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The stellar dynamics of early-type galaxies (ETGs)
The stellar dynamics of early-type galaxies (ETGs)
Massive early-type galaxies (ETGs) are powerful tools for probing galaxy evolution, as they reside at the centers of massive dark matter halos. As some of the oldest and most evolved galaxies in the Universe, they hold a wealth of information about cosmic history. My research focuses on constructing stellar dynamical models of fast-rotating galaxies from the MASSIVE Survey, providing insights into their internal structures and evolutionary trajectories.
ETGs can be classified as either fast or slow rotators based on their rotational properties and ellipticity, each group exhibiting distinct kinematic and photometric characteristics. These distinctions have been thoroughly studied through large integral field unit (IFU) surveys. As galaxies evolve, their stellar kinematics carry the imprints of the physical processes they have undergone. By modeling their kinematics, we can uncover key details about their formation and evolutionary histories, which have been shown to differ between fast and slow rotators.
Figure adapted from Veale et al. 2018 illustrating the relationship between fast and slow rotators, characterized by their angular momentum and ellipticity. Fast rotators typically have a flatter, more elliptical shapes and significant rotational motion, whereas slow rotators tend to be rounder with less rotation.
Delgado Andrade et al. in Preparation
Delgado Andrade et al. in Preparation
For this work I am doing a dynamical analysis of 16 fast-rotating galaxies from the MASSIVE Survey using K-band WIRCam photometry from the Canada-France-Hawaii Telescope (CFHT) and spatially-resolved kinematic data from the Mitchell integral field spectrograph.g. Using Jeans Anisotropic Models (JAM), we model their stellar kinematics to measure their stellar dynamical K-band mass-to-light ratios, stellar and dark matter content, and orbital structure. Through this work we can the initial mass function (IMF), quantify the amount of dark matter within one effective radius, and explore radial variations in orbital anisotropy. Our findings reveal significant insights into the distribution of stars and dark matter, and highlight how the anisotropy and stellar dynamics differ across the sample.
To model the surface brightness distribution of each galaxy, we use a Multi-Gaussian Expansion (MGE), which fits the K-band photometry with a series of 2D Gaussian components. This MGE captures the light distribution across the inner and outer regions, providing a detailed representation of the galaxy's photometric structure. Above, we highlight four representative galaxies from our sample.
The super masssive black hole (SMBH) in NGC 2693
The super masssive black hole (SMBH) in NGC 2693
Massive ETGs are known host some some of the most massive super-massive black holes (SMBHs) in the Universe...
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