14127729
THE ORIGIN OF THE DUST ARCH IN THE HALO OF NGC 4631: AN EXPANDING SUPERBUBBLE?
We study the nature and the origin of the dust arch in the halo of the edge-on galaxy NGC 4631 detected by Neininger & Dumke. We present CO observations made using the new on-the-fly mapping mode with the Five College Radio Astronomy Observatory 14 m telescope and find no evidence for CO emission associated with the dust arch. Our examination of previously published H I data shows that, if previous assumptions about the dust temperature and gas/dust ratio are correct, then there must be molecular gas associated with the arch, below our detection threshold. If this is true, then the molecular mass associated with the dust arch is between 1.5 × 108 M⊙ and 9.7 × 108 M⊙, and likely toward the low end of the range. A consequence of this is that the maximum allowed value for the CO-to-H2 conversion factor is 6.5 times the Galactic value, but most likely closer to the Galactic value. The kinematics of the H I apparently associated with the dust arch reveals that the gas here is not part of an expanding shell or outflow but is instead two separate features (a tidal arm and a plume of H I sticking out into the halo) that are seen projected together and appear as a shell. Thus there is no connection between the dust "arch" and the hot X-ray–emitting gas that appears to surround the galaxy.
14490517
Discovery of Molecular Gas in the Outflow and Tidal Arms around M82
We present the first fully sampled map of 12CO (1-0) emission from M82 covering the entire galaxy. Our map contains an ~12 × 15 kpc2 area. We find that extraplanar CO emission, previously reported at short distances above the galactic plane, extends to heights of up to 6 kpc above the disk. Some of this emission is associated with tidal arms seen in H I, implying either that M82 contained substantial amounts of molecular gas in the outer disk or that molecular gas formed after the tidal features. CO emission along the direction of the outflow extends to distances of ~3 kpc above and below the disk. At this distance, the line is shifted in velocity ~100 km s-1 and has the same sense as the galactic outflow from the central starburst. This implies that molecular gas may be entrained into the outflow.
15184441
A High-Resolution Mosaic of Molecular Gas in Stephan’s Quintet
We present high-resolution 12CO J = 1-0 observations of the molecular gas in the Hickson compact group Stephan's Quintet (HCG 92). Our observations consist of multiple pointings and mosaics covering all the regions where CO and star formation have been detected. Within the 100'' field of view centered on the easternmost tidal tail, we detect three clumps of emission that may be partially resolved at our resolution of 8''; two of these are new detections not previously seen in ISM studies of this region. Two of these clumps lie in the optical tidal tail, while the third lies to the southeast and is coincident with a large H I feature, but it does not correspond to any features at other wavelengths. We also tentatively detect CO emission from the star-forming regions in the "old tail" corresponding to recent star formation activity detected in recent UV and Hα observations. Observations of the rest of the compact group do not show detections, even though strong emission was detected with single-dish telescopes, which suggests that the CO emission originates from a diffuse molecular gas cloud or from at least three separate clumps with separations greater than around 3 kpc.
14072620
Light Meson Mass Spectrum from Gauge Fields on Supergravity Backgrounds
We propose that the spectrum of light mesons (the $\pi$ and $\rho$, together with their radial excitations) can be calculated in the limit of vanishing light quark masses by studying gauge theory (open string theory) on suitable higher dimensional background geometries. Using the metric proposed by Witten for glueball calculations as a paradigmatic example, we find a spectrum which is in startlingly good agreement with the masses tabulated by the Particle Data Group. These calculations have only one free parameter, corresponding to the overall mass scale. We make predictions for the next several particles in the spectrum.
120828806
HAMILTONIAN BRST QUANTIZATION OF THE INTERACTING ANTISYMMETRIC TENSOR FIELD
Abstract We study the hamiltonian BRST quantization of the non-abelian antisymmetric tensor field. We find the constrained system which arises from the standard action by Dirac's procedure, and eliminate the second-class constraints by introducing Dirac brackets. Having isolated the underlying first-class constrained system, we quantize it using the hamiltonian BRST techniques of Batalin and Fradkin. We study the Lorentz covariant gauge fixing of this system, and discuss the relationship between our results and other recent studies of the interacting antisymmetric tensor field.
15060218
Observing Disoriented Chiral Condensates
We speculate that, in very high energy hadronic collisions, large fireballs may be produced with interiors which have anomalous chiral order parameters. Such a process would result in radiation of pions with distinctive momentum and isospin distributions, and may provide an explanation of Centauro and related phenomena in cosmic-ray events. The phenomenology of such events is reviewed, with emphasis on the possibility of observing such phenomena at Fermilab experiment T-864 (MiniMax), or at a Full Acceptance Detector (FAD) at the SSC.
120220028
MiniMax: What has been learned thus far
SummaryA small experiment, «MiniMax», has been set up in the C0 intersection region of the Fermilab Tevatron to seek evidence for disoriented chiral condensates and to study other forward physics phenomena. The experiment consists of a proportional wire chamber telescope accompanied by scintillation (trigger) counters, a lead converter, and followed by an electromagnetic calorimeter. The solid angle accepted is a cone centered at pseudorapidity (η) of 4.1 and of radius (in η-ϕ space) of about 0.6. Over 2.5 million events thus far have demonstrated the successful operation of the apparatus, however to date the analysis has not progressed sufficiently to permit any conclusions concerning disoriented chiral condensates.
121598535
Stochastic quantization of gauge theories
Abstract The equivalence between a scalar quantum field theory in D dimensions and its classical counterpart in D + 2 dimensions which is coupled to an external random source with Gaussian correlations was observed by previous authors. This stochastic quantization is extended to gauge theories. The proof exploits the supersymmetry formalism suggested by Parisi and Sourlas.