144 research outputs found
Analysis of aircraft microwave measurements of the ocean surface
A data system was developed to process, from calibrated brightness temperature to computation of estimated parameters, the microwave measurements obtained by the NASA CV-990 aircraft during the 1972 Meteorological Expedition. A primary objective of the study was the implementation of an integrated software system at the computing facility of NASA/GSFC, and its application to the 1972 data. A single test case involving measurements away from and over a heavy rain cell was chosen to examine the effect of clouds upon the ability to infer ocean surface parameters. The results indicate substantial agreement with those of the theoretical study; namely, that the values obtained for the surface properties are consistent with available ground-truth information, and are reproducible except within the heaviest portions of the rain cell, at which nonlinear (or saturation) effects become apparent. Finally, it is seen that uncorrected instrumental effects introduce systematic errors which may limit the accuracy of the method
Giant Molecular Clouds are More Concentrated to Spiral Arms than Smaller Clouds
From our catalog of Milky Way molecular clouds, created using a temperature
thresholding algorithm on the Bell Laboratories 13CO Survey, we have extracted
two subsets:(1) Giant Molecular Clouds (GMCs), clouds that are definitely
larger than 10^5 solar masses, even if they are at their `near distance', and
(2) clouds that are definitely smaller than 10^5 solar masses, even if they are
at their `far distance'. The positions and velocities of these clouds are
compared to the loci of spiral arms in (l, v) space. The velocity separation of
each cloud from the nearest spiral arm is introduced as a `concentration
statistic'. Almost all of the GMCs are found near spiral arms. The density of
smaller clouds is enhanced near spiral arms, but some clouds (~10%) are
unassociated with any spiral arm. The median velocity separation between a GMC
and the nearest spiral arm is 3.4+-0.6 km/s, whereas the median separation
between smaller clouds and the nearest spiral arm is 5.5+-0.2 km/s.Comment: 11 pages, 3 figure
Radio Astronomy
Contains research objectives and reports on three research projects.Joint Services Electronics Programs (U. S. Army, U.S. Navy, and U.S. Air Force) under Contract DA 28-043-AMC-02536(E)U. S. Navy (Office of Naval Research) under Contract N00014-67-A-0204-0009National Science Foundation (Grant GP-7046)National Aeronautics and Space Administration (Contract NSR-22-009-120)National Aeronautics and Space Administration (Grant NsG-419
Optical and Infrared Spectroscopy
Contains research objectives and reports on one research project
Radio Astronomy
Contains reports on three research projects.National Aeronautics and Space Administration (Grant NsG-419)National Aeronautics and Space Administration (Contract NSR-22-009-120)Lincoln Laboratory Purchase Order No. 74
Radio Astronomy
Contains reports on three research projects, with one broken into two subsections.National Aeronautics and Space Administration (Grant NsG-419)National Aeronautics and Space Administration (Contract NSR-22-009-120)Joint Services Electronics Programs (U.S. Army, U.S. Navy, and U.S. Air Force) under Contract DA 28-043-AMC-02536(E
Radio Astronomy
Contains reports on five research projects.National Aeronautics and Space Administration (Grant NsG-419)National Aeronautics and Space Administration (Contract NSR-22-009-120)Lincoln Laboratory Purchase Order No. 74
Hard X-ray emission in the star-forming region ON2: discovery with XMM-Newton
We obtained X-ray XMM-Newton observations of the open cluster Berkeley 87 and
the massive star-forming region (SFR) ON 2. In addition, archival infrared
Spitzer Space Telescope observations were used. It is likely that the SFR ON 2
and Berkeley 87 are at the same distance, 1.23 kpc, and hence are associated.
The XMM-Newton observations detected X-rays from massive stars in Berkeley 87
as well as diffuse emission from the SFR ON 2. The two patches of diffuse X-ray
emission are encompassed in the shell-like H II region GAL 75.84+0.40 in the
northern part of ON 2 and in the ON 2S region in the southern part of ON 2. The
diffuse emission from GAL 75.84+0.40 suffers an absorption column equivalent to
A_V approx. 28 mag. Its spectrum can be fitted either with a thermal plasma
model at T < 30 MK or by an absorbed power-law model with gamma; approx. -2.6.
The X-ray luminosity of GAL 75.84+0.40 is L_X approx. 6 10^31 erg/s. The
diffuse emission from ON 2S is adjacent to the ultra-compact H II (UCHII)
region Cygnus 2N, but does not coincide with it or with any other known UCHII
region. It has a luminosity of L_X approx. 4 10^31 erg/s. The spectrum can be
fitted with an absorbed power-law model with gamma; approx.-1.4. We adopt the
view of Turner and Forbes (1982) that the SFR ON 2 is physically associated
with the massive star cluster Berkeley 87 hosting the WO type star WR 142. We
discuss different explanations for the apparently diffuse X-ray emission in
these SFRs. These include synchrotron radiation, invoked by the co-existence of
strongly shocked stellar winds and turbulent magnetic fields in the
star-forming complex, cluster wind emission, or an unresolved population of
discrete sources.Comment: ApJ 2010, 712, 763. Reduced fig. resolution. Full resolution version
is at
http://www.astro.physik.uni-potsdam.de/research/abstracts/oskinova-ber87.htm
Radio Astronomy
Contains reports on five research projects.National Aeronautics and Space Administration (Grant NsG-419)National Science Foundation (Grant GP-7046)National Aeronautics and Space Administration (Contract NSR-22-009-120)Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U, S. Air Force, under Contract DA 28-043-AMC-02536(E)U. S. Navy (Office of Naval Research) under Contract N00014-67-A-0204-000
Radio Astronomy
Contains reports on seven research projects.U. S. Navy (Office of Naval Research) under Contract N00014-67-A-0204-0009National Aeronautics and Space Administration (Grant NsG-419)National Science Foundation (Grant GP-7046)National Aeronautics and Space Administration (Contract NSR-22-009-120)Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U.S. Air Force, Under Contract DA 28-043-AMC-02536(E
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