824 research outputs found
Suzaku observations of subhalos in the Coma cluster
We observed three massive subhalos in the Coma cluster with {\it Suzaku}.
These subhalos, labeled "ID 1", "ID 2", and "ID 32", were detected with a
weak-lensing survey using the Subaru/Suprime-Cam (Okabe et al. 2014a), and are
located at the projected distances of 1.4 , 1.2 , and 1.6
from the center of the Coma cluster, respectively. The subhalo "ID 1"
has a compact X-ray excess emission close to the center of the weak-lensing
mass contour, and the gas mass to weak-lensing mass ratio is about 0.001. The
temperature of the emission is about 3 keV, which is slightly lower than that
of the surrounding intracluster medium (ICM) and that expected for the
temperature vs. mass relation of clusters of galaxies. The subhalo "ID 32"
shows an excess emission whose peak is shifted toward the opposite direction
from the center of the Coma cluster. The gas mass to weak-lensing mass ratio is
also about 0.001, which is significantly smaller than regular galaxy groups.
The temperature of the excess is about 0.5 keV and significantly lower than
that of the surrounding ICM and far from the temperature vs. mass relation of
clusters. However, there is no significant excess X-ray emission in the "ID 2"
subhalo. Assuming an infall velocity of about 2000 , at the
border of the excess X-ray emission, the ram pressures for "ID 1" and "ID 32"
are comparable to the gravitational restoring force per area. We also studied
the effect of the Kelvin-Helmholtz instability to strip the gas. Although we
found X-ray clumps associated with the weak-lensing subhalos, their X-ray
luminosities are much lower than the total ICM luminosity in the cluster
outskirts.Comment: 19 pages, 8 figures, ApJ in pres
Scaling of soaring seabirds and its implication for the maximum size of flying pterosaurs
The flight ability of animals is restricted by the scaling effects imposed by physical and physiological factors. In comparisons of the power available from muscle and the mechanical power required to fly, theoretical studies have predicted that the margin between the powers should decrease with body size and that flying animals have a maximum body size. However, predicting an absolute value of this upper limit has been difficult because wing morphology and flight styles vary among species. Albatrosses and petrels have long, narrow, aerodynamically efficient wings and are considered to be soaring birds. Here, using animal-borne accelerometers, we show that scaling analyses of wing-flapping frequencies in these seabirds indicate that the maximum size limit for soaring animals is a body mass of 41 kg and a wingspan of 5.1 m. Soaring seabirds were observed to have two modes of flapping frequencies: vigorous flapping during takeoff and sporadic flapping during cruising flight. In these species, high and low flapping frequencies were found to scale with body mass (_mass_ ^-0.30^ and _mass_ ^-0.18^) in a manner similar to the predictions from biomechanical flight models (_mass_ ^-1/3^ and _mass_ ^-1/6^). The scaling relationships predicted that animals larger than the limit will not be able to flap fast enough to stay aloft under unfavourable wind conditions. Our result therefore casts doubt on the flying ability of large, extinct pterosaurs. The largest extant soarer, the wandering albatross, weighs about 10 kg, which might be a pragmatic limit to maintain a safety margin for sustainable flight and to survive in a variable environment
Molecular Characterization of a Novel Polymycovirus From Penicillium janthinellum With a Focus on Its Genome-Associated PASrp
The genus Polymycovirus of the family Polymycoviridae accommodates fungal RNA viruses with different genomic segment numbers (four, five, or eight). It is suggested that four members form no true capsids and one forms filamentous virus particles enclosing double-stranded RNA (dsRNA). In both cases, viral dsRNA is associated with a viral protein termed "proline-alanine-serine-rich protein" (PASrp). These forms are assumed to be the infectious entity. However, the detailed molecular characteristics of PASrps remain unclear. Here, we identified a novel five-segmented polymycovirus, Penicillium janthinellum polymycovirus 1 (PjPmV1), and characterized its purified fraction form in detail. The PjPmV1 had five dsRNA segments associated with PASrp. Density gradient ultracentrifugation of the PASrp-associated PjPmV1 dsRNA revealed its uneven structure and a broad fractionation profile distinct from that of typical encapsidated viruses. Moreover, PjPmV1-PASrp interacted in vitro with various nucleic acids in a sequence-non-specific manner. These PjPmV1 features are discussed in view of the diversification of genomic segment numbers of the genus Polymycovirus
Duality of a Supersymmetric Standard Model without R parity
Recently one of the authors proposed a dual theory of a Supersymmetric
Standard Model (SSM), in which it is naturally understood that at least one
quark (the top quark) should be heavy, i.e., almost the same order as the weak
scale, and the supersymmetric Higgs mass parameter can naturally be
expected to be small. Unfortunately, the model cannot possess Yukawa couplings
of lepton sector. In this paper, we examine a dual theory of a Supersymmetric
Standard Model without R parity. In this scenario, we can introduce Yukawa
couplings of lepton sector. In order to induce the enough large Yukawa
couplings of leptons, we must introduce fairly large R parity breaking terms,
which may be observed in the near future.Comment: 7 pages + 2 uuencoded eps figures, LaTe
Suzaku observations of the Hydra A cluster out to the virial radius
We report Suzaku observations of the northern half of the Hydra A cluster out
to ~1.4 Mpc, reaching the virial radius. This is the first Suzaku observations
of a medium-size (kT ~3 keV) cluster out to the virial radius. Two observations
were conducted, north-west and north-east offsets, which continue in a filament
direction and a void direction of the large-scale structure of the Universe,
respectively. The X-ray emission and distribution of galaxies elongate in the
filament direction. The temperature profiles in the two directions are mostly
consistent with each other within the error bars and drop to 1.5 keV at 1.5
r_500. As observed by Suzaku in hot clusters, the entropy profile becomes
flatter beyond r_500, in disagreement with the r^1.1 relationship that is
expected from accretion shock heating models. When scaled with the average
intracluster medium (ICM) temperature, the entropy profiles of clusters
observed with Suzaku are universal and do not depend on system mass. The
hydrostatic mass values in the void and filament directions are in good
agreement, and the Navarro, Frenk, and White universal mass profile represents
the hydrostatic mass distribution up to ~ 2 r_500. Beyond r_500, the ratio of
gas mass to hydrostatic mass exceeds the result of the Wilkinson microwave
anisotropy probe, and at r_100, these ratios in the filament and void
directions reach 0.4 and 0.3, respectively. We discuss possible deviations from
hydrostatic equilibrium at cluster outskirts. We derived radial profiles of the
gasmass- to-light ratio and iron-mass-to-light ratio out to the virial radius.
Within r_500, the iron-mass-to-light ratio of the Hydra A cluster was compared
with those in other clusters observed with Suzaku.Comment: 16 pages, 15 figures; Accepted for publication in PAS
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