4,647 research outputs found

    Arizona-NASA Atlas of infrared solar spectrum, a preliminary report, number 123

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    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

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    Calibration of water absorption bands in near infrared regio

    Partial Isometries of a Sub-Riemannian Manifold

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    In this paper, we obtain the following generalisation of isometric C1C^1-immersion theorem of Nash and Kuiper. Let MM be a smooth manifold of dimension mm and HH a rank kk subbundle of the tangent bundle TMTM with a Riemannian metric gHg_H. Then the pair (H,gH)(H,g_H) defines a sub-Riemannian structure on MM. We call a C1C^1-map f:(M,H,gH)(N,h)f:(M,H,g_H)\to (N,h) into a Riemannian manifold (N,h)(N,h) a {\em partial isometry} if the derivative map dfdf restricted to HH is isometric; in other words, fhH=gHf^*h|_H=g_H. The main result states that if dimN>k\dim N>k then a smooth HH-immersion f0:MNf_0:M\to N satisfying fhH<gHf^*h|_H<g_H can be homotoped to a partial isometry f:(M,gH)(N,h)f:(M,g_H)\to (N,h) which is C0C^0-close to f0f_0. In particular we prove that every sub-Riemannian manifold (M,H,gH)(M,H,g_H) admits a partial isometry in Rn\R^n provided nm+kn\geq m+k.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

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    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

    EU Agricultural Trade Relations with Asian countries

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    A high-resolution solar spectrometer for air-borne infrared observations, number 126

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    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

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    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

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    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 nl=1.22(4)n_{\rm l}=-1.22(4), 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

    Testing Gaussian random hypothesis with the cosmic microwave background temperature anisotropies in the three-year WMAP data

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    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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