# Peculiar motions of the gas at the centre of the barred galaxy UGC 4056

## TL;DR

This study analyzes the gas and stellar motions in the barred galaxy UGC 4056, revealing peculiar central gas dynamics likely influenced by the bar potential and associated with AGN activity, using MaNGA survey data.

## Contribution

It provides the first detailed analysis of gas and stellar circular velocity curves in UGC 4056, highlighting peculiar gas motions related to the galaxy's bar and AGN.

## Key findings

- Gas shows a velocity bump within 3 kpc
- Stellar velocity decreases smoothly to zero
- Gas inflow likely caused by bar potential

## Abstract

We derive the circular velocity curves of the gaseous and stellar discs of UGC 4056, a giant barred galaxy with an active galactic nucleus (AGN). We analyse UGC 4056 using the 2D spectroscopy obtained within the framework of the Mapping Nearby Galaxies at APO (MaNGA) survey. Using images and the colour index g-r from the Sloan Digital Sky Survey (SDSS), we determined the tilt of the galaxy, which allows us to conclude that the galaxy rotates clockwise with trailing spiral arms. We found that the gas motion at the central part of the UGC 4056 shows peculiar features. The rotation velocity of the gaseous disc shows a bump within around three kiloparsecs while the rotation velocity of the stellar disc falls smoothly to zero with decreasing galactocentric distance. We demonstrate that the peculiar radial velocities in the central part of the galaxy may be caused by the inflow of the gas towards the nucleus of the galaxy. The unusual motion of the gas takes place at the region with the AGN-like radiation and can be explained by the gas response to the bar potential.