First Look at z > 1 Bars in the Rest-frame Near-infrared with JWST Early CEERS Imaging

[摘要] Stellar bars are key drivers of secular evolution in galaxies and can be effectively studied using rest-frame near-infrared (NIR) images, which trace the underlying stellar mass and are less impacted by dust and star formation than rest-frame UV or optical images. We leverage the power of JWST CEERS NIRCam images to present the first quantitative identification and characterization of stellar bars atz> 1 based on rest-frame NIR F444W images of high resolution (∼1.3 kpc atz∼ 1–3). We identify stellar bars in these images using quantitative criteria based on ellipse fits. For this pilot study, we present six examples of robustly identified bars atz> 1 with spectroscopic redshifts, including the two highest-redshift bars atz∼ 2.136 and 2.312 quantitatively identified and characterized to date. The stellar bars atz∼ 1.1–2.3 presented in our study have projected semimajor axes of ∼2.9–4.3 kpc and projected ellipticities of ∼0.41–0.53 in the rest-frame NIR. The barred host galaxies have stellar masses ∼1×10¹⁰ to 2×10¹¹ M _⊙ and star formation rates of ∼21–295M _⊙ yr⁻¹, and several have potential nearby companions. Our finding of bars atz∼ 1.1–2.3 demonstrates the early onset of such instabilities and supports simulations where bars form early in massive dynamically cold disks. It also suggests that if these bars at lookback times of 8–11 Gyr survive out to present epochs, bar-driven secular processes may operate over a long time and have a significant impact on some galaxies byz∼ 0.