Evidence in favour of density wave theory through age gradients observed in star formation history maps and spatially resolved stellar clusters

• DOI: 10.1093/mnras/stac459
• Publication Date: 2022-02-17T12:08:46Z
• Authors: Shameer Abdeen; Benjamin L Davis; Rafael Eufrasio; Daniel Kennefick; Julia Kennefick; Ryan Miller; Deanna Shields; Erik B Monson; Calla Bassett; Harry O’Mara
• Keywords: Stellar density; Density wave theory

ABSTRACT Quasi-stationary density wave theory predicts the existence of an age gradient across spiral arms with a phase crossing at corotation radius. We have examined evidence for such gradients using star formation history (SFH) maps derived from lightning, spectral energy distribution fitting procedure, and by spatially resolved stellar clusters. Three galaxies LEGUS survey were used to analyse azimuthal offsets Kernel estimation plots cluster distance reveal prominent central peaks secondary on positive side, relative NGC 5194 5236. These downstream in distributions show overall gradient. 628 shows both sides wave. The also increasing spatial spread age, consistent expectation that they born SFH 12 nearby analysed spirality, matlab-based code, which synthetic over FITS images. gradual decrement (tightening) pitch angles age. By analysing angle differences between adjacent bins error function, average probabilities $69{{\ \rm per\ cent}}\pm 25{{\ cent}}$ chance values decrease (tighten) Thus, we see tightening pattern galaxies, when segregating populations specifically or more generally colour, as was shown our previous studies.