342 research outputs found
Results from the CASTLES Survey of Gravitational Lenses
We show that most gravitational lenses lie on the passively evolving
fundamental plane for early-type galaxies. For burst star formation models (1
Gyr of star formation, then quiescence) in low Omega_0 cosmologies, the stellar
populations of the lens galaxies must have formed at z_f > 2. Typical lens
galaxies contain modest amounts of patchy extinction, with a median
differential extinction for the optical (radio) selected lenses of E(B-V) =
0.04 (0.07) mag. The dust can be used to determine both extinction laws and
lens redshifts. For example, the z_l=0.96 elliptical lens in MG0414+0534 has an
R_V=1.7 +/- 0.1 mean extinction law. Arc and ring images of the quasar and AGN
source host galaxies are commonly seen in NICMOS H band observations. The hosts
are typically blue, L < L_* galaxies.Comment: 12 pages, 10 figures, from Proceedings of the 9th Annual Astrophysics
Conference in Maryland, After the Dark Ages: When Galaxies Were Youn
The reaction from threshold up to 570 MeV
The reaction has been studied in a
kinematically complete measurement with a large acceptance time-of-flight
spectrometer for incident neutron energies between threshold and 570 MeV. The
proton-proton invariant mass distributions show a strong enhancement due to the
pp() final state interaction. A large anisotropy was found in the
pion angular distributions in contrast to the reaction . At small energies, a large forward/backward asymmetry has been
observed. From the measured integrated cross section , the isoscalar cross section has been extracted.
Its energy dependence indicates that mainly partial waves with Sp final states
contribute. Note: Due to a coding error, the differential cross sections as shown in Fig. 9 are too small by a factor of two, and
inn Table 3 the differential cross sections
are too large by a factor of . The integrated cross sections and all
conclusions remain unchanged. A corresponding erratum has been submitted and
accepted by European Physics Journal.Comment: 18 pages, 16 figure
Analysing powers for the reaction and for np elastic scattering from 270 to 570 MeV
The analysing power of the reaction for neutron energies between threshold and 570 MeV has been determined
using a transversely polarised neutron beam at PSI. The reaction has been
studied in a kinematically complete measurement using a time-of-flight
spectrometer with large acceptance. Analysing powers have been determined as a
function of the c.m. pion angle in different regions of the proton-proton
invariant mass. They are compared to other data from the reactions and . The np elastic scattering analysing power was determined as a
by-product of the measurements.Comment: 12 pages, 6 figures, subitted to EPJ-
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