3,181 research outputs found
Remote sensing of floe size distribution and surface topography
Floe size can be measured by several properties p- for instance, area or mean caliper diameter. Two definitions of floe size distribution seem particularly useful. F(p), the fraction of area covered by floes no smaller than p; and N(p), the number of floes per unit area no smaller than p. Several summertime distributions measured are a graph, their slopes range from -1.7 to -2.5. The variance of an estimate is also calculated
Structure in the Epislon Eridani dusty disk caused by mean motion resonances with a 0.3 eccentricity planet at periastron
The morphology of the epsilon Eridani dust ring is reproduced by a numerical
simulation of dust particles captured into the 5:3 and 3:2 exterior mean-motion
resonances with a 0.3 eccentricity 10^-4 solar mass planet at periastron at a
semi-major axis of 40 AU. The morphology will differ when the planet is at
aphelion, in about 140 years. Moderate eccentricity planets in outer
extra-solar systems will cause observable variations in the morphology of
associated dusty rings.Comment: accepted to ApJ
The Concepts of Reliability and Homogeneity
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67956/2/10.1177_001316445001000103.pd
Turbulence driven by outflow-blown cavities in the molecular cloud of NGC 1333
Outflows from young stellar objects have been identified as a possible source
of turbulence in molecular clouds. To investigate the relationship between
outflows, cloud dynamics and turbulence, we compare the kinematics of the
molecular gas associated with NGC 1333, traced in 13CO(1-0), with the
distribution of young stellar objects (YSOs) within. We find a velocity
dispersion of ~ 1-1.6 km/s in 13CO that does not significantly vary across the
cloud, and is uncorrelated with the number of nearby young stellar outflows
identified from optical and submillimeter observations. However, from velocity
channel maps we identify about 20 cavities or depressions in the 13CO intensity
of scales > 0.1-0.2 pc and velocity widths 1-3 km/s. The cavities exhibit limb
brightened rims in both individual velocity channel maps and position velocity
diagrams, suggesting that they are slowly expanding. We interpret these
cavities to be remnants of past YSO outflow activity: If these cavities are
presently empty, they would fill in on time scales of a million years. This can
exceed the lifetime of a YSO outflow phase, or the transit time of the central
star through the cavity, explaining the the absence of any clear correlation
between the cavities and YSO outflows. We find that the momentum and energy
deposition associated with the expansion of the cavities is sufficient to power
the turbulence in the cloud. In this way we conclude that the cavities are an
important intermediary step between the conversion of YSO outflow energy and
momentum into cloud turbulent motions.Comment: Accepted for publication in ApJ. Check out
http://astro.pas.rochester.edu/~aquillen/coolpics.html for channel map and
PosVel movies of N133
Recommended from our members
Updated position and ice velocity for the AIDJEX manned camps. volume 1. 11 April 1975 to 17 October 1975
Re-processed data from camps in Beaufort Sea. Higher co-variance factor allows data of inertial period and longer to pass through filter with <1% attenuation
Recommended from our members
Updated position and ice velocity for the AIDJEX manned camps. Volume 2. 18 October 1975 to 4 May 1976
Constraints on the R-parity- and Lepton-Flavor-Violating Couplings from B0 Decats to Two Charged Leptons
We derive the upper bounds on certain products of R-parity- and
lepton-flavor-violating couplings from the decays of the neutral meson into
two charged leptons. These modes of decays can constrain the product
combinations of the couplings with one or more heavy generation indices. We
find that most of these bounds are stronger than the previous ones.Comment: Table is changed; version to appear in Phys. Rev.
Analysis of Charge Asymmetry in Rare Dilepton Decays
We analyze forward-backward charge asymmetry of the lepton production in rare
decays and , including
vector-resonance effects. Certain regions of phase space, in which the
asymmetry is sensitive to individual short-distance coefficients, are pointed
out. In particular, we suggest a method to test the coupling of the leptonic
axial vector current to the left-handed quark current experimentally.Comment: 27 pages, 4 figures available up to requiremen
Isospin-mixing corrections for fp-shell Fermi transitions
Isospin-mixing corrections for superallowed Fermi transitions in {\it
fp}-shell nuclei are computed within the framework of the shell model. The
study includes three nuclei that are part of the set of nine accurately
measured transitions as well as five cases that are expected to be measured in
the future at radioactive-beam facilities. We also include some new
calculations for C. With the isospin-mixing corrections applied to the
nine accurately measured values, the conserved-vector-current hypothesis
and the unitarity condition of the Cabbibo-Kobayashi-Maskawa (CKM) matrix are
tested.Comment: 13 pages plus five tables. revtex macro
Using to Probe Top Quark Couplings
Possible anomalous couplings of the top-quark to on-shell photons and gluons
are constrained by the recent results of the CLEO Collaboration on both
inclusive and exclusive radiative decays. We find that the process \bsg\
can lead to reasonable bounds on both the anomalous electric and magnetic
dipole moments of the top-quark, while essentially no limits are obtained on
the corresponding chromoelectric and chromomagnetic moments, which enter the
expression for the decay rate only through operator mixing.Comment: 10 pages plus 6 figures (available by request), LaTex,
ANL-HEP-PR-93-3
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