Deep Spectroscopic Follow-Up of Maisie's Galaxy -- A Typical Galaxy in the Early Universe

The first several years of JWST observations have yielded surprisingly large numbers of bright z>10 galaxies, with follow-up spectroscopy of many of these sources implying extreme star formation activity and/or AGN content. Here, we present a combination of two deep Cycle 3 NIRSpec G395M programs, totaling over 19 hours of exposure time, plus MIRI/LRS observations for one such high-redshift source: Maisie's Galaxy. We provide an updated redshift measurement of z = 11.408 plus or minus 0.005 for this source. Measurements of the [OII] doublet in these data yield an electron density (n e = 108.56+873.9-35.37) and a star-formation rate (SFR[OII] = 1.3 plus or minus 0.35), placing it along the star-formation main sequence (SFMS) and indicating that this is a much more typical, rather than extreme, source in the early Universe. We also report fluxes for the [OIII] lambda 5008 and [NeIII] lambda 3869 lines that provide us with a (Ne3O2) = -0.219 plus or minus 0.145 and a (O32) =0.724 plus or minus 0.191. We estimate the metallicity (Z/Z = 0.17 plus or minus 0.05) and ionization parameter ((U) = -2.26 plus or minus 0.13) from the Ne3O2 ratio. We place this galaxy in the context of other z>10 sources with similar line detections and compare the results to those obtained from SED fitting. The results suggest that we should go deeper with our observations to better understand the average galaxy population at these early times.