An isolated, well-defined infrared cirrus cloud
T. Herter, D. L. Shupe, D. F. Chernoff;
ApJ, 1990, 352, 149
ABSTRACT:High spatial resolution H I measurements of a high-latitude FIR cirrus cloud (l = 9 deg, b = 51 deg) were obtained with the Arecibo 310 m telescope.
The
cloud is well isolated spatially and has a velocity well-separated from
other H I clouds, providing an ideal laboratory for studying diffuse
interstellar clouds.
The Iv(100)/N(H) and Iv(60)/Iv(100) ratios are consistent
with the Draine and Anderson model which includes a distribution of grain
sizes down to 3 A.
The small grains undergo transient heating and affect the
60 micron FIR continuum emission.
Current models, however,
underpredict Iv(12)/Iv(100) and Iv(25)/Iv(100) by more than a factor of 2.
The
effects small grains have on the thermal equilibrium of diffuse interstellar
clouds are discussed.
KEYWORDS: infrared cirrus (astronomy), interstellar matter, milky way galaxy, absorption spectra, h lines, infrared astronomy satellite, interstellar gas, spatial resolution
PERSOKEY:h_i, 21 cm, cirrus, dust, iras, fir, mir, ,
CODE: herter90