4,647 research outputs found
Arizona-NASA Atlas of infrared solar spectrum, a preliminary report, number 123
Photometric tracings of infrared solar spectrum from NASA CV-990 jet during July-August 196
Calibration of weak 1.4 and 1.9 mu water-vapor absorptions
Calibration of water absorption bands in near infrared regio
Partial Isometries of a Sub-Riemannian Manifold
In this paper, we obtain the following generalisation of isometric
-immersion theorem of Nash and Kuiper. Let be a smooth manifold of
dimension and a rank subbundle of the tangent bundle with a
Riemannian metric . Then the pair defines a sub-Riemannian
structure on . We call a -map into a Riemannian
manifold a {\em partial isometry} if the derivative map restricted
to is isometric; in other words, . The main result states that
if then a smooth -immersion satisfying
can be homotoped to a partial isometry which is
-close to . In particular we prove that every sub-Riemannian manifold
admits a partial isometry in provided .Comment: 13 pages. This is a revised version of an earlier submission (minor
revision
A search for 183-GHz emission from water in late-type stars
A search was made for 183 GHz line emission from water vapor in the direction of twelve Mira and two semiregular variables. Upper limits to the emission are in the range of 2000 to 5000 Jy. It is estimated that thermal emission from the inner regions of late type stellar envelopes will be on the order of ten Jy. Maser emission, according to one model, would be an order of magnitude stronger. From the limited set sampled, the possibility of very strong maser emission at 183 GHz cannot yet be ruled out
A high-resolution solar spectrometer for air-borne infrared observations, number 126
High resolution solar spectrometer for CV-990 aircraft infrared observation
Solar comparison spectra, 1.0-2.5 mu, from altitudes 1.5-12.5 km
Solar and telluric infrared spectra from altitudes between 1.5 and 12.5 k
Pulsar spin-down: the glitch-dominated rotation of PSR J0537-6910
The young, fast-spinning, X-ray pulsar J0537-6910 displays an extreme glitch
activity, with large spin-ups interrupting its decelerating rotation every ~100
days. We present nearly 13 years of timing data from this pulsar, obtained with
the {\it Rossi X-ray Timing Explorer}. We discovered 22 new glitches and
performed a consistent analysis of all 45 glitches detected in the complete
data span. Our results corroborate the previously reported strong correlation
between glitch spin-up size and the time to the next glitch, a relation that
has not been observed so far in any other pulsar. The spin evolution is
dominated by the glitches, which occur at a rate ~3.5 per year, and the
post-glitch recoveries, which prevail the entire inter-glitch intervals. This
distinctive behaviour provides invaluable insights into the physics of
glitches. The observations can be explained with a multi-component model which
accounts for the dynamics of the neutron superfluid present in the crust and
core of neutron stars. We place limits on the moment of inertia of the
component responsible for the spin-up and, ignoring differential rotation, the
velocity difference it can sustain with the crust. Contrary to its rapid
decrease between glitches, the spin-down rate increased over the 13 years, and
we find the long-term braking index , the only negative
braking index seen in a young pulsar. We briefly discuss the plausible
interpretations of this result, which is in stark contrast to the predictions
of standard models of pulsar spin-down.Comment: Minor changes to match the MNRAS accepted versio
The infrared spectrum of carbon suboxide. Part 1 - Region 1-2.5 microns. Part 2 - Region 2-15 microns. Part 3 - Classification of carbon suboxide vibrational bands
Laboratory tests of infrared spectrum of carbon suboxide, to determine presence in Venus and Mars atmosphere
Testing Gaussian random hypothesis with the cosmic microwave background temperature anisotropies in the three-year WMAP data
We test the hypothesis that the temperature of the cosmic microwave
background is consistent with a Gaussian random field defined on the celestial
sphere, using de-biased internal linear combination (DILC) map produced from
the 3-year WMAP data. We test the phases for spherical harmonic modes with l <=
10 (which should be the cleanest) for their uniformity, randomness, and
correlation with those of the foreground templates. The phases themselves are
consistent with a uniform distribution, but not for l <= 5, and the differences
between phases are not consistent with uniformity. For l=3 and l=6, the phases
of the CMB maps cross-correlate with the foregrounds, suggestion the presence
of residual contamination in the DLC map even on these large scales. We also
use a one-dimensional Fourier representation to assemble a_lm into the \Delta
T_l(\phi) for each l mode, and test the positions of the resulting maxima and
minima for consistency with uniformity randomness on the unit circle. The
results show significant departures at the 0.5% level, with the one-dimensional
peaks being concentrated around \phi=180 degs. This strongly significant
alignment with the Galactic meridian, together with the cross-correlation of
DILC phases with the foreground maps, strongly suggests that even the lowest
spherical harmonic modes in the map are significantly contaminated with
foreground radiation.Comment: submitted to ApJL, one paragraph is added in Section 3 and some more
in the Referenc
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