Using angular momentum maps to detect kinematically distinct galactic components

Irodotou, Dimitrios; Thomas, P.

doi:10.1093/mnras/staa3804

Cited by 6 publications

(3 citation statements)

References 123 publications

(150 reference statements)

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“…In this manner, they are able also to defined a counter-rotating component. Through this kind of angular separation, Irodotou & Thomas (2021) distinguish rotation supported structures from dispersion supported ones, and find the properties of these components comparable to the ones obtained with more traditional decomposition methods, such as those considered by Thob et al.…”

Section: Previous Decompositions Of Eagle Galaxiessupporting

confidence: 52%

Milky Way-like galaxies: stellar population properties of dynamically defined disks, bulges and stellar halos

Sara¹,

Obreja²,

Domínguez-Tenreiro³

et al. 2022

Preprint

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The formation of galaxies can be understood in terms of the assembly patterns of each type of galactic component. To perform this kind of analysis, is necessary to define some criteria to separate those components. Decomposition methods based on dynamical properties are more physically motivated than photometry-based ones. We use the unsupervised Gaussian Mixture model of galactic structure finder to extract the components of a sub-sample of galaxies with Milky Way-like masses from the EAGLE simulations. A clustering in the space of first and second order dynamical moments of all identified substructures reveals five types of galaxy components: thin and thick disks, stellar halos, bulges and spheroids. We analyse the dynamical, morphological and stellar population properties of these five component types, exploring to what extent these properties correlate with each other, and how much they depend on the total galaxy stellar and dark matter halo masses. All galaxies contain a bulge, a stellar halo and a disk. 60% of objects host two disks (thin and thick), and 68% host also a spheroid. The dynamical diskto-total ratio does not depend on stellar mass, but the median rotational velocities of the two disks do. Thin disks are well separated in stellar ages, [Fe/H] and 𝛼-enhancement from the three dispersion-dominated components, while thick disks are in between. Except for thin disks, all components show correlations among their stellar population properties: older ages mean lower metallicities and larger 𝛼-enhancement. Finally, we quantify the weak dependence of stellar population properties on each component's dynamics.

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Section: Previous Decompositions Of Eagle Galaxiessupporting

confidence: 52%

Milky Way-like galaxies: stellar population properties of dynamically defined disks, bulges and stellar halos

Sara¹,

Obreja²,

Domínguez-Tenreiro³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Simulations that resolve galaxies self-consistently typically model mass elements either on a grid or as particles. Particle-based decomposition methods (e.g., Abadi et al 2003;Crain et al 2010;Thob et al 2019;Irodotou & Thomas 2021;Zana et al 2022) have been used extensively in order to split galaxies into different morphological classes and facilitate a comparison between observed and simulated galactic properties (Tissera et al 2012;Pillepich et al 2015;Irodotou et al 2019;Monachesi et al 2019;Trayford et al 2019;Rodriguez-Gomez et al 2022). However, the true morphology of a system may not always be accurately captured, as particle-based methods can be sensitive to small perturbations in the distribution of particles, which become progressively more significant at lower stellar masses as these galaxies are resolved with fewer particles.…”

Section: Predictions From Simulationsmentioning

confidence: 99%

“…particles with a mass of a few ×10 6 M e each). We use the method developed in Irodotou & Thomas (2021) to decompose galaxies by first creating a Mollweide projection of the angular momentum map of each galaxyʼs stellar particles. Then, stellar particles are assigned to a disk or spheroid component based on their angular separation from the densest grid cell.…”

Section: Predictions From Simulationsmentioning

confidence: 99%

The JWST Hubble Sequence: The Rest-frame Optical Evolution of Galaxy Structure at 1.5 < z < 6.5

Ferreira,

Conselice,

Sazonova

et al. 2023

ApJ

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We present results on the morphological and structural evolution of a total of 3956 galaxies observed with JWST at 1.5 < z < 6.5 in the JWST CEERS observations that overlap with the CANDELS EGS field. This is the biggest visually classified sample observed with JWST yet, ∼20 times larger than previous studies, and allows us to examine in detail how galaxy structure has changed over this critical epoch. All sources were classified by six individual classifiers using a simple classification scheme aimed at producing disk/spheroid/peculiar classifications, whereby we determine how the relative number of these morphologies has evolved since the Universe’s first billion years. Additionally, we explore structural and quantitative morphology measurements using Morfometryka, and show that galaxies with M * > 109 M ⊙ at z > 3 are not dominated by irregular and peculiar structures, either visually or quantitatively, as previously thought. We find a strong dominance of morphologically selected disk galaxies up to z = 6 in this mass range. We also find that the stellar mass and star formation rate densities are dominated by disk galaxies up to z ∼ 6, demonstrating that most stars in the Universe were likely formed in a disk galaxy. We compare our results to theory to show that the fraction of types we find is predicted by cosmological simulations, and that the Hubble Sequence was already in place as early as one billion years after the Big Bang. Additionally, we make our visual classifications public for the community.

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Probabilistic model for dynamic galaxy decomposition

Jagvaral

Campbell

Mandelbaum

et al. 2021

Monthly Notices of the Royal Astronomical Society

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In the era of precision cosmology and ever-improving cosmological simulations, a better understanding of different galaxy components such as bulges and discs will give us new insight into galactic formation and evolution. Based on the fact that the stellar populations of the constituent components of galaxies differ by their dynamical properties, we develop two simple models for galaxy decomposition using the TNG100 cosmological hydrodynamical simulation from the IllustrisTNG project. The first model uses a single dynamical parameter and can distinguish four components: thin disc, thick disc, counter-rotating disc, and bulge. The second model uses one more dynamical parameter, was defined in a probabilistic manner, and distinguishes two components: bulge and disc. We demonstrate the improved robustness of these models compared to a widely used method in literature involving cuts on the circularity parameter. The number fraction of disc-dominated galaxies at a given stellar mass obtained by our models agrees well with observations for masses exceeding log10(M*/M⊙) = 10. The galaxies classified as bulge-dominated by the second model are mostly red; however, the population classified as disc-dominated contains significant number of red galaxies alongside the blue population. The contributions of the different galaxy components to the total stellar mass budget exhibits similar trends with stellar mass compared to the observational data, although there is a quantitative disagreement at high and low masses. The Sérsic indices and half-mass radii for the bulge and disc components agree well with those of real galaxies.

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Using angular momentum maps to detect kinematically distinct galactic components

Cited by 6 publications

References 123 publications

Milky Way-like galaxies: stellar population properties of dynamically defined disks, bulges and stellar halos

Milky Way-like galaxies: stellar population properties of dynamically defined disks, bulges and stellar halos

The JWST Hubble Sequence: The Rest-frame Optical Evolution of Galaxy Structure at 1.5 < z < 6.5

Probabilistic model for dynamic galaxy decomposition

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