We present new maps of the Galactic Center in total intensity and polarization made with the Atacama Cosmology Telescope (ACT). We combine dedicated, arcminute-resolution ACT observations over a 32 deg^2 field with Planck intensity and polarization data at similar frequencies to produce maps with fidelity on both small and large angular scales...

# Events Archive

## Gravity Group Seminar

### Gravity Group Lunch Seminar | Yilun Guan (Pittsburgh) & Brandon Hensley (Princeton) "The ACT View of the Galactic Center"

### Gravity Group Seminar | Zach Atkins, "Map-based Noise Simulations for ACT Data" Suren Gourapura, "r Error Budget for SPIDER's First Flight"

### Gravity Group Lunch Seminar | Sarah Marie Bruno, "The projected impact of commercial satellite constellations on ground-based astronomy" & Roman Kolevatov, "The DMRadio Experiment at Princeton"

Sarah Marie Bruno, Princeton University **"The projected impact of commercial satellite constellations on ground-based astronomy"**

### Gravity Group Seminar | Xue (Sherry) Song, Joseph van der List, and Corwin Shiu, PU "B-mode Constraint from SPIDER's First Flight"

SPIDER is a balloon-borne telescope designed to map the B-mode polarization of the cosmic microwave background (CMB) on degree angular scales. SPIDER’s 2015 flight mapped 4.8% of the sky at 95 and 150 GHz.

### Gravity Group Lunch Seminar | Oliver Philcox, PU "Have we exhausted the galaxy two-point function?"

Throughout the past three decades, the analysis of spectroscopic surveys has focussed around the two-point function of the galaxy overdensity field, masquerading either as the correlation function or the Fourier-space power spectrum. Today, theoretical interest has shifted towards other statistics, in particular the higher-point functions.

### Gravity Group Lunch Seminar, Saptarshi Chaudhuri | Princeton "Axions and DM Radio at Princeton"

I introduce DM Radio, a lumped-LC oscillator search for axion dark matter. I review the detection scheme and design, current experimental status, and future prospects, including the use of electromagnetic quantum metrology in previously-unexplored kHz and MHz frequency ranges.

### Gravity Group Lunch Seminar, Anne Gambrel | KICP, U. Chicago "The XFaster Power Spectrum and Likelihood Estimator and its Application to SPIDER"

Every analysis of cosmic microwave background observations faces the challenge of compressing large amounts of data into the comparatively tiny spaces of power spectra and cosmological parameters.

### Gravity Group Seminar | Speakers TBA "The Simons Observatory Instrument: Status of Ongoing Research at Princeton"

The Simons Observatory (SO) will be a cosmic microwave background (CMB) survey experiment with four small-aperture telescopes (SATs) and one large-aperture telescope, which will observe from the Atacama Desert in Chile.

### Gravity Group Seminar | Status of the Atacama Cosmology Telescope

Adri Duivenvoorden, Zack Li, Brandon Hensley, Jo Dunkley, and Lyman Page will update us on the status of the Atacama Cosmology Telescope (ACT).

### Gravity Group Lunch Seminar, Justin Ripley | DAMTP "Classical modifications to Einstein's General Relativity around black holes"

In this talk I will discuss recent work on the dynamics of black holes in Einstein dilaton Gauss-Bonnet (EDGB) gravity. This modified gravity theory can be motivated by effective field theory reasoning, and admits scalarized black hole solutions.

### Gravity Group Seminar | Meet the Gravity Group

We will kick off this season with a "Meet the Gravity Group" event. The format will be the same as last year's: all of us, be we juniors getting started on our Fall papers or emeritus, will get one slide and one minute to introduce ourselves to our new colleagues and share our spring / summer updates with the group.

### Gravity Group Lunch Seminar, Daniel Dutcher | U. Chicago “Measuring the Polarization of the CMB with SPT-3G”

Observations of the cosmic microwave background form the pillar of our current understanding of cosmology. Measurements of the temperature and polarization anisotropies of the CMB extending to small angular scales set tight constraints on cosmological parameters, probing both the standard LCDM model and the physics of inflation.

### Gravity Group Lunch Seminar, Justin Ripley & Joseph van der List | Princeton

**Justin Ripley, Princeton University** "Modeling the 'ringdown' of a Kerr black hole"

### Gravity Group Lunch Seminar, Zack Li & Rita Sonka | Princeton

**Zack Li, Princeton University**

"ABS, ACT, and Planck via the Simons Observatory Power Spectrum Pipeline"

### Gravity Group Lunch Seminar, Ivan Padilla | JHU "Cosmology Large Angular Scale Surveyor: Circular polarization at 40 GHz"

Large angular scale polarimetry of the CMB will provide powerful constraints on the cosmological parameters r, the tensor-to-scalar ratio, and tau, the optical depth to the epoch of reionization.

### Gravity Initiative Lunch, Antonios Tsokaros | University of Illinois "Numerical methods in general relativity and the physics of compact objects"

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.

### Gravity Group Lunch Seminar, Oliver Philcox | Princeton University "Detection and Removal of Dust Foregrounds in the B-mode CMB via Statistical Anisotropy"

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.

### Gravity Group Lunch Seminar, Andrew Chael | PCTS "The black hole-jet connection in M87: linking simulations to VLBI images"

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.

### Gravity Group Lunch Seminar, Corwin Shiu | Princeton "A design of a wideband 30/40 GHz diplexed camera suitable for BICEP Array"

**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...