Nebular Emission From Supermassive Dark Stars

The James Webb Space Telescope (JWST) already brought some revolutionary and exciting data, which is poised to change our understanding of the cosmic dawn era. Namely, JWST discovered an unexpectedly large number of compact, yet very bright objects, that formed very early on. According to simulations, those objects should not exist. This is the so called ``too many too massive too soon'' JWST puzzle. In addition, the origin of the massive seeds of Super Massive Black Holes (SMBH) powering high redshift quasars is another unsolved mystery in astronomy. Supermassive stars powered by Dark Matter annihilations (Supermassive Dark Stars, i.e. SMDSs) provide a natural solution for both puzzles, as we will explain in detail in this talk. In fact, the SMDS hypothesis is consistent with JWST data, with the first three candidates having been identified in Ilie et al [2023]. One of those, JADES-GS-z13 is the most distant object in the universe, whose light was emitted less than 350 million years after the big bang. In this work we used Cloudy to consider the potentially important effect Nebular Emission could have on the spectra of Supermassive Dark Stars, and, in turn, on their observable signatures. Gas surrounding sufficiently hot stars can get ionized and emit a glow called nebular emission. We find that for the hottest SMDSs nebular emission can be significant, and drastically alter their spectra. Additionally, we find that the nebular emission is almost insensitive to the density of the surrounding gas cloud.