Project A

Spiral arms as drivers of chemical enrichment in galaxies

Laura Sánchez Menguiano & Dimitri Gadotti

(email advisors)

Are spiral arms more metal-rich than the underlying galaxy disc? Join us on the effort to answer this question and unveil the role of the spiral structure in the evolution of their host galaxies.

Spiral arms are one of the most characteristic features in disc galaxies. Easily distinguishable due to their association with bright, newly-born stars, they are key dynamical agents in the evolution of galaxies. However, despite being responsible for most of the redistribution of material in galaxies, the impact of spiral arms in the overall chemical evolution of their host galaxies is still unclear.

After decades attempting to study the distribution of metals in spiral galaxies from spatially limited datasets, we are living an unprecedented revolution in which spectroscopic instruments covering the two-dimensional (2D) extension of galaxies are starting to unveil the 2D metallicity distribution in large samples of spiral galaxies. For the first time, astronomers have tackled the effect of 2D structures, such as spiral arms, on the chemical evolution of galaxies. A growing number of studies are reporting the presence of more metal-rich gas associated with the spiral structure in individual galaxies. However, recent attempts analysing larger samples find conflicting results. While some systems show no evidence for significant large-scale azimuthal variations related to the spiral pattern, others do reveal clear enrichment patterns along them. In this regard, detailed studies focused on individual galaxies would assess the particular conditions that induce this enrichment pattern associated with the spiral arms.

In this project, the student will perform a thorough analysis of the gas metallicity distribution in NGC 4981 searching for enrichment patterns linked to its spiral structure. The student will have the opportunity to work with impressive high-resolution observations (part of the TIMER project) collected with the powerful MUSE instrument mounted on the VLT telescope in Chile. They will gain experience analysing optical spectroscopic data, performing tasks such as fitting spectra to derive the gas emission and chemical abundances, as well as tracing spiral arms.

#spectroscopy #MUSE #VLT #optical #spiralgalaxies #gasmetallicity #spiralarms #python

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