Observations of the motion and distribution of the ionized gas in the central parsec of the galaxy. II

Journal Article · Wed Oct 01 00:00:00 EDT 1980 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/158324· OSTI ID:6677985

Lacy, J H; Townes, C H; Geballe, T R; Hollenbach, D J

Observations of infrared fine-structure line emission from compact clouds of ionized gas within Sgr A West are presented. These clouds have diameters of 0.1--0.5 pc, internal velocity dispersions approx.100 km s/sup -1/ (FWHM), and line center velocities up to +- 260 km s/sup -1/. Their masses are not accurately determined but are probably between 0.1 and 10 M/sub sun/. They are ionized by radiation like that of stars of T/sub eff/< or approx. =35,000 K. The clouds are shown to have lifetimes approx.10/sup 4/ yr and so must be generated and dissipated at a rate of a few per 10/sup 3/ yr. From analysis of the distribution of the velocities of the clouds, a most probable mass distribution is derived which includes a central pointlike mass of several x 10/sup 6/ M/sub sun/ in addition to several x 10/sup 6/ M/sub sun/ of stars within 1 pc of the center. However, the small number of clouds (14) makes the mass determination quite uncertain. A distributed mass of approx.10/sup 7/ M/sub sun/ within the central parsec, with no central massive object, has a likelihood 1.4sigma below that of the most probable distribution.

• Research Organization: Department of Physics, University of California, Berkeley
• OSTI ID: 6677985
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 241:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics &amp; Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CHARGED PARTICLES
COSMIC GASES
COSMIC RADIO SOURCES
DATA
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
EXPERIMENTAL DATA
FLUIDS
GALAXIES
GALAXY NUCLEI
GASES
H2 REGIONS
INFORMATION
INFRARED RADIATION
IONS
MILKY WAY
NEBULAE
NEON IONS
NUMERICAL DATA
RADIATIONS
SPECTRA