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http://hdl.handle.net/20.500.12386/27952
Title: | The stellar orbit distribution in present-day galaxies inferred from the CALIFA survey | Authors: | Zhu, Ling van de Ven, Glenn van den Bosch, Remco Rix, Hans-Walter Lyubenova, Mariya Falcón-Barroso, Jesús Martig, Marie Mao, Shude Xu, Dandan Jin, Yunpeng Obreja, Aura Grand, Robert J. J. Dutton, Aaron A. Macciò, Andrea V. Gómez, Facundo A. Walcher, Jakob C. García-Benito, Rubén ZIBETTI, Stefano Sánchez, Sebastian F. |
Issue Date: | 2018 | Journal: | NATURE ASTRONOMY | Number: | 2 | First Page: | 233 | Abstract: | Galaxy formation entails the hierarchical assembly of mass, along with the condensation of baryons and the ensuing, self-regulating star formation<SUP>1,2</SUP>. The stars form a collisionless system whose orbit distribution retains dynamical memory that can constrain a galaxy's formation history<SUP>3</SUP>. The orbits dominated by ordered rotation, with near-maximum circularity λ<SUB>z</SUB> ≈ 1, are called kinematically cold, and the orbits dominated by random motion, with low circularity λ<SUB>z</SUB> ≈ 0, are kinematically hot. The fraction of stars on `cold' orbits, compared with the fraction on `hot' orbits, speaks directly to the quiescence or violence of the galaxies' formation histories<SUP>4,5</SUP>. Here we present such orbit distributions, derived from stellar kinematic maps through orbit-based modelling for a well-defined, large sample of 300 nearby galaxies. The sample, drawn from the CALIFA survey<SUP>6</SUP>, includes the main morphological galaxy types and spans a total stellar mass range from 10<SUP>8.7</SUP> to 10<SUP>11.9</SUP> solar masses. Our analysis derives the orbit-circularity distribution as a function of galaxy mass and its volume-averaged total distribution. We find that across most of the considered mass range and across morphological types, there are more stars on `warm' orbits defined as 0.25 ≤ λ<SUB>z</SUB> ≤ 0.8 than on either `cold' or `hot' orbits. This orbit-based `Hubble diagram' provides a benchmark for galaxy formation simulations in a cosmological context. | URI: | http://hdl.handle.net/20.500.12386/27952 | URL: | https://www.nature.com/articles/s41550-017-0348-1 | ISSN: | 2397-3366 | DOI: | 10.1038/s41550-017-0348-1 | Bibcode ADS: | 2018NatAs...2..233Z | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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File | Description | Size | Format | |
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1711.06728.pdf | preprint | 2.77 MB | Adobe PDF | View/Open |
Nature astr.s41550-017-0348-1.pdf | [Administrators only] | 3.69 MB | Adobe PDF |
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