Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Robust Cross-correlation-based Measurement of Clump Sizes in Galaxies   Stars form in molecular complexes that are visible as giant clouds ($\sim
10^{5-6} \mathrm{M}_\odot$) in nearby galaxies and as giant clumps ($\sim
10^{8-9}\mathrm{M}_\odot$) in galaxies at redshifts $z\approx1$$-$$3$.
Theoretical inferences on the origin and evolution of these complexes often
require robust measurements of their characteristic size, which is hard to
measure at limited resolution and often ill-defined due to overlap and
quasi-fractal substructure. We show that maximum and luminosity-weighted sizes
of clumps seen in star formation maps (e.g.\ H$\alpha$) can be recovered
statistically using the two-point correlation function (2PCF), if an
approximate stellar surface density map is taken as the normalizing random
field. After clarifying the link between Gaussian clumps and the 2PCF
analytically, we design a method for measuring the diameters of Gaussian clumps
with realistic quasi-fractal substructure. This method is tested using mock
images of clumpy disk galaxies at different spatial resolutions and perturbed
by Gaussian white noise. We find that the 2PCF can recover the input clump
scale at $\sim20\%$ accuracy, as long as this scale is larger than the spatial
resolution. We apply this method to the local spiral galaxy NGC 5194, as well
as to three clumpy turbulent galaxies from the DYNAMO-HST sample. In both
cases, our statistical H$\alpha$-clump size measurements agree with previous
measurements and with the estimated Jeans lengths. However, the new
measurements are free from subjective choices when fitting individual clumps.

14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs