HIPASS Detection of an Intergalactic Gas Cloud in the NGC 2442 Group

S. D. Ryder; B. Koribalski; L. Staveley-Smith; V. Kilborn; D. Malin; G. Banks; D. Barnes; R. Bhatal; W. de Blok; P. Boyce; M. Disney; M. Drinkwater; R. Ekers; K. Freeman; B. Gibson; P. Henning; H. Jerjen; P. Knezek; M. Marquarding; R. Minchin; J. Mould; T. Oosterloo; R. Price; M. Putman; E. Sadler; I. Stewart; F. Stootman; R. Webster; A. Wright

doi:10.1086/321453

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HIPASS Detection of an Intergalactic Gas Cloud in the NGC 2442 Group

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Abstract

We report the discovery, from the HI Parkes All-Sky Survey (HIPASS), of a gas cloud associated with the asymmetric spiral galaxy NGC 2442. This object, designated HIPASS J0731-69, contains ~10^9 M_sun of HI, or nearly one-third as much atomic gas as NGC 2442 itself. No optical counterpart to any part of HIPASS J0731-69 has yet been identified, consistent with the gas being diffuse, and with its stream-like kinematics. If the gas in HIPASS J0731-69 was once part of NGC 2442, then it was most likely a fairly recent tidal encounter with a moderately massive companion which tore it loose, although the possibility of ram-pressure stripping cannot be ruled out. This discovery highlights the potential of the HIPASS data for yielding new clues to the nature of some of the best-known galaxies in the local universe.

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S. D. Ryder, B. Koribalski, L. Staveley-Smith, V. Kilborn, D. Malin, G. Banks, D. Barnes, R. Bhatal, W. de Blok, P. Boyce, M. Disney, M. Drinkwater, R. Ekers, K. Freeman, B. Gibson, P. Henning, H. Jerjen, P. Knezek, M. Marquarding, R. Minchin, J. Mould, T. Oosterloo, R. Price, M. Putman, E. Sadler, I. Stewart, F. Stootman, R. Webster, A. Wright. 2001-03-06. HIPASS Detection of an Intergalactic Gas Cloud in the NGC 2442 Group. https://doi.org/10.1086/321453

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