One of the most significant longstanding questions is how rapidly the most massive galaxies build up in the early universe. Addressing this question directly has not been possible due to a lack of a sizeable sample of spectroscopically-confirmed, especially high-mass galaxies in the early Universe on which to execute physical studies. Excitingly enough, we are now on the brink of making significant progress thanks to identification of a large sample of massive galaxies in the z>6.5 universe from ongoing ALMA large program observations. Galaxies have spectroscopic redshifts from [CII] and show prominent emission in the far-IR. We propose to obtain NIRSpec IFU R100 observations for 12 of the brightest [CII]-detected sources from this sample. Our IFU observations will provide us with a unique high spatial resolution view of both the stellar mass and unobscured star formation rates in these high-mass sources, as well as the metallicity and radiation fields. Thanks to the size of our sample, we will be able to evaluate the efficiency of star formation in galaxies at early times, determine the impact of merger-driven star formation on stellar mass growth in z>6 galaxies, and explore correlations between a wide variety of different physical properties deriveable from the joint JWST+ALMA data set. The significantly higher mass/SFRs of sources in our sample as compared to JADES and CEERS program will allow us to uniquely explore the properties of galaxies to very high masses. The resulting JWST+ALMA dataset will establish a reference sample of reionization epoch galaxies with unique panchromatic information for the JWST era and beyond.
|Publication status||Published - 1-Mar-2021|