4,995 research outputs found
Gas kinematics and star formation in the filamentary molecular cloud G47.06+0.26
We performed a multi-wavelength study toward the filamentary cloud
G47.06+0.26 to investigate the gas kinematics and star formation. We present
the 12CO (J=1-0), 13CO (J=1-0) and C18O (J=1-0) observations of G47.06+0.26
obtained with the Purple Mountain Observation (PMO) 13.7 m radio telescope to
investigate the detailed kinematics of the filament. The 12CO (J=1-0) and 13CO
(J=1-0) emission of G47.06+0.26 appear to show a filamentary structure. The
filament extends about 45 arcmin (58.1 pc) along the east-west direction. The
mean width is about 6.8 pc, as traced by the 13CO (J=1-0) emission. G47.06+0.26
has a linear mass density of about 361.5 Msun/pc. The external pressure (due to
neighboring bubbles and H II regions) may help preventing the filament from
dispersing under the effects of turbulence. From the velocity-field map, we
discern a velocity gradient perpendicular to G47.06+0.26. From the Bolocam
Galactic Plane Survey (BGPS) catalog, we found nine BGPS sources in
G47.06+0.26, that appear to these sources have sufficient mass to form massive
stars. We obtained that the clump formation efficiency (CFE) is about 18% in
the filament. Four infrared bubbles were found to be located in, and adjacent
to, G47.06+0.26. Particularly, infrared bubble N98 shows a cometary structure.
CO molecular gas adjacent to N98 also shows a very intense emission. H II
regions associated with infrared bubbles can inject the energy to surrounding
gas. We calculated the kinetic energy, ionization energy, and thermal energy of
two H II regions in G47.06+0.26. From the GLIMPSE I catalog, we selected some
Class I sources with an age of about 100000 yr, which are clustered along the
filament. The feedback from the H II regions may cause the formation of a new
generation of stars in filament G47.06+0.26.Comment: 10 pages, 11 figures, accepted for publication in A&
Choosing the in loss: rate adaptivity on the symmetric location problem
Given univariate random variables with the
distribution, the sample midrange
is the MLE for and estimates
with error of order , which is much smaller compared with the
error rate of the usual sample mean estimator. However, the sample midrange
performs poorly when the data has say the Gaussian
distribution, with an error rate of . In this paper, we
propose an estimator of the location with a rate of convergence that
can, in many settings, adapt to the underlying distribution which we assume to
be symmetric around but is otherwise unknown. When the underlying
distribution is compactly supported, we show that our estimator attains a rate
of convergence of up to polylog factors, where the rate
parameter can take on any value in and depends on the moments
of the underlying distribution. Our estimator is formed by the
-center of the data, for a chosen in a data-driven
way -- by minimizing a criterion motivated by the asymptotic variance. Our
approach can be directly applied to the regression setting where is
a function of observed features and motivates the use of loss
function for in certain settings.Comment: 60 pages; 7 figure
Focal Spot, Winter 1983/84
https://digitalcommons.wustl.edu/focal_spot_archives/1036/thumbnail.jp
Demonstration of Einstein-Podolsky-Rosen Steering with Enhanced Subchannel Discrimination
Einstein-Podolsky-Rosen (EPR) steering describes a quantum nonlocal
phenomenon in which one party can nonlocally affect the other's state through
local measurements. It reveals an additional concept of quantum nonlocality,
which stands between quantum entanglement and Bell nonlocality. Recently, a
quantum information task named as subchannel discrimination (SD) provides a
necessary and sufficient characterization of EPR steering. The success
probability of SD using steerable states is higher than using any unsteerable
states, even when they are entangled. However, the detailed construction of
such subchannels and the experimental realization of the corresponding task are
still technologically challenging. In this work, we designed a feasible
collection of subchannels for a quantum channel and experimentally demonstrated
the corresponding SD task where the probabilities of correct discrimination are
clearly enhanced by exploiting steerable states. Our results provide a concrete
example to operationally demonstrate EPR steering and shine a new light on the
potential application of EPR steering.Comment: 16 pages, 8 figures, appendix include
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