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Session 45 - Radio Astronomy, Yesterday, Today and Tomorrow.
Display session, Tuesday, June 11
Great Hall,

[45.02] CO Observations of Hickson Compact Group Spirals

T. K. Menon (U. British Columbia), S. Leon, F. Combes (DEMIRM, Obs. de Paris)

Observations of CO(1-0) and CO(2-1) lines in an IRAS-selected sample of 70 galaxies belonging to 45 northern Hickson Compact Groups (HCG) have been carried out using the IRAM-30m telescope (22^\prime\prime and 11^\prime\prime beams respectively). We detected CO in 55 galaxies.. We find in these galaxies an enhancement of the star formation eficiency (SFE), as traced by the L_ir/M(H_2) ratio, confirming earlier studies of such effects in tidally disturbed systems. This enhancement correlates with the closest galaxy separation distance, suggesting a tidal trigger for the star formation. The inferred H_2 masses are strongly correlated with radio continuum luminosities of the HCG galaxies. Since for the vast majority of the HCG galaxies the radio emission is confined to the nuclear regions it would appear that the enhancement of star formation is taking place mostly in the nuclear regions lending further support for the tidal enhancement of nuclear star formation activity in these systems.

Program listing for Tuesday