2024/09/30 by Xiao-Lan Liu, Liu, Xiao-Lan, Ming Zhu +13
Physics and Astronomy · Engineering · #Astronomy and Astrophysical Research #Astronomical Observations and Instrumentation #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2409.20109
We report a new high-sensitivity HI mapping observation of the NGC 5055 galaxy group over an area of 1.^∘5×0.^∘75 with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Our observation reveals that the warped H \sc i disk of NGC~5055 is more extended than what previously observed by WSRT, out to 23.'9 (61.7 kpc). The total HI mass of NGC 5055 is determined to be \rm∼ 1.1×1010 M_\odot. We identified three HI clouds with HI masses of the order of \rm ∼ 107 M_\odot at the southeastern edge of the HI disk, as well as a candidate high-velocity cloud with an HI mass of \rm (1.2±0.5) ×106 M_\odot to the north of NGC 5055. The HI content of UGCA 337 is robustly detected for the first time by the FAST observations. It has a narrow HI linewidth of W50=17.4±3.8 km s-1 with a total \HI mass of (\rm 3.5±0.3)×106 M_\odot. Comparing the gas content and g-r color of UGCA 337 with typical low-mass dwarf galaxies, UGCA~337 appears relatively gas-poor despite its blue color. This suggests that UGCA 337 may have undergone gas stripping in the past. We also analyzed the possible origin of the diffuse HI clouds located at the outskirts of NGC 5055, and speculate that they might be the remnant features of a merger event in the past.