KICP Friday Noon Seminars
KICP Seminars - Usually Fridays, 12 PM, LASR conference room, unless otherwise specified.

Current & Future KICP Seminars
DateTalk TitleSpeaker
January 30, 2015Decisively Testing Sub-GeV Dark Matter Through the Vector PortalGordan Krnjaic, Perimeter Institute for Theoretical Physics
February 6, 2015Double Feature: ''SZ in AGN'' and ''The Cosmology Large Angular Scale Surveyor''Tobias Marriage, Johns Hopkins University
February 20, 2015Consistency Relations for Large Scale StructureMarko Simonovic, IAS, Princeton
April 17, 2015TBAAlyson Brooks, Rutgers University
April 24, 2015Gamma-rays from type Ia supernova SN2014JEugene Churazov, Max Planck Institute for Astrophysics
May 8, 2015TBACora Dvorkin, Harvard University

Past KICP Seminars
DateTalk TitleSpeaker
January 23, 2015Observing the Assembly of Dark Matter and Baryons in Massive GalaxiesAndrew B Newman, Carnegie Observatories
January 16, 2015Dark matter halos as particle collidersSean Tulin, York University
January 9, 2015First results from the High Altitude Water Cherenkov ObservatoryMiguel A. Mostafa, Penn State University

First results from the High Altitude Water Cherenkov Observatory
January 9, 2015 | LASR conference room | 12:00 PM
Miguel A. Mostafa, Penn State University

Dark matter halos as particle colliders
January 16, 2015 | LASR Conference Room | 12:00 PM
Sean Tulin, York University

Astrophysical observations of structure can be used to study the non-gravitational particle interactions of dark matter. I discuss small scale structure anomalies for cold dark matter and their possible implications for dark matter physics. New results on cluster scales provide a new important handle for constraining dark matter's particle interactions.

Observing the Assembly of Dark Matter and Baryons in Massive Galaxies
January 23, 2015 | LASR Conference Room | 12:00 PM
Andrew B Newman, Carnegie Observatories

Massive galaxies are central to many pressing questions in galaxy formation and cosmology. Observations of the evolving distributions of baryons and dark matter within massive galaxies can constrain the astrophysical processes that drive their formation and growth. In the first part of the talk, I will present results from a program aimed at understanding the assembly of the stellar halos of massive galaxies over the last 10 Gyr. Beginning as compact "nuggets" at z~2, these galaxies undergo a remarkably rapid period of growth. By combining HST imaging with unique spectroscopic surveys conducted on large telescopes, I will show how measurements of the sizes, stellar populations, internal dynamics, and satellite systems of z>1 massive galaxies have provided new insights into their remarkable growth. In the second part, I will turn to the dark matter distribution at the centers of massive galaxies and clusters. Through a synthesis of multiple observational probes, including strong lensing, weak lensing, and stellar dynamics, I have constrained the slope of the inner dark matter density profile. Surprisingly, this analysis implies a slope that is shallower than the universal CDM profile in the central ~30 kpc of massive clusters. I will review attempts to explain this finding in recent numerical simulations as a consequence of the "back-reaction" of baryons on their host halos, or alternatively as a possible probe of dark matter microphysics.

Decisively Testing Sub-GeV Dark Matter Through the Vector Portal
January 30, 2015 | LASR Conference Room | 12:00 PM
Gordan Krnjaic, Perimeter Institute for Theoretical Physics

In a broad class of consistent models, MeV to few-GeV dark matter (DM) interacts with ordinary matter through kinetically-mixed vector mediators ("dark photons"). We outline a two-pronged experimental program to decisively test nearly all such scenarios. The first prong involves placing a suitable meter-scale detector downstream of an existing electron beam-dump to directly observe DM produced in electron-nucleus collisions. Once produced, the DM scatters in the detector and induces highly-energetic electron or nuclear recoils. This approach can explore a well-motivated and otherwise inaccessible region of DM parameter space with sensitivity several orders of magnitude beyond existing direct detection and LHC constraints. This approach would also probe invisibly decaying dark-photons down to kinetic mixing of epsilon ~ 10^{-4}, including the range of parameters relevant for explaining the (g-2)_{mu} discrepancy. The second, more powerful prong of this discovery program relies entirely on the distinctive kinematics of the DM production in electron-nucleus interactions. In this setup, individual electrons are fired through a thin target adjacent to a tracker and calorimeter. If DM particles are produced as the electron passes through the target, they carry away a large fraction of the incident electron's electron energy. Surprisingly, with suitable trigger and kinematic requirements, such events serve as powerful probes of DM-electron interactions and can explore kinetic mixing parameters down to epsilon ~ 10^{-7}, which covers nearly all the parameter space consistent with a thermal relic abundance, thereby testing all vector-portal models that have ever achieved thermal equilibrium with the Standard Model.

Double Feature: ''SZ in AGN'' and ''The Cosmology Large Angular Scale Surveyor''
February 6, 2015 | LASR Conference Room | 12:00 PM
Tobias Marriage, Johns Hopkins University

Part 1: Evidence is mounting that Active Galactic Nuclei (AGN) are responsible for the lack of star-formation in the most massive galaxies. Attention has been drawn to the role of energetic radio-mode feedback from AGN in heating the gas around massive halos and preventing star-formation. I will present the first measurement using the Sunyaev-Zel'dovich (SZ) effect of the pressure of the gas around radio-loud AGN.

Part 2: The Cosmology Large Angular Scale Surveyor (CLASS) is a project to measure the imprint of gravitational waves from inflation in the polarization of the cosmic microwave background. I will present an overview of the CLASS strategy for measuring the E-modes and B-modes from both recombination and reionization and give an update on the project status.

Consistency Relations for Large Scale Structure
February 20, 2015 | LASR Conference Room | 12:00 PM
Marko Simonovic, IAS, Princeton

Consistency relations for LSS are general, non-perturbative statements about correlation functions of density perturbations. They relate the squeezed limit of an (n+1)-point function with the corresponding n-point function. I this talk I will review the derivation of the consistency relations in the non-relativistic limit and full GR, and show how these results can be applied in constraining the Equivalence Principle on cosmological scales and the BAO reconstruction.

April 17, 2015 | LASR Conference Room | 12:00 PM
Alyson Brooks, Rutgers University

Gamma-rays from type Ia supernova SN2014J
April 24, 2015 | LASR Conference Room | 12:00 PM
Eugene Churazov, Max Planck Institute for Astrophysics

May 8, 2015 | LASR Conference Room | 12:00 PM
Cora Dvorkin, Harvard University