Kinematic unrest of low mass galaxy groups
In an effort to better understand the formation of galaxy groups, we examine the kinematics of a large sample of spectroscopically confirmed X-ray galaxy groups in the Cosmic Evolution Survey (COSMOS) with a high sampling of galaxy group members up to $z=1$. We compare our results with predictions f...
| Main Authors: | , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
EDP Sciences
2020
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| _version_ | 1811140303563784192 |
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| author | Devriendt, J Gozaliasl, G Finoguenov, A Khosroshahi, HG Laigle, C Kirkpatrick, CC Kiiveri, K Dubois, Y Ahoranta, J |
| author_facet | Devriendt, J Gozaliasl, G Finoguenov, A Khosroshahi, HG Laigle, C Kirkpatrick, CC Kiiveri, K Dubois, Y Ahoranta, J |
| author_sort | Devriendt, J |
| collection | OXFORD |
| description | In an effort to better understand the formation of galaxy groups, we examine
the kinematics of a large sample of spectroscopically confirmed X-ray galaxy
groups in the Cosmic Evolution Survey (COSMOS) with a high sampling of galaxy
group members up to $z=1$. We compare our results with predictions from the
cosmological hydrodynamical simulation of {\sc Horizon-AGN}. Using a
phase-space analysis of dynamics of groups with halo masses of
$M_{\mathrm{200c}}\sim 10^{12.6}-10^{14.50}M_\odot$, we show that the brightest
group galaxies (BGG) in low mass galaxy groups ($M_{\mathrm{200c}}<2 \times
10^{13} M_\odot$) have larger proper motions relative to the group velocity
dispersion than high mass groups. The dispersion in the ratio of the BGG proper
velocity to the velocity dispersion of the group,
$\sigma_{\mathrm{BGG}}/\sigma_{group}$, is on average $1.48 \pm 0.13$ for low
mass groups and $1.01 \pm 0.09$ for high mass groups. A comparative analysis of
the {\sc Horizon-AGN} simulation reveals a similar increase in the spread of
peculiar velocities of BGGs with decreasing group mass, though consistency in
the amplitude, shape, and mode of the BGG peculiar velocity distribution is
only achieved for high mass groups. The groups hosting a BGG with a large
peculiar velocity are more likely to be offset from the $L_x-\sigma_{v}$
relation; this is probably because the peculiar motion of the BGG is influenced
by the accretion of new members. |
| first_indexed | 2024-03-06T18:28:04Z |
| format | Journal article |
| id | oxford-uuid:08ab5883-28c6-41e1-9563-106481cf4718 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-09-25T04:19:50Z |
| publishDate | 2020 |
| publisher | EDP Sciences |
| record_format | dspace |
| spelling | oxford-uuid:08ab5883-28c6-41e1-9563-106481cf47182024-08-07T16:32:10ZKinematic unrest of low mass galaxy groupsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:08ab5883-28c6-41e1-9563-106481cf4718EnglishSymplectic ElementsEDP Sciences2020Devriendt, JGozaliasl, GFinoguenov, AKhosroshahi, HGLaigle, CKirkpatrick, CCKiiveri, KDubois, YAhoranta, JIn an effort to better understand the formation of galaxy groups, we examine the kinematics of a large sample of spectroscopically confirmed X-ray galaxy groups in the Cosmic Evolution Survey (COSMOS) with a high sampling of galaxy group members up to $z=1$. We compare our results with predictions from the cosmological hydrodynamical simulation of {\sc Horizon-AGN}. Using a phase-space analysis of dynamics of groups with halo masses of $M_{\mathrm{200c}}\sim 10^{12.6}-10^{14.50}M_\odot$, we show that the brightest group galaxies (BGG) in low mass galaxy groups ($M_{\mathrm{200c}}<2 \times 10^{13} M_\odot$) have larger proper motions relative to the group velocity dispersion than high mass groups. The dispersion in the ratio of the BGG proper velocity to the velocity dispersion of the group, $\sigma_{\mathrm{BGG}}/\sigma_{group}$, is on average $1.48 \pm 0.13$ for low mass groups and $1.01 \pm 0.09$ for high mass groups. A comparative analysis of the {\sc Horizon-AGN} simulation reveals a similar increase in the spread of peculiar velocities of BGGs with decreasing group mass, though consistency in the amplitude, shape, and mode of the BGG peculiar velocity distribution is only achieved for high mass groups. The groups hosting a BGG with a large peculiar velocity are more likely to be offset from the $L_x-\sigma_{v}$ relation; this is probably because the peculiar motion of the BGG is influenced by the accretion of new members. |
| spellingShingle | Devriendt, J Gozaliasl, G Finoguenov, A Khosroshahi, HG Laigle, C Kirkpatrick, CC Kiiveri, K Dubois, Y Ahoranta, J Kinematic unrest of low mass galaxy groups |
| title | Kinematic unrest of low mass galaxy groups |
| title_full | Kinematic unrest of low mass galaxy groups |
| title_fullStr | Kinematic unrest of low mass galaxy groups |
| title_full_unstemmed | Kinematic unrest of low mass galaxy groups |
| title_short | Kinematic unrest of low mass galaxy groups |
| title_sort | kinematic unrest of low mass galaxy groups |
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