The SAMI Galaxy Survey: Revisiting Galaxy Classification through High-order Stellar Kinematics
Recent cosmological hydrodynamical simulations suggest that integral field spectroscopy can connect the high-order stellar kinematic moments h_3 (~skewness) and h_4 (~kurtosis) in galaxies to their cosmological assembly history. Here, we assess these results by measuring the stellar kinematics on a...
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ftcaltechauth:oai:authors.library.caltech.edu:9zbct-mej53 2024-09-09T20:06:07+00:00 The SAMI Galaxy Survey: Revisiting Galaxy Classification through High-order Stellar Kinematics van de Sande, Jesse Medling, Anne M. 2017-01-20 https://doi.org/10.3847/1538-4357/835/1/104 unknown American Astronomical Society https://arxiv.org/abs/1611.07039 https://doi.org/10.3847/1538-4357/835/1/104 oai:authors.library.caltech.edu:9zbct-mej53 eprintid:73771 resolverid:CaltechAUTHORS:20170127-091339895 info:eu-repo/semantics/openAccess Other Astrophysical Journal, 835(1), Art. No. 104, (2017-01-20) cosmology: observations – galaxies: evolution – galaxies: formation – galaxies: kinematics and dynamics – galaxies: stellar content – galaxies: structure info:eu-repo/semantics/article 2017 ftcaltechauth https://doi.org/10.3847/1538-4357/835/1/104 2024-08-06T15:35:05Z Recent cosmological hydrodynamical simulations suggest that integral field spectroscopy can connect the high-order stellar kinematic moments h_3 (~skewness) and h_4 (~kurtosis) in galaxies to their cosmological assembly history. Here, we assess these results by measuring the stellar kinematics on a sample of 315 galaxies, without a morphological selection, using two-dimensional integral field data from the SAMI Galaxy Survey. Proxies for the spin parameter (λ_(R_e)) and ellipticity (ε_e) are used to separate fast and slow rotators; there exists a good correspondence to regular and non-regular rotators, respectively, as also seen in earlier studies. We confirm that regular rotators show a strong h_3 versus V/σ anti-correlation, whereas quasi-regular and non-regular rotators show a more vertical relation in h_3 and V/σ. Motivated by recent cosmological simulations, we develop an alternative approach to kinematically classify galaxies from their individual h_3 versus V/σ signatures. Within the SAMI Galaxy Survey, we identify five classes of high-order stellar kinematic signatures using Gaussian mixture models. Class 1 corresponds to slow rotators, whereas Classes 2–5 correspond to fast rotators. We find that galaxies with similar λ_(R_e) - ε_e values can show distinctly different h_3 - V/σ signatures. Class 5 objects are previously unidentified fast rotators that show a weak h_3 versus V/σ anti-correlation. From simulations, these objects are predicted to be disk-less galaxies formed by gas-poor mergers. From morphological examination, however, there is evidence for large stellar disks. Instead, Class 5 objects are more likely disturbed galaxies, have counter-rotating bulges, or bars in edge-on galaxies. Finally, we interpret the strong anti-correlation in h_3 versus V/σ as evidence for disks in most fast rotators, suggesting a dearth of gas-poor mergers among fast rotators. © 2017 The American Astronomical Society. Received 2016 September 30; revised 2016 November 15; accepted 2016 November 16; ... Article in Journal/Newspaper sami Caltech Authors (California Institute of Technology) The Astrophysical Journal 835 1 104 |
institution |
Open Polar |
collection |
Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
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unknown |
topic |
cosmology: observations – galaxies: evolution – galaxies: formation – galaxies: kinematics and dynamics – galaxies: stellar content – galaxies: structure |
spellingShingle |
cosmology: observations – galaxies: evolution – galaxies: formation – galaxies: kinematics and dynamics – galaxies: stellar content – galaxies: structure van de Sande, Jesse Medling, Anne M. The SAMI Galaxy Survey: Revisiting Galaxy Classification through High-order Stellar Kinematics |
topic_facet |
cosmology: observations – galaxies: evolution – galaxies: formation – galaxies: kinematics and dynamics – galaxies: stellar content – galaxies: structure |
description |
Recent cosmological hydrodynamical simulations suggest that integral field spectroscopy can connect the high-order stellar kinematic moments h_3 (~skewness) and h_4 (~kurtosis) in galaxies to their cosmological assembly history. Here, we assess these results by measuring the stellar kinematics on a sample of 315 galaxies, without a morphological selection, using two-dimensional integral field data from the SAMI Galaxy Survey. Proxies for the spin parameter (λ_(R_e)) and ellipticity (ε_e) are used to separate fast and slow rotators; there exists a good correspondence to regular and non-regular rotators, respectively, as also seen in earlier studies. We confirm that regular rotators show a strong h_3 versus V/σ anti-correlation, whereas quasi-regular and non-regular rotators show a more vertical relation in h_3 and V/σ. Motivated by recent cosmological simulations, we develop an alternative approach to kinematically classify galaxies from their individual h_3 versus V/σ signatures. Within the SAMI Galaxy Survey, we identify five classes of high-order stellar kinematic signatures using Gaussian mixture models. Class 1 corresponds to slow rotators, whereas Classes 2–5 correspond to fast rotators. We find that galaxies with similar λ_(R_e) - ε_e values can show distinctly different h_3 - V/σ signatures. Class 5 objects are previously unidentified fast rotators that show a weak h_3 versus V/σ anti-correlation. From simulations, these objects are predicted to be disk-less galaxies formed by gas-poor mergers. From morphological examination, however, there is evidence for large stellar disks. Instead, Class 5 objects are more likely disturbed galaxies, have counter-rotating bulges, or bars in edge-on galaxies. Finally, we interpret the strong anti-correlation in h_3 versus V/σ as evidence for disks in most fast rotators, suggesting a dearth of gas-poor mergers among fast rotators. © 2017 The American Astronomical Society. Received 2016 September 30; revised 2016 November 15; accepted 2016 November 16; ... |
format |
Article in Journal/Newspaper |
author |
van de Sande, Jesse Medling, Anne M. |
author_facet |
van de Sande, Jesse Medling, Anne M. |
author_sort |
van de Sande, Jesse |
title |
The SAMI Galaxy Survey: Revisiting Galaxy Classification through High-order Stellar Kinematics |
title_short |
The SAMI Galaxy Survey: Revisiting Galaxy Classification through High-order Stellar Kinematics |
title_full |
The SAMI Galaxy Survey: Revisiting Galaxy Classification through High-order Stellar Kinematics |
title_fullStr |
The SAMI Galaxy Survey: Revisiting Galaxy Classification through High-order Stellar Kinematics |
title_full_unstemmed |
The SAMI Galaxy Survey: Revisiting Galaxy Classification through High-order Stellar Kinematics |
title_sort |
sami galaxy survey: revisiting galaxy classification through high-order stellar kinematics |
publisher |
American Astronomical Society |
publishDate |
2017 |
url |
https://doi.org/10.3847/1538-4357/835/1/104 |
genre |
sami |
genre_facet |
sami |
op_source |
Astrophysical Journal, 835(1), Art. No. 104, (2017-01-20) |
op_relation |
https://arxiv.org/abs/1611.07039 https://doi.org/10.3847/1538-4357/835/1/104 oai:authors.library.caltech.edu:9zbct-mej53 eprintid:73771 resolverid:CaltechAUTHORS:20170127-091339895 |
op_rights |
info:eu-repo/semantics/openAccess Other |
op_doi |
https://doi.org/10.3847/1538-4357/835/1/104 |
container_title |
The Astrophysical Journal |
container_volume |
835 |
container_issue |
1 |
container_start_page |
104 |
_version_ |
1809938517567995904 |