Events Archive

Gravity Initiative Lunch, Antonios Tsokaros | University of Illinois "Numerical methods in general relativity and the physics of compact objects"
Mon, Dec 9, 2019, 12:30 pm12:30 pm

Every astrophysically realistic simulation needs accurate initial data and in this talk I will present methods to obtain such solutions for a variety of problems. In particular I will focus on a new initial data formulation to solve the full set of Einstein equations for spacetimes that contain a black hole under general conditions. As an…

Gravity Group Lunch Seminar, Oliver Philcox | Princeton University "Detection and Removal of Dust Foregrounds in the B-mode CMB via Statistical Anisotropy"
Fri, Dec 6, 2019, 12:00 pm12:00 pm

Searches for inflationary gravitational wave signals in the CMB B-mode polarization are expected to reach unprecedented power over the next decade. A major difficulty in these ongoing searches is that Galactic foregrounds such as dust can easily mimic inflationary signals. Though typically foregrounds are separated from primordial signals using…

Gravity Group Lunch Seminar, Andrew Chael | PCTS "The black hole-jet connection in M87: linking simulations to VLBI images"
Fri, Nov 22, 2019, 12:00 pm12:00 pm

The Event Horizon Telescope (EHT) has produced the first image of the 1.3 mm-wavelength emission around the black hole "shadow" at the heart of M87. The hot plasma in the accretion flow around M87's central black hole illuminates the spacetime, and the flow's magnetic field extracts energy from the black hole to launch the famous relativistic…

Gravity Group Lunch Seminar, Corwin Shiu | Princeton "A design of a wideband 30/40 GHz diplexed camera suitable for BICEP Array"
Fri, Oct 25, 2019, 12:00 pm12:00 pm

Abstract: Accurate understanding of astrophysical foregrounds is crucial in recovering the underlying CMB signal. In this talk I will discuss the design and performance of a camera that will be powerful at characterizing synchrotron emissions. The camera is comprised of slotted bowtie antenna elements coherently summed in a…

Gravity Group Seminar | October 04, 2019
Fri, Oct 4, 2019, 12:00 pm12:00 pm
Gravity Group Seminar, Charles Romero | UPenn "High resolution SZ observations of galaxy clusters"
Tue, Jun 4, 2019, 2:00 pm2:00 pm

The Sunyaev-Zel'dovich (SZ) effect was first proposed in 1970, but it took until the 1990s before SZ observations became possible without enormous effort. However, the resolution of these observations were always above an arcminute, and thus SZ measurements were primarily sought for determining global properties of the…

Gravity Group Seminar, Simons Observatory | Instrument Overview
Fri, May 31, 2019, 12:00 pm12:00 pm

Details to come...

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Joint Thunch / Gravity Group Seminar, Kris Pardo | Princeton "Implications for the Stochastic Gravitational Wave Background from a Massive Quasar-binary"
Thu, Apr 25, 2019, 12:30 pm12:30 pm

Implications for the Stochastic Gravitational Wave Background from a Massive Quasar-binary The collective inspirals of very close-separation supermassive black holes (SMBHs) are expected to produce a stochastic gravitational wave background (GWB) at nHz frequencies, which is accessible to pulsar timing arrays. However, we have…

Gravity Group Lunch Seminar, Colin Hill | IAS/CCA "Extragalactic Foreground Biases in Primordial non-Gaussianity Measurements from the CMB"
Fri, Apr 19, 2019, 12:00 pm12:00 pm

Abstract: The cosmic microwave background (CMB) temperature bispectrum is currently the most precise tool for constraining non-Gaussianity (NG) in the primordial curvature perturbations.  The Planck temperature data tightly constrain the amplitude of local-type NG, as could be generated in (e.g.) multi-field inflation: f_NL^loc = 2.5 +/- 5.7. …

Gravity Group Lunch Seminar, Xue (Sherry) Song and Joseph van der List | Princeton
Fri, Mar 15, 2019, 12:00 pm12:00 pm

Xue (Sherry) Song and Joseph van der List will lead our first journal club discussion of the academic year. The focus will be on attempts to resolve the inconsistency between local and cosmological measurements of the Hubble constant (H_0): Joseph will discuss "Model…

Gravity Group Lunch Seminar, Max Abitbol | Oxford "Foregrounds of CMB B-modes and spectral distortions"
Fri, Mar 8, 2019, 12:00 pm12:00 pm

I will discuss topics related to foregrounds of two different CMB science cases. For the first part, I will introduce an expansion to foreground SED parameterizations in terms of moments of the parameter distributions. I will then discuss a power spectrum based foreground cleaning algorithm for the Simons Observatory B-mode analysis pipeline…

Gravity Group Lunch Seminar, Jo Dunkley | Princeton "Science forecasts for the Simons Observatory"
Fri, Mar 1, 2019, 12:00 pm12:00 pm

The Simons Observatory (SO) is a new CMB experiment being built in the Atacama Desert in Chile (with many contributions from Princeton) due to begin observations in the early 2020s. We will describe SO's science goals: to characterize the primordial perturbations and look for primordial gravitational waves, to measure the mass of neutrino…

Gravity Group Lunch Seminar, Steve Benton | Princeton "Spider, SuperBIT, Taurus, and Cosmology from the Stratosphere"
Fri, Feb 22, 2019, 12:00 pm12:00 pm

As cosmological measurements increase in precision, foregrounds are increasingly problematic. One foreground that's possible to reduce is Earth's atmosphere. I will talk about experiments that use stratospheric balloons to achieve higher sensitivity and lower systematic errors than are possible on the ground, and at much lower cost than in…

Gravity Group Lunch Seminar, Susan Clark | IAS "The magnetic interstellar medium and the polarized dust foreground"
Fri, Feb 15, 2019, 12:00 pm12:00 pm

The interstellar medium (ISM) is multi-phase, turbulent, and magnetic. This makes the ISM an ideal laboratory for studying the multi-scale physics of star formation and galactic evolution. This also makes the ISM a formidable foreground for cosmology experiments, such as the search for inflationary gravitational wave B-mode polarization in the…

Gravity Group Lunch Seminar, Jean-Loup Puget, IAS (Orsay) and ENS (Paris) "Planck 2018"
Fri, Feb 8, 2019, 12:00 pm12:00 pm

The Planck collaboration is in the process of delivering the "Planck results 2018" papers and data. The improvement of the map making will be described together with a new set of maps with some improvements for polarization at large scales. The consequences for the cosmological parameters are driven by a new determination of the reionization…