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

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Richards, S. N., Schaefer, A. L., Lopez-Sanchez, A. R., Croom, S. M., Bryant, J. J., Sweet, S. M., Konstantopoulos, I. S., Allen, J. T., Bland-Hawthorn, J., Bloom, J. V., Brough, S., Fogarty, L. M. R., Goodwin, M., Green, A. W., Ho, I. -T., Kewley, L. J., Koribalski, B. S., Lawrence, J. S., Owers, M. S., Sadler, E. M., Sharp, R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press 2014
• Subjects: Galaxies: dwarf; Galaxies: evolution; Galaxies: star formation; Galaxies: starburst; HII regions; Techniques: spectroscopic; 1912 Space and Planetary Science; 3103 Astronomy and Astrophysics; sami
• Online Access: https://espace.library.uq.edu.au/view/UQ:677065/UQ677065_OA.pdf; https://espace.library.uq.edu.au/view/UQ:677065

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⊙ yrand 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.