Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence in favour of density wave theory through star formation history
  maps and spatially resolved stellar clusters   Stationary Density Wave Theory predicts the existence of an age gradient
across the spiral arms with a phase crossing at the co-rotation radius. Using
star formation history (SFH) maps of 12 nearby spiral galaxies derived from
\textsc{LIGHTNING} \citep{Eufracio:2017}, a spectral energy distribution (SED)
fitting procedure, and by using \textsc{Spirality} \citep{Shield:2015} a
\textsc{MATLAB}-based code which plots synthetic spiral arms over \textsc{FITS}
images, we have found a gradual decrement in pitch angles with increasing age,
thus providing us with evidence in favour of the Stationary Density Wave
Theory. We have also used azimuthal offsets of spatially resolved stellar
clusters in 3 LEGUS galaxies to observe age trends.

31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs