192 research outputs found
Sub-Arcsecond Near-Infrared Images of Massive Star Formation Region NGC 6334 V
We present high spatial resolution (0\farcs3) polarimetric images in the
and bands and direct images in the and bands of the NGC 6334
V infrared nebulae. The images show complex structures including the
multi-shells and various knots in the nebulae. The appearances and colors of
the eastern and western nebulae differ considerably. Our polarization images
also show differences between the illuminating sources of the nebulae: the
eastern nebula is illuminated by a deeply embedded mid-infrared source, KDJ 4,
and the western nebula by our newly detected near-infrared source, WN-A1. The
degree of polarization of the nebulae is very large, up to 70% at and 60%
at , which is consistent with a single scattering of near-infrared radiation
from each source at the walls of the mass outflows
First Two-Micron Imaging Polarimetry of Beta Pictoris
High-resolution K band imaging polarimetry of the beta Pic dust disk has been
conducted with adaptive optics and a coronagraph using the Subaru 8.2-m
telescope. Polarization of ~10 % is detected out to r ~ 120 AU with a
centro-symmetric vector pattern around the central star, confirming that the
disk is seen as an infrared reflection nebula. We have modeled our
near-infrared and previous optical polarization results in terms of dust
scattering in the disk and have found that both the degrees of polarization and
the radial intensity profiles are well reproduced. We argue that the observed
characteristics of the disk dust are consistent with the presence of ice-filled
fluffy aggregates consisting of submicron grains in the beta Pic system. There
is a gap around 100 AU in both the intensity and polarization profiles, which
suggests a paucity of planetesimals in this region. The radial intensity
profile also shows ripple-like structures, which are indicative of the presence
of multiple planetesimal belts, as in the case of the M-type Vega-like star AU
Mic.Comment: 18 pages, 6 figures, accepted for Jp
Studies on the Chemical Composition and Quality of Silage : (X) The Relation Between the Quality and Digestibility of Silage
サイレージの発酵的品質と消化率との関係を知る目的で,同一材料から品質の異なる5区のサイレージを調製し,それについて,in vivo および in vitro 消化試験を実施し,品質と消化率との関係を調査した. 実験結果の要約は次のようである. 1)でき上がりサイレージのFLIEG法による評点は,それぞれ100点(優),89点(優),51点(可),42点(可)および18点(下)であった. 2)サイレージの評点と,乾物,有機物,粗タンパク質,粗繊維および純タンパク質の消化率との間に,統計的な有意なプラスの相関が認められた. 3)サイレージの評点と乾物中のTDNとの間に,プラスの相関(r-0.992,p<0.01)が認められた. 4)各埋蔵材料のin vitro DMDと,でき上がりサイレージのin vitro DMDとの間に,有意な相関は認められなかった. サイレージのin vitro DMDとin vivo DMDの値は,劣質サイレージを除きよく一致し,両法で得たDMD間に有意なプラスの相関が認められた. 本実験の結果は,前報までの結果と同様,サイレージ醗酵の良否が,それの飼料価値を左右する因子の一つであることを示唆している
Characteristic Scales of Baryon Acoustic Oscillations from Perturbation Theory: Non-linearity and Redshift-Space Distortion Effects
An acoustic oscillation of the primeval photon-baryon fluid around the
decoupling time imprints a characteristic scale in the galaxy distribution
today, known as the baryon acoustic oscillation (BAO) scale. Several on-going
and/or future galaxy surveys aim at detecting and precisely determining the BAO
scale so as to trace the expansion history of the universe. We consider
nonlinear and redshift-space distortion effects on the shifts of the BAO scale
in -space using perturbation theory. The resulting shifts are indeed
sensitive to different choices of the definition of the BAO scale, which needs
to be kept in mind in the data analysis. We present a toy model to explain the
physical behavior of the shifts. We find that the BAO scale defined as in
Percival et al. (2007) indeed shows very small shifts ( 1%) relative
to the prediction in {\it linear theory} in real space. The shifts can be
predicted accurately for scales where the perturbation theory is reliable.Comment: 21 pages, 9 figures, references and supplementary sections added,
accepted for publication in PAS
Near-Infrared Extinction in The Coalsack Globule 2
We have conducted J, H, and Ks imaging observations for the Coalsack Globule
2 with the SIRIUS infrared camera on the IRSF 1.4 m telescope at SAAO, and
determined the color excess ratio, E(J-H)/E(H-Ks). The ratio is determined in
the same photometric system as our previous study for the rho Oph and Cha
clouds without any color transformation; this enables us to directly compare
the near-infrared extinction laws among these regions. The current ratio
E(J-H)/E(H-Ks) = 1.91 +- 0.01 for the extinction range 0.5 < E(J-H) <1.8 is
significantly larger than the ratios for the rho Oph and Cha clouds
(E(J-H)/E(H-Ks) = 1.60-1.69). This ratio corresponds to a large negative index
alpha = 2.34 +- 0.01 when the wavelength dependence of extinction is
approximated by a power law which might indicate little growth of dust grains,
or larger abundance of dielectric non-absorbing components such as silicates,
or both in this cloud. We also confirm that the color excess ratio for the
Coalsack Globule 2 has a trend of increasing with decreasing optical depth,
which is the same trend as the rho Oph and Cha clouds have.Comment: 13 pages, 5 figures, and 2 tables, Ap
Cool core disturbed: Observational evidence for coexistence of sub-sonic sloshing gas and stripped shock-heated gas around the core of RX J1347.5-1145
RXJ1347.5-1145 (z = 0.451) is one of the most luminous X-ray galaxy clusters,
which hosts a prominent cool core and exhibits a signature of a major merger.
We present the first direct observational evidence for sub-sonic nature of
sloshing motion of the cool core. We find that a residual X-ray image from the
Chandra X-ray Observatory after removing the global emission shows a clear
dipolar pattern characteristic of gas sloshing, whereas we find no significant
residual in the Sunyaev-Zel'dovich effect (SZE) image from the Atacama Large
Millimeter/submillimeter Array (ALMA). We estimate the equation of state of
perturbations in the gas from the X-ray and SZE residual images. The inferred
velocity is 420 +310 -420 km s-1, which is much lower than the adiabatic sound
speed of the intracluster medium in the core. We thus conclude that the
perturbation is nearly isobaric, and gas sloshing motion is consistent with
being in pressure equilibrium. Next, we report evidence for gas stripping of an
infalling subcluster, which likely shock-heats gas to high temperature well in
excess of 20 keV. Using mass distribution inferred from strong lensing images
of the Hubble Space Telescope (HST), we find that the mass peak is located away
from the peak position of stripped gas with statistical significance of >
5{\sigma}. Unlike for the gas sloshing, the velocity inferred from the equation
of state of the excess hot gas is comparable to the adiabatic sound speed
expected for the 20 keV intracluster medium. All of the results support that
the southeast substructure is created by a merger. On the other hand, the
positional offset between the mass and the gas limits the self-interaction
cross section of dark matter to be less than 3.7 h-1 cm2 g-1 (95% CL).Comment: 18 pages, 10 figures, accepted for publication in Ap
IL-4–Stat6 Signaling Induces Tristetraprolin Expression and Inhibits TNF-α Production in Mast Cells
Increasing evidence has revealed that mast cell–derived tumor necrosis factor α (TNF-α) plays a critical role in a number of inflammatory responses by recruiting inflammatory leukocytes. In this paper, we investigated the regulatory role of interleukin 4 (IL-4) in TNF-α production in mast cells. IL-4 inhibited immunoglobulin E–induced TNF-α production and neutrophil recruitment in the peritoneal cavity in wild-type mice but not in signal transducers and activators of transcription 6 (Stat6)–deficient mice. IL-4 also inhibited TNF-α production in cultured mast cells by a Stat6-dependent mechanism. IL-4–Stat6 signaling induced TNF-α mRNA destabilization in an AU-rich element (ARE)–dependent manner, but did not affect TNF-α promoter activity. Furthermore, IL-4 induced the expression of tristetraprolin (TTP), an RNA-binding protein that promotes decay of ARE-containing mRNA, in mast cells by a Stat6-dependent mechanism, and the depletion of TTP expression by RNA interference prevented IL-4–induced down-regulation of TNF-α production in mast cells. These results suggest that IL-4–Stat6 signaling induces TTP expression and, thus, destabilizes TNF-α mRNA in an ARE-dependent manner
Submillimeter detection of the Sunyaev -- Zel'dovich effect toward the most luminous X-ray cluster at z=0.45
We report on the detection of the Sunyaev -- Zel'dovich (SZ) signals toward
the most luminous X-ray cluster RXJ1347-1145 at Nobeyama Radio Observatory (21
and 43 GHz) and at James Clerk Maxwell Telescope (350 GHz). In particular the
latter is the first successful detection of the SZ temperature increment in the
submillimeter band which resolved the profile of a cluster of galaxies. Both
the observed spectral dependence and the radial profile of the SZ signals are
fully consistent with those expected from the X-ray observation of the cluster.
The combined analysis of 21GHz and 350GHz data reproduces the temperature and
core-radius of the cluster determined with the ROSAT and ASCA satellites when
we adopt the slope of the density profile from the X-ray observations.
Therefore our present data provide the strongest and most convincing case for
the detection of the submillimeter SZ signal from the cluster, as well as in
the Rayleigh -- Jeans regime. We also discuss briefly the cosmological
implications of the present results.Comment: 11 pages, The Astrophysical Journal (Letters), in pres
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