On the bar pattern speed determination of NGC 3367

TL;DR

This paper evaluates the Tremaine-Weinberg method for measuring bar pattern speeds in galaxies, analyzing data quality effects through simulations, and applies it to NGC 3367, obtaining a specific pattern speed estimate.

Contribution

It demonstrates the robustness of the Tremaine-Weinberg method under different data noise conditions and applies it to real galaxy data for the first time.

Findings

Signal-to-noise ratio of ~5 yields ~20% error with Gaussian noise.

White noise causes errors up to ~50%.

Pattern speed of NGC 3367 is 43 ± 6 km/s/kpc.

Abstract

An important dynamic parameter of barred galaxies is the bar pattern speed. Among several methods that are used for the determination of the pattern speed the Tremaine-Weinberg method has the advantage of model independency and accuracy. In this work we apply the method to a simulated bar including gas dynamics and study the effect of 2D spectroscopy data quality on robustness of the method. We added a white noise and a Gaussian random field to the data and measured the corresponding errors in the pattern speed. We found that a signal to noise ratio in surface density ~5 introduces errors of ~20% for the Gaussian noise, while for the white noise the corresponding errors reach ~50%. At the same time the velocity field is less sensitive to contamination. On the basis of the performed study we applied the method to the NGC 3367 spiral galaxy using H{\alpha} Fabry-Perot interferometry data. We found for the pattern speed 43 \pm 6 km/s/kpc for this galaxy.