Astronomers Detect Coolest Radio Star . ... The new radio-star is much smaller and colder than our Sun.€а With a surface temperature not much higher than that of a giant planet, and a size comparable to JupiterтАЩs, it is scarcely visible in optical light.€а Yet the radio flares seen at Arecibo show it must have a strong magnetic field, implying that the same could be true of other similar stars. ...

... 2.3 Data acquisition Spectra generated by the Multibeam correlator contain the usual structure seen in spectra from other H i instruments: a bandpass spectrum which is the sum of the sky , ground and receiver temperatures multiplied by the product of the filters in the receiver chain; superimposed on this is a noise ... Note also that sources extended much beyond ,40 arcmin can be imaged poorly in HIPASS images because of the bandpass sidelobe effect described in Section 3.3. ...