117 research outputs found
The relationship between a topological Yang-Mills field and a magnetic monopole
We show that a Jackiw-Nohl-Rebbi solution, as the most general two-instanton,
generates a circular loop of magnetic monopole in four-dimensional Euclidean
SU(2) Yang-Mills theory.Comment: 3 pages, 2 figure; to be published in the proceedings of
"BARYONS'10", Dec. 7-11, 2010, Osaka, Japa
Magnetic monopole loops generated from two-instanton solutions: Jackiw-Nohl-Rebbi versus 't Hooft instanton
In our previous paper (Fukui et al., 2010), we have shown that the
Jackiw-Nohl-Rebbi two-instanton generates a circular loop of magnetic monopole
in the four-dimensional Euclidean SU(2) Yang-Mills theory. On the other hand,
it is claimed in Brower, Orginos and Tan (1997) that the 't Hooft two-instanton
does not generate magnetic monopole loop. It seems that two results are
inconsistent with each other, since the JNR two-instanton converges to the 't
Hooft two-instanton in a certain limit. In this paper, we clarify that two
results are compatible with each other by demonstrating how the magnetic
monopole loop generated from the JNR two-instanton deforms in the process of
taking the 't Hooft two-instanton limit.Comment: 4pages, 2 figures, minor change
Wortmannin, a specific inhibitor of phosphatidylinositol-3 kinase, blocks osteoclastic bone resorption
AbstractThe biological role of phosphatidylinositol (PI)-3 kinase was examined in osteoclast-like multinucleated cells (OCLs) formed in co-cultures of mouse osteoblastic cells and bone marrow cells. The expression of PI-3 kinase in OCLs was confirmed by Western blot analysis. Wortmannin (WT), a specific inhibitor of PI-3 kinase, inhibited PI-3 kinase activity in OCLs both in vitro and in vivo. WT also inhibited pit-forming activity on dentine slices and disrupted a ringed structure of F-actin-containing dots (an actin ring) in OCLs in a dose-dependent manner. The inhibitory profiles of WT for pit and actin ring formation were similar to that for PI-3 kinase activity in OCLs. Electron microscopic analysis revealed that OCLs treated with WT did not form ruffled borders. Instead, numerous electron lucent vacuoles of differing sizes were found throughout the cytoplasm. These results suggest that PI-3 kinase is important in osteoclastic bone resorption
High Excitation Molecular Gas in the Galactic Center Loops; 12CO(J =2-1 and J =3-2) Observations
We have carried out 12CO(J =2-1) and 12CO(J =3-2) observations at spatial
resolutions of 1.0-3.8 pc toward the entirety of loops 1 and 2 and part of loop
3 in the Galactic center with NANTEN2 and ASTE. These new results revealed
detailed distributions of the molecular gas and the line intensity ratio of the
two transitions, R3-2/2-1. In the three loops, R3-2/2-1 is in a range from 0.1
to 2.5 with a peak at ~ 0.7 while that in the disk molecular gas is in a range
from 0.1 to 1.2 with a peak at 0.4. This supports that the loops are more
highly excited than the disk molecular gas. An LVG analysis of three
transitions, 12CO J =3-2 and 2-1 and 13CO J =2-1, toward six positions in loops
1 and 2 shows density and temperature are in a range 102.2 - 104.7 cm-3 and
15-100 K or higher, respectively. Three regions extended by 50-100 pc in the
loops tend to have higher excitation conditions as characterized by R3-2/2-1
greater than 1.2. The highest ratio of 2.5 is found in the most developed foot
points between loops 1 and 2. This is interpreted that the foot points indicate
strongly shocked conditions as inferred from their large linewidths of 50-100
km s-1, confirming the suggestion by Torii et al. (2010b). The other two
regions outside the foot points suggest that the molecular gas is heated up by
some additional heating mechanisms possibly including magnetic reconnection. A
detailed analysis of four foot points have shown a U shape, an L shape or a
mirrored-L shape in the b-v distribution. It is shown that a simple kinematical
model which incorporates global rotation and expansion of the loops is able to
explain these characteristic shapes.Comment: 59 pages, accepted to PAS
Sub-millimeter Observations of Giant Molecular Clouds in the Large Magellanic Cloud: Temperature and Density as Determined from J=3-2 and J=1-0 transitions of CO
We have carried out sub-mm 12CO(J=3-2) observations of 6 giant molecular
clouds (GMCs) in the Large Magellanic Cloud (LMC) with the ASTE 10m sub-mm
telescope at a spatial resolution of 5 pc and very high sensitivity. We have
identified 32 molecular clumps in the GMCs and revealed significant details of
the warm and dense molecular gas with n(H2) 10 cm and
Tkin 60 K. These data are combined with 12CO(J=1-0) and 13CO(J=1-0)
results and compared with LVG calculations. We found that the ratio of
12CO(J=3-2) to 12CO(J=1-0) emission is sensitive to and is well correlated with
the local Halpha flux. We interpret that differences of clump propeties
represent an evolutionary sequence of GMCs in terms of density increase leading
to star formation.Type I and II GMCs (starless GMCs and GMCs with HII regions
only, respectively) are at the young phase of star formation where density does
not yet become high enough to show active star formation and Type III GMCs
(GMCs with HII regions and young star clusters) represents the later phase
where the average density is increased and the GMCs are forming massive stars.
The high kinetic temperature correlated with \Halpha flux suggests that FUV
heating is dominant in the molecular gas of the LMC.Comment: 74 pages, including 41 figures, accepted for publication in ApJ
High-Mass Cloud Cores in the eta Carinae Giant Molecular Cloud
We carried out an unbiased survey for massive dense cores in the giant
molecular cloud associated with eta Carinae with the NANTEN telescope in 12CO,
13CO, and C18O 1-0 emission lines. We identified 15 C18O cores. Two of the 15
cores are associated with IRAS point sources whose luminosities are larger than
10^4 Lo, which indicates that massive star formation is occuring within these
cores. Five cores including the two with IRAS sources are associated with MSX
point sources. We detected H13CO+ (1-0) emission toward 4 C18O cores, one of
which is associated with neither IRAS nor MSX point sources. This core shows
the presence of a bipolar molecular outflow in 12CO (2-1), which indicates that
star formation is also occuring in the core. In total, six C18O cores out of 15
are experienced star formation, and at least 2 of 15 are massive-star forming
cores in the eta Car GMC. We found that massive star formation occurs
preferentially in cores with larger column density, mass, number density, and
smaller ratio of virial mass to LTE mass Mvir/M. We also found that the cores
in the eta Car GMC are characterized by large line width and Mvir/M on average
compared to the cores in other GMCs. We investigated the origin of a large
amount of turbulence in the eta Car GMC. We propose the possibility that the
large turbulence was pre-existing when the GMC was formed, and is now
dissipating. Mechanisms such as multiple supernova explosions in the Carina
flare supershell may have contributed to form a GMC with a large amount of
turbulence.Comment: 41 pages, including 11 fugures and 9 tables. Accepted by ApJ. Author
changed. Paper with high resolution figures is available at
http://astrol.cias.osakafu-u.ac.jp/~yonekura/work/paper/etaCar
Temperature and Density in the Foot Points of the Molecular Loops in the Galactic Center; Analysis of Multi-J Transitions of 12CO(J=1-0, 3-2, 4-3, 7-6), 13CO(J=1-0) and C18O(J=1-0)
Fukui et al. (2006) discovered two molecular loops in the Galactic center and
argued that the foot points of the molecular loops, two bright spots at both
loops ends, represent the gas accumulated by the falling motion along the
loops, subsequent to magnetic flotation by the Parker instability. We have
carried out sensitive CO observations of the foot points toward l=356 deg at a
few pc resolution in the six rotational transitions of CO; 12CO(J=1-0, 3-2,
4-3, 7-6), 13CO(J=1-0) and C18O(J=1-0). The high resolution image of 12CO
(J=3-2) has revealed the detailed distribution of the high excitation gas
including U shapes, the outer boundary of which shows sharp intensity jumps
accompanying strong velocity gradients. An analysis of the multi-J CO
transitions shows that the temperature is in a range from 30-100 K and density
is around 10^3-10^4 cm^-3, confirming that the foot points have high
temperature and density although there is no prominent radiative heating source
such as high mass stars in or around the loops. We argue that the high
temperature is likely due to the shock heating under C-shock condition caused
by the magnetic flotation. We made a comparison of the gas distribution with
theoretical numerical simulations and note that the U shape is consistent with
numerical simulations. We also find that the region of highest temperature of
~100 K or higher inside the U shape corresponds to the spur having an upward
flow, additionally heated up either by magnetic reconnection or bouncing in the
interaction with the narrow neck at the bottom of the U shape. We note these
new findings further reinforce the magnetic floatation interpretation.Comment: 40 pages, 23 figures, accepted by PASJ on Vol.62 No.
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