Observation of neutral hydrogen in the globular cluster NGC 2808
- Mount Stromlo and Siding Springs Observatories, Weston (Australia) CSIRO, Australia Telescope National Facility, Parkes (Australia)
The Parkes 64-m reflector of the Australia Telescope National Facility was used to observe globular clusters in the 21-cm line. In the direction of NGC 2808, H I emission was detected with the following characteristics: (1) the peak of the spatial distribution is located on the cluster's center; (2) the peak of the velocity distribution matches the cluster's published radial velocity of 98 km/s to within its quoted uncertainly of 4 km/s; and (3) the FWHM of the H I profile is consistent with the cluster's published stellar velocity dispersion and escape velocity. The characteristics of this emission are very suggestive of its being due, at least in part, to gas which is physically associated with the cluster. This is not beyond dispute, however, since there is known to be an extended region around the cluster exhibiting foreground 21-cm emission at about the cluster's radial velocity. If further observations confirm that the emitting gas is intrinsic to NGC 2808, this would constitute the first significant detection of H I within a globular cluster. 32 refs.
- OSTI ID:
- 5262201
- Journal Information:
- Astrophysical Journal; (United States), Journal Name: Astrophysical Journal; (United States) Vol. 374; ISSN ASJOA; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC GASES
COSMIC RADIO SOURCES
DETECTION
DISTRIBUTION
ELEMENTS
EMISSION SPECTRA
FLUIDS
GASES
H1 REGIONS
HYDROGEN
INTERSTELLAR SPACE
NONMETALS
RADIAL VELOCITY
SPACE
SPATIAL DISTRIBUTION
SPECTRA
STAR CLUSTERS
VELOCITY