Galaxy with the highest star formation

Astronomers studying the light from the galaxy J1148+5251 have estimated that stars are being born there at a rate of around one thousand solar masses per year - around a thousand times greater than the rate for star formation in our own galaxy. J1148+5251 is a distant active galaxy known as a quasar. At 12.8 billion light years away we see its light from 12.8 billion years ago. Thus astronomers are watching its star forming activity as it was 12.8 billion years in the past.