Extreme submillimetre starburst galaxies

Understand

We use two catalogues, a Herschel catalogue selected at 500 mu (HerMES) and an IRAS catalogue selected at 60 mu (RIFSCz), to contrast the sky at these two wavelengths.

• Both surveys demonstrate the existence of extreme starbursts, with star-formation rates (SFRs) > 5000 Msun/yr.
• The maximum intrinsic star-formation rate appears to be ~30,000 Msun/yr.
• The sources with apparent SFR estimates higher than this are in all cases either lensed systems, blazars, or erroneous photometric redshifts.