SIMBAD references

We present results from the EDGE survey, a spatially resolved CO(1-0) follow-up to CALIFA, an optical Integral Field Unit survey of local galaxies. By combining the data products of EDGE and CALIFA, we study the variation in molecular gas depletion time (τ_dep) on kiloparsec scales in 52 galaxies. We divide each galaxy into two parts: the center, defined as the region within 0.1 R₂₅, and the disk, defined as the region between 0.1 and 0.7 R₂₅. We find that 14 galaxies show a shorter τ_dep (∼1 Gyr) in the center relative to that in the disk (τ_dep ∼ 2.4 Gyr), which means the central region in those galaxies is more efficient at forming stars per unit molecular gas mass. This finding implies that the centers with shorter τ_dep resemble the intermediate regime between galactic disks and starburst galaxies. Furthermore, the central drop in τ_dep is correlated with a central increase in the stellar surface density, suggesting that a shorter τ_dep is associated with molecular gas compression by the stellar gravitational potential. We argue that varying the CO-to-H₂ conversion factor only exaggerates the central drop of τ_dep.