Probable detection of H-alpha emission from a very high velocity cloud in Cetus

Journal Article · Fri Sep 01 04:00:00 EDT 1989 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/185518· OSTI ID:5246979

Kutyrev, A S; Reynolds, R J ^[1]

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1. Moskovskii Gosudarstvennyi Universitet, Moscow (USSR)

A high-sensitivity search for H-alpha emission from a -300 km/s H-I cloud in Cetus was performed using a large-aperture Fabry-Perot spectrometer. Weak emission features were noted in the H-alpha spectra at radial velocities coinciding with the 21-cm emission. The H-alpha surface brightness of the cloud is found to be 2.0 + or - 0.5 x 10 to the -8th ergs/sq cm per s per sr. The results are used to set an upper limit of 200,000/sq cm per s on the flux of Lyman-continuum photons in the vicinity of the cloud, almost a factor of 10 lower than the flux estimated to be present within the Galactic halo and comparable to some estimates for the intergalactic EUV radiation field. 17 refs.

• OSTI ID: 5246979
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 344; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BALMER LINES
BRIGHTNESS
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
GALAXIES
H1 REGIONS
INTERSTELLAR SPACE
MEASURING INSTRUMENTS
MILKY WAY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIAL VELOCITY
RADIATIONS
SPACE
SPECTRA
SPECTROMETERS
ULTRAVIOLET RADIATION
VELOCITY