James Webb Space Telescope Feed Post

Harvard ADS: Blue Monsters at z>10. Where has all their dust gone?

Paper abstract: The properties of luminous, blue (a.k.a. Blue Monsters), super-early galaxies at redshift z>10 have been successfully explained by the attenuation-free model (AFM) in which dust is pushed to kpc-scales by radiation-driven outflows. As an alternative to AFM, here we assess whether *attenuation-free* conditions can be replaced by a *dust-free* scenario in which dust is produced in very limited amounts and/or later destroyed in the interstellar medium. To this aim we compare the predicted values of the dust-to-stellar mass ratio, \xi_d, with those measured in 15 galaxies at z>10 from JWST spectra, when outflows are not included. Our model constrains \xi_d as a function of several parameters by allowing wide variations in the IMF, dust/metal production, and dust destruction for a set of SN progenitor models and explosion energies. We find \log \xi_d ~ -2.2 for all systems, indicative of the dominant role of SN dust production over destruction in these early galaxies. Such value is strikingly different from the data, which instead indicate \log \xi_d < -4. We conclude that dust destruction alone can hardly explain the transparency of Blue Monsters. Other mechanisms, such as outflows, might be required.