The SAMI galaxy survey: the discovery of a luminous, low-metallicity H II 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.
• Other Authors: Swinburne University of Technology
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Oxford University Press (OUP) 2014
• Subjects: sami
• Online Access: http://hdl.handle.net/1959.3/436061; https://doi.org/10.1093/mnras/stu1820

We present the discovery of a luminous unresolved H ii 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 H ii emission that contributes ∼70 per cent of the galaxy's Hα luminosity, located at the top end of established H ii region luminosity functions. For the H ii 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 H i 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 H ii 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 show that 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.