"Indirect detection of axion dark matter with neutron stars" I will argue that axion dark matter may be detectable through narrow radio lines emitted from neutron stars. Neutron star magnetospheres host both a strong magnetic field and a plasma frequency that increases towards the neutron star surface. As the axions pass through the magnetosphere, they can resonantly convert into radio photons when the plasma frequency matches the axion mass, making the radio photon signal an analogue of indirect detection for axions. I will show sensitivity projection from a proposal recently submitted to the Green Bank radio telescope, which shows that a few hours of observation may provide sensitivity competitive with future ADMX runs in the mass range near 4 x 10-6 eV.
2:00 - 2:30 Dan Baxter
"Achieving Ultra-Low Background Detectors to Search for Dark Matter" The quest to directly detect dark matter interactions has ushered in the era of ultra-low background experiments, able to search for unprecedentedly low event rates. This rapid advance in sensitive detector technologies must be matched by comparable advances in background controls and modeling. I will talk about some of the background controls being implemented today by various collaborations and show some clever new calibration techniques being used to better characterize detector performance.
2:30 - 3:00 David Martin
"The BEBOP radial velocity survey for circumbinary planets" Planets orbiting two stars - circumbinary planets - are astrophysical gems. These triple systems expand our knowledge of both planet and binary formation, exhibit rapid, observable orbital dynamics and provide a unique observational probe of the habitable zone. However, our present knowledge is largely limited to a biased sample of a dozen transiting planets. I will demonstrate efforts to expand this field using radial velocities, by presenting the BEBOP survey. With over 7 years of HARPS and CORALIE data, we can reach a precision of a couple of metres per second. Using this, I will show work to answer fundamental questions about the circumbinary abundance, multiplicity and inclination distribution, with the latter being a key probe of various three-body dynamical processes. Applications will also be made to radial velocity reconnaissance of the future TESS and PLATO missions.
3:00 - 3:30 Coffee break
3:30 - 4:00 Colby Haggerty
"Relativistic Hybrid Simulations of Cosmic Ray Generation and Transport " The generation and transport of Cosmic Rays (CR) is an inherently multiscale phenomenon. Linking the dynamics of a cold thermal background plasma with low density, relativistic CRs through the shared magnetic field requires modeling the physics of both populations. To better study these problems, we have developed a kinetic ion, fluid electron hybrid code to include relativistic ion dynamics (dHybridR). With dHybridR, we perform the first simulations of non relativistic collisionless shock, self-consistently accelerating relativistic ions. We document the effects of the transition of accelerated particles to relativistic velocities and we show that the shock develops a CR induced precursor which modifies the macroscopic shock quantities (i.e. compression ratio and shock speed). In addition to CR generation, we present simulations of CR transport and the associated streaming instabilities. We show that for weak CR currents, simulations initially agree with linear theory and that the thermal population is indirectly heated through landau damping.
4:00 - 4:30 Noah Kurinsky
"Challenges for Direct Detection of Electron-Recoiling Dark Matter" I will give a brief overview of the measurement techniques and background challenges associated with the latest light dark matter experiments with a focus on the work being done in the Chicago area with DAMIC, SENSEI, and SuperCDMS, and discuss the path towards detecting fermionic dark matter down to the substructure limit (~4 keV). I will focus on the current limits set by semiconductor technologies, and then discuss how we improve the sensitivity of semiconductors and move below the eV-scale bandgaps. This talk will be part overview, part advertisement, and part crazy ideas.
4:30 - 5:00 Kimmy Wu
5:00 - 5:30 Christine Simpson
"Big challenges from little galaxies?" I will give a brief overview of the challenges that dwarf and satellite galaxies present to LCDM and/or galaxy formation. I'll discuss the role simulations play in this area and what problems have been solved (some have!) and what issues remain. If there is any time left, I will discuss a few avenues forward for resolving these issues with numerical simulations and observations.
5:30 - 6:30 Wine & Cheese Reception
Spring 2018 Postdocs Symposium
May 11, 2018 | 12:30 PM | ERC 401
13:00 Start of talks (5 x 10+5 min)
13:00 - 13:15 Eric Oberla: Radio Arrays for Ultra High Neutrino Detection at the South Pole
13:15 - 13:30 Rito Thakur: Playing with Sub-mm Photons
13:30 - 13:45 Dan Scolnic: Host Galaxy Issues for Type Ia Supernova Cosmology
13:45 - 14:00 Faustin Carter: Wirebonds? Really? For Ten Minutes?