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Title: Are there really intergalactic hydrogen clouds in the Sculptor group

Abstract

High-sensitivity 21 cm observations of the region of the Sculptor group of galaxies reveal at least 30 H I clouds distributed over only the southern sector of the group. These new data add two striking complications to the picture of the clouds as H I companions of Sculptor galaxies: first, a much wider spatial distribution of clouds in marked contrast with the clustering of clouds around NGC 55 and NGC 300 previously reported by Mathewson, Cleary, and Murray; and second, a cloud velocity distribution which does not match that of the galaxies.We cannot reconcile the spatial and velocity distributions of the H I clouds with those of the group or of any subgroup. We conclude that there are no intergalactic H I clouds of > or =10/sup 8/ M/sub sun/ and galactic dimensions within the Sculptor group. Of a number of explanations alternative to group membership, we favor the identification of the clouds as a component of the Magellanic Stream which is seen in projection. Observations reported here of other nearby groups, combined with those of Sculptor, rule out the existence of a significant population of discrete H I clouds having the above properties.

Authors:
;
Publication Date:
Research Org.:
Astronomy Department, Indiana University
OSTI Identifier:
6291737
Resource Type:
Journal Article
Journal Name:
Astrophys. J.; (United States)
Additional Journal Information:
Journal Volume: 227:3
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GALAXY CLUSTERS; H1 REGIONS; SPATIAL DISTRIBUTION; COSMIC RADIO SOURCES; ENERGY SPECTRA; INTERGALACTIC SPACE; RADIOWAVE RADIATION; DISTRIBUTION; ELECTROMAGNETIC RADIATION; RADIATIONS; SPACE; SPECTRA; 640105* - Astrophysics & Cosmology- Galaxies

Citation Formats

Haynes, M.P., and Roberts, M.S. Are there really intergalactic hydrogen clouds in the Sculptor group. United States: N. p., 1979. Web. doi:10.1086/156785.
Haynes, M.P., & Roberts, M.S. Are there really intergalactic hydrogen clouds in the Sculptor group. United States. doi:10.1086/156785.
Haynes, M.P., and Roberts, M.S. Thu . "Are there really intergalactic hydrogen clouds in the Sculptor group". United States. doi:10.1086/156785.
@article{osti_6291737,
title = {Are there really intergalactic hydrogen clouds in the Sculptor group},
author = {Haynes, M.P. and Roberts, M.S.},
abstractNote = {High-sensitivity 21 cm observations of the region of the Sculptor group of galaxies reveal at least 30 H I clouds distributed over only the southern sector of the group. These new data add two striking complications to the picture of the clouds as H I companions of Sculptor galaxies: first, a much wider spatial distribution of clouds in marked contrast with the clustering of clouds around NGC 55 and NGC 300 previously reported by Mathewson, Cleary, and Murray; and second, a cloud velocity distribution which does not match that of the galaxies.We cannot reconcile the spatial and velocity distributions of the H I clouds with those of the group or of any subgroup. We conclude that there are no intergalactic H I clouds of > or =10/sup 8/ M/sub sun/ and galactic dimensions within the Sculptor group. Of a number of explanations alternative to group membership, we favor the identification of the clouds as a component of the Magellanic Stream which is seen in projection. Observations reported here of other nearby groups, combined with those of Sculptor, rule out the existence of a significant population of discrete H I clouds having the above properties.},
doi = {10.1086/156785},
journal = {Astrophys. J.; (United States)},
number = ,
volume = 227:3,
place = {United States},
year = {1979},
month = {2}
}