A SPectroscopic Survey of Biased Halos in the Reionization Era (ASPIRE): Spectroscopically Complete Census of Obscured Cosmic Star Formation Rate Density at z = 4–6
Hennawi, Joseph F.; Shen, Yue; Fan, Xiaohui; Colina, Luis; Cai, Zheng; Lin, Xiaojing; Li, Mingyu; Wu, Yunjing; Rieke, George H.; Walter, Fabian; Meyer, Romain A.; Egami, Eiichi; Sun, Fengwu; Jun, Hyunsung D.; Yang, Jinyi; Wang, Feige; Bañados, Eduardo; Liu, Weizhe; Li, Zihao; Champagne, Jaclyn B.; Decarli, Roberto; Jin, Xiangyu; Khusanova, Yana; Tee, Wei Leong; Venemans, Bram; Zhang, Huanian; Zou, Siwei; Pudoka, Maria A.
United States, Italy, Germany, China, Spain, Netherlands, South Korea, Denmark, Switzerland
Abstract
We present a stringent measurement of the dust-obscured star formation rate density (SFRD) at z = 4–6 from the ASPIRE JWST Cycle-1 medium and ALMA Cycle-9 large program. We obtained JWST/NIRCam grism spectroscopy and ALMA 1.2 mm continuum map along 25 independent quasar sightlines, covering a total survey area of ∼35 arcmin2 where we search for dusty star-forming galaxies (DSFGs) at z = 0–7. We identify eight DSFGs in seven fields at z = 4–6 through the detection of Hα or [O III] λ5008 lines, including fainter lines such as Hβ, [O III] λ4960, [N II] λ6585, and [S II] λλ6718,6733 for six sources. With this spectroscopically complete DSFG sample at z = 4–6 and negligible impact from cosmic variance (shot noise), we measure the infrared luminosity function (IRLF) down to LIR ∼ 2 × 1011 L⊙. We find flattening of IRLF at z = 4–6 towards the faint end (power-law slope