High-resolution spectroscopy and direct imaging of the dwarf galaxy I Zw 18

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · Astronomical Journal; (USA)

DOI:https://doi.org/10.1086/115100· OSTI ID:5710682

Davidson, K; Kinman, T D; Friedman, S D ^[1]

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1. Minnesota Univ., Minneapolis (USA)

Observations of the velocity profile of H-alpha emission in I Zw 18 suggest that the ionized gas may form an incomplete shell, ring, or double structure several arcsec across. Several faint continuum objects are noted along a line extending 1.5 arcsec northwest of the bright condensations in I Zw 18. Results are presented for the effect of Galactic interstellar Na I 5890-A absorption on the redshifted He I 5876-A emission from I Zw 18. A helium abundance of about 0.234 + or - 0.016 is implied for this object. 30 refs.

• OSTI ID: 5710682
• Journal Information: Astronomical Journal; (USA), Journal Name: Astronomical Journal; (USA) Vol. 97; ISSN 0004-6256; ISSN ANJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
ABUNDANCE
BALMER LINES
CHARGE-COUPLED DEVICES
ELEMENTS
FLUIDS
GALAXIES
GASES
HELIUM
IONIZED GASES
MORPHOLOGY
NONMETALS
RARE GASES
RED SHIFT
SEMICONDUCTOR DEVICES
SPECTRA
SPECTROSCOPY
VELOCITY