Evolution of low surface brightness ultra-thin galaxies: The role of dark matter halo and bar formation on disk thickness
Fuente:
arXiv
Saved in:
| Main Authors: | , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866915497180659712 |
|---|---|
| author | Aditya, K. Banerjee, Arunima |
| author_facet | Aditya, K. Banerjee, Arunima |
| contents | We investigate how stellar disks sustain their ultrathin structure throughout their evolution. We follow the evolution of ultrathin stellar disks with varying dark matter (DM) halo concentration ($c$) using collisionless $N$-body simulations with \texttt{AREPO}. We test models embedded in steep ($c = 12$), shallow ($c = 2$), and intermediate ($c = 6$) DM concentrations. Our models match the observed structural properties of the stellar disk in the low surface brightness (LSB) ultrathin galaxy FGC~2366, specifically its surface brightness, disk scalelength, and vertical thinness ($h_{z}/R_{D} = 0.1$), while excluding gas, allowing us to isolate the effects of DM. The internal disk heating mechanism driven by bars is suppressed in the LSB ultrathin stellar disks regardless of the DM concentration. The ratio of disk thickness ($h_z$) to scalelength ($R_D$) remains constant at $\leq 0.1$ throughout their evolution. To clearly establish that the LSB nature of stellar disks is the key to preventing disk thickening, we construct the initial conditions by increasing the stellar mass fraction from $f_{s} \sim 0.01$ to $0.02$ and $0.04$, respectively, while keeping the total mass equal to $10^{11} M_\odot$ and $h_z/R_D \leq 0.1$ unchanged. We find that models with a higher stellar mass fraction embedded in a shallow DM potential ($c = 2$) form bars and undergo significant disk thickening ($h_{z}/R_{D} \gg 0.1$) concurrent with the bar growth. We conclude that if the LSB disks are thin to begin with, they remain so throughout their evolution in isolation, regardless of the concentration of the DM halo. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_12966 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Evolution of low surface brightness ultra-thin galaxies: The role of dark matter halo and bar formation on disk thickness Aditya, K. Banerjee, Arunima Astrophysics of Galaxies We investigate how stellar disks sustain their ultrathin structure throughout their evolution. We follow the evolution of ultrathin stellar disks with varying dark matter (DM) halo concentration ($c$) using collisionless $N$-body simulations with \texttt{AREPO}. We test models embedded in steep ($c = 12$), shallow ($c = 2$), and intermediate ($c = 6$) DM concentrations. Our models match the observed structural properties of the stellar disk in the low surface brightness (LSB) ultrathin galaxy FGC~2366, specifically its surface brightness, disk scalelength, and vertical thinness ($h_{z}/R_{D} = 0.1$), while excluding gas, allowing us to isolate the effects of DM. The internal disk heating mechanism driven by bars is suppressed in the LSB ultrathin stellar disks regardless of the DM concentration. The ratio of disk thickness ($h_z$) to scalelength ($R_D$) remains constant at $\leq 0.1$ throughout their evolution. To clearly establish that the LSB nature of stellar disks is the key to preventing disk thickening, we construct the initial conditions by increasing the stellar mass fraction from $f_{s} \sim 0.01$ to $0.02$ and $0.04$, respectively, while keeping the total mass equal to $10^{11} M_\odot$ and $h_z/R_D \leq 0.1$ unchanged. We find that models with a higher stellar mass fraction embedded in a shallow DM potential ($c = 2$) form bars and undergo significant disk thickening ($h_{z}/R_{D} \gg 0.1$) concurrent with the bar growth. We conclude that if the LSB disks are thin to begin with, they remain so throughout their evolution in isolation, regardless of the concentration of the DM halo. |
| title | Evolution of low surface brightness ultra-thin galaxies: The role of dark matter halo and bar formation on disk thickness |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2509.12966 |