At the same time, the fireball produced by the collision would continue to glow in X-rays for several days, and in weaker, visible light for weeks or months. Researchers speculate that they are looking at the remnants of that visible glow as it gets filtered through the intervening cloud.
Still, all these scenarios are for now mostly speculation. "There are many, many models--all of them [fantasies] like the tooth fairy," said astrophysicist Chryssa Kouveliotou of the Marshall Space Flight Center in Alabama. "Astronomy is like archeology. We're looking into the past. We're detectives, trying to get as much information as we can to tell us about our universe, and about how we came to be."