12 strong galactic bars CO spectra

Results. We detect molecular gas along the bars of all probed galaxies. Molecular gas and SFR surface densities span the ranges log10({Sigma}_mol_/[M_{sun}_/pc^2^]){in}[0.4,2.4] and log10({Sigma}_SFR_/[M_{sun}_/pc/kpc^2^]){in}[-3.25,-0.75], respectively.

The star formation efficiency (SFE=SFR/Mmol) in bars varies between galaxies by up to an order of magnitude (SFE{in}[0.1,1.8]Gyr^-1^). On average, SFEs are roughly constant along bars. SFEs are not significantly different from the mean value in spiral galaxies reported in the literature (~0.43Gyr^-1^), regardless of whether we estimate Mmol from CO(1-0) or CO(2-1).

Interestingly, the higher the total stellar mass of the host galaxy, the lower the SFE within their bars. In particular, the two galaxies in our sample with lowest SFE and {Sigma}_SFR_ (NGC 4548 and NGC 5850, SFE<=0.25Gyr^-1^, {Sigma}_SFR_<=10^-2.25^M_{sun}_/yr/kpc^2^, M*<=10^10.7^M_{sun}_) are also the ones hosting massive bulges and signs of past interactions with nearby companions. We present a statistical analysis of the SFE in bars for a sample of 12 galaxies.

The SFE in strong bars is not systematically inhibited (either in the central, mid- or end-parts of the bar). Both environmental and internal quenching are likely responsible for the lowest SFEs reported in this work.