the impact that hydrodynamics and feedback processes have on the evolution of galaxies. In my talk, I will present galaxy formation simulations that couple a novel... More »
March 9, 2015, 2:00 pm US/Central	GRBs, LIGO, and multi-messenger astronomy	LIGO should be on the verge of directly detecting gravitational waves. The most likely sources are the inspirals and mergers of stellar mass binary systems, such as pairs of neutron stars and/or black holes. In addition to being extraordinarily loud in gravitational waves, these coalescences may be associated with short gamma-ray bursts, and thus hold... More »
March 10, 2015, 2:00 pm US/Central	Impacts of Galaxy Formation and Alternative Dark Matter Models on Milky Way Satellite Kinematics	We apply the Jeans equation to identify subhalos in high-resolution numerical simulations that are potentially consistent with observed properties of Milky Way dwarf spheroidal (dSph) galaxies. We investigate the effects found by several recent studies that show changes to the dynamical properties of galactic substructure: the properties of dark matter (DM), and galaxy formation physics.... More »
March 17, 2015, 2:00 pm US/Central	Baryon Acoustic Oscillations: A Robust and Precise Route to the Cosmological Distance Scale	I will discuss how the acoustic oscillations that propagate in the photon-baryon fluid during the first million years of the Universe provide a robust method for measuring the cosmological distance scale. The distance that the sound can travel can be computed to high precision and creates a signature in the late-time clustering of matter that... More »
March 23, 2015, 2:00 pm US/Central	Testing the accuracy of the Frontier-Fields Observatory of Bologna	I will show the preliminary results of the Frontier Fields Lens Modeling Comparison Project. The Frontier Field Initiative is currently a major effort of the HST to provide ultra-deep observations of up to six strong lensing clusters. The goal of this survey is to combine the sensitivity of HST with the magnification power of these... More »
March 30, 2015, 2:00 pm US/Central	The Milky Way's stellar and dark mass distributions	Observations of the structure and dynamics of different stellar populations in the Milky Way’s disk provide a unique perspective on disk formation, evolution, and dynamics. I will present recent progress in our knowledge of the chemo-orbital structure of the disk and discuss the implications for our understanding of how the Milky Way formed and evolved... More »
March 31, 2015, 2:00 pm US/Central	A search for dark matter annihilation in the newly discovered dwarf galaxy Reticulum 2	I will present results from a search for gamma-ray emission in nine Milky Way satellites recently discovered in the Dark Energy Survey. The nearest of these, Reticulum 2, shows evidence for a signal in public Fermi data. The detected emission is consistent with annihilating dark matter with a particle mass less than a few hundred... More »
April 6, 2015, 2:00 pm US/Central	Status of the DarkSide experiment	DarkSide-50 is a direct-detection dark matter experiment operating at the Gran Sasso National Laboratory, searching for nuclear recoils possibly induced by Weakly Interacting Massive Particles (WIMPs). The detector is a 50 kg liquid argon Time Projection Chamber (TPC) that is surrounded by an organic liquid scintillator neutron veto and a water Cherenkov cosmogenic veto. I... More »
April 20, 2015, 2:00 pm US/Central	Enabling Dark Energy Survey Science with redMaPPer and redMaGic	The Dark Energy Survey is currently taking data, and is poised to be the leading Dark Energy experiment of the second half of this decade. I will present the redMaPPer and redMaGic algorithms, designed to photometrically select clusters and luminous red galaxies respectively, discussing their performance, and how they will enable cluster abundance and baryon... More »
April 27, 2015, 2:00 pm US/Central	The Evolution of Quasars with Cosmic Time	While the luminosity and mass distributions of quasars has evolved dramatically with cosmic time, the physical properties of quasars of a given luminosity are remarkably independent of redshift. I will describe recent results on the spectra of luminous quasars, the dark matter halos in which they sit, and the intergalactic medium of their host galaxies,... More »
May 6, 2015, 2:00 pm US/Central	Probing New Physics Beyond the Standard Model with Cosmology	Cosmological observations have provided us with answers to age-old questions, involving the age, geometry, and composition of the universe. However, there are profound questions that still remain unanswered. In this talk, I will describe ongoing efforts to shed light on some of these questions. The origin of the small anisotropies that later grew into the... More »
May 18, 2015, 2:00 pm US/Central	Particle Physics at the Yoctowatt Scale: The ADMX-HF Experiment	The axion is a hypothetical particle first postulated to explain the absence of CP violation in strong interactions; it is also a well-motivated cold dark matter candidate. Dark matter axions may be detected via their resonant conversion into photons in a high-Q microwave cavity permeated by a strong magnetic field. The Axion Dark Matter eXperiment... More »
May 26, 2015, 2:00 pm US/Central	The vicissitudes of the cold dark matter model of cosmology	One of the most impressive advances in Physics and Astronomy over the past three decades is the development of the ”standard model of cosmology,” LCDM (where L stands for Einstein’s cosmological constant and CDM for cold dark matter). LCDM accounts for an impressive array of data on the structure of the Universe on large-scale scales,... More »
June 1, 2015, 2:00 pm US/Central	The Present and Future of Multi-Object Fiber Spectroscopy	The Michigan/Magellan Fiber System (M2FS) has been operational for almost two years and has carried out a wide range of studies from searching for exoplanets, to probing the dark matter content of nearby galaxies, to mapping the distribution of high-redshift galaxies at redshifts of 4-6. I describe some of these results and also discuss how... More »
June 8, 2015, 2:00 pm US/Central	SPIDER: exploring the dawn of time from above the clouds	TEST Our account of cosmic history begins with inflation, a moment of rapid expansion that set the stage for our universe’s evolution. This inflationary epoch should have left a very faint imprint upon the sky at millimeter wavelengths: a “B-mode” (odd-parity) pattern of polarization in the cosmic microwave background (CMB). January 1st saw the successful... More »
Nov. 9, 2015, 2:00 pm US/Central	The Nearby Universe as a Cosmological Lens	Over the last decade, large sky surveys have revolutionized our view of the Milky Way and the dwarf galaxies orbiting around it. Much of this observational progress has been motivated by a series of apparent “crises” for the cold dark matter cosmological model. However, these challenges have effectively functioned as flashlights pointing us to interesting... More »
Nov. 16, 2015, 2:00 pm US/Central	The Future of Large Mass Calorimeters	The detector technology behind SuperCDMS is nearly 20 years old, and thus there is quite reasonable assumption in the scientific community that it is has reached maturity. Alas, this isn’t the case at all! In this talk, I’ll discuss how we hope to improve the energy sensitivity of athermal phonon detectors by 2 orders of... More »
Nov. 23, 2015, 2:00 pm US/Central	Darkside-50: Results with UAr	DarkSide-50 (DS-50) at Gran Sasso underground laboratory, Italy, is a direct dark matter search experiment based on a Time Projection Chamber (TPC) with liquid argon from underground sources. The DS-50 TPC, with 50 kg of active argon and a fiducial mass of ~37 kg, is installed inside an active neutron veto based on a boron-loaded... More »
Nov. 30, 2015, 2:00 pm US/Central	Antimatter Gravity with Muons	A longstanding question in physics is whether antimatter falls up. If it does, a simpler cosmology, with no inflation or baryon asymmetry, and no need for dark matter and energy, may be possible. Alternatively, antimatter may fall at nearly the same rate as matter, but violate the equivalence principle slightly, pointing towards a future quantum... More »
Dec. 7, 2015, 2:00 pm US/Central	PICO bubble chambers for dark matter	The PICO Collaboration, formed from the merger of the Chicago-based COUPP and the Canadian-based PICASSO experiments, uses bubble chambers to search for dark matter. Bubble chambers are a unique dark matter detector technology. They provide very high 10^10 intrinsic electron recoil rejection, the ability to switch nuclear targets, acoustic rejection of alpha events, simple data... More »
Dec. 14, 2015, 2:00 am US/Central	Recent Results and Future Prospects in UHECR Observations	Ultra-high energy cosmic rays (UHECRs) are the most energetic particles in the universe. Their origins could be related to extremely energetic astronomical phenomena or other exotic processes, such as the decay of the super-heavy dark matter in the halo of our galaxy or topological defects created in an early phase of the development of the... More »