Strong NIR emission following the long duration GRB 211211A: Dust heating as an alternative to a kilonova

Understand

The prolonged near infrared (NIR) emission observed following the long duration GRB 211211A is inconsistent with afterglow emission from the shock driven into the circum-stellar medium (CSM), and with emission from a possible underlying supernova.

• It has therefore been suggested that the observed NIR flux is the signature of a kilonova -- a radioactive ejecta that is similar to the outcome of the binary neutron star merger GW170817.
• We propose here an alternative plausible explanation.
• We show that the NIR flux is consistent with thermal emission from dust, heated by UV and soft X-ray radiation produced by the interaction of the GRB jet plasma with the CSM.