An H <i>α</i> view of galaxy buildup in the first 2 Gyr: Luminosity functions at <i>z</i>   ∼  4−6.5 from NIRCam/grism spectroscopy

The H α nebular emission line is an optimal tracer for recent star formation in galaxies. With the advent of JWST , this line has recently become observable at z &gt; 3 for the first time. We present a catalog of 1050 H α emitters at 3.7 &lt; z &lt; 6.7 in the GOODS fields obtained from a blind search in JWST NIRCam/grism data. We made use of the FRESCO survey’s 124 arcmin 2 of observations in GOODS-North and GOODS-South with the F444W filter, probing H α at 4.9 &lt; z &lt; 6.7, and the CONGRESS survey’s 62 arcmin 2 of observations in GOODS-North with F356W, probing H α at 3.8 &lt; z &lt; 5.1. We found an overdensity with…