Authors:
Van Driel W., O'Neil K., Cayatte V., Duc P.-A., Dickey J.M., Balkowski C., Hernández H., Iglesias-Páramo J., Papaderos P., Vílchez J.M., Thuan T.X.
Journal:
Astronomy and Astrophysics
Abstract:
21 cm H I line observations were made with the Arecibo Gregorian telescope of 9 H I clouds in the Hercules Cluster which were reported as tentative detections in a VLA H I study of the cluster (Dickey 1997) and for which our deep CCD imaging failed to find any optical counterparts. No sensitive observations could be made of one of these (sw-174) due to the presence of a close-by strong continuum source. The other 8 tentative H I detections were not confirmed by the Arecibo H I measurements. The CCD images did reveal faint, low surface brightness counterparts near the centres of two other VLA H I sources invisible on the Palomar Sky Survey, sw-103 and sw-194.
Keywords:
Galaxies: clusters: general; Galaxies: clusters: individual: Hercules cluster; Galaxies: ISM; Radio lines: galaxies