| Neutral hydrogen(HI)gas is the fundamental material for star formation that drives the evolution of a galaxy.For starburst dwarf galaxy NGC 5253,previous study has observed HI gas distributed asymmetrically with?7kpc extension toward north-east direction using the radio interferometry.This extension is likely indicating the dynamical connection between NGC 5253 and its nearby spiral galaxy M83.To investigate the possible HI bridge between these two galactic systems,we acquire the HI mapping data around NGC 5253 in radio L-band from the Robert C.Byrd Green Bank Telescope.Through the self-built program,we have detected the 7 possible HI gas clouds between NGC 5253 and M83 with a signal-to-noise ratio of more than 3.9,which ensured the authenticity of the search to a certain extent.These HI gas cloud candidates distribute mainly in the north-east direction extending over 60 kpc from NGC5253.Among them,cloud D is the closest to NGC 5253,which is 25 kpc.After analysis,cloud D may be composed of two interrelated cloud clusters.Judging from the position and speed of cloud D,it has a great correlation with NGC 5253,and may be injecting into or leaving NGC5253 galaxy.The candidate mass of HI gas cloud detected in this paper is 1.0?11.2×10~5M?is close to the middle and lower limit of the mass range of gas clouds in M31 system,M81/M82 system and galaxy.The total mass of HI gas cloud candidates detected in this paper is 28.4×10~5 M?is 2%of the total HI mass of NGC 5253.If all gases can enter NGC 5253,it will have little impact on the whole,but it may squeeze the original gas and trigger a starburst.The existence of these cloud candidates may be caused by the interaction between NGC 5253and M83,or by the inward falling phenomenon of HI gas near NGC 5253.These clouds could play an important role in triggering intensive star formation activity in the dwarf galaxy NGC5253. |
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