841 research outputs found
The Outer Disks of Early-Type Galaxies. I. Surface-Brightness Profiles of Barred Galaxies
We present a study of 66 barred, early-type (S0-Sb) disk galaxies, focused on
the disk surface brightness profile outside the bar region and the nature of
Freeman Type I and II profiles, their origins, and their possible relation to
disk truncations. This paper discusses the data and their reduction, outlines
our classification system, and presents -band profiles and classifications
for all galaxies in the sample.
The profiles are derived from a variety of different sources, including the
Sloan Digital Sky Survey (Data Release 5). For about half of the galaxies, we
have profiles derived from more than one telescope; this allows us to check the
stability and repeatability of our profile extraction and classification. The
vast majority of the profiles are reliable down to levels of mu_R ~ 27 mag
arcsec^-2; in exceptional cases, we can trace profiles down to mu_R > 28. We
can typically follow disk profiles out to at least 1.5 times the traditional
optical radius R_25; for some galaxies, we find light extending to ~ 3 R_25.
We classify the profiles into three main groups: Type I (single-exponential),
Type II (down-bending), and Type III (up-bending). The frequencies of these
types are approximately 27%, 42%, and 24%, respectively, plus another 6% which
are combinations of Types II and III. We further classify Type II profiles by
where the break falls in relation to the bar length, and in terms of the
postulated mechanisms for breaks at large radii ("classical trunction" of star
formation versus the influence of the Outer Lindblad Resonance of the bar). We
also classify the Type III profiles by the probable morphology of the outer
light (disk or spheroid). Illustrations are given for all cases. (Abridged)Comment: 41 pages, 26 PDF figures. To appear in the Astronomical Journal.
Version with full-resolution figures available at
http://www.mpe.mpg.de/~erwin/research
A Rare Case of Effusive Constrictive Cholesterol Pericarditis: A Case Report and Review
Effusive constrictive cholesterol pericarditis is exceedingly rare. Most cases have an unclear etiology but can be associated with rheumatoid arthritis, tuberculosis infection, and hypothyroidism. The hallmark of the effusion is the distinctively high levels of cholesterol. We present the case of a 68-year-old male with prolonged symptoms of dyspnea with associated moderate pericardial effusion that were later determined to be constrictive effusive etiology, and the patient was referred for stripping with pathologic cholesterol crystal formation on pathology review
Influence of roughness on capillary forces between hydrophilic surfaces
Capillary forces have been measured by Atomic Force Microscopy in the
plate-sphere setup between gold, borosilicate glass, GeSbTe, titanium, and UV
irradiated amorphous titaniumdioxide surfaces. The force measurements were
performed as a function contact time and surface roughness in the range 0.2 -
15 nm rms, and relative humidity ranging between 2 and 40 %. It is found that
even for the lowest attainable relative humidity 2 % very large capillary
forces are still present. The latter suggests the persistence of a nanometers
thick adsorbed water layer that acts as a capillary bridge between contacting
surfaces. Moreover, we found a significantly different scaling behavior of the
force with rms roughness for materials with different hydrophilicity as
compared to gold-gold surfaces
Transformation kinetics of alloys under non-isothermal conditions
The overall solid-to-solid phase transformation kinetics under non-isothermal
conditions has been modeled by means of a differential equation method. The
method requires provisions for expressions of the fraction of the transformed
phase in equilibrium condition and the relaxation time for transition as
functions of temperature. The thermal history is an input to the model. We have
used the method to calculate the time/temperature variation of the volume
fraction of the favored phase in the alpha-to-beta transition in a zirconium
alloy under heating and cooling, in agreement with experimental results. We
also present a formulation that accounts for both additive and non-additive
phase transformation processes. Moreover, a method based on the concept of path
integral, which considers all the possible paths in thermal histories to reach
the final state, is suggested.Comment: 16 pages, 7 figures. To appear in Modelling Simul. Mater. Sci. En
Force-velocity relation and density profiles for biased diffusion in an adsorbed monolayer
In this paper, which completes our earlier short publication [Phys. Rev.
Lett. 84, 511 (2000)], we study dynamics of a hard-core tracer particle (TP)
performing a biased random walk in an adsorbed monolayer, composed of mobile
hard-core particles undergoing continuous exchanges with a vapor phase. In
terms of an approximate approach, based on the decoupling of the third-order
correlation functions, we obtain the density profiles of the monolayer
particles around the TP and derive the force-velocity relation, determining the
TP terminal velocity, V_{tr}, as the function of the magnitude of external bias
and other system's parameters. Asymptotic forms of the monolayer particles
density profiles at large separations from the TP, and behavior of V_{tr} in
the limit of small external bias are found explicitly.Comment: Latex, 31 pages, 3 figure
Control of hypersonic aerodynamic forces with surface blowing
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76211/1/AIAA-10846-311.pd
Strongly Accelerated and Humidity-Independent Drying of Nanochannels Induced by Sharp Corners
Next-to-leading order predictions for Z gamma+jet and Z gamma gamma final states at the LHC
We present next-to-leading order predictions for final states containing
leptons produced through the decay of a Z boson in association with either a
photon and a jet, or a pair of photons. The effect of photon radiation from the
final state leptons is included and we also allow for contributions arising
from fragmentation processes. Phenomenological studies are presented for the
LHC in the case of final states containing charged leptons and in the case of
neutrinos. We also use the procedure introduced by Stewart and Tackmann to
provide a reliable estimate of the scale uncertainty inherent in our
theoretical calculations of jet-binned Z gamma cross sections. These
computations have been implemented in the public code MCFM.Comment: 30 pages, 10 figure
Gluon induced contributions to Z gamma production at hadron colliders
We study the contribution of gluon induced partonic subprocesses to Z gamma
pair production at hadron colliders. These processes contribute only at
next-to-next-to-leading order but are potentially enhanced by two factors of
the gluon parton densities. However, we find that their contribution is modest
and that next-to-leading order calculations give reliable predictions.Comment: 7 pages, 1 figur
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