TY - JOUR
T1 - MeerKAT-64 discovers wide-spread tidal debris in the nearby NGC 7232 galaxy group
AU - Namumba, Brenda
AU - Koribalski, Baerbel Silvia
AU - Józsa, Gyula I. G.
AU - Lee-Waddell, Karen
AU - Jones, Michael Gordon
AU - Carignan, Claude
AU - Verdes-Montenegro, Lourdes
AU - Ianjamasimanana, Roger
AU - Blok, Erwin W. J. G. de
AU - Cluver, Michelle
AU - Garrido, Julian
AU - Sanchez-Exposito, Susana
AU - Ramaila, Athanaseus
AU - Thorat, Kshitij
AU - Andanti, Lexy A. L.
AU - Hugo, Benjamin
AU - Kleiner, Dane
AU - Kamphuis, Peter
AU - Serra, Paolo
AU - Smirnov, Oleg
AU - Maccagni, Filippo
AU - Makhathini, Sphesihle
AU - Molnar, Daniel Csaba Csaba
AU - Perkins, Simon
AU - Ramatsoku, Mpati
AU - White, Sarah V.
AU - Loi, Francesca
PY - 2021/8/1
Y1 - 2021/8/1
N2 - 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).
AB - 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).
KW - astro-ph.GA
KW - 85A04
U2 - 10.1093/mnras/stab1524
DO - 10.1093/mnras/stab1524
M3 - Article
SN - 0035-8711
VL - 505
SP - 3795
EP - 3809
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -