A new method for age-dating the formation of bars in disc galaxies. The TIMER view on NGC1433's old bar and the inside-out growth of its nuclear disc

de Sá-Freitas, Camila; Fragkoudi, Francesca; Gadotti, Dimitri A.; Falcón-Barroso, Jesús; Bittner, Adrian; Sánchez-Blázquez, Patricia; van de Ven, Glenn; Bieri, Rebekka; Coccato, Lodovico; Coelho, Paula; Fahrion, Katja; Gonçalves, Geraldo; Kim, Taehyun; de Lorenzo-Cáceres, Adriana; Martig, Marie; Martín-Navarro, Ignacio; Mendez-Abreu, Jairo; Neumann, Justus; Querejeta, Miguel
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Astronomy and Astrophysics

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The epoch in which galactic discs settle is a major benchmark for testing models of galaxy formation and evolution but remains largely unknown. Once discs settle and become sufficiently self-gravitating, stellar bars are able to form; therefore, determining the ages of bars can shed light on the epoch of disc settling, and on the onset of secular evolution. Nevertheless, timing when the bar formed has proven challenging. In this work we present a new methodology for obtaining the bar age, using the star formation history of nuclear discs. Nuclear discs are rotation-supported structures, built by gas pushed to the centre via bar-induced torques, and their formation is thus coincident with bar formation. In particular, we used integral field spectroscopic data from the TIMER survey to disentangle the star formation history of the nuclear disc from that of the underlying main disc, which enables us to more accurately determine when the nuclear disc formed. We demonstrate the methodology on the galaxy NGC 1433 - which we find to host an old bar that is 7.5−1.1+1.6(sys)−0.5+0.2(stat) Gyr old - and describe a number of tests carried out on both the observational data and numerical simulations. In addition, we present evidence that the nuclear disc of NGC 1433 grows in accordance with an inside-out formation scenario. This methodology is applicable to high-resolution integral field spectroscopic data of barred galaxies with nuclear discs, making it ideally suited for the TIMER survey sample. In the future we will thus be able to determine the bar age for a large sample of galaxies, shedding light on the epoch of disc settling and bar formation.
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Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology
We are a large, diverse, and very active research group aiming to provide a comprehensive picture for the formation of galaxies in the Universe. Rooted in detailed stellar population analysis, we are constantly exploring and developing new tools and ideas to understand how galaxies came to be what we now observe.
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Nuclear Activity in Galaxies: a 3D Perspective from the Nucleus to the Outskirts
This project consists of two main research lines. First, the study of quasar-driven outflows in luminous and nearby obscured active galactic nuclei (AGN) and the impact that they have on their massive host galaxies (AGN feedback). To do so, we have obtained Gran Telescopio CANARIAS (GTC) infrared and optical observations with the instruments
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