Speaker
Description
The James Webb Space Telescope has found more than 700 high redshift objects (z>10), far too many to be compatible with the number of galaxies predicted in LCDM. We investigate the possibility that some could instead be Dark Stars. These would have been the first stars in the Universe, made (almost entirely) of hydrogen and helium from the Big Bang, with 0.1% of the mass in the form of Dark Matter. DS would be powered by the heat from Dark Matter annihilation rather than by fusion. The relevant types of dark matter include Weakly Interacting Massive Particles (WIMPs), and Self Interacting Dark Matter (SIDM). Although dark matter constitutes only ≲0.1% of the stellar mass, this amount is sufficient to power the star for millions to billions of years. They are very bright diffuse puffy objects (10 AU in radius) and grow to be very massive. In fact, they can grow up to ten million solar masses with up to ten billion solar luminosities. We show that three of four hi-z JADES objects in JWST data could in fact be Supermassive Dark Stars: the spectra are a good match, and in the future with better spectra the detection of a HeII 1640 absorption line would be a smoking gun for a Dark Star vs a galaxy. Once the dark matter fuel runs out and the dark star dies, it may collapse to a black hole. Thus dark stars may provide seeds for as yet unexplained supermassive black holes observed at early times as well as in galaxies today.
