The SAMI galaxy survey: The discovery of a luminous, low-metallicity HII complex in the dwarf galaxy GAMA J141103.98-003242.3

S. N. Richards*, A. L. Schaefer, A. R. López-Sánchez, S. M. Croom, J. J. Bryant, S. M. Sweet, I. S. Konstantopoulos, J. T. Allen, J. Bland-Hawthorn, J. V. Bloom, S. Brough, L. M.R. Fogarty, M. Goodwin, A. W. Green, I. T. Ho, L. J. Kewley, B. S. Koribalski, J. S. Lawrence, M. S. Owers, E. M. SadlerR. Sharp

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

We present the discovery of a luminous unresolved HII complex on the edge of dwarf galaxy GAMA J141103.98-003242.3 using data from the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey. This dwarf galaxy is situated at a distance of ~100 Mpc and contains an unresolved region of HII emission that contributes ~70 per cent of the galaxy's Hα luminosity, located at the top end of established HII region luminosity functions. For the HII complex, we measure a star formation rate of 0.147 ± 0.041 M⊙ yr-1and a metallicity of 12+log(O/H) = 8.01 ± 0.05 that is lower than the rest of the galaxy by ~0.2 dex. Data from the HI Parkes All-Sky Survey (HIPASS) indicate the likely presence of neutral hydrogen in the galaxy to potentially fuel ongoing and future star-forming events. We discuss various triggering mechanisms for the intense star formation activity of this HII complex, where the kinematics of the ionized gas are well described by a rotating disc and do not show any features indicative of interactions. We showthat SAMI is an ideal instrument to identify similar systems to GAMA J141103.98-003242.3, and the SAMI Galaxy Survey is likely to find many more of these systems to aid in the understanding of their formation and evolution.

Original languageEnglish
Pages (from-to)1104-1113
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume445
Issue number2
DOIs
Publication statusPublished - 1 Dec 2014

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