11,382,379 research outputs found
The third transit of snow-line exoplanet Kepler-421b
The Kepler Mission has uncovered a handful of long-period transiting exoplanets that orbit from the cold outer reaches of their systems, despite their low transit probabilities. The atmospheres of these cold gas giant exoplanets are amenable to transit transmission spectroscopy enabling tests of planetary formation and evolution theories. Of particular scientific interest is Kepler-421b, a Neptune-sized exoplanet with a 704-day orbital period residing near the snow-line. Since the Kepler Spacecraft only observed two transits of Kepler-421b, the transit ephemeris is relatively uncertain. We observed Kepler-421 during the anticipated third transit of Kepler-421b in order to constrain the existence and extent of transit timing variations (TTVs). Barring significant TTVs, our visible light, time-series observations from the 4.3-meter Discovery Channel Telescope (DCT) were designed to capture pre-transit baseline and the partial transit of Kepler-421b. We find strong evidence in favor of transit models with no TTVs, suggesting that Kepler-421b is either alone in its system or is only experiencing minor dynamic interactions with an unseen companion. With the combined Kepler and DCT observations, we calculate the timing of future transits and discuss the unique opportunity to characterize the atmosphere of this cold, long-period exoplanet via transmission spectroscopy.http://adsabs.harvard.edu/abs/2016DPS....4812208DPublished versio
Comparing the Line Crossing Feature Approach with the Graph Approach for Invoice Automation
Di dalam dunia bisnis, invoice merupakan salah satu dokumen penting yang erat kaitannya dengan aktivitas penjualan dan pembelian di dalam suatu Perusahaan. Setiap invoice yang diperoleh oleh suatu Perusahaan akan menjadi sumber informasi atas berapa besarnya hutang atau piutang yang dimiliki oleh suatu Perusahaan. Ketika jumlah transaksi di dalam suatu Perusahaan masih tidak terlalu banyak, pencatatan invoice ke dalam database Perusahaan secara manual masih dimungkinkan. Mengingat bahwa jumlah transaksi di dalam suatu Perusahaan dapat menjadi besar, suatu metode untuk melakukan pencatatan invoice secara otomatis dapat membantu proses pencatatan data ke dalam database Perusahaan agar menjadi lebih efisien. Dua pendekatan pencatatan invoice secara otomatis yang akan dibandingkan di dalam karya ilmiah ini adalah Line Crossing Feature Approach dan Graph Approach. Berdasarkan perbandingan atas kelebihan dan kekurangan masing-masing pendekatan, Graph Approach secara pribadi dapat dinilai sebagai sebagai pendekatan yang lebih tepat untuk pencatatan invoice secara otomatis karena fleksibilitasnya dalam mengenali berbagai jenis dokumen. Kata kunci: invoice, information extraction, Line Crossing Feature Approach, Graph Approach, INFORMys metho
The T-Wilson Line
We argue that soft-collinear effective theory, as is currently formulated,
lacks an ingredient which is essential for obtaining a gauge invariant
definitions of certain non-perturbative matrix elements relevant for
semi-inclusive high-energy processes. Those processes and the companion
cross-sections are to be analyzed and measured at the Large Hadron Collider.
The missing feature is a gauge link constructed only from the transverse
component of the gluon field denoted by the "-Wilson line"'. It is neither
soft nor collinear. As such it is a new feature of the theory.Comment: 4 pages. To appear in the proceedings of "Quark Confinement and
Hadron Nuclei", Madrid 201
Redistricting: Drawing the Line
We develop methods to evaluate whether a political districting accurately
represents the will of the people. To explore and showcase our ideas, we
concentrate on the congressional districts for the U.S. House of
representatives and use the state of North Carolina and its redistrictings
since the 2010 census. Using a Monte Carlo algorithm, we randomly generate over
24,000 redistrictings that are non-partisan and adhere to criteria from
proposed legislation. Applying historical voting data to these random
redistrictings, we find that the number of democratic and republican
representatives elected varies drastically depending on how districts are
drawn. Some results are more common, and we gain a clear range of expected
election outcomes. Using the statistics of our generated redistrictings, we
critique the particular congressional districtings used in the 2012 and 2016 NC
elections as well as a districting proposed by a bipartisan redistricting
commission. We find that the 2012 and 2016 districtings are highly atypical and
not representative of the will of the people. On the other hand, our results
indicate that a plan produced by a bipartisan panel of retired judges is highly
typical and representative. Since our analyses are based on an ensemble of
reasonable redistrictings of North Carolina, they provide a baseline for a
given election which incorporates the geometry of the state's population
distribution.Comment: Corrected typos from previous version; added new plots showing
stability; corrected error in EG plots and analysi
Pulsations detected in the line profile variations of red giants: Modelling of line moments, line bisector and line shape
Contents: So far, red giant oscillations have been studied from radial
velocity and/or light curve variations, which reveal frequencies of the
oscillation modes. To characterise radial and non-radial oscillations, line
profile variations are a valuable diagnostic. Here we present for the first
time a line profile analysis of pulsating red giants, taking into account the
small line profile variations and the predicted short damping and re-excitation
times. We do so by modelling the time variations in the cross correlation
profiles in terms of oscillation theory.
Aims: The performance of existing diagnostics for mode identification is
investigated for known oscillating giants which have very small line profile
variations. We modify these diagnostics, perform simulations, and characterise
the radial and non-radial modes detected in the cross correlation profiles.
Methods: Moments and line bisectors are computed and analysed for four
giants. The robustness of the discriminant of the moments against small
oscillations with finite lifetimes is investigated. In addition, line profiles
are simulated with short damping and re-excitation times and their line shapes
are compared with the observations.
Results: For three stars, we find evidence for the presence of non-radial
pulsation modes, while for Hydrae perhaps only radial modes are present.
Furthermore the line bisectors are not able to distinguish between different
pulsation modes and are an insufficient diagnostic to discriminate small line
profile variations due to oscillations from exoplanet motion.Comment: 12 pages, 10 figures, accepted by A&
The Broad-Line and Narrow-Line Regions of the LINER NGC 4579
We report the discovery of an extremely broad H-alpha emission line in the
LINER nucleus of NGC 4579. From ground-based observations, the galaxy was
previously known to contain a Type 1 nucleus with a broad H-alpha line of FWHM
= 2300 km/s and FWZI ~ 5000 km/s. New spectra obtained with the Hubble Space
Telescope and a 0.2 arcsec-wide slit reveal an H-alpha component with FWZI ~
18,000 km/s. The line is not obviously double-peaked, but it does possess
shoulders on the red and blue sides which resemble the H-alpha profiles of
double-peaked emitters such as NGC 4203 and NGC 4450. This similarity suggests
that the very broad H-alpha profile in NGC 4579 may represent emission from an
accretion disk. Three such objects have been found recently in two HST programs
which have targeted a total of 30 galaxies, demonstrating that double-peaked or
extremely broad-line emission in LINERs must be much more common than would be
inferred from ground-based surveys. The ratio of the narrow [S II] 6716, 6731
lines shows a pronounced gradient indicating a steep rise in density toward the
nucleus. The direct detection of a density gradient within the inner arcsecond
of the narrow-line region confirms expectations from previous observations of
linewidth-critical density correlations in several LINERs.Comment: 8 pages, includes 3 figures. To appear in The Astrophysical Journa
The Narrow-Line Region of Narrow-Line Seyfert 1 Galaxies
We have studied the physical properties of a sample of narrow-line Seyfert 1
(NLS1) galaxies, and present a summary of our previous results, and new
results. In particular, we have previously shown that (1) the locus of NLS1
galaxies on the M_BH-sigma_[OIII] plane does follow the relation of non-active
galaxies after removing objects obviously dominated by outflows as evidenced by
their [OIII] core blueshifts. We have (2) identified a number of so-called
'blue outliers' with large outflow velocities revealed by their emission-line
kinematic shifts. We also (3) present new correlations and trends which link
black hole mass, Eddington ratio and physical parameters of the emission-line
regions.Comment: 9 pages, 6 figures, Proceedings of the Workshop "Narrow-Line Seyfert
1 Galaxies and Their Place in the Universe", Milano, April 4-6, 2011
(Proceedings of Science,
http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=126
- …
