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Astronomy Tea Talk

Monday, October 17, 2022
4:00pm to 5:00pm
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Online and In-Person Event
The evolution of color gradients within galaxies and its effect on galaxy morphology
Tim Miller, Yale University,

Galaxy morphology provides a crucial constraint on their formation process however most studies focus on the half-light radii at optical wavelengths. Optical light can be biased away from the underlying stellar mass distribution of galaxies by color gradients, which trace variation in the mass-to-light ratio (M/L). In this talk, I will present results measuring color gradients and half-mass radii for roughly 3000 galaxies between 1 < z < 2 using HST data from the CANDELS survey. We use a new method, imcascade which flexibly represents galaxy profiles using a series of Gaussians to accurately measure the profiles of galaxies. I will discuss the evolution of color gradients with redshift and how they affect the ratio between half-mass and half-light radii. I will highlight that most of the evolution of the half-light radii of galaxies between redshifts one and two is due to changing color gradients rather than changes to the intrinsic stellar mass distribution of galaxies. Finally I will discuss some very exciting results using early JWST data that measure rest frame NIR sizes of galaxies and understanding variations in stellar populations using NIR color gradients.

For more information, please contact Liam Connor by email at [email protected] or visit