14,385 research outputs found
An outburst scenario for the X-ray spectral variability in 3C 111
We present a combined Suzaku and Swift BAT broad-band E=0.6-200keV spectral
analysis of three 3C 111 observations obtained in 2010. The data are well
described with an absorbed power-law continuum and a weak (R~0.2) cold
reflection component from distant material. We constrain the continuum cutoff
at E_c~150-200keV, which is in accordance with X-ray Comptonization corona
models and supports claims that the jet emission is only dominant at much
higher energies. Fe XXVI Ly\alpha emission and absorption lines are also
present in the first and second observations, respectively. The modelling and
interpretation of the emission line is complex and we explore three
possibilities. If originating from ionized disc reflection, this should be
emitted at r_in> 50r_g or, in the lamp-post configuration, the illuminating
source should be at a height of h> 30r_g over the black hole. Alternatively,
the line could be modeled with a hot collisionally ionized plasma with
temperature kT = 22.0^{+6.1}_{-3.2} keV or a photo-ionized plasma with
log\xi=4.52^{+0.10}_{-0.16} erg s^{-1} cm and column density N_H > 3x10^23
cm^{-2}. However, the first and second scenarios are less favored on
statistical and physical grounds, respectively. The blue-shifted absorption
line in the second observation can be modelled as an ultra-fast outflow (UFO)
with ionization parameter log\xi=4.47^{+0.76}_{-0.04} erg s^{-1} cm, column
density N_H=(5.3^{+1.8}_{-1.3})x 10^{22} cm^{-2} and outflow velocity v_out =
0.104+/-0.006 c. Interestingly, the parameters of the photo-ionized emission
model remarkably match those of the absorbing UFO. We suggest an outburst
scenario in which an accretion disc wind, initially lying out of the line of
sight and observed in emission, then crosses our view to the source and it is
observed in absorption as a mildly-relativistic UFO.Comment: Accepted for publication in MNARS on July 1st 201
A study of the effect of surfaces on oxygen atom recombination at low pressures Technical status report, 1 Nov. 1968 - 30 Apr. 1969
Satellite mass spectrometer measurements of metal surfaces interacting with oxygen atom at low pressure
Cereal variety trials 1955-56
As an important step in the work of bringing new and improved cereal varieties to West Australian farmers, variety trials are carried out each season on the six wheatbelt research stations in this State. This provides a comparison of the performance, under actual field conditions, of recently produced varieties against those now in general cultivation
Unsupervised classification and areal measurement of land and water coastal features on the Texas coast
Multispectral scanner (MSS) digital data from ERTS-1 was used to delineate coastal land, vegetative, and water features in two portions of the Texas Coastal Zone. Data (Scene ID's 1037-16244 and 1037-16251) acquired on August 29, 1972, were analyzed on NASA Johnson Space Center systems through the use of two clustering algorithms. Seventeen to 30 spectrally homogeneous classes were so defined. Many classes were identified as being pure features such as water masses, salt marsh, beaches, pine, hardwoods, and exposed soil or construction materials. Most classes were identified to be mixtures of the pure class types. Using an objective technique for measuring the percentage of wetland along salt marsh boundaries, an analysis was made of the accuracy of areal measurement of salt marshes. Accuracies ranged from 89 to 99 percent. Aircraft photography was used as the basis for determining the true areal size of salt marshes in the study sites
Oat trials and usage in the Wheatbelt, 1956
The increasing acreages planted to oats in the Western Australian wheat growing districts have been associated with the improvement of farms for the carrying of stock and the need for a convenient change crop from wheat. Production of coarse grains, both oats and barley, has substantially increased the total area of cereals grown annually in Western Australia since 1930
- …