551 research outputs found
Age Dating of a High-Redshift QSO B1422+231 at Z=3.62 and its Cosmological Implications
The observed Fe II(UV+optical)/Mg II lambda lambda 2796,2804 flux ratio from
a gravitationally lensed quasar B1422+231 at z=3.62 is interpreted in terms of
detailed modeling of photoionization and chemical enrichment in the broad-line
region (BLR) of the host galaxy. The delayed iron enrichment by Type Ia
supernovae is used as a cosmic clock. Our standard model, which matches the Fe
II/Mg II ratio, requires the age of 1.5 Gyr for B1422+231 with a lower bound of
1.3 Gyr, which exceeds the expansion age of the Einstein-de Sitter Omega_0=1
universe at a redshift of 3.62 for any value of the Hubble constant in the
currently accepted range, H_0=60-80 km,s^{-1},Mpc^{-1}. This problem of an age
discrepancy at z=3.62 can be unraveled in a low-density Omega_0<0.2 universe,
either with or without a cosmological constant, depending on the allowable
redshift range of galaxy formation. However, whether the cosmological constant
is a required option in modern cosmology awaits a thorough understanding of
line transfer processes in the BLRs.Comment: 7 pages including 3 figures, to appear in ApJ Letter
Cold Molecular Gas Along the Merger Sequence in Local Luminous Infrared Galaxies
We present an initial result from the 12CO (J=1-0) survey of 79 galaxies in
62 local luminous and ultra-luminous infrared galaxy (LIRG and ULIRG) systems
obtained using the 45 m telescope at the Nobeyama Radio Observatory. This is
the systematic 12CO (J=1-0) survey of the Great Observatories All-sky LIRGs
Survey (GOALS) sample. The molecular gas mass of the sample ranges 2.2 x 10^8 -
7.0 x 10^9 Msun within the central several kiloparsecs subtending 15" beam. A
method to estimate a size of a CO gas distribution is introduced, which is
combined with the total CO flux in the literature. The method is applied to a
part of our sample and we find that the median CO radius is 1-4 kpc. From the
early stage to the late stage of mergers, we find that the CO size decreases
while the median value of the molecular gas mass in the central several kpc
region is constant. Our results statistically support a scenario where
molecular gas inflows towards the central region from the outer disk, to
replenish gas consumed by starburst, and that such a process is common in
merging LIRGs.Comment: 25 pages, 22 figures, accepted for publication in Ap
Directional Soliton and Breather Beams
Solitons and breathers are nonlinear modes that exist in a wide range of
physical systems. They are fundamental solutions of a number of nonlinear wave
evolution equations, including the uni-directional nonlinear Schr\"odinger
equation (NLSE). We report the observation of slanted solitons and breathers
propagating at an angle with respect to the direction of propagation of the
wave field. As the coherence is diagonal, the scale in the crest direction
becomes finite, consequently, a beam dynamics forms. Spatio-temporal
measurements of the water surface elevation are obtained by
stereo-reconstructing the positions of the floating markers placed on a regular
lattice and recorded with two synchronized high-speed cameras. Experimental
results, based on the predictions obtained from the (2D+1) hyperbolic NLSE
equation, are in excellent agreement with the theory. Our study proves the
existence of such unique and coherent wave packets and has serious implications
for practical applications in optical sciences and physical oceanography.
Moreover, unstable wave fields in this geometry may explain the formation of
directional large amplitude rogue waves with a finite crest length within a
wide range of nonlinear dispersive media, such as Bose-Einstein condensates,
plasma, hydrodynamics and optics
Spatially-resolved Radio-to-Far-infrared SED of the Luminous Merger Remnant NGC 1614 with ALMA and VLA
We present the results of Atacama Large Millimeter/Submillimeter Array (ALMA)
108, 233, 352, and 691 GHz continuum observations and Very Large Array (VLA)
4.81 and 8.36 GHz observations of the nearby luminous merger remnant NGC 1614.
By analyzing the beam (1".0 * 1".0) and uv (> 45 k{\lambda}) matched ALMA and
VLA maps, we find that the deconvolved source size of lower frequency emission
(< 108 GHz) is more compact (420 pc * 380 pc) compared to the higher frequency
emission (> 233 GHz) (560 pc * 390 pc), suggesting different physical origins
for the continuum emission. Based on an SED model for a dusty starburst galaxy,
it is found that the SED can be explained by three components, (1) non-thermal
synchrotron emission (traced in the 4.81 and 8.36 GHz continuum), (2) thermal
free-free emission (traced in the 108 GHz continuum), and (3) thermal dust
emission (traced in the 352 and 691 GHz continuum). We also present the
spatially-resolved (sub-kpc scale) Kennicutt-Schmidt relation of NGC 1614. The
result suggests a systematically shorter molecular gas depletion time in NGC
1614 (average {\tau}_gas of 49 - 77 Myr and 70 - 226 Myr at the starburst ring
and the outer region, respectively) than that of normal disk galaxies (~ 2 Gyr)
and a mid-stage merger VV 114 (= 0.1 - 1 Gyr). This implies that the star
formation activities in U/LIRGs are efficiently enhanced as the merger stage
proceeds, which is consistent with the results from high-resolution numerical
merger simulations.Comment: 10 pages, 6 figures, accepted for publication in PAS
Comparison with horizontal characteristics of gravity waves observed by airglow imaging of different sampling periods
Experimental demonstration of quantum teleportation of a squeezed state
Quantum teleportation of a squeezed state is demonstrated experimentally. Due
to some inevitable losses in experiments, a squeezed vacuum necessarily becomes
a mixed state which is no longer a minimum uncertainty state. We establish an
operational method of evaluation for quantum teleportation of such a state
using fidelity, and discuss the classical limit for the state. The measured
fidelity for the input state is 0.85 0.05 which is higher than the
classical case of 0.730.04. We also verify that the teleportation process
operates properly for the nonclassical state input and its squeezed variance is
certainly transferred through the process. We observe the smaller variance of
the teleported squeezed state than that for the vacuum state input.Comment: 7 pages, 1 new figure, comments adde
Velocity fields of blood flow in microchannels using a confocal micro-PIV system
The in vitro experimental investigations provide an excellent approach to understand
complex blood flow phenomena involved at a microscopic level. This paper emphasizes
an emerging experimental technique capable to quantify the flow patterns inside
microchannels with high spatial and temporal resolution. This technique, known as
confocal micro-PIV, consists of a spinning disk confocal microscope, high speed camera
and a diode-pumped solid state (DPSS) laser. Velocity profiles of pure water (PW),
physiological saline (PS) and in vitro blood were measured in a 100mm glass square and
rectangular polydimethysiloxane (PDMS) microchannel. The good agreement obtained
between measured and estimated results suggests that this system is a very promising
technique to obtain detail information about micro-scale effects in microchannels by
using both homogeneous and non-homogeneous fluids such as blood flow.This study was supported in part by the following grants: 21st Century COE Program for Future Medical Engineering based on Bio-nanotechnology, International Doctoral Program in Engineering from the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), “Revolutionary Simulation Software (RSS21)” next-generation IT program of MEXT; Grants-in-Aid for Scientific Research from MEXT and JSPS Scientific Research in Priority Areas (768) “Biomechanics at Micro- and Nanoscale Levels,” Scientific
Research (A) No.16200031 “Mechanism of the formation, destruction, and movement of thrombi responsible for ischemia of vital organs.” The authors also thank all members of Esashi, Ono and Tanaka Lab. for their assistance in fabricating the PDMS microchannel
Diffuse galactic light in the field of the translucent high galactic latitude cloud MBM32
We have conducted B-, g-, V-, and R-band imaging in a 45′ × 40′ field containing part of the high Galactic latitude translucent cloud MBM32, and correlated the intensity of diffuse optical light S ν(λ) with that of 100 μm emission S ν(100 μm).
Velocity measurements of blood flow in a rectangular PDMS microchannel assessed by confocal micro-PIV system
This paper examines the ability to measure the
velocity of both physiological saline (PS) and in vitro blood in a
rectangular polydimethysiloxane (PDMS) microchannel by
means of the confocal micro-PIV system. The PDMS microchannel,
was fabricated by conventional soft lithography, had
a microchannel near to a perfect rectangular shape (300μm
wide, 45μm deep) and was optically transparent, which is
suitable to measure both PS and in vitro blood using the confocal
system. By using this latter combination, the measurements
of trace particles seeded in the flow were performed for both
fluids at a constant flow rate (Re=0.021). Generally, all the
velocity profiles were found to be markedly blunt in the central
region mainly due to the low aspect ratio (h/w=0.15) of the
rectangular microchannel. Predictions by a theoretical model
for the rectangular microchannel have showed fairly good
correspondence with the experimental micro-PIV results for
the PS fluid. Conversely, for the in vitro blood with 20%
haematocrit, small fluctuations were found on velocity profiles.This study was supported in part by the following grants: International Doctoral Program in Engineering from the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), “Revolutionary Simulation Software (RSS21)” next-generation IT program of MEXT; Grants-in-Aid for Scientific Research from MEXT and JSPS Scientific Research in Priority Areas (768) “Biomechanics at Micro- and Nanoscale Levels,” Scientific Research (A) No.16200031 “Mechanism of the formation, destruction, and movement of thrombi responsible for ischemia of vital organs.” The authors also thank all members of Esashi, Ono and Tanaka Lab. for their assistance in fabricating the PDMS microchannel
Spatially resolved CO SLED of the Luminous Merger Remnant NGC 1614 with ALMA
We present high-resolution (1".0) Atacama Large Millimeter/submillimeter
Array (ALMA) observations of CO (1-0) and CO (2- 1) rotational transitions
toward the nearby IR-luminous merger NGC 1614 supplemented with ALMA archival
data of CO (3-2), and CO (6-5) transitions. The CO (6-5) emission arises from
the starburst ring (central 590 pc in radius), while the lower- CO lines are
distributed over the outer disk ( 3.3 kpc in radius). Radiative transfer
and photon dominated region (PDR) modeling reveal that the starburst ring has a
single warmer gas component with more intense far-ultraviolet radiation field
( 10 cm, 42 K, and
10) relative to the outer disk (
10 cm, 22 K, and
10). A two-phase molecular interstellar medium with a warm and
cold ( 70 K and 19 K) component is also an applicable model for the
starburst ring. A possible source for heating the warm gas component is
mechanical heating due to stellar feedback rather than PDR. Furthermore, we
find evidence for non-circular motions along the north-south optical bar in the
lower- CO images, suggesting a cold gas inflow. We suggest that star
formation in the starburst ring is sustained by the bar-driven cold gas inflow,
and starburst activities radiatively and mechanically power the CO excitation.
The absence of a bright active galactic nucleus can be explained by a scenario
that cold gas accumulating on the starburst ring is exhausted as the fuel for
star formation, or is launched as an outflow before being able to feed to the
nucleus.Comment: 20 pages, 19 figures, 2 tables, accepted for publication in Ap
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