Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Panchromatic Hubble Andromeda Treasury XVI. Star Cluster Formation
  Efficiency and the Clustered Fraction of Young Stars   We use the Panchromatic Hubble Andromeda Treasury (PHAT) survey dataset to
perform spatially resolved measurements of star cluster formation efficiency
($\Gamma$), the fraction of stellar mass formed in long-lived star clusters. We
use robust star formation history and cluster parameter constraints, obtained
through color-magnitude diagram analysis of resolved stellar populations, to
study Andromeda's cluster and field populations over the last $\sim$300 Myr. We
measure $\Gamma$ of 4-8% for young, 10-100 Myr old populations in M31. We find
that cluster formation efficiency varies systematically across the M31 disk,
consistent with variations in mid-plane pressure. These $\Gamma$ measurements
expand the range of well-studied galactic environments, providing precise
constraints in an HI-dominated, low intensity star formation environment.
Spatially resolved results from M31 are broadly consistent with previous trends
observed on galaxy-integrated scales, where $\Gamma$ increases with increasing
star formation rate surface density ($\Sigma_{\mathrm{SFR}}$). However, we can
explain observed scatter in the relation and attain better agreement between
observations and theoretical models if we account for environmental variations
in gas depletion time ($\tau_{\mathrm{dep}}$) when modeling $\Gamma$,
accounting for the qualitative shift in star formation behavior when
transitioning from a H$_2$-dominated to a HI-dominated interstellar medium. We
also demonstrate that $\Gamma$ measurements in high $\Sigma_{\mathrm{SFR}}$
starburst systems are well-explained by $\tau_{\mathrm{dep}}$-dependent
fiducial $\Gamma$ models.

1
The categories of this paper are: cs
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
2
The categories of this paper are: math
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org