Measurements of the 21 centimeter Zeeman effect in high-latitude directions

Journal Article · Sat Apr 01 04:00:00 EST 1989 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/167284· OSTI ID:5841937

Verschuur, G L

A new series of measurements of the Zeeman effect at 21 cm has been launched using the 140 foot (43 m) telescope of the NRAO. The observations of high-latitude sources reveal tremendous improvement in sensitivity over measurements done in previous era. The detection of a field of + 5.5 micro G in the direction of the North Polar Spur, in the H I equivalent of CO cloud 40 of Magnani, Blitz, and Mundy, is reported. Field limits as low as a few microgauss were set in the direction of two very cold H I clouds after only 4 hr of integration. The detection of a field of the order of 7 micro G in one of the expanding H I shells observed by Troland and Heiles is confirmed, and the field varies significantly on a scale of 20 arcmin (0.6 pc at the shell). The detection of a field in the direction of the Orion region by Heiles and Troland is confirmed in one direction but not in another. 14 refs.

• OSTI ID: 5841937
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 339; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BRIGHTNESS
COSMIC GASES
COSMIC RADIO SOURCES
EMISSION SPECTRA
EXPANSION
FLUIDS
GALAXIES
GASES
H1 REGIONS
INTERSTELLAR MAGNETIC FIELDS
MAGNETIC FIELDS
MILKY WAY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SPECTRA
TELESCOPES
ZEEMAN EFFECT