I will present an overview of the JWST NIRCam wide-field slitless spectroscopy (WFSS). This observing mode is highly efficient in spectroscopically confirming galaxies in the Epoch of Reionization through rest-frame optical emission lines (e.g., [OIII] and Hα). With NIRCam WFSS, galaxies at z>6 can be easily detected and confirmed with ~10-min integration. The following studies will be highlighted in my talk:
1) Direct measurement of [OIII] and Hα luminosity functions (LFs) at z>6. We find substantial brightening of [OIII] LF from z=3 to 6, and weak/no evolution of Hα LF from z=2 to 6. This suggests the ubiquity of strong emission-line galaxies in the early Universe.
2) Discoveries and characterization of galaxy overdensities at z=5-9 in both the GOODS-S/N fields. Coma-progenitor-like galaxy protoclusters are highly abundant when the Universe is only 1 Gyr old, and they host ~50% of cosmic star formation at this epoch.
3) Spectroscopic confirmation of "HST-dark" dusty star-forming galaxies (DSFGs) at z>5 that are selected by (sub)-millimeter surveys (e.g., ALMA). This promises the direct measurement of dust-obscured cosmic SFR density at z>5 with spectroscopically complete sample of DSFGs.
I will also introduce my Cycle-2 medium program, MAGNIF (GO-2883) as PI. This novel cosmological experiment will use the NIRCam WFSS mode to study the cosmic reionization photon budget through gravitationally lensed dwarf galaxies at z=6-9.
BIO
Fengwu Sun will begin his postdoc researcher position at Steward Observatory, the University of Arizona in July 2023. Before that, he received bachelor’s degree at Department of Astronomy, Peking University in 2018, and Ph.D. at Steward Observatory under the supervision of Dr. Eiichi Egami and Dr. Marcia Rieke in 2023. Fengwu’s research focuses on observations of star-forming galaxies at cosmological distances, especially using millimeter interferometers like ALMA and space telescopes like JWST. On the ALMA side, he is one of the nine selected “ALMA ambassadors” in 2022. On the JWST side, he is a member of the NIRCam instrument and science team and commissioned the grism slitless spectroscopic mode of the instrument. He is leading and contributing to multiple ALMA and JWST observation programs in the latest cycle to study the evolution of galaxies across the cosmic history.
