Subaru/HSC deep optical imaging of infrared sources in the AKARI North Ecliptic Pole-Wide field. Issue 4 (20th October 2020)

• Record Type: Journal Article
• Authors: Oi, Nagisa; Goto, Tomotsugu; Matsuhara, Hideo; Utsumi, Yousuke; Momose, Rieko; Toba, Yoshoki; Malkan, Matthew; Takagi, Toshinobu; Huang, Ting-Chi; Kim, Seong Jin; Ohyama, Youichi
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 500:Issue 4(2021)
• Page Start: 5024
• Page End: 5042
• Publication Date: 2020-10-20
• Subjects: galaxies: evolution -- galaxies: photometry -- galaxies: starburst -- galaxies: star formation -- infrared: galaxies; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa3080
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present a five-broad-band ( grizy ) photometric catalogue of Subaru/Hyper Suprime-Cam (HSC) optical imaging observations at around the North Ecliptic Pole (NEP) where the AKARI infrared (IR) satellite conducted a large survey (NEP-Wide survey). The observations cover almost all the NEP-Wide survey field down to the depth of 28.1, 26.8, 26.3, 25.5, and 25.0 mag (5σ) at grizy, respectively. The five-band HSC catalogue contains about 2.6 million objects, and 70 959 AKARI NEP-Wide counterpart sources are identified in the catalogue. We added existing supplementary catalogues from the u band to the far-IR band, and estimated photo- z for the AKARI-HSC sources. We achieved σΔ z /(1 + zs ) = 0.06 and an outlier rate of 13.4 per cent at z = 0.2–1.5. Using the spectral energy distribution (SED) template fitting, we classified the AKARI-HSC galaxies into four categories, namely quiescent, star-forming, Type1 active galactic nucleus (AGN), and Type2 AGN, in each redshift bin. At z > 1, the mean SED of star-forming galaxies in mid-IR (3–10 μ m) range is significantly different from that of spiral galaxies in the nearby Universe, indicating that many of star-forming galaxies at z > 1 contain a heat source capable of heating dust to temperatures that radiate thermal emission in the mid-IR range. Furthermore, we estimated the number fraction of AGNs ( f AGN ) in each bin of redshift and IR luminosity ( L IR ), and examined the dependence of redshift and L IR . In log( L IR /L⊙ ) = 11.0–14.0, the f AGN shows a significant increase with increasing redshift, regardless of the L IR bins. In contrast, the f AGN shows a slight increase against L IR at z < 1 and no increase with increasing L IR at z > 1.