KICP Colloquia: 2017
DateTalk TitleSpeaker
January 18, 2017The Milky Way's Dark CompanionsAlex Drlica-Wagner, Fermilab
February 8, 2017 cancelledDigging into the Large Scale Structure of the UniverseShirley Ho, Berkeley Lab/ BCCP / Carnegie Mellon
March 1, 2017 cancelledDigging into the Large Scale Structure of the UniverseShirley Ho, Berkeley Lab/ BCCP / Carnegie Mellon
April 5, 2017News from PICO and COHERENTJuan I. Collar, University of Chicago
April 19, 2017Observing, Mapping and Mocking our Cosmic BeginningsJ. Richard Bond, Canadian Institute for Theoretical Astrophysics, University of Toronto
May 17, 2017Fast Radio Bursts!Albert Stebbins, Fermilab
May 24, 2017Automated Object Classification for Large Scale Future Surveys: A Strong Lensing Example with Machine LearningCamille Avestruz, University of Chicago
May 31, 2017Mapping the Cosmos with the Dark Energy Survey - sneak peek of the first year weak lensing resultsChihway Chang, University of Chicago
September 27, 2017First observation of coherent elastic neutrino-nucleus scatteringGrayson C Rich, Triangle Universities Nuclear Lab
October 11, 2017The Limits of CosmologyJoe Silk, IAP/JHU
October 25, 2017Probing Cosmology with the Dark Energy SurveyJosh Frieman, The University of Chicago
November 8, 2017Journey to the Beginning of Time: Turning Metaphysics into PhysicsLawrence M Krauss, Arizona State University
December 6, 2017The not so boring ultra-high energy cosmic ray skyEdivaldo Moura Santos, University of San Paolo

The Milky Way's Dark Companions
January 18, 2017 | ERC 161 | 3:30 PM
Click on the image to enlarge
Alex Drlica-Wagner, Fermilab

PDF | Video
Our Milky Way galaxy is surrounded by a host of small, dark-matter-dominated satellite galaxies. Over the past two years, the Dark Energy Camera (DECam) has nearly doubled the number of known Milky Way satellite galaxies compared to the previous 80 years combined. While these discoveries continue to help resolve the "missing satellites problem", they have also raised new questions about the influence of the Magellanic Clouds on the Milky Way's satellite population. In the near future, the rapidly growing population of dwarf galaxies will be sensitive to deviations from ΛCDM at small scales, while definitively testing whether the annihilation of dark matter particles could be responsible for excess gamma-ray emission from the Galactic center. I will summarize recent results, outstanding questions, and upcoming advancements in the study of the Milky Way's dark companions.

Digging into the Large Scale Structure of the Universe
February 8, 2017 cancelled | ERC 161 | 3:00 PM
Shirley Ho, Berkeley Lab/ BCCP / Carnegie Mellon

CANCELLED

Galaxy spectroscopic surveys provide the means to map out this cosmic large-scale structure in three dimensions, furnishing a cornerstone of observational cosmology. The information is given in the form of galaxy locations, and is typically condensed into a single function of scale, such as the galaxy correlation function or power-spectrum. However, galaxy correlation functions are not the only information those surveys provide. One of the most striking features of N-body simulations is the network of filaments into which dark matter particles arrange themselves. We however traditionally only use the information contained in the positions of the galaxies, and in some occasions, we look at other cosmic structures of the Universe such as voids.
In this colloquium, I explore the information beyond the galaxy positions in large sky surveys combining novel ideas with recent techniques in statistical methods and machine learning algorithms. In particular, we will investigate the following two topics: the ''cosmic web'' that are mostly ignored in any large scale structure analyses in the Universe and how it affects the surrounding galaxies; and explores the additional information beyond the typical 2 point statistics by using novel statistical and machine learning techniques.

Digging into the Large Scale Structure of the Universe
March 1, 2017 cancelled | ERC 161 | 3:00 PM
Shirley Ho, Berkeley Lab/ BCCP / Carnegie Mellon

CANCELLED

Galaxy spectroscopic surveys provide the means to map out this cosmic large-scale structure in three dimensions, furnishing a cornerstone of observational cosmology. The information is given in the form of galaxy locations, and is typically condensed into a single function of scale, such as the galaxy correlation function or power-spectrum. However, galaxy correlation functions are not the only information those surveys provide. One of the most striking features of N-body simulations is the network of filaments into which dark matter particles arrange themselves. We however traditionally only use the information contained in the positions of the galaxies, and in some occasions, we look at other cosmic structures of the Universe such as voids.
In this colloquium, I explore the information beyond the galaxy positions in large sky surveys combining novel ideas with recent techniques in statistical methods and machine learning algorithms. In particular, we will investigate the following two topics: the ''cosmic web'' that are mostly ignored in any large scale structure analyses in the Universe and how it affects the surrounding galaxies; and explores the additional information beyond the typical 2 point statistics by using novel statistical and machine learning techniques.

News from PICO and COHERENT
April 5, 2017 | ERC 401 | 3:30 PM
Click on the image to enlarge
Juan I. Collar, University of Chicago

Video
I will discuss the most recent results from PICO, a search for WIMP dark matter using bubble chambers, as well as future plans and some exciting lines of related research. I will then move on to cover COHERENT, an ongoing effort at ORNL's Spallation Neutron Source to detect and exploit coherent neutrino-nucleus scattering, soon to produce first results. The "glue" between these two subjects will be an elaboration on the overlap in techniques and methods used in modern neutrino and astroparticle physics. Abundant examples of this cross-talk will be provided.

Observing, Mapping and Mocking our Cosmic Beginnings
April 19, 2017 | ERC 161 | 3:30 PM
Click on the image to enlarge
J. Richard Bond, Canadian Institute for Theoretical Astrophysics, University of Toronto

Video
I will give my take on the phenomenology (and yes theory) of inflation as revealed in Planck and other CMB) and LSS experiments, but with an eye to the glorious CMB future of AdvACT, CCAT-p, Simons Observatory, Stage 4, and the LSS of Euclid, Chime, and much more besides that we mock. Apart from displaying linear and quadratic maps of the primordial universe, a compression of what we now know, i will chat about CMB/LSS anomalies, in practice and in theory, pointing to post-inflation chaotic dynamical systems that can lead to subdominant non-Gaussian signals unlike the ones we have put such stringent constraints on with Planck 2015; and relate everything to non-equilibrium entropies, including the formation of all cosmic structure.

Fast Radio Bursts!
May 17, 2017 | ERC 161 | 3:30 PM
Click on the image to enlarge
Albert Stebbins, Fermilab

Video
On a human scale most astronomical sources are large and vary slowly. They must be large enough to produce enough light be to seen at astronomical distances and the light travel time across a large source limits the timescale for observable variations. Nevertheless in recent years extremely rapidly varying radio emission has been detected and found to be a common phenomena. The most extreme case has timescales as small as one nanosecond, inferred size smaller than one meter, peak luminosity exceeding that of the Sun, and is observed at a distance of 2kpc. More numerous and further away are Fast Radio Bursts (FRBs), originating at cosmological distances, lasting a millisecond and arriving at Earth a few times a minute. These events are the brightest sources known in terms of an off-scale brightness temperature, yet the emission mechanism is undetermined. I will discuss some ideas for the origin of this emission and how these bright bursts could be used to augment gravitational wave and neutrino astronomy as well as the study of cosmological parameters and the intergalactic medium.

Automated Object Classification for Large Scale Future Surveys: A Strong Lensing Example with Machine Learning
May 24, 2017 | ERC 161 | 3:30 PM
Camille Avestruz, University of Chicago

Video
Gravitational lensing offers a direct probe of the underlying mass distribution of lensing systems, a window to the high redshift universe, and a geometric probe of cosmological models. The advent of large scale surveys such as the Large Synoptic Sky Telescope and Euclid has prompted a need for automatic and efficient identification of strong lensing systems. We present (1) (ALL) Automated Lensing Learner, a strong lensing identification pipeline that will be publicly released as open source software, and (2) a publicly available mock LSST dataset with strong galaxy-galaxy lenses. In this first application of the pipeline, we employ a fast feature extraction method, Histogram of Oriented Gradients (HOG), to capture edge patterns that are characteristic of strong gravitational arcs in galaxy-galaxy lensing. We use logistic regression to train a supervised classifier model on the HOG of HST- and LSST-like images. Our tests demonstrate an efficient and effective method for automatically identifying strong lenses that captures much of the complexity of the arc finding problem. The linear classifier both runs on a personal laptop and can easily scale to large data sets on a computing cluster, all while using existing open source tools.

Mapping the Cosmos with the Dark Energy Survey - sneak peek of the first year weak lensing results
May 31, 2017 | ERC Auditorium 161 | 3:30 PM
Image credit: Andreas Papadopoulos
Click on the image to enlarge
Chihway Chang, University of Chicago

Video
Weak gravitational lensing, or weak lensing, is one of the most powerful tools in cosmology. The technique relies on measuring accurately the shape of a large number of galaxies, and statistically translating the shape measurements into (dark matter) mass distributions. The first year data from the Dark Energy Survey (DES Y1) provides the most powerful weak lensing dataset to date. In this talk I will first give an update on the status of the cosmology analysis from DES Y1 data and present some preliminary results. Next, I will describe our work in generating and testing the wide-field weak lensing mass maps from the galaxy shape measurements and some exciting applications for the maps. I will end with thoughts on how weak lensing could also inform us on various topics of galaxy formation, which is essential for completing the story behind the Universe we see today.

First observation of coherent elastic neutrino-nucleus scattering
September 27, 2017 | ERC 161 | 3:30 PM
Click on the image to enlarge
Grayson C Rich, Triangle Universities Nuclear Lab

Video
The process of coherent elastic neutrino-nucleus scattering (CEvNS) was predicted in 1974 by D.Z. Freedman, who suggested that attempts to detect CEvNS “may be an act of hubris” due to several profound experimental challenges. More than 40 years after its initial description, the world’s smallest functional neutrino detector has been used by the COHERENT Collaboration to produce the first observation of the process: a 14.6-kg CsI[Na] scintillator was deployed to the Spallation Neutron Source of Oak Ridge National Lab and observed, with high significance, evidence for a CEvNS process in agreement with the prediction of the Standard Model. I will discuss CEvNS and its connection to a range of exciting physics, including: its potential role in supernova dynamics; the possibility to use neutrinos as a tool for studying nuclear structure and neutron stars; its relationship to upcoming direct searches for WIMP dark matter; and the ways in which CEvNS could offer insight into physics beyond the Standard Model. The experimental program and the recent result from the COHERENT Collaboration will be presented along with ongoing efforts within the collaboration and future plans.

The Limits of Cosmology
October 11, 2017 | ERC 161 | 3:30 PM
Image courtesy: J. Lazio
Click on the image to enlarge
Joe Silk, IAP/JHU

Video
One of our greatest challenges in cosmology is understanding the origin of the structure of the universe, and in particular the formation of the galaxies. I will describe how the fossil radiation from the beginning of the universe, the cosmic microwave background, has provided a window for probing the initial conditions from which structure evolved and seeded the formation of the galaxies, and the outstanding issues that remain to be resolved. I will address our optimal choice of future strategy in order to make further progress on understanding our cosmic origins.

Probing Cosmology with the Dark Energy Survey
October 25, 2017 | ERC 161 | 3:30 PM
Josh Frieman, The University of Chicago

Video
I will overview the Dark Energy Survey (DES) project and highlight its early science results, focusing on the recently released cosmology results from the first year of the survey. The DES collaboration built the 570-megapixel Dark Energy Camera for the Blanco 4-meter telescope at NOAO's Cerro Tololo Inter-American Observatory in Chile to carry out a deep, wide-area, multi-band optical survey of several hundred million galaxies and a time-domain survey to discover several thousand supernovae. The survey started in Aug. 2013 and is now in its fifth observing season. DES was designed to address the questions: why is the expansion of the Universe speeding up? Is cosmic acceleration due to dark energy or does it require a modification of General Relativity? DES is addressing these questions by measuring the history of cosmic expansion and the growth of structure through multiple complementary techniques: galaxy clusters, the large-scale galaxy distribution, gravitational lensing, and supernovae, as well as through cross-correlation with other data sets. I will also discuss how the DES data are being used to make a variety of other astronomical discoveries, from the outer Solar System to ultra-faint dwarf galaxies to the kilonova counterpart of a binary neutron star gravitational-wave source.

Journey to the Beginning of Time: Turning Metaphysics into Physics
November 8, 2017 | ERC 161 | 3:30 PM
Click on the image to enlarge
Lawrence M Krauss, Arizona State University

Video
Even a generation ago, fundamental existential questions such as, "How did the Universe Begin?, How will it End?, Are we Alone, and, Are there OTHER Universes?," and other less grand but no less interesting questions such as "Do Black Holes Exist?" may have appeared as forever inaccessible metaphysical questions. Gravitational waves have now been discovered by LIGO, opening up a vast new window on the Universe. I will explain how we might eventually unambiguously detect a gravitational signal from moments after the Big Bang, pushing our direct empirical handle on the Universe back in time by 49 orders of magnitude, and revealing what we might learn about own origins, the nature of gravity, grand unification, and even the possible existence of other universes.

The not so boring ultra-high energy cosmic ray sky
December 6, 2017 | ERC 161 | 3:30 PM
Click on the image to enlarge
Edivaldo Moura Santos, University of San Paolo

Video
After more than 12 years of continuous data taking, the Pierre Auger Observatory has collected the largest dataset of ultra-high energy cosmic rays (UHECR) to date. It combines a set of fluorescence telescopes to measure the tiny emission of light from air molecules excited by the passage of air showers and an array of ground based water Cherenkov tanks to sample the shower particles at the ground level, Such a hybrid detection system has allowed a redundancy in reconstruction variables as well as the elimination of large systematic uncertainties associated to the absolute energy scale of atmospheric cascades through a data-driven cross-calibration procedure between the two detectors. The results obtained in the last years include, for example, precise and accurate measurements of the UHECR flux across a few decades in energy, revealing distinctive spectral features that can bring valuable information on different astrophysical processes like: the transition from galactic to extragalactic fluxes; the different energy loss processes to which ultra-relativistic charged particles are subject during their propagation; the energetics of the production and acceleration of particles at the candidate sources. In this colloquium I should however focus on a particular observational probe, that is, the small levels of anisotropy in the flux of UHECR at different angular scales: from the small and intermediate ones, important for the identification of possible point sources, to the large angular scales, usually used to search for signs of the galactic to extragalactic transition. In particular, special attention will be devoted to the first observation of a large scale anisotropy signal at the highest energies recently reported by the collaboration.