Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Morphology and enhanced star formation in a Cartwheel-like ring galaxy   We use hydrodynamical simulations of a Cartwheel-like ring galaxy, modelled
as a nearly head-on collision of a small companion with a larger disc galaxy,
to probe the evolution of the gaseous structures and flows, and to explore the
physical conditions setting the star formation activity. Star formation is
first quenched by tides as the companion approaches, before being enhanced
shortly after the collision. The ring ploughs the disc material as it radially
extends, and almost simultaneously depletes its stellar and gaseous reservoir
into the central region, through the spokes, and finally dissolve 200 Myr after
the collision. Most of star formation first occurs in the ring before this
activity is transferred to the spokes and then the nucleus. We thus propose
that the location of star formation traces the dynamical stage of ring
galaxies, and could help constrain their star formation histories. The ring
hosts tidal compression associated with strong turbulence. This compression
yields an azimuthal asymmetry, with maxima reached in the side furthest away
from the nucleus, which matches the star formation activity distribution in our
models and in observed ring systems. The interaction triggers the formation of
star clusters significantly more massive than before the collision, but less
numerous than in more classical galaxy interactions. The peculiar geometry of
Cartwheel-like objects thus yields a star (cluster) formation activity
comparable to other interacting objects, but with notable second order
differences in the nature of turbulence, the enhancement of the star formation
rate, and the number of massive clusters formed.

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The categories of this paper are: dg-ga
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The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: math
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The categories of this paper are: econ
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The categories of this paper are: hep-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: nlin
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The categories of this paper are: nucl-th