arXiv subjects

Karol Chim-Ramirez

Publications and source records attributed to Karol Chim-Ramirez.

2 recordsLinked to original sources

arXiv2025

Bar Formation in Disc Galaxies: Internal Kinematics and Environmental Influence in MaNGA Galaxies

We explore how the physical properties of disc galaxies relate to the presence of bars using data from the SDSS-IV MaNGA survey. By combining internal kinematical properties and environmental diagnostics, we find that barred galaxies are more frequently associated with centrally concentrated stellar mass distributions (within 1 and 2 effective radii) and exhibit lower values of the stellar angular momentum $λ_{Re}$. At fixed total stellar mass, barred galaxies exhibit: (i) higher stellar mass, and (ii) lower angular momentum, both in their inner regions than their unbarred counterparts. We find a bimodal dependence of the bar fraction on tidal interactions produced by the nearest neighbour. Specifically, the bar fraction peaks in the most isolated galaxies, where bars form unequivocally through internal secular processes, decreases at intermediate interaction strengths, and rises again in the strong interaction regime, likely reflecting the role of dense environments in sustaining or triggering bars. Our results suggest that internal gravitational instabilities are the primary driver of bar formation. External tidal perturbations play a secondary role, capable of triggering or enhancing bar formation in galaxies that are already internally predisposed. Our findings provide robust observational validation of theoretical bar formation and evolution models in galaxies.

astro-ph.GA↗

arXiv2025

Study of barred galaxies in IllustrisTNG100: the case of low surface brightness galaxies

In this work, we compare the presence of stellar bars in low and high surface brightness galaxies (LSBs and HSBs, respectively) using the TNG100 simulation of the IllustrisTNG project. The sample consists of 4,244 disc galaxies at $z=0$ with stellar mass M$\star \geq 10^{10}$ M$\odot$. We find a bar fraction of $24 \pm 1.73 \%$ in LSBs, similar to the $28 \pm 0.74\%$ found in HSBs, consistent with observations. For a given stellar mass range, HSBs consistently exhibit a higher bar fraction compared to LSBs, except at M$\star > 10^{11}$ M$\odot$, where the difference vanishes. To explore the origin of this trend and its relation to host galaxy properties, we construct several control samples matched in stellar mass, spin, gas mass fraction, and bulge-to-total mass ratio. For galaxies with M$\star<10^{11}$ M$\odot$, the lower bar fraction in LSBs appears to be associated with their higher spin and gas content -factors known to inhibit bar formation and growth. At the high mass end, only the bulge-to-total mass ratio is capable of enhancing the bar fraction difference, although its effect is limited. We also study the role of the local environment through the tidal parameter. Our results suggest that, unlike in HSBs, where the bar fraction remains largely unaffected, tidal interactions may promote bar formation in LSBs, albeit with a smaller impact than the intrinsic physical properties. These findings provide insight into the physical conditions that shape the presence of bars in LSBs.

astro-ph.GA↗