Poster Presentation

Constructing the Largest Sample of Infrared-bright Dust-Obscured Galaxies with HSC-SSP Final Data: SED Classification and Properties

Author(s): Yui Nishimura(Ritsumeikan University) ,Yoshiki Toba(Ritsumeikan University),Tohru Nagao(Ehime University),Taketo Yoshida(Ehime University),Naomichi Yutani(Kobe University)

Presenter: Yui Nishimura (Ritsumeikan University)

Dust-Obscured Galaxies (DOGs) represent a crucial phase in galaxy evolution and are expected to harbor rapidly growing supermassive black holes (SMBHs). They provide essential insights into the maximum growth phase of SMBH–galaxy co-evolution, which is typically obscured by significant amounts of surrounding dust. However, the statistical and physical properties of DOGs, particularly the infrared (IR)-bright population, remain poorly understood. In this study, we conducted a systematic search utilizing the latest HSC-SSP data (s23a_wide) combined with VIKING DR4 and ALLWISE data. This multiwavelength approach yielded 1,037 DOGs, constituting the largest sample of IR-bright DOG candidates to date. Based on the optical-to-mid-IR SEDs, we classified the candidates following the criteria of Toba et al. (2015). The sample consisted of 270 power-law (PL) DOGs, 290 Bump DOGs, and 436 broken-PL (BPL) DOGs (BPL DOGs; Yoshida et al. 2025), with the remaining 41 sources left unclassified due to insufficient data. Furthermore, we successfully identified 10 Blue-excess DOGs (BluDOGs; Noboriguchi et al. 2019). The WISE color–color diagram reveals that 86.7% of the PL and 86.0% of the BPL DOGs fall within the AGN wedge, indicating dominant AGN contributions. Notably, all BluDOGs reside in the AGN region, suggesting that intense AGN activity plays a significant role in these optically blue dusty systems. This study significantly expands the sample of IR-bright DOGs, providing a vital statistical foundation for discussing their physical properties and role in the cosmic history of SMBH growth.