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Monday, November 04, 2024
4:00 PM - 5:00 PM
Cahill 370

Astronomy Tea Talk

The Prevalence of Distant Giant Companions to Inner Small Planets / Kinematic Lensing with the Roman Space Telescope and other experiments
Judah Van Zandt, Final-year Ph.D. student, Division of Astronomy & Astrophysics, University of California, Los Angeles,
Tim Eifler, Associate Professor of Physics and Astronomy, Department of Physics, The University of Arizona,

Speaker 1: Judah Van Zandt

Title: The Prevalence of Distant Giant Companions to Inner Small Planets

Abstract:

I present a measurement of the conditional occurrence of distant giant planets in the presence of close-in small planets, demonstrating that such giants are slightly enhanced over the field rate when they have a small inner neighbor. In January of 2024 I completed the Distant Giants Survey, a 3-year radial velocity (RV) survey to estimate the conditional occurrence of long-period Jupiter analogs in systems hosting small transiting planets. Kepler taught us that small close-in planets occur at a rate of ~1 per Sun-like star. Meanwhile, ground-based RV surveys have shown that long-period gas giants are rarer, with an occurrence rate of ~0.15 per Sun-like star. By searching for giant planets in systems with known close-in small planets, I found that giant planets are more common (~0.3 per star) when a close-in small planet is present. This finding will help to refine exoplanet formation models and determine whether the solar system's architecture is a common outcome of exosystem evolution.

Speaker 2: Dr. Tim Eifler

Title: Kinematic Lensing with the Roman Space Telescope and other experiments

Abstract:

The Nancy Grace Roman Space will address science cases ranging from exoplanets to galaxy evolution to fundamental physics. The High Latitude Survey (HLS) component is designed to constrain dark energy evolution and deviations from General Relativity with excellent control of systematics via space-quality imaging, photometry across 4 near-infrared (NIR) bands, and 400-800 resolution grism spectroscopy. 

In this talk I will discuss a novel cosmological probe, so-called Kinematic Lensing (KL), that can be extracted from the joint imaging and spectroscopic dataset of Roman. A Roman-KL survey has the potential to reduce the largest noise contribution in traditional Weak Lensing (WL) by more than an order of magnitude. Further, it is immune to the most worrisome systematics that haunt WL, most prominently shear calibration and photo-z uncertainties and galaxy intrinsic alignment. I will detail the basics of the KL method and corresponding cosmological forecasts, and discuss remaining obstacles and next steps in the KL endeavor with Roman and other experiments (e.g. DESI, JWST)

For more information, please contact Raphael Skalidis or Steven A. Giacalone by email at [email protected], [email protected].