Similarity between Compact Extremely Red Objects Discovered with JWST in Cosmic Dawn and Blue-excess Dust-obscured Galaxies Known in Cosmic Noon

• Published in: Astrophysical journal. Letters 2023-12, Vol.959 (2), p.L14
• Main Authors: Noboriguchi, Akatoki, Inoue, Akio K., Nagao, Tohru, Toba, Yoshiki, Misawa, Toru
• Format: Article
• Language: English
• Subjects: Active galactic nuclei; Astronomical models; Black holes; Color; Cosmic dust; Dust; Galaxies; Galaxy evolution; James Webb Space Telescope; Quasars; Similarity; Space telescopes; Star formation; Ultraviolet spectra
• ISSN: 2041-8205; 2041-8213
• DOI: 10.3847/2041-8213/ad0e00

Spatially compact objects with extremely red color in the rest-frame optical to near-infrared (0.4–1 μ m) and blue color in the rest-frame ultraviolet (UV; 0.2–0.4 μ m) have been discovered at 5 < z < 9 using the James Webb Space Telescope (JWST). These extremely red objects (JWST-EROs) exhibit spectral energy distributions (SEDs) that are difficult to explain using a single component of either star-forming galaxies or quasars, leading to two-component models in which the blue UV and extremely red optical are explained using less-dusty and dusty spectra of galaxies or quasars, respectively. Here, we report the remarkable similarity in SEDs between JWST-EROs and blue-excess dust-obscured galaxies (BluDOGs) identified at 2 < z < 3. BluDOGs are a population of active galactic nuclei (AGNs) with black hole masses of ∼10 8–9 M ⊙ , which are 1 order of magnitude larger than those in some JWST-EROs. The Eddington ratios of BluDOGs are 1 or higher, whereas those of JWST-EROs are in the range of 0.1–1. Therefore, JWST-EROs are less massive, less active, and more common counterparts in higher- z of BluDOGs in cosmic noon. Conversely, JWST-EROs have a significantly higher fraction of those with blue excess than DOGs. We present the average UV spectra of BluDOGs as a comparison to JWST-EROs and discuss a coherent evolutionary scenario for dusty AGN populations.