How old are bars? Determining the cosmic epoch of bar formation using archeological data of nearby galaxies
Description
The epoch in which galactic discs settle and secular evolution takes place is a major benchmark to test models of galaxy formation and evolution. Yet, this epoch is still largely unknown. Once discs settle and become self-gravitating enough, stellar bars are able to form and act on the evolution of the host galaxy; therefore, determining the ages of bars can shed light on the epoch of disc settling, and on the onset of secular evolution. Nevertheless, until now, timing when bars in nearby galaxies have formed has proven challenging. In this talk, I will present a new methodology for obtaining the bar age together with the first results. In particular, we use integral field spectroscopic (IFS) data from the TIMER survey to disentangle the light of the central region of galaxies and derive independent star formation histories. Since the bar gravitational torques bring gas inwards, it builds nuclear structures that can be used to time when the bar itself formed. I will present the first results of this methodology for the TIMER sample, including the old bar hosted by NGC1433, with an estimated age of 7.5 Gyrs. Additionally, I will present preliminary results showing that bars can be young and recently formed, discs can still be settling in the Local Universe, and how these galaxies compared to the Milky Way. This methodology is applicable to high-resolution IFS data of barred galaxies with bar-built nuclear structures. Thus, in the future we will be able to determine the bar age for a large sample of galaxies, shedding light on the epoch of disc settling and bar formation as a function of stellar mass and other galactic properties.
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CdeSaFreitas.pdf
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(14.5 MB)
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