The coherent satellite velocity field around the interacting spiral galaxy pair NGC5713/19: signature of two galaxy groups merging
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arXiv
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| Auteurs principaux: | , , , |
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| Format: | Preprint |
| Publié: |
2025
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| _version_ | 1866916863336775680 |
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| author | Jerjen, Helmut Deeley, Simon Baumgardt, Holger Sweet, Sarah M. |
| author_facet | Jerjen, Helmut Deeley, Simon Baumgardt, Holger Sweet, Sarah M. |
| contents | The luminous spirals NGC5713 and NGC5719 form an interacting galaxy pair 94 kpc apart and are connected by a straight, elongated neutral hydrogen structure extending over 200 kpc. Their 14 velocity-confirmed satellite galaxies and the two hosts separate into two distinct subgroups in their line-of-sight velocities and on-sky distribution revealing a prominent coherent kinematic structure with a velocity amplitude of 67+-12 kms-1 . We test four scenarios to explain the observed velocity field: isotropic motions in a dark matter halo, a plane of satellites seen nearly face-on, and a kinematically mixed satellite system with a co-rotating edge-on plane and an isotropic component, and a merger of two small galaxy groups. Taking the geometry and dynamical state of the NGC5713/19 pair into account together with their positions and motions in the Bootes Strip the most consistent picture is the infall of two satellite systems that follow their host galaxies along a cosmic filament. We believe this is the first clear example of an equal-mass L* disk galaxy merger where a kinematically coherent satellite system is in the process of formation. These observations reinforce the importance of major mergers as a channel for producing co-rotating satellite systems. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_18912 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | The coherent satellite velocity field around the interacting spiral galaxy pair NGC5713/19: signature of two galaxy groups merging Jerjen, Helmut Deeley, Simon Baumgardt, Holger Sweet, Sarah M. Astrophysics of Galaxies The luminous spirals NGC5713 and NGC5719 form an interacting galaxy pair 94 kpc apart and are connected by a straight, elongated neutral hydrogen structure extending over 200 kpc. Their 14 velocity-confirmed satellite galaxies and the two hosts separate into two distinct subgroups in their line-of-sight velocities and on-sky distribution revealing a prominent coherent kinematic structure with a velocity amplitude of 67+-12 kms-1 . We test four scenarios to explain the observed velocity field: isotropic motions in a dark matter halo, a plane of satellites seen nearly face-on, and a kinematically mixed satellite system with a co-rotating edge-on plane and an isotropic component, and a merger of two small galaxy groups. Taking the geometry and dynamical state of the NGC5713/19 pair into account together with their positions and motions in the Bootes Strip the most consistent picture is the infall of two satellite systems that follow their host galaxies along a cosmic filament. We believe this is the first clear example of an equal-mass L* disk galaxy merger where a kinematically coherent satellite system is in the process of formation. These observations reinforce the importance of major mergers as a channel for producing co-rotating satellite systems. |
| title | The coherent satellite velocity field around the interacting spiral galaxy pair NGC5713/19: signature of two galaxy groups merging |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2507.18912 |