59 research outputs found
Far-Infrared Astronomy with The Kuiper Airborne Observatory
This report summarizes work made possible by NASA's Kuiper Airborne Observatory. The results of the work have appeared in over 80 papers. The publications fall in three main areas: instrumentation, observations, and analysis. Although there is considerable overlap between these categories it will be convenient to group them separately
Characterization of Turbulence from Submillimeter Dust Emission
In this paper we use our recent technique for estimating the turbulent
component of the magnetic field to derive the structure functions of the
unpolarized emission as well as that of the Stokes Q and U parameters of the
polarized emission. The solutions for the structure functions to 350-um SHARP
polarization data of OMC-1 allow the determination of the corresponding
turbulent correlation length scales. The estimated values for these length
scales are 9.4" +/- 0.1", 7.3" +/- 0.1", 12.6" +/- 0.2" (or 20.5 +/- 0.2, 16.0
+/- 0.2, and 27.5 +/- 0.4 mpc at 450 pc, the adopted distance for OMC-1) for
the Stokes Q and U parameters, and for the unpolarized emission N,
respectively. Our current results for Q and U are consistent with previous
results obtained through other methods, and may indicate presence of anisotropy
in magnetized turbulence. We infer a weak coupling between the dust component
responsible for the unpolarized emission N and the magnetic field B from the
significant difference between their turbulent correlation length scales.Comment: 14 pages, 3 figures; accepted for publication in the Ap
Method of Reducing Odor Associated with Hexanal Production in Plant Products
A method of reducing the formation of hexanal by plant parts comprises breaking the plant parts, adding thereto an agent comprising lipoxygenase 3 enzyme and allowing the plant parts to remain in contact with the enzyme under conditions effective to attain the desired effect. A method of producing a low odor plant part meal or flour comprises breaking up the plant parts, adding an agent with lipoxygenase 3 enzyme and allowing the plant parts to remain in contact with the enzyme under conditions effective to attain the desired effect. An improved composition comprises a hexanal producing plant part meal or flour and an agent with lipoxygenase 3 enzyme which is substantially devoid of lipoxygenase enzyme 1 and 2 activities, optionally with other edible ingredients such as other low-hexanal producing flours. Improved edible products are produced using the invention which have less objectionable odor and flavor. This invention facilitates better tailoring of the flavor of food products to the desires of the consumers
Dispersion of Magnetic Fields in Molecular Clouds. II.
We expand our study on the dispersion of polarization angles in molecular clouds. We show how the effect of signal integration through the thickness of the cloud as well as across the area subtended by the telescope beam inherent to dust continuum measurements can be incorporated in our analysis to correctly account for its effect on the measured angular dispersion and inferred turbulent to large-scale magnetic field strength ratio. We further show how to evaluate the turbulent magnetic field correlation scale from polarization data of sufficient spatial resolution and high enough spatial sampling rate. We apply our results to the molecular cloud OMC-1, where we find a turbulent correlation length of ÎŽ â 16 mpc, a turbulent to large-scale magnetic field strength ratio of approximately 0.5, and a plane-of-the-sky large-scale magnetic field strength of approximately 760 ÎŒG
Dispersion of Magnetic Fields in Molecular Clouds. III
We apply our technique on the dispersion of magnetic fields in molecular
clouds to high spatial resolution Submillimeter Array polarization data
obtained for Orion KL in OMC-1, IRAS 16293, and NGC 1333 IRAS 4A. We show how
one can take advantage of such high resolution data to characterize the
magnetized turbulence power spectrum in the inertial and dissipation ranges.
For Orion KL we determine that in the inertial range the spectrum can be
approximately fitted with a power law k^-(2.9\pm0.9) and we report a value of
9.9 mpc for {\lambda}_AD, the high spatial frequency cutoff presumably due to
turbulent ambipolar diffusion. For the same parameters we have \sim
k^-(1.4\pm0.4) and a tentative value of {\lambda}_AD \simeq 2.2 mpc for NGC
1333 IRAS 4A, and \sim k^-(1.8\pm0.3) with an upper limit of {\lambda}_AD < 1.8
mpc for IRAS 16293. We also discuss the application of the technique to
interferometry measurements and the effects of the inherent spatial filtering
process on the interpretation of the results.Comment: 25 pages, 9 figures; accepted for publication in The Astrophysical
Journa
Dispersion of Magnetic Fields in Molecular Clouds. IV - Analysis of Interferometry Data
We expand on the dispersion analysis of polarimetry maps toward applications to interferometry data. We show how the filtering of low spatial frequencies can be accounted for within the idealized Gaussian turbulence model, initially introduced for single-dish data analysis, to recover reliable estimates for correlation lengths of magnetized turbulence, as well as magnetic field strengths (plane-of-the-sky component) using the DavisâChandrasekharâFermi method. We apply our updated technique to TADPOL/CARMA data obtained on W3(OH), W3 Main, and DR21(OH). For W3(OH), our analysis yields a turbulence correlation length ÎŽ â 19 mpc, a ratio of turbulent-to-total magnetic energy â©BâȘ_^2_t/â©B^2âȘ â 0.58, and a magnetic field strength B_0 ~ 1.1 mG for W3 Main ÎŽ â 22mpc, â©B_t^2âȘ/â©B^2âȘ â 0.74, and B_0 ~ 0.7 mG while for DR21(OH) ÎŽ â 12 mpc, â©B_t^2âȘ/â©B^2âȘ â 0.70, and B_0 ~ 1.2 mG
On the Measurement of the Magnitude and Orientation of the Magnetic Field in Molecular Clouds
We demonstrate that the combination of Zeeman, polarimetry and ion-to-neutral
molecular line width ratio measurements permits the determination of the
magnitude and orientation of the magnetic field in the weakly ionized parts of
molecular clouds. Zeeman measurements provide the strength of the magnetic
field along the line of sight, polarimetry measurements give the field
orientation in the plane of the sky and the ion-to-neutral molecular line width
ratio determines the angle between the magnetic field and the line of sight. We
apply the technique to the M17 star-forming region using a HERTZ 350 um
polarimetry map and HCO+-to-HCN molecular line width ratios to provide the
first three-dimensional view of the magnetic field in M17.Comment: 37 pages, 12 figures, 3 table
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