KICP Seminars & Colloquia, Fall 2017

Seminar schedule for Fall 2017
September 27, 2017
Wednesday colloquium
Grayson C Rich
Triangle Universities Nuclear Lab
First observation of coherent elastic neutrino-nucleus scattering   [Abstract | Video]
September 29, 2017
Friday noon seminar
Francois Lanusse
Carnegie Mellon University
Machine Learning and Signal Processing for Weak Lensing Science: from galaxy image simulations to 3D mass maps   [Abstract]
September 29, 2017
Open Group seminar
Teresita Suarez Nogue
University College London
Large-scale fluctuations in the cosmic ionising background   [Abstract]
October 3, 2017
Astronomy Tuesday Seminar
Alison Coil
University of California, San Diego
Unconscious Bias: How It Works and How to Counter It   [Abstract | PDF]
October 4, 2017
Astronomy Colloquium
Alison Coil
University of California, San Diego
AGN-driven outflows at z~2   [Abstract]
October 6, 2017
Friday noon seminar
Adam Solomon
University of Pennsylvania
Aspects of field theory with higher derivatives   [Abstract]
October 9, 2017
Open Group seminar
Bohua Li
University of Texas at Austin
Cosmology in a University with Bose-Einstein-Condensed Scalar Field Dark Matter   [Abstract]
October 11, 2017
Wednesday colloquium
Joe Silk
IAP/JHU
The Limits of Cosmology   [Abstract | Video]
October 13, 2017
Friday noon seminar
Marko Simonovic
Institute for Advanced Study
Efficient Evaluation of Cosmological Statistics Using FFTLog   [Abstract]
October 18, 2017
Astronomy Colloquium
Gregg Hallinan
Caltech
Imaging All the Sky All the Time in Search of Radio Exoplanets   [Abstract]
October 24, 2017
Astronomy Tuesday Seminar
Lena Murchikova
Caltech
The first detection of warm ionized disk around the Galactic Center Black Hole SgrA*   [Abstract]
October 25, 2017
Wednesday colloquium
Josh Frieman
The University of Chicago
Probing Cosmology with the Dark Energy Survey   [Abstract]
October 27, 2017
Friday noon seminar
Shunsaku Horiuchi
Virginia Tech
The status of sterile neutrino dark matter   [Abstract]
November 1, 2017
Astronomy Colloquium
Dan Hooper
University of Chicago
TBA
November 3, 2017
Friday noon seminar
Simone Ferraro
UC Berkeley
New information from the small scale CMB
November 7, 2017
Astronomy Tuesday Seminar
Adrian Hamers
IAS
TBA
November 14, 2017
Astronomy Tuesday Seminar
Sumit Sarbadhicary
UPitt
TBA
November 15, 2017
Astronomy Colloquium
Anatoly Spitkovsky
Princeton
TBA
November 28, 2017
Astronomy Tuesday Seminar
Yong Zheng
Columbia
The Cycle of Gaseous Baryons between the Disk and Halo   [Abstract]
November 29, 2017
Astronomy Colloquium
Bekki Dawson
Pennsylvania State University
TBA
 
WEDNESDAY COLLOQUIA

  • September 27, 2017 | 3:30 PM | ERC 161
    First observation of coherent elastic neutrino-nucleus scattering
    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.
  • October 11, 2017 | 3:30 PM | ERC 161
    The Limits of Cosmology
    Joe Silk, IAP/JHU

    Image courtesy: J. Lazio
    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.
  • October 25, 2017 | 3:30 PM | ERC 161
    Probing Cosmology with the Dark Energy Survey
    Josh Frieman, The University of Chicago
    Note: Reception in ERC 401 at 4:30 pm

    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.

 
FRIDAY NOON SEMINARS

  • September 29, 2017 | 12:00 PM | ERC 401
    Machine Learning and Signal Processing for Weak Lensing Science: from galaxy image simulations to 3D mass maps
    Francois Lanusse, Carnegie Mellon University

    The next generation of large-scale cosmological surveys, such as LSST, WFIRST and Euclid, aim at answering fundamental questions on the nature of dark energy and dark matter by measuring the weak lensing signal (gravitationally induced deformation of galaxy images) over large areas of the sky. In this talk, I will illustrate how the most recent advances in Machine Learning and Statistical Signal Processing open new perspectives for addressing some of the challenges faced by these new surveys as well as exploiting this wealth of data in new and exciting ways. In particular, I will focus on our work with Deep Generative Models in two different settings: simulating realistic galaxy images for shape measurement calibration purposes, and modeling the intrinsic alignment signal (the tendency of galaxies to align with the large scale structure) in hydrodynamical simulations, with the aim of producing realistic mock galaxy catalogs. Both of these applications aim to address some of the main systematics of future wide field lensing surveys. Finally, I will present an application of sparse signal processing which makes possible the reconstruction of high-resolution 3D weak lensing mass maps, with the ability to disentangle structures along the line of sight and resolve individual clusters.
  • October 6, 2017 | 12:00 PM | ERC 401
    Aspects of field theory with higher derivatives
    Adam Solomon, University of Pennsylvania

    I will discuss related aspects of field theories with higher-derivative Lagrangians but second-order equations of motion, with a focus on the Lovelock and Horndeski classes that have found use in modifications to general relativity. In the first half I will discuss how non-perturbative effects, like domain walls and quantum tunneling, are modified in the presence of these kinetic terms. In the second half I will investigate when restricting to such terms is and is not well-justified from an effective field theory perspective.
  • October 13, 2017 | 12:00 PM | ERC 401
    Efficient Evaluation of Cosmological Statistics Using FFTLog
    Marko Simonovic, Institute for Advanced Study

    The FFTLog algorithm can be seen as a way to decompose the linear power spectrum onto a basis of complex power-law functions. On the other hand, many important integrals in cosmology that involve power spectra have simple analytical solutions for a power-law universe. In this talk I will show how to combine these two ideas in practice. I will discuss applications to evaluation of the angular power spectrum and bispectrum of arbitrary observables, as well as evaluation of the loop integrals in cosmological perturbation theory of large-scale structure.
  • October 27, 2017 | 12:00 PM | ERC 401
    The status of sterile neutrino dark matter
    Shunsaku Horiuchi, Virginia Tech

    The sterile neutrino is a warm dark matter candidate with a host of observable signatures that have recently been sensitively tested. I will first review the sterile neutrino before introducing constraints arising from structure formation and high-energy astrophysics. These offer important complementarity in covering the sterile neutrino parameter space and I will highlight some of the recent rapid progress. I will also discuss ways forwards to test whether the 3.5 keV line detected in multiple dark matter concentrations may be arising from sterile neutrino dark matter.
  • November 3, 2017 | 12:00 PM | ERC 401
    New information from the small scale CMB
    Simone Ferraro, UC Berkeley

 
OPEN GROUP SEMINARS

  • September 29, 2017 | 4:00 PM | ERC 419
    Large-scale fluctuations in the cosmic ionising background
    Teresita Suarez Nogue, University College London

    Effects of non-uniform cosmic ionizing background from quasars on statistics of the Ly alpha forest.
  • October 9, 2017 | 10:30 AM | ERC 419
    Cosmology in a University with Bose-Einstein-Condensed Scalar Field Dark Matter
    Bohua Li, University of Texas at Austin

    We consider an alternative to WIMP cold dark matter (CDM), ultralight bosonic dark matter (m≥10^-22eV) described by a complex scalar field (SFDM) with global U(1) symmetry, for which the comoving particle number density is conserved after particle production during standard reheating. We allow for a repulsive self-interaction. In a ΛSFDM universe, SFDM starts relativistic, evolving from stiff (w=1) to radiation-like (w=1/3), before becoming nonrelativistic at late times (w=0). Thus, before the familiar radiation-dominated era, there is an earlier era of stiff-SFDM-domination, during which the expansion rate is higher than in ΛCDM. SFDM particle mass m and coupling strength λ, of a quartic self-interaction, are therefore constrained by cosmological observables, particularly N_eff and z_eq. Furthermore, since the stochastic gravitational-wave background (SGWB) from inflation is amplified during the stiff era, it can contribute a radiation-like component large enough to affect these observables by further boosting the expansion rate. Remarkably, this same amplification makes detection of the SGWB possible at high frequencies by current laser interferometer experiments, e.g., aLIGO/Virgo and LISA. For SFDM particle parameters that satisfy these cosmological constraints, the amplified SGWB is detectable by LIGO for a broad range of reheat temperatures T_reheat, for values of tensor-to-scalar ratio r currently allowed by CMB polarization measurements. The SGWB is maximally detectable if modes that reentered the horizon when reheating ended have frequencies today in the LIGO sensitive frequency band. Upper limits on the SGWB reported by aLIGO O1 are used to place a new kind of cosmological constraint on SFDM. A wider range of SFDM parameters and T_reheat should be accessible to aLIGO/Virgo O5. For r=0.01 and λ/(mc^2)^2=10^-18 eV^-1 cm^3, 3σ detection is predicted for 600≤T_reheat(GeV)≤10^7 by O5.

 
ASTRONOMY COLLOQUIA

  • October 4, 2017 | 3:30 PM | ERC 161
    AGN-driven outflows at z~2
    Alison Coil, University of California, San Diego

    AGN-driven outflows are assumed to be a key driver of galaxy evolution, determining the shape of the galaxy stellar mass function at high masses and regulating, perhaps even quenching, star formation as galaxies become quiescent. However, the details of how common this feedback is and how it impacts the host galaxy are generally unclear. I will present new results using Chandra data in the CANDELS and UltraVISTA surveys showing which galaxies host AGN of a given accretion rate and how this correlates with star formation in the host galaxy from z~0 to z~4. I will further present new results from the MOSDEF survey on AGN-driven outflows at z~2, discussing their incidence, kinematics, and physical extent. We find that fast, galaxy-wide AGN-driven outflows are common in typical star-forming galaxies at z~2 and that they likely help regulate star formation at the cosmic peak of galaxy growth.
  • October 18, 2017 | 3:30 PM | ERC 161
    Imaging All the Sky All the Time in Search of Radio Exoplanets
    Gregg Hallinan, Caltech

    All the magnetized planets in our solar system, including Earth, produce bright emission at low radio frequencies, predominantly originating in high magnetic latitudes and powered by auroral processes. It has long been speculated that similar radio emission may be detectable from exoplanets orbiting nearby stars, which would provide the first direct confirmation of the presence, strength and extent of exoplanetary magnetospheres, as well as informing on their role in shielding the atmospheres of potentially habitable exoplanets. Despite 4 decades of observations, no detection has been achieved. Surprisingly, however, brown dwarfs have been found to produce both radio and optical emissions that are strikingly similar to the auroral emissions from solar system planets, albeit 10,000 times more luminous, bolstering the continued search for similar emission from exoplanets. I will discuss the auroral radio emission from exoplanets and brown dwarfs and introduce a new radio telescope, consisting of 352 antennas spaced across 2.5 km, that images the entire viewable sky every ten seconds at low radio frequencies, thereby monitoring thousands of stellar systems simultaneously in the search for radio emission from exoplanets.
  • November 1, 2017 | 3:30 PM | ERC 161
    TBA
    Dan Hooper, University of Chicago
    Note: Refreshments served at 4:30 PM, Hubble Lounge
  • November 15, 2017 | 3:30 PM | ERC 161
    TBA
    Anatoly Spitkovsky, Princeton
    Note: Refreshments served at 4:30 PM, Hubble Lounge
  • November 29, 2017 | 3:30 PM | ERC 161
    TBA
    Bekki Dawson, Pennsylvania State University
    Note: Refreshments served at 4:30 PM, Hubble Lounge

 
ASTRONOMY TUESDAY SEMINARS

  • October 3, 2017 | 12:00 PM | ERC 576
    Unconscious Bias: How It Works and How to Counter It
    Alison Coil, University of California, San Diego

    PDF
    Unconscious or implicit bias is a preference for groups that operates outside of our awareness and is based on stereotypes or attitudes that we hold and have been taught. I will present results from a variety of studies that show how unconscious bias plays out, and how systemic it is, with a focus on academia. While I will mainly discuss faculty hiring, I will also touch on graduate admissions, review panels, recommendation letters, and interruptions during talks. I will discuss how the use of rubrics can help counter unconscious bias and other techniques to use when evaluating candidates.
  • October 24, 2017 | 12:00 PM | ERC 576
    The first detection of warm ionized disk around the Galactic Center Black Hole SgrA*
    Lena Murchikova, Caltech

    Image Credit Armitage and Christopher S. Reynolds, MNRAS, 341, 1041 (2003)
    The Milky Way's own supermassive black hole SgrA* is our best hope for studying black holes' immediate environments and their growth. There is a wide variety of accretion models, but the only thing we know with certainty is that the amount of the material around SgrA* is small and its accretion is very low. I report the first detection of the warm 10^4 K ionized disk within 0.015pc the black hole with recombination line of Hydrogen (n=31 -> 30 transition) with ALMA. I will discuss the disk dynamics, and describe our future observations making use of the close flyby of the S2 star by the galactic center in April 2018. We will be able to determine the presence of neutral hydrogen in the accretion zone and study the disk dynamics. Image Credit Armitage and Christopher S. Reynolds, MNRAS, 341, 1041 (2003)
  • November 7, 2017 | 12:00 PM | ERC 576
    TBA
    Adrian Hamers, IAS
  • November 14, 2017 | 12:00 PM | ERC 576
    TBA
    Sumit Sarbadhicary, UPitt
  • November 28, 2017 | 12:00 PM | ERC 576
    The Cycle of Gaseous Baryons between the Disk and Halo
    Yong Zheng, Columbia

    The disks of galaxies closely interact with their circumgalactic media (CGM) through the disk-halo interfaces. The disks grow by inflows from the CGM, while the CGM is enriched, stirred, and heated by outflows from the disks. Recent years have seen great breakthroughs in observations of the inflows/outflows at the disk-halo interfaces; however, inflow detections are still rare and the structure of the disk-halo interface is unclear. In my talk, I will first show HST/COS observations of ionized gas inflows at M33s disk-halo interface, which is among the first to unambiguously reveal the existence of disk-wide galactic inflows. Then I will present a 3D kinematic model of the disk-halo interface of the Milky Way (MW), which incorporates co-rotation, halo lagging, inflow, and turbulence broadening. I will show that the MW's low-velocity (|v|<100 km/s) ionized gas contents seen toward background quasars are not only from its interstellar medium and disk-halo interface; there is a significant fraction (~70%) of gas contributed by the MW's CGM moving at low velocities. Order-of-magnitude estimates on the mass of the low-velocity MW's CGM suggest that the MW's CGM may be as massive as those of L~L* star-forming galaxies at z~0.2.