2023-12-04 テキサス大学オースチン校(UT Austin)
◆これまで希少とされたこのタイプのギャラクシーが、初期宇宙で予想以上に一般的である可能性が浮上。ジェームズ・ウェッブ宇宙望遠鏡はその感度から、塵に覆われたギャラクシーを初めて詳細に観測でき、初期宇宙の歴史理解に新たな視点を提供する可能性がある。
＜関連情報＞
- https://news.utexas.edu/2023/12/04/ghostlike-dusty-galaxy-reappears-in-james-webb-space-telescope-image/
- https://iopscience.iop.org/article/10.3847/1538-4357/acf614
COSMOS-Web に見る、z ∼ 5 の近赤外線微光・遠赤外線塵銀河 A Near-infrared-faint, Far-infrared-luminous Dusty Galaxy at z ∼ 5 in COSMOS-Web
Jed McKinney, Sinclaire M. Manning, Olivia R. Cooper, Arianna S. Long, Hollis Akins, Caitlin M. Casey, Andreas L. Faisst, Maximilien Franco, Christopher C. Hayward, Erini Lambrides, Georgios Magdis, Katherine E. Whitaker, Min Yun, Jaclyn B. Champagne, Nicole E. Drakos, Fabrizio Gentile, Steven Gillman, Ghassem Gozaliasl, Olivier Ilbert, Shuowen Jin, Anton M. Koekemoer, Vasily Kokorev, Daizhong Liu, R. Michael Rich, Brant E. Robertson, Francesco Valentino, John R. Weaver, Jorge A. Zavala, Natalie Allen, Jeyhan S. Kartaltepe, Henry Joy McCracken, Louise Paquereau, Jason Rhodes, Marko Shuntov, and Sune Toft
The Astrophysical Journal Published 2023 October 10
DOI:10.3847/1538-4357/acf614
Abstract
A growing number of far-infrared (FIR) bright sources completely invisible in deep extragalactic optical surveys hint at an elusive population of z > 4 dusty, star-forming galaxies. Cycle 1 JWST surveys are now detecting their rest-frame optical light, which provides key insight into their stellar properties and statistical constraints on the population as a whole. This work presents the JWST Near Infrared Camera (NIRCam) counterpart from the COSMOS-Web survey to an FIR SCUBA-2 and Atacama Large Millimeter/submillimeter Array (ALMA) source, AzTECC71, which was previously undetected at wavelengths shorter than 850 μm. AzTECC71, among the reddest galaxies in COSMOS-Web with F277W − F444W ∼ 0.9, is undetected in NIRCam/F150W and F115W and fainter in F444W than other submillimeter galaxies identified in COSMOS-Web by 2–4 magnitudes. This is consistent with the system having both a lower stellar mass and higher redshift than the median dusty, star-forming galaxy. With deep ground- and space-based upper limits combined with detections in F277W, F444W, and the FIR including ALMA Band 6, we find a high probability (99%) that AzTECC71 is at z > 4 with Zphot=5.7−0.7+0.8. This galaxy is massive (logM∗/M⊙∼10.7) and infrared-luminous (logLIR/L⊙∼12.7), comparable to other optically undetected but FIR-bright dusty, star-forming galaxies at z > 4. This population of luminous, infrared galaxies at z > 4 is largely unconstrained but comprises an important bridge between the most extreme dust-obscured galaxies and more typical high-redshift star-forming galaxies. If further FIR-selected galaxies that drop out of the F150W filter in COSMOS-Web have redshifts z > 4 like AzTECC71, then the volume density of such sources may be ∼3–10 × greater than previously estimated.
