A search for intergalactic H I gas in the NGC 1808 group of galaxies

M. Dahlem*, M. Ehle, S. D. Ryder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


A mosaic of six H I line observations with the Australia Telescope Compact Array is used to search for intergalactic gas in the NGC 1808 group of galaxies. Within the field of view of about 1°.4 × 1°.2 no emission from intergalactic H I gas is detected, either in the form of tidal plumes or tails, intergalactic H I clouds, or as gas associated with tidal dwarf galaxies, with a 5 δ limiting sensitivity of about 3 × 1018 cm-2 (or 1.4 × 107 M⊙ at a distance of 10.9 Mpc, for the given beam size of 127″.9 × 77″.3). The H I data of NGC 1792 and NGC 1808, with a velocity resolution of 6.6 km s-1, confirm the results of earlier VLA observations. Simultaneous wide-band 1.34 GHz continuum observations also corroborate the results of earlier studies. However, the continuum flux of NGC 1808 measured by us is almost 20% higher than reported previously. No radio continuum emission was detected from the type Ia supernova SN1993af in the north-eatern spiral arm of NGC 1808. A comparison of NGC 1792 and NGC 1808 shows that it is not primarily the total energy input that makes the big difference between the starburst-related outflow in NGC 1808 and the absence of such extraplanar features in NGC 1792, but the area over which the energy released by stellar winds and supernovae is injected into the ISM.

Original languageEnglish
Pages (from-to)485-493
Number of pages9
JournalAstronomy and Astrophysics
Issue number2
Publication statusPublished - 1 Jan 2001
Externally publishedYes


  • Galaxies: general
  • Galaxies: individual: NGC 1792, NGC 1808
  • Galaxies: interactions
  • Galaxies: ISM
  • Intergalactic medium


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