W30 revealed - Separation and analysis of thermal and nonthermal emission in a Galactic complex

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169107· OSTI ID:6482501

Kassim, N E; Weiler, K W ^[1]

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1. Naval Research Laboratory, Washington, DC (USA)

The VLA has been used to observe the W30 H II/SNR Galactic complex at 90 and 20 cm, and the observations have been used to estimate spectra for each of the known thermal sources. Upper limits to the emission measures have been derived for H II regions which are optically thin at 90 cm, and lower limits have been set to both their emission measures and filling factors. The results indicate that the 90 cm VLA observations provide a method for easily screening thermal sources for compact structure. The relative contributions of thermal and nonthermal emission in the complex are established, and improved estimates of the spectrum and morphology of the W30 SNR are obtained. Distance estimates to H II regions in W30 are used to show that the SNR is one of the largest known in the Galaxy, with a physical size of about 80 pc. 39 refs.

• OSTI ID: 6482501
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 360; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
640105 -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RADIO SOURCES
DISTANCE
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
GALAXIES
H2 REGIONS
LIMITING VALUES
MILKY WAY
MORPHOLOGY
PULSARS
RADIATIONS
RADIOWAVE RADIATION
SPECTRA
SPECTROSCOPY
SUPERNOVA REMNANTS