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 h₃ (~skewness) and h₄ (~kurtosis) in galaxies to their cosmological assembly history. Here, we assess these results by measuring the stellar kinematics on a sa...
Main Authors: | , , , , , , , , , , , , , , , , , , , , , |
---|---|
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Institute of Physics Publishing
2017
|
Subjects: | |
Online Access: | http://hdl.handle.net/1959.13/1399011 |
id |
ftunivnewcastnsw:uon:34514 |
---|---|
record_format |
openpolar |
spelling |
ftunivnewcastnsw:uon:34514 2023-05-15T18:11:29+02:00 The Sami Galaxy Survey: revisiting galaxy classification through high-order stellar kinematics van De Sande, Jesse Bland-Hawthorn, Joss Cecil, Gerard Colless, Matthew Couch, Warrick J. Davies, Roger Elahi, Pascal J. Foster, Caroline Goldstein, Gregory Goodwin, Michael Groves, Brent Ho, I.-Ting Fogarty, Lisa M. R. Jeong, Hunjin Jones, D. Heath Cortese, Luca D'Eugenio, Francesco Croom, Scott M. Scott, Nicholas Allen, James T. Brough, Sarah Bryant, Julia J. The University of Newcastle. Academic Division, Centre for English Language and Foundation Studies 2017 http://hdl.handle.net/1959.13/1399011 eng eng Institute of Physics Publishing Astrophysical Journal Vol. 835, Issue 1 10.3847/1538-4357/835/1/104 cosmology galaxies galaxy evolution galaxy formation kinematics stellar content galaxy structure journal article 2017 ftunivnewcastnsw 2019-03-25T23:24:08Z Recent cosmological hydrodynamical simulations suggest that integral field spectroscopy can connect the high-order stellar kinematic moments h₃ (~skewness) and h₄ (~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 Rₑ ) and ellipticity (ϵₑ) 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 h₃ versus V/σ anti-correlation, whereas quasi-regular and non-regular rotators show a more vertical relation in h₃ and V/σ. Motivated by recent cosmological simulations, we develop an alternative approach to kinematically classify galaxies from their individual h₃ 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 Rₑ - ϵₑ values can show distinctly different h₃ - V/σ signatures. Class 5 objects are previously unidentified fast rotators that show a weak h₃ 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 h₃ versus V/σ as evidence for disks in most fast rotators, suggesting a dearth of gas-poor mergers among fast rotators. Article in Journal/Newspaper sami NOVA: The University of Newcastle Research Online (Australia) |
institution |
Open Polar |
collection |
NOVA: The University of Newcastle Research Online (Australia) |
op_collection_id |
ftunivnewcastnsw |
language |
English |
topic |
cosmology galaxies galaxy evolution galaxy formation kinematics stellar content galaxy structure |
spellingShingle |
cosmology galaxies galaxy evolution galaxy formation kinematics stellar content galaxy structure van De Sande, Jesse Bland-Hawthorn, Joss Cecil, Gerard Colless, Matthew Couch, Warrick J. Davies, Roger Elahi, Pascal J. Foster, Caroline Goldstein, Gregory Goodwin, Michael Groves, Brent Ho, I.-Ting Fogarty, Lisa M. R. Jeong, Hunjin Jones, D. Heath Cortese, Luca D'Eugenio, Francesco Croom, Scott M. Scott, Nicholas Allen, James T. Brough, Sarah Bryant, Julia J. The Sami Galaxy Survey: revisiting galaxy classification through high-order stellar kinematics |
topic_facet |
cosmology galaxies galaxy evolution galaxy formation kinematics stellar content galaxy structure |
description |
Recent cosmological hydrodynamical simulations suggest that integral field spectroscopy can connect the high-order stellar kinematic moments h₃ (~skewness) and h₄ (~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 Rₑ ) and ellipticity (ϵₑ) 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 h₃ versus V/σ anti-correlation, whereas quasi-regular and non-regular rotators show a more vertical relation in h₃ and V/σ. Motivated by recent cosmological simulations, we develop an alternative approach to kinematically classify galaxies from their individual h₃ 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 Rₑ - ϵₑ values can show distinctly different h₃ - V/σ signatures. Class 5 objects are previously unidentified fast rotators that show a weak h₃ 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 h₃ versus V/σ as evidence for disks in most fast rotators, suggesting a dearth of gas-poor mergers among fast rotators. |
author2 |
The University of Newcastle. Academic Division, Centre for English Language and Foundation Studies |
format |
Article in Journal/Newspaper |
author |
van De Sande, Jesse Bland-Hawthorn, Joss Cecil, Gerard Colless, Matthew Couch, Warrick J. Davies, Roger Elahi, Pascal J. Foster, Caroline Goldstein, Gregory Goodwin, Michael Groves, Brent Ho, I.-Ting Fogarty, Lisa M. R. Jeong, Hunjin Jones, D. Heath Cortese, Luca D'Eugenio, Francesco Croom, Scott M. Scott, Nicholas Allen, James T. Brough, Sarah Bryant, Julia J. |
author_facet |
van De Sande, Jesse Bland-Hawthorn, Joss Cecil, Gerard Colless, Matthew Couch, Warrick J. Davies, Roger Elahi, Pascal J. Foster, Caroline Goldstein, Gregory Goodwin, Michael Groves, Brent Ho, I.-Ting Fogarty, Lisa M. R. Jeong, Hunjin Jones, D. Heath Cortese, Luca D'Eugenio, Francesco Croom, Scott M. Scott, Nicholas Allen, James T. Brough, Sarah Bryant, Julia J. |
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 |
Institute of Physics Publishing |
publishDate |
2017 |
url |
http://hdl.handle.net/1959.13/1399011 |
genre |
sami |
genre_facet |
sami |
op_relation |
Astrophysical Journal Vol. 835, Issue 1 10.3847/1538-4357/835/1/104 |
_version_ |
1766184143007252480 |