... Confirm Dark Galaxy Existence . ... New evidence from NASA's Hubble Space Telescope and the Westerbork Synthesis Radio Telescope in the Netherlands has been used to rule out all but one of the ideas put forward to explain the existence of VIRGOHI 21, an intergalactic gas cloud 50 million light-years from the Earth. ... Are there more such dark galaxies out there? ... Credit: R. Minchin / Arecibo Observatory / Cardiff University / Isaac Newton Telescope / Westerbork Synthesis Radio Telescope . ...
... 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. ...