HIPASS detection of an intergalactic gas cloud in the NGC 2442 group

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

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Abstract

We report the discovery from the H I Parkes All-Sky Survey (HIPASS) of a gas cloud associated with the asymmetric spiral galaxy NGC 2442. This object, designated HIPASS J0731-69, contains ∼109 M of H I, 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 its streamlike 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 that 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.

Original languageEnglish
Pages (from-to)232-239
Number of pages8
JournalThe Astrophysical Journal
Volume555
Issue number1 PART 1
DOIs
Publication statusPublished - 1 Jul 2001
Externally publishedYes

Keywords

  • Galaxies : intergalactic medium
  • Galaxies: individual (NGC 2442)
  • Galaxies: interactions
  • Radio lines : galaxies

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