Tracing young star-forming clumps in the nearby flocculent spiral galaxy
  NGC 7793 with UVIT imaging
  Star formation in galaxies is a hierarchical process with a wide range of
scales from smaller clusters to larger stellar complexes. Here, we present an
ultra-violet imaging study of the nearby flocculent spiral galaxy NGC 7793,
observed with the Ultra-Violet Imaging Telescope (UVIT). We find that the disk
scale-length estimated in Far-UV (2.64$\pm$0.16 kpc) is larger than that in
Near-UV (2.21$\pm$0.21 kpc) and optical (1.08 kpc), which supports the
inside-out growth scenario of the galaxy disk. The star-forming UV disk is also
found to be contained within the extent of H~I gas of column density greater
than $10^{21}$cm$^{-2}$. With the spatial resolution of UVIT (1 pixel $\sim$
6.8 pc), we identified 2046 young star-forming clumps in the galaxy with radii
between $\sim$ 12 - 70 pc, which matches well with the size of GMCs detected in
the galaxy. Around 61\% of the regions identified in our study have age younger
than 20 Myr, which points to a recent enhancement of star formation across the
galaxy. We also noticed that the youngest star-forming regions, with age $<$ 10
Myr, distinctly trace the flocculent arms of the galaxy. The estimated mass of
the clumps cover a range between $10^3 - 10 ^6 M_{\odot}$. We noticed a
gradient in the mass distribution of identified clumps along the spiral arms.
We have also studied the nuclear star cluster of the galaxy and found that the
stellar populations in the cluster outskirts are younger than the inner part.
