The Nuclear Ring in the Barred Spiral Galaxy IC 4933

Abstract

We present infrared imaging from IRIS2 on the Anglo-Australian Telescope that shows the barred spiral galaxy IC 4933 has not just an inner ring encircling the bar, but also a star-forming nuclear ring 1.5 kpc in diameter. Imaging in the u' band with GMOS on Gemini South confirms that this ring is not purely an artifact due to dust. Optical and near-infrared colours alone however cannot break the degeneracy between age, extinction, and burst duration that would allow the star formation history of the ring to be unraveled. Integral field spectroscopy with the GNIRS spectrograph on Gemini South shows the equivalent width of the Pa-beta line to peak in the north and south quadrants of the ring, indicative of a bipolar azimuthal age gradient around the ring. The youngest star-forming regions do not appear to correspond to where we expect to find the contact points between the offset dust lanes and the nuclear ring unless the nuclear ring is oval in shape, causing the contact points to lead the bar by more than 90 degrees.

9 pages, 7 figures, uses psfig.sty. Updated references to reflect published version in PASA.

References in corpus (8)

• The HIPASS Catalogue - I. Data Presentation
• A SINFONI view of Galaxy Centers: Morphology and Kinematics of five Nuclear Star Formation Rings
• A Connection between Star Formation in Nuclear Rings and their Host Galaxies
• Dynamical Decoupling of Nested Bars: Self-Gravitating Gaseous Nuclear Bars
• The Star Formation History and Evolution of the Circumnuclear Region of M100
• Star formation and stellar populations across nuclear rings in galaxies
• Induced Nested Galactic Bars Inside Assembling Dark Matter Halos
• Examining the Seyfert - Starburst Connection with Arcsecond Resolution Radio Continuum Observations

Cited by in corpus (6)

• Star Formation in Nuclear Rings of Barred Galaxies
• Effects of Spiral Arms on Star Formation in Nuclear Rings of Barred-spiral Galaxies
• Formation of Dense Molecular Gas and Stars at the Circumnuclear Starburst Ring in the Barred Galaxy NGC 7552
• Star clusters in a nuclear star-forming ring: The disappearing string of pearls
• Equilibrium Sequences and Gravitational Instability of Rotating Isothermal Rings
• The Large Deficit of HMXB Emission from Luminous Infrared Galaxies: the Case of the Circumnuclear Starburst Ring in NGC 7552