Seminar archive 2017 | Fermilab Cosmic Physics Center

Event date	Title	Speakers	Host	Summary
Jan. 23, 2017, 2:00 pm US/Central	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 »
Jan. 30, 2017, 2:00 pm US/Central	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 »
Feb. 6, 2017, 2:00 pm US/Central	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 »
Feb. 13, 2017, 2:00 pm US/Central	Canceled
Feb. 20, 2017, 2:00 pm US/Central	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 »
Feb. 27, 2017, 2:00 pm US/Central	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 »
March 6, 2017, 2:00 pm US/Central	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 »
March 13, 2017, 2:00 pm US/Central	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 »
March 20, 2017, 2:00 pm US/Central	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 »
March 27, 2017, 2:00 pm US/Central	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 »
April 3, 2017, 2:00 pm US/Central	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 »
April 10, 2017, 2:00 pm US/Central	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 »
April 17, 2017, 2:00 pm US/Central	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 »
April 24, 2017, 2:00 pm US/Central	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 »
May 1, 2017, 2:00 pm US/Central	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.
May 8, 2017, 2:00 pm US/Central	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 »
May 15, 2017, 2:00 pm US/Central	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.
May 22, 2017, 2:00 pm US/Central	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 »
May 30, 2017, 2:00 pm US/Central	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 »
June 5, 2017, 2:00 pm US/Central	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 »
June 12, 2017, 2:00 pm US/Central	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 »
June 19, 2017, 2:00 pm US/Central	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 »
June 26, 2017, 2:00 pm US/Central	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 »
July 5, 2017, 2:00 pm US/Central	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 »
July 10, 2017, 2:00 pm US/Central	TBD	Annika Peter, Ohio State University
July 17, 2017, 2:00 pm US/Central	TBD	Mathias Pierre
July 24, 2017, 2:00 pm US/Central	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 »
July 31, 2017, 2:00 pm US/Central	No seminar -- DPF meeting
Aug. 7, 2017, 2:00 pm US/Central	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 »
Aug. 14, 2017, 2:00 pm US/Central	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 »
Aug. 21, 2017, 2:00 pm US/Central	No seminar -- Solar Eclipse
Aug. 28, 2017, 2:00 pm US/Central	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 »
Sept. 4, 2017, 2:00 pm US/Central	No seminar -- Labor Day
Sept. 11, 2017, 2:00 pm US/Central	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 »
Sept. 18, 2017, 2:00 pm US/Central	TBD	Marilena Loverde, Stony Brook
Sept. 25, 2017, 2:00 pm US/Central	TBD	Vadim Semenov, University of Chicago
Oct. 2, 2017, 2:00 pm US/Central	TBD	Phil Cowperthwaite, Harvard
Oct. 9, 2017, 2:00 pm US/Central	TBD	Scott Hertel, University of Massachusetts Amherst
Oct. 16, 2017, 2:00 pm US/Central	TBD	Nick Battaglia, Princeton
Oct. 23, 2017, 2:30 pm US/Central	TBD	TBD
Oct. 30, 2017, 2:00 pm US/Central	TBD	TBD
Nov. 6, 2017, 2:00 pm US/Central	TBD	Liang Dai, Princeton
Nov. 13, 2017, 2:00 pm US/Central	TBD	Peter Behroozi, University of Arizona
Nov. 20, 2017, 2:00 pm US/Central	TBD	Robert Lasenby, Perimeter
Nov. 27, 2017, 2:00 pm US/Central	TBD	TBD
Dec. 4, 2017, 2:00 pm US/Central	TBD	TBD
Dec. 11, 2017, 2:00 pm US/Central	TBD	Doug Finkbeiner, Harvard
Dec. 18, 2017, 2:00 pm US/Central	TBD	TBD