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Title: High resolution radio and optical observations of the central starburst in the low-metallicity dwarf galaxy II Zw 40

The extent to which star formation varies in galaxies with low masses, low metallicities, and high star formation rate surface densities is not well constrained. To gain insight into star formation under these physical conditions, this paper estimates the ionizing photon fluxes, masses, and ages for young massive clusters in the central region of II Zw 40—the prototypical low-metallicity dwarf starburst galaxy—from radio continuum and optical observations. Discrete, cluster-sized sources only account for half the total radio continuum emission; the remainder is diffuse. The young (≲ 5 Myr) central burst has a star formation rate surface density that significantly exceeds that of the Milky Way. Three of the 13 sources have ionizing photon fluxes (and thus masses) greater than R136 in 30 Doradus. Although isolating the effects of galaxy mass and metallicity is difficult, the H II region luminosity function and the internal extinction in the center of II Zw 40 appear to be primarily driven by a merger-related starburst. The relatively flat H II region luminosity function may be the result of an increase in interstellar medium pressure during the merger and the internal extinction is similar to that generated by the clumpy and porous dust in other starburstmore » galaxies.« less
Authors:
; ; ;  [1]
  1. Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States)
Publication Date:
OSTI Identifier:
22340012
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 147; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DENSITY; DUSTS; EMISSION; GAIN; GALAXY CLUSTERS; LUMINOSITY; MASS; METALLICITY; MILKY WAY; PHOTONS; POROUS MATERIALS; RADIO TELESCOPES; RESOLUTION; STARS; SURFACES; TELESCOPES