Seminar archive 2017

Raw date Event date Title Speakers Host Summary Links
20170123 Jan. 23, 2017, 2:00 pm Coherent Neutrino-Nucleus Scattering: signal of background? The next generation of dark matter direct detection experiments will be sensitive to coherent nuclear scattering of solar neutrinos. This presents an irreducible background to dark matter searches, the so called ‘neutrino floor’. However, this effect that has yet to be observed and so provides an opportunity for discovery. Dedicated experiments are racing to observe... More »
20170130 Jan. 30, 2017, 2:00 pm The ANDES Deep Underground Laboratory in South America: status and prospects The construction of the Agua Negra tunnel through the Andes between Argentina and Chile is a unique opportunity to build a world class deep underground laboratory in the southern hemisphere, with 1750m of rock overburden. At 30 degrees latitude south, far from nuclear power plants, it provides a unique site for Dark Matter searches and... More »
20170206 Feb. 6, 2017, 2:00 pm Discovery of the First Quad(-like) Lensed Quasar System in the Dark Energy Survey Strong gravitational lensing systems provide valuable tools for studying the properties and evolution of galaxies and quasars, for measuring the distribution of dark matter, and for constraining cosmological parameters. In particular, lensed quasar systems, when accompanied by accurate time delay measurements and careful lens modeling, can provide powerful cosmological constraints that are complementary to those... More »
20170213 Feb. 13, 2017, 2:00 pm Canceled
20170220 Feb. 20, 2017, 2:00 pm Cross-Correlating 2D and 3D Galaxy Surveys Galaxy surveys probe both structure formation and the expansion rate, making them promising avenues for understanding the dark universe. Photometric surveys accurately map the 2D distribution of galaxy positions and shapes in a given redshift range, while spectroscopic surveys provide sparser 3D maps of the galaxy distribution. In this talk, I will present a way... More »
20170227 Feb. 27, 2017, 2:00 pm Interplay between dark and baryonic matter in galaxy centers: new constraints from dynamics and lensing The central 5-10 kpc of elliptical galaxies, while in long term steady state, are not truly relaxed. The primary reason is that baryons and dark matter are not fully mixed with each other. We demonstrate this by comparing observed and simulated galaxies to theoretically derived prediction for dynamically relaxed collisionless systems, and by examining the... More »
20170306 March 6, 2017, 2:00 pm Direct Detection of sub-GeV Dark Matter Dark matter with MeV-to-GeV masses is a theoretically and phenomenologically appealing possibility. In this talk, I will describe how direct-detection experiments can probe this under-explored mass range. A demonstrated technique with significant potential for improvement is that dark matter scatters off electrons, causing ionization or excitation of atoms in a detector target material, which can... More »
20170313 March 13, 2017, 2:00 pm Cores in Dwarf Galaxies from Fermi Repulsion James Unwin, UIC Cold dark matter provides a remarkably good description of cosmology and astrophysics. However, observations connected with small scales might be in tension with this framework. In particular, structure formation simulations suggest that the density profiles of dwarf spheroidal galaxies should exhibit cusps, in contrast to observations. I will show that Fermi repulsion can explain the... More »
20170320 March 20, 2017, 2:00 pm Compact dark matter Marc Kamionkowski, Johns Hopkins Considerable attention has focused the past year on the possibility that some or all of the dark matter could be composed of compact dark objects with masses around 30 solar masses.  The hypothesis has led to interesting connections to gravitational-wave astrophysics, fast radio bursts, pulsar timing arrays, galaxy surveys, gravitational lensing, and stellar dynamics.  I... More »
20170327 March 27, 2017, 2:00 pm Weyl Symmetry, Inflation, and Spontaneous Generation of the Planck Mass Christopher Hill, Fermilab Scalar fields can be coupled non-minimally to curvature and satisfy: (i) the theory has no mass input parameters, including M_Planck=0; (ii) the scalars have arbitrary values and gradients, but undergo a general expansion and relaxation to constant values that satisfy a nontrivial elliptical constraint K(phi)=constant; (iii) this constraint breaks scale symmetry spontaneously, and the Planck... More »
20170403 April 3, 2017, 2:00 pm New Insights into the Cosmic-Ray Positron Excess Dan Hooper, Fermilab Recent Measurements of the Gaming and B0656+14 pulsars by the gamma-ray telescope HAWC (along with earlier measurements by Milagro) indicate that these objects generate significant fluxes of very high-energy electrons. From the measured gamma-ray intensity and spectrum of these pulsars, one can calculate and constrain their expected contributions to the local cosmic-ray positron  spectrum. Among... More »
20170410 April 10, 2017, 2:00 pm Extrasolar Planets: Lessons From Kelper Yoram Lithwick, Northwestern University Astronomers have been discovering extrasolar planets at an astonishing pace.  The Kepler space telescope has discovered thousands of planets smaller than Neptune. Many of these planets’ properties were completely unexpected, based on how planets were thought to form. I will describe these surprising properties, and explain how we have inferred the densities and eccentricities of... More »
20170417 April 17, 2017, 2:00 pm The Search for Dark Photons at the SeaQuest E906 Experiment Arun Tadepalli, Rutgers The SeaQuest E906 experiment is a fixed target Drell-Yan experiment which is aimed at studying the anti-quark distributions in the nucleon and nuclei. 120 GeV protons from the Main Injector at Fermilab could also be used to search for massive dark gauge bosons or dark photons that could be generated when a proton beam dump... More »
20170424 April 24, 2017, 2:00 pm Gamma-ray Constraints on Decaying Dark Matter and Implications for IceCube Nicholas Rodd, MIT Utilizing the Fermi measurement of the gamma-ray spectrum toward the inner Galaxy, I will explain how to derive some of the strongest constraints on dark matter lifetimes in the mass range from hundreds of MeV to above an EeV.  The limits derived disfavour a decaying DM interpretation of the astrophysical neutrino flux observed by IceCube,... More »
20170501 May 1, 2017, 2:00 pm Gravitational Lensing of the CMB Gil Holder, UIUC Gravitational lensing of the cosmic microwave background is emerging as a new and powerful cosmological tool. I will discuss recent results from the South Pole Telescope, as well as prospects for cosmological measurements of neutrino masses and detection of gravitational waves from the early universe.
20170508 May 8, 2017, 2:00 pm A Cosmic Census – and the means to do it right Peter Melchior, Princeton Weak gravitational lensing is an important driver of large astronomical surveys. It presents the only way to determine the mass distribution in the universe over a wide range of scales: galaxies, galaxy clusters, voids, and the cosmic web as a whole. I will show the latest results of the Dark Energy Survey for each of... More »
20170515 May 15, 2017, 2:00 pm Particle cosmological exploration for light dark matter Kenji Kadota, Institute for Basic Science, S. Korea A few examples for the light dark matter will be
presented along with their cosmological (e.g. galaxies, supernova) and 
the particle physics (collider, dark matter search) constraints to illustrate the complementarity
between the particle physics and cosmology probes.
20170522 May 22, 2017, 2:00 pm New Physics in Astrophysical Neutrino Flavor Teppei Katori, Queen Mary Neutrino oscillation physics is very successful in the last 20 years. Now, our understanding of the Neutrino Standard Model (nuSM) is very matured, and there are world wide effort to measure last missing pieces of nuSM. On the other hand, neutrino oscillation itself can be a tool to look for new physics beyond the nuSM,... More »
20170530 May 30, 2017, 2:00 pm Twinkling Quasars Lensed by Galaxies Lensing Quasars Paul Schechter, MIT Nobody who has looked carefully at the two broad classes of stellar mass estimates for galaxies will question the need for another method. Quasars that are multiply imaged by galaxies twinkle as a result of micro-lensing by the stars that comprise the galaxies.  We have used this to estimate stellar masses for the lensing galaxies. ... More »
20170605 June 5, 2017, 2:00 pm Looking for the WIMP next door Jessie Shelton, UIUC Dark matter (DM) freezing out in a hidden sector is a simple and compelling scenario for the missing 25% of our universe, which can parametrically explain null results in searches to date.  I will demonstrate that the requirement that the dark sector was once in thermal equilibrium with the SM defines a UV-insensitive cosmological history... More »
20170612 June 12, 2017, 2:00 pm Lines, Excesses, and Dwarfs, Oh My! Dark Matter Searches and the Fermi-LAT sky Regina Caputo, University of Maryland/NASA/GAFC The era of precision cosmology has revealed that ~80% of the total amount of matter in the universe is dark matter. One promising candidate, motivated by both particle physics and astrophysics, is the Weakly Interacting Massive Particle (WIMP). WIMPs are predicted to produce gamma rays via annihilation or decay which are detectable by the Fermi... More »
20170619 June 19, 2017, 2:00 pm LUX Postscripts and an LZ Preface Kim Palladino, UW-Madison Liquid xenon time projection chambers are a technology well suited to WIMP direct dark matter searches. The LUX detector completed operations in 2016, and has set its final spin-independent and spin-dependent limits, as well as a limit on axion-like particles. A second generation experiment, LZ, will occupy the cavern vacated by LUX. But first, we... More »
20170626 June 26, 2017, 2:00 pm A New Look at Dark Matter in the Cores of galaxies Thomas Lacroix, University of Montpellier / CNRS Indirect detection techniques are a very promising avenue to look for dark matter (DM) particles by exploiting astrophysical observations. This is especially interesting when studying the centers of galaxies, where DM over-densities are expected. Moreover, DM particles may be significantly clustered in galactic cores around supermassive black holes, forming density spikes. I will present several... More »
20170705 July 5, 2017, 2:00 pm Squeezed Light for Gravitational Wave Interferometers Lee McCuller, MIT Craig Hogan Gravitational Wave detectors use optical interferometry enhanced with long baseline resonant cavities to achieve the sensitivity required for the recent detections of binary black hole inspirals. Advanced LIGO will soon add squeezed coherent states to enhance sensitivity by quantum mechanics. This talk will detail the detector and why this improvement will initially only improve the... More »
20170710 July 10, 2017, 2:00 pm TBD Annika Peter, Ohio State University
20170717 July 17, 2017, 2:00 pm TBD Mathias Pierre
20170724 July 24, 2017, 2:00 pm AGN Feedback in Massive Galaxies Pawel Biernacki, ETH-Zurich Abstract: Supermassive Black Holes (SMBH) are found in the central region of massive galaxies at all redshift in the form of Active Galactic Nuclei (AGN) and are believed to regulate star formation in massive galaxies. Using improved sink particle algorithm to model SMBH in the RAMSES code we studied effects of coevolution of SMBH and... More »
20170731 July 31, 2017, 2:00 pm No seminar -- DPF meeting
20170807 Aug. 7, 2017, 2:00 pm Galaxy Clusters: A Standard Cannon for Cosmology Chris Miller, University of Michigan Einstein’s theory of general relativity (GR) entwines the dynamics of matter-energy and the universe’s expansion. It is often said: matter-energy tells space-time how to curve and space-time tells matter-energy how to move. In the weak-field limits of GR, Newtonian dynamics allows us to relate the escape speed to the local potential via the Poisson equation.... More »
20170814 Aug. 14, 2017, 2:00 pm What We Can Tell About the Sources of IceCube’s Neutrinos, and What IceCube Can Tell Us About Gamma Ray Bursts Peter Denton, Niels Bohr International Academy IceCube has recently detected high energy astrophysical neutrinos for the first time. While many known astrophysical processes are anticipated to create high energy neutrinos, the origin of the observed neutrinos remains unclear. In this talk I will first present evidence disfavoring the Milky Way as the primary origin of the flux based on anisotropy arguments.... More »
20170821 Aug. 21, 2017, 2:00 pm No seminar -- Solar Eclipse
20170828 Aug. 28, 2017, 2:00 pm Cosmology with Clusters of Galaxies Adam Mantz, Stanford The gas mass fractions and the distribution in mass and redshift of the galaxy cluster population provide powerful probes of cosmology, constraining the cosmic matter density, the amplitude of the matter power spectrum, properties of dark energy, and the mass of neutrinos, among other parameters. Improvements in cluster data on several fronts have yielded significant... More »
20170904 Sept. 4, 2017, 2:00 pm No seminar -- Labor Day
20170911 Sept. 11, 2017, 2:00 pm Resolving the physical scale of star formation in a lensed galaxy at z=2.5 Traci Johnson, University of Michigan Clumpy substructure in galaxies 1<z<3 is prevalent and forms from gravitational instabilities in the disk as cold gas accretes from the intergalactic medium. These clumps are the launching points of outflows from massive stars, and will merge over time to build up the exponential disks of today’s galaxies. Even with HST, the highest spatial resolution... More »
20170918 Sept. 18, 2017, 2:00 pm TBD Marilena Loverde, Stony Brook