Bar-driven gas redistribution suppresses star formation in spiral galaxies: Evidence from dust lanes in NGC 3351

Abstract

We present observational evidence, based on high-resolution imaging from HST, ALMA, and AstroSat/UVIT, that the redistribution of gas driven by the bar in the face-on spiral galaxy NGC 3351 results in suppressed star formation in its central regions. Dust and molecular gas coexist in galaxies, allowing dust lanes observed in galaxies to be used to probe the distribution of gas. In the central regions of NGC 3351, covered by the stellar bar, dust lanes are visible in the HST F438W–F814W colour map, but surprisingly, these areas lack molecular gas and recent star formation. The inward orientation of the dust lane morphology towards the galaxy’s centre suggests that molecular gas was once present in this region but was redistributed to the centre due to the stellar bar’s action. The direction of the dust lanes therefore indicates the past inflows of gas towards the galaxy centre, with their morphology consistently oriented inwards along the bar. These findings support a scenario in which the stellar bar has efficiently channelled molecular gas into the nucleus, building the central reservoir while suppressing star formation along the bar.