Bar ages derived for the first time in nearby galaxies: Insights on secular evolution from TIMER

The epoch in which galactic discs settle and secular evolution starts is a major benchmark to test galaxy formation and evolution models. Yet, this epoch is still largely unknown. Once galaxies settle their discs and become self-gravitating, stellar bars can form, driving the subsequent evolution of their host galaxy. Determining the ages of bars can, therefore, shed light on the epoch of the onset of secular evolution. Nevertheless, until recently, timing when bars have formed has been challenging. In this talk, I will present the results of the first broadly applicable methodology to derive bar ages from a sample of 20 nearby galaxies. The method is based on the co-eval build-up of nuclear structures and bars, using integral field spectroscopic data from MUSE/VLT. We derive independent star formation histories of the nuclear discs by removing the background population. This allows us to time its formation epoch and, thus, the bar. We estimate the bar formation epoch of nearby galaxies from the TIMER survey, creating the largest sample of galaxies with known bar ages to date. We find bar formation epochs varying between 1 and 13 Gyrs ago, illustrating how disc-settling and bar formation are ongoing processes that first took place in an early Universe. We infer the bar fraction over cosmological time within our sample, finding remarkable agreement with the observed bar. We will also derive results on secular evolution processes such as quenching, bar evolution, and downsizing