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تسجيل مستخدم جديدMeerKAT-64 discovers wide-spread tidal debris in the nearby NGC 7232 galaxy group
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We report the discovery of large amounts of previously undetected cold neutral atomic hydrogen (HI) around the core triplet galaxies in the nearby NGC~7232 galaxy group with MeerKAT. With a physical resolution of $sim$1 kpc, we detect a complex web of low surface brightness HI emission down to a 4$sigma$ column density level of $sim$1 $times$ 10$^{19}$ cm$^{-2}$ (over 44 kms ). The newly discovered H,{sc i} streams extend over $sim$20 arcmin corresponding to 140~kpc in projection. This is $sim$3 times the HI extent of the galaxy triplet (52 kpc). The HI debris has an HI mass of $sim$6.6 $times 10^9$~M$_{odot}$, more than 50% of the total HI mass of the triplet. Within the galaxy triplet, NGC~7233 and NGC~7232 have lost a significant amount of HI while NGC~7232B appears to have an excess of HI. The HI deficiency in NGC~7232 and NGC~7233 indicates that galaxy-galaxy interaction in the group concentrates on this galaxy pair while the other disc galaxies have visited them over time. In comparison to the AMIGA sample of isolated galaxies we find that with regards to its total HI mass the NGC~7232/3 galaxy triplet is not HI deficient. Despite the many interactions associated to the triplet galaxies, no HI seems to have been lost from the group (yet).
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