Australia Telescope Compact Array H i observations of the NGC 6845 galaxy group |
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| Authors: | Scott Gordon Bärbel Koribalski Keith Jones |
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| Institution: | Department of Physics, University of Queensland, St Lucia, Brisbane, QLD 4072, Australia;Australia Telescope National Facility, CSIRO, PO Box 76, Epping, NSW 1710, Australia |
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| Abstract: | We present the results of Australia Telescope Compact Array (ATCA) H i line and 20-cm radio continuum observations of the galaxy quartet NGC 6845. The H i emission extends over all four galaxies but can only be associated clearly with the two spiral galaxies, NGC 6845A and B, which show signs of strong tidal interaction. We derive a total H i mass of at least 1.8 × 1010 M⊙ , most of which is associated with NGC 6845A, the largest galaxy of the group. We investigate the tidal interaction between NGC 6845A and B by studying the kinematics of distinct H i components and their relation to the known H ii regions. No H i emission is detected from the two lenticular galaxies, NGC 6845C and D. A previously uncatalogued dwarf galaxy, ATCA J2001?4659 , was detected 4.4 arcmin NE from NGC 6845B and has an H i mass of ～5 × 108 M⊙ . No H i bridge is visible between the group and its newly detected companion. Extended 20-cm radio continuum emission is detected in NGC 6845A and B as well as in the tidal bridge between the two galaxies. We derive star formation rates of 15–40 M⊙ yr?1 . |
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| Keywords: | galaxies: individual: NGC 6845 galaxies: interactions radio continum: galaxies radio lines: galaxies |
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