Comparison of Bar Formation Mechanisms. II. Does a Tidally Induced Bar Grow Faster than an Internally Developed Bar?
Bar structures can form internally due to the instability of their host galaxies or externally due to perturbations from other galaxies. We systematically quantify the growth timescales ( τ _bar ) of bars formed through these two mechanisms with a series of controlled N -body simulations. In galaxie...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/adcf93 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850214077100457984 |
|---|---|
| author | Yirui Zheng Juntai Shen Xufen Wu Bin-Hui Chen |
| author_facet | Yirui Zheng Juntai Shen Xufen Wu Bin-Hui Chen |
| author_sort | Yirui Zheng |
| collection | DOAJ |
| description | Bar structures can form internally due to the instability of their host galaxies or externally due to perturbations from other galaxies. We systematically quantify the growth timescales ( τ _bar ) of bars formed through these two mechanisms with a series of controlled N -body simulations. In galaxies susceptible to bar instability, tidally induced bars display τ _bar values comparable to those of internally developed bars within the same disk. Tidal perturbations promote (delay) bar formation by advancing (postponing) its onset, but the growth rate of the bar structure remains largely unchanged. In these interaction scenarios, the bar formation is still driven primarily by the galaxy’s internal nature, which remains unaffected by tidal perturbations. As the external perturbation wave reaches the galaxy’s center, it evokes a “seed bar” that is then swing amplified. In this scenario, the onset of bar formation is advanced. Conversely, bar formation may be delayed if the external perturbation wave is out of phase with the preexisting spontaneously developed “seed bar,” which causes destructive interference and limits bar growth. In the hot disk model that resists bar formation in isolation, the τ _bar of the tidally forced bar correlates with the strength of the perturbation. The bar growth in this model deviates from an exponential profile and is better described by a linear function. The varied τ _bar and the preference for linear growth contrast with bars formed in galaxies inherently susceptible to bar instability. These tidally forced bars may not adhere to the swing amplification mechanism that predicts exponential bar growth. |
| format | Article |
| id | doaj-art-061edab785d64dd3983554769d6565f0 |
| institution | OA Journals |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-061edab785d64dd3983554769d6565f02025-08-20T02:09:00ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198619010.3847/1538-4357/adcf93Comparison of Bar Formation Mechanisms. II. Does a Tidally Induced Bar Grow Faster than an Internally Developed Bar?Yirui Zheng0https://orcid.org/0000-0001-7707-5930Juntai Shen1https://orcid.org/0000-0001-5604-1643Xufen Wu2https://orcid.org/0000-0002-1378-8082Bin-Hui Chen3https://orcid.org/0000-0001-8962-663XDepartment of Astronomy, School of Physics and Astronomy, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, People’s Republic of China ; jtshen@sjtu.edu.cn; State Key Laboratory of Dark Matter Physics, School of Physics and Astronomy, Shanghai Jiao Tong University , Shanghai 200240, People's Republic of ChinaDepartment of Astronomy, School of Physics and Astronomy, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, People’s Republic of China ; jtshen@sjtu.edu.cn; State Key Laboratory of Dark Matter Physics, School of Physics and Astronomy, Shanghai Jiao Tong University , Shanghai 200240, People's Republic of ChinaDepartment of Astronomy, University of Science and Technology of China , Hefei 230026, People’s Republic of China; School of Astronomy and Space Science, University of Science and Technology of China , Hefei 230026, People’s Republic of ChinaDepartment of Astronomy, School of Physics and Astronomy, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, People’s Republic of China ; jtshen@sjtu.edu.cn; State Key Laboratory of Dark Matter Physics, School of Physics and Astronomy, Shanghai Jiao Tong University , Shanghai 200240, People's Republic of China; Tsung-Dao Lee Institute, Shanghai Jiao Tong University , Shanghai 200240, People’s Republic of ChinaBar structures can form internally due to the instability of their host galaxies or externally due to perturbations from other galaxies. We systematically quantify the growth timescales ( τ _bar ) of bars formed through these two mechanisms with a series of controlled N -body simulations. In galaxies susceptible to bar instability, tidally induced bars display τ _bar values comparable to those of internally developed bars within the same disk. Tidal perturbations promote (delay) bar formation by advancing (postponing) its onset, but the growth rate of the bar structure remains largely unchanged. In these interaction scenarios, the bar formation is still driven primarily by the galaxy’s internal nature, which remains unaffected by tidal perturbations. As the external perturbation wave reaches the galaxy’s center, it evokes a “seed bar” that is then swing amplified. In this scenario, the onset of bar formation is advanced. Conversely, bar formation may be delayed if the external perturbation wave is out of phase with the preexisting spontaneously developed “seed bar,” which causes destructive interference and limits bar growth. In the hot disk model that resists bar formation in isolation, the τ _bar of the tidally forced bar correlates with the strength of the perturbation. The bar growth in this model deviates from an exponential profile and is better described by a linear function. The varied τ _bar and the preference for linear growth contrast with bars formed in galaxies inherently susceptible to bar instability. These tidally forced bars may not adhere to the swing amplification mechanism that predicts exponential bar growth.https://doi.org/10.3847/1538-4357/adcf93Galaxy dynamicsGalaxy kinematicsGalaxy structureBarred spiral galaxies |
| spellingShingle | Yirui Zheng Juntai Shen Xufen Wu Bin-Hui Chen Comparison of Bar Formation Mechanisms. II. Does a Tidally Induced Bar Grow Faster than an Internally Developed Bar? The Astrophysical Journal Galaxy dynamics Galaxy kinematics Galaxy structure Barred spiral galaxies |
| title | Comparison of Bar Formation Mechanisms. II. Does a Tidally Induced Bar Grow Faster than an Internally Developed Bar? |
| title_full | Comparison of Bar Formation Mechanisms. II. Does a Tidally Induced Bar Grow Faster than an Internally Developed Bar? |
| title_fullStr | Comparison of Bar Formation Mechanisms. II. Does a Tidally Induced Bar Grow Faster than an Internally Developed Bar? |
| title_full_unstemmed | Comparison of Bar Formation Mechanisms. II. Does a Tidally Induced Bar Grow Faster than an Internally Developed Bar? |
| title_short | Comparison of Bar Formation Mechanisms. II. Does a Tidally Induced Bar Grow Faster than an Internally Developed Bar? |
| title_sort | comparison of bar formation mechanisms ii does a tidally induced bar grow faster than an internally developed bar |
| topic | Galaxy dynamics Galaxy kinematics Galaxy structure Barred spiral galaxies |
| url | https://doi.org/10.3847/1538-4357/adcf93 |
| work_keys_str_mv | AT yiruizheng comparisonofbarformationmechanismsiidoesatidallyinducedbargrowfasterthananinternallydevelopedbar AT juntaishen comparisonofbarformationmechanismsiidoesatidallyinducedbargrowfasterthananinternallydevelopedbar AT xufenwu comparisonofbarformationmechanismsiidoesatidallyinducedbargrowfasterthananinternallydevelopedbar AT binhuichen comparisonofbarformationmechanismsiidoesatidallyinducedbargrowfasterthananinternallydevelopedbar |