A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE). VIII. Modeling ram pressure stripping of diffuse gas in the Virgo cluster spiral galaxy NGC 4330

TL;DR

This study models ram pressure stripping in the Virgo galaxy NGC 4330, incorporating diffuse ionized gas to better match observed gas and star formation features, revealing the importance of diffuse gas removal in galaxy evolution within clusters.

Contribution

Introduces a new dynamical model including diffuse ionized gas stripping, improving the match to observed gas distributions and star formation histories in NGC 4330.

Findings

Diffuse gas stripping significantly alters gas emission morphologies.

Models with diffuse gas stripping better fit observed data.

Preferred model predicts peak ram pressure in 140 Myr.

Abstract

NGC 4330 is one of the Virgo galaxies whose UV distribution shows a tail structure. An associated tail structure is also observed in the HI and H$\alpha$ emission distributions. Previous dynamical modeling showed that the galaxy is approaching the cluster center and is therefore undergoing increasing ram pressure stripping. Recent stellar population fitting of deep optical spectra together with multiband photometry lead to the determination of the time when star formation was quenched in the galactic disk. We introduce a new version of the dynamical model that includes the diffuse ionized gas and aim to reproduce the HI, H$\alpha$, UV distributions together with the star formation histories of the outer gas-free parts of the galactic disk. The results of 50 simulations with five different Lorentzian temporal ram-pressure profiles and five different delays between the simulation onset and peak ram pressure are presented. The inclusion of diffuse gas stripping changes significantly the HI, UV, and H$\alpha$ emission distributions. The simulations with diffuse gas stripping naturally lead to vertical low surface density filaments in the downwind region of the galactic disk. These filaments occur less frequently in the simulations without diffuse gas stripping. The simulations with diffuse gas stripping lead to better joint fits to the SEDs and optical spectra. The HI, NUV, and H$\alpha$ morphologies of the model snapshots which best reproduce the SEDs and optical spectra are sufficiently different to permit a selection of best-fit models. We conclude that the inclusion of diffuse gas stripping significantly improves the resemblance between the model and observations. Our preferred model yields a time to peak ram pressure of 140 Myr in the future. The spatial coincidence of the radio continuum and diffuse H$\alpha$ tails suggests that both gas phases are stripped together.