516 research outputs found
Polarization studies of Rotating Radio Transients
We study the polarization properties of 22 known rotating radio transients
(RRATs) with the 64-m Parkes radio telescope and present the Faraday rotation
measures (RMs) for the 17 with linearly polarized flux exceeding the off-pulse
noise by 3. Each RM was estimated using a brute-force search over trial
RMs that spanned the maximum measurable range (in steps of 1 ), followed by an
iterative refinement algorithm. The measured RRAT RMs are in the range |RM|
to rad m with an average linear polarization
fraction of per cent. Individual single pulses are observed to be up
to 100 per cent linearly polarized. The RMs of the RRATs and the corresponding
inferred average magnetic fields (parallel to the line-of-sight and weighted by
the free electron density) are observed to be consistent with the Galactic
plane pulsar population. Faraday rotation analyses are typically performed on
accumulated pulsar data, for which hundreds to thousands of pulses have been
integrated, rather than on individual pulses. Therefore, we verified the
iterative refinement algorithm by performing Monte Carlo simulations of
artificial single pulses over a wide range of S/N and RM. At and above a S/N of
17 in linearly polarized flux, the iterative refinement recovers the simulated
RM value 100 per cent of the time with a typical mean uncertainty of
rad m. The method described and validated here has also been
successfully used to determine reliable RMs of several fast radio bursts (FRBs)
discovered at Parkes.Comment: Submitted to MNRAS, 10 pages, 6 figure
The Prevalence and Indications of Intravenous Rehydration Therapy in Hospital Settings: A Systematic Review
Investigation of octupole vibrational states in 150Nd via inelastic proton scattering (p,p'g)
Octupole vibrational states were studied in the nucleus
via inelastic proton scattering with \unit[10.9]{MeV} protons which are an
excellent probe to excite natural parity states. For the first time in
, both the scattered protons and the rays were
detected in coincidence giving the possibility to measure branching ratios in
detail. Using the coincidence technique, the ratios of the decaying
transitions for 10 octupole vibrational states and other negative-parity states
to the yrast band were determined and compared to the Alaga rule. The positive
and negative-parity states revealed by this experiment are compared with
Interacting Boson Approximation (IBA) calculations performed in the (spdf)
boson space. The calculations are found to be in good agreement with the
experimental data, both for positive and negative-parity states
Observation of isotonic symmetry for enhanced quadrupole collectivity in neutron-rich 62,64,66Fe isotopes at N=40
The transition rates for the 2_{1}^{+} states in 62,64,66Fe were studied
using the Recoil Distance Doppler-Shift technique applied to projectile Coulomb
excitation reactions. The deduced E2 strengths illustrate the enhanced
collectivity of the neutron-rich Fe isotopes up to N=40. The results are
interpreted by the generalized concept of valence proton symmetry which
describes the evolution of nuclear structure around N=40 as governed by the
number of valence protons with respect to Z~30. The deformation suggested by
the experimental data is reproduced by state-of-the-art shell calculations with
a new effective interaction developed for the fpgd valence space.Comment: 4 pages, 2 figure
Observations of a high‐latitude stable electron auroral emission at ∼16 MLT during a large substorm
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94792/1/jgra21045.pd
High-Spin Study of the Shell Model Nucleus \u3csup\u3e88\u3c/sup\u3eY\u3csub\u3e49\u3c/sub\u3e
The near-yrast structure of the near-magic, odd-odd nucleus, 8839Y49, has been studied into the high-spin regime. Investigations were performed at the Wright Nuclear Structure Laboratory, Yale University, using the 74Ge(18O,p3n) and 76Ge(18O,p5n) fusion-evaporation reactions at beam energies of 60 and 90 MeV, respectively. Gamma-ray energy coincidence analyses using both double (γ2) and triple (γ3) fold coincidences, together with angular correlation measurements, have been used to extend the previously reported level scheme to an excitation energy of 8.6 MeV and a spin and parity of 19(−). The presented level scheme is compared with predictions of a truncated valence space shell-model calculation, which assumes an inert 56Ni core with proton and neutron excitations allowed within the f5/2, p3/2, p1/2, and g9/2 single-particle states. The shell-model calculations show a reasonable comparison with the experimental data for the yrast, positive-parity states up to spin 18 ℏ, with larger variations evident for negative-parity states with spins greater than 16 ℏ. In spite of a significant increase in angular momentum input associated with the thin target 76Ge(18O,p5n) reaction channel, as compared to the backed target data using the 74Ge target, no additional discrete states were identified in the former data set, suggesting that the level scheme for this nucleus fragments significantly above the observed states, possibly indicating cross-shell excitations becoming dominant for I \u3e19 ℏ
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