A Survey of Hidden Molecular Clouds in the Milky Way J.M. Hughes ad S.J. Gibson Western Kentucky University Star formation, a critical process within galaxies, occurs in the coldest, densest interstellar clouds, whose gas and dust content are observed primarily at radio and infrared wavelengths. ... Through a comparative study, we find substantial dark molecular hydrogen that is not detected in CO emission. ... Identify cold atomic hydrogen emission clouds 21cm 2. ...

... 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. ...