THE INTERNAL KINEMATICS OF THE H II GALAXY II Zw 40

Journal Article · Sun May 10 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/696/2/1668; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21300648

Bordalo, Vinicius; Telles, Eduardo ^[1]; Plana, Henri ^[2]

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1. Observatorio Nacional, Rua Jose Cristino, 77, Rio de Janeiro, RJ, 20921-400 (Brazil)
2. Lab. AstrofIsica Teorica e Observacional, Univ. Estadual de Santa Cruz, Rod. Ilheus-Itabuna km16, 45650-000 Ilheus (Brazil)

We present a study of the kinematic properties of the ionized gas in the dominant giant H II region of the well known H II galaxy: II Zw 40. High spatial and spectral resolution spectroscopy has been obtained using the Integral Field Unit mode on the Gemini Multi-Object Spectrograph instrument at the Gemini-North{sup 7}Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (USA), the Science and Technology Facilities Council (UK), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina). telescope. The observations allow us to obtain the H{alpha} intensity map, the radial velocity and velocity dispersion maps as well as estimate some physical conditions in the inner region of the starburst, such as oxygen abundance (O/H) and electron density. We have used a set of kinematics diagnostic diagrams, such as the intensity versus velocity dispersion (I-{sigma}), intensity versus radial velocity (I-V), and V-{sigma}, for global and individual analysis in the subregions of the nebula. We aim to separate the main line broadening mechanisms responsible for producing a smooth supersonic integrated line profile for the giant H II region. Bubbles and shells driven by stellar winds and possibly supernovae, covering a large fraction on the face of the nebula, are identified on scales larger than 50 pc. We found that unperturbed or 'free from shells' regions showing the lowest {sigma} values ({approx}20 km s{sup -1}) should be good indicators for the {sigma}{sub grav} component in II Zw 40. The brightest central region (R {approx} 50 pc) is responsible for {sigma} derived from a single fit to the integrated line profile. The dominant action of gravity, and possibly unresolved winds of young (<10 Myr) massive stars, in this small region should be responsible for the characteristic H{alpha} velocity profile of the starburst region as a whole ({sigma} = 32-35 km s{sup -1}). Our observations show that the complex structure of the interstellar medium of this galactic scale star-forming region is very similar to that of nearby extragalactic giant H II regions in the Local Group galaxies.

• OSTI ID: 21300648
• Journal Information: Astrophysical Journal, Vol. 696, Issue 2; Other Information: DOI: 10.1088/0004-637X/696/2/1668; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ABUNDANCE
ARGENTINA
ASTRONOMY
AUSTRALIA
BRAZIL
BUBBLES
CANADA
CHILE
ELECTRON DENSITY
GALAXIES
GRAVITATION
INTERNATIONAL COOPERATION
LINE BROADENING
NATIONAL SCIENCE FOUNDATION
NEBULAE
RADIAL VELOCITY
SPECTROSCOPY
STELLAR WINDS
SUPERNOVAE
TELESCOPES