New evidence for a Dark Galaxy FOR RELEASE: Thursday January 12, 2006 9:20 AM EST New evidence that VIRGOHI 21, a mysterious cloud of hydrogen light-years from the Ear th, is a D ark Galaxy was pres ented today Society meeting in Washington, D . ... As Professor Mike Disney of Cardiff University puts it, "The new observations make it even harder to escape the conclusion that VIRGOHI 21 is a Dark Galaxy ." ... CRED IT: Arecibo Observatory / Car diff U niversity / 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. ...