Kavli Affiliate: Luis C. Ho
| First 5 Authors: Xinyue Liang, Si-Yue Yu, Taotao Fang, Luis C. Ho,
| Summary:
Understanding the methodological robustness in identifying and quantifying
high-redshift bars is essential for studying their evolution with the {it
James} {it Webb} Space Telescope (JWST). Using a sample of nearby spiral
galaxies, we created simulated images consistent with the observational
conditions of the Cosmic Evolution Early Release Science (CEERS) survey.
Through a comparison of measurements before and after image degradation, we
show that the bar measurements for massive galaxies remain robust against
noise. While the bar position angle measurement is unaffected by resolution,
both the bar size ($a_{rm bar}$) and bar ellipticity are typically
underestimated, with the extent depending on $a_{rm bar}/{rm FWHM}$. To
address these effects, correction functions are derived. We find that the
detection rate of bars remains at $sim$ 1 when the $a_{rm bar}/{rm FWHM}$ is
above 2, below which the rate drops sharply, quantitatively validating the
effectiveness of using $a_{rm bar}>2times {rm FWHM}$ as a bar detection
threshold. By holding the true bar fraction ($f_{rm bar}$) constant and
accounting for both resolution effects and intrinsic bar size growth, the
simulated CEERS images yield an apparent F444W-band $f_{rm bar}$ that
decreases significantly with higher redshifts. Remarkably, this simulated
apparent $f_{rm bar}$ is in good agreement with JWST observations reported by
Conte et al., suggesting that the observed $f_{rm bar}$ is significantly
underestimated, especially at higher redshifts, leading to an overstated
evolution of the $f_{rm bar}$. Our results underscore the importance of
disentangling the true $f_{rm bar}$ evolution from resolution effects and bar
size growth.
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