Characterizing Massive Star-Forming Galaxies across the Cosmic Time through ALMA and JWST NIRCam Grism Spectroscopy

Abstract

Over the past decade, our knowledge of the formation and evolution of massive galaxies has been greatly expanded with the Atacama Large Millimeter/submillimeter Array (ALMA). With unprecedented sensitivity and angular resolution, ALMA enables the secure identification of numerous dusty star-forming galaxies (DSFGs) across the bulk of cosmic history, resolving the cold dust and gas components of these galaxies in great detail. Leveraging off the gravitational lensing effects from massive galaxy clusters, I conduct spatially resolved studies of the stellar and dust components of lensed submillimeter galaxies (SMGs) at z=1-3. I find that although the majority of SMGs host compact dust continuum emission when compared with their stellar components, this is not the case for certain SMGs with relatively low millimeter surface brightness and extended dust profiles. These sources can potentially be interpreted as galaxies undergoing the "inside-out" quenching after the cessation of central starbursts, which is also seen in certain local post-starburst galaxies with extended molecular gas reservoirs. The combination of ALMA observations and gravitational lensing is so powerful that it enables the detection of faint DSFGs that are below the detection limit of traditional blank field surveys. With the ALMA Lensing Cluster Survey and the Herschel Lensing Survey, I obtain accurate dust mass and temperature measurements of 109 lensed DSFGs across z=0.5-6, whose star-formation rates are much lower than those of conventional SMGs. At given infrared luminosities, I show that the redshift evolution of cold dust temperature remains weak. The high-redshift subset (z~4) of our sample is dominated by optical/near-IR-dark galaxies that are typically missed in surveys conducted by the Hubble Space Telescope. I conclude that such galaxies are compact in both stellar and dust components, and they could contribute to ~10% of the cosmic star formation rate density and trace the early phase of massive galaxy formation. Such galaxies can also trace overdense galaxy environments and massive dark matter halos, which is demonstrated through the case study of HDF850.1 at z=5.18, the most luminous SMG in the Hubble Deep Field. Finally, with the long-awaited launch and operation of the James Webb Space Telescope (JWST), the study of massive galaxy formation at high redshifts (z>~6) has been rapidly revolutionized by the unprecedented imaging and spectroscopic capability at infrared wavelengths. I highlight my contribution to the successful commissioning and calibration of the wide-field slitless spectroscopy (WFSS) observing mode of the Near-InfraRed Camera (NIRCam), which enables one of the first direct detections of rest-frame optical emission lines ([O III] 5007, Halpha) from normal star-forming galaxies in the Epoch of Reionization. I obtain the first direct measurement of [O III] and Halpha luminosity function at z>6, which confirms the ubiquity of strong emission-line galaxies in the early universe. I demonstrate that the NIRCam WFSS mode is highly efficient in spectroscopically confirming massive star-forming galaxies at high redshifts (z~5-9), and also the large-scale overdense environment that they trace. This sheds light on highly complete spectroscopic surveys of star-forming galaxies, no matter whether dusty or not, towards the Epoch of Reionization, which will further transform our understanding of massive galaxy formation and evolution in the upcoming decade.