Kavli Affiliate: Linhua Jiang
| Summary:
We combine wide-area COSMOS-3D observations with deeper GOODS-N data from JWST/NIRCam F444W wide-field slitless spectroscopy to trace cosmic star formation over $zsim0$–9. The observations cover approximately $0.33~mathrmdeg^2$ in COSMOS and $60.9~mathrmarcmin^2$ in GOODS-N, with typical $3σ$ integrated line-flux limits of $3.2times10^-18$ and $1.04times10^-18~mathrmerg,s^-1,cm^-2$, respectively. The common $3.9$–$5.0,μ$m wavelength window probes Br$α$, Br$β$, Pa$α$, Pa$β$, H$α$, and H$β$ across the local Universe, cosmic noon, and reionization. Our final sample contains 9146 galaxies, including 7883 in COSMOS and 1263 in GOODS-N. COSMOS constrains luminous emitters, while GOODS-N extends the luminosity functions toward fainter sources. We measure dust-corrected line luminosities, account for line-detection completeness, and convert the six lines to equivalent H$α$ luminosities assuming Case B recombination. Schechter fits reveal an increase in the characteristic H$α$-equivalent luminosity toward cosmic noon. Integrating the resulting star formation rate functions above $0.24,M_odot,mathrmyr^-1$, we trace the cosmic star formation rate density from the local Universe to reionization. The combined Brackett, Paschen, and Balmer measurements are broadly consistent with the canonical UV- and IR-based cosmic star formation history at $zlesssim6$. Fixed-slope tests show that the H$β$ estimate at $zsim8$ remains sensitive to the external photometric faint-end constraint and extrapolation below our spectroscopic limit. These measurements provide complementary constraints on the distribution and integrated rate of star formation across cosmic time.
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