Hostname: page-component-848d4c4894-8bljj Total loading time: 0 Render date: 2024-06-15T18:47:50.295Z Has data issue: false hasContentIssue false

Neutral hydrogen in galactic clusters

Published online by Cambridge University Press:  14 August 2015

F. D. Drake*
Affiliation:
Harvard College Observatory, Cambridge, Massachusetts, U.S.A.

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Observations of the neutral hydrogen content of the galactic clusters h and χ Persei, the Pleiades, the cluster in Coma Berenices, Praesepe, and M 67 have been made with the Harvard College Observatory 60-foot radio telescope. The receiver used was the original receiver made by the Ewen Knight Corporation for the Harvard 24-foot radio telescope. The observations were of three kinds: (1) right-ascension drift curves at 50 kc/s bandwidth, with the receiver fixed-tuned to the frequency of maximum cluster emission, if known, or to the frequency given by the cluster optical radial velocity; (2) conventional frequency profiles at the position of maximum cluster radiation; (3) “residual” frequency profiles, where there is significant general galactic radiation at the cluster frequency and position. These data provide the spatial distribution of any H i in the cluster vicinity that is in excess of the general galactic H i, and a frequency profile for this excess hydrogen. Any excess H i found is considered associated with the cluster if it agrees in velocity and position with the optical cluster.

Type
Part III: Galactic and Extragalactic Radio Sources
Copyright
Copyright © Stanford University Press 1959