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Fast mode of rotating atoms in one-dimensional lattice rings  [PDF]
T. Wang,S. F. Yelin
Physics , 2007, DOI: 10.1103/PhysRevA.76.033619
Abstract: We study the rotation of atoms in one-dimensional lattice rings. In particular, the "fast mode", where the ground state atoms rotate faster than the stirring rotating the atoms, is studied both analytically and numerically. The conditions for the transition to the fast mode are found to be very different from that in continuum rings. We argue that these transition frequencies remain unchanged for bosonic condensates described in a mean field. We show that Fermionic interaction and filling factor have a significant effect on the transition to the fast mode, and Pauli principle may suppress it altogether.
Generic occurrence of rings in rotating systems  [PDF]
L. Benet,T. H. Seligman
Physics , 2000, DOI: 10.1016/S0375-9601(00)00500-4
Abstract: In rotating scattering systems, the generic saddle-center scenario leads to stable islands in phase space. Non-interacting particles whose initial conditions are defined in such islands will be trapped and form rotating rings. This result is generic and also holds for systems quite different from planetary rings.
Are rotating planes of satellite galaxies ubiquitous?  [PDF]
John I. Phillips,Michael C. Cooper,James S. Bullock,Michael Boylan-Kolchin
Physics , 2015, DOI: 10.1093/mnras/stv1770
Abstract: We compare the dynamics of satellite galaxies in the Sloan Digital Sky Survey to simple models in order to test the hypothesis that a large fraction of satellites co-rotate in coherent planes. We confirm the previously-reported excess of co-rotating satellite pairs located near diametric opposition with respect to the host, but show that this signal is unlikely to be due to rotating discs (or planes) of satellites. In particular, no overabundance of co-rotating satellites pairs is observed within $\sim 20^{\circ}-50^{\circ}$ of direct opposition, as would be expected for planar distributions inclined relative to the line-of-sight. Instead, the excess co-rotation for satellite pairs within $\sim 10^{\circ}$ of opposition is consistent with random noise associated with undersampling of an underlying isotropic velocity distribution. We conclude that at most $10\%$ of the hosts in our sample harbor co-rotating satellite planes (as traced by the luminous satellite population).
Rotating Nuclear Rings and Extreme Starbursts in Ultraluminous Galaxies  [PDF]
D. Downes,P. M. Solomon
Physics , 1998, DOI: 10.1086/306339
Abstract: New high resolution interferometer data of 10 IR ultraluminous galaxies shows the molecular gas is in rotating nuclear rings or disks with radii 300 to 800 pc. Most of the CO flux comes from a moderate-density, warm, intercloud medium rather than self-gravitating clouds. Gas masses of ~ 5 x 10^9 Msun, 5 times lower than the standard method are derived from a model of the molecular disks. The ratio of molecular gas to dynamical mass, is M_gas/M_dyn ~ 1/6 with a maximum ratio of gas to total mass surface density of 1/3. For the galaxies VIIZw31, Arp193, and IRAS 10565+24, there is good evidence for rotating molecular rings with a central gap. In addition to the rotating rings a new class of star formation region is identified which we call an Extreme Starburst. They have a characteristic size of only 100 pc., about 10^9 Msun of gas and an IR luminosity of ~3 x 10^11 Lsun. Four extreme starbursts are identified in the 3 closest galaxies in the sample Arp220, Arp193 and Mrk273. They are the most prodigious star formation events in the local universe, each representing about 1000 times as many OB stars as 30 Doradus. In Arp220, the CO and 1.3 mm continuum maps show the two ``nuclei'' embedded in a central ring or disk and a fainter structure extending 3 kpc to the east, normal to the nuclear disk. There is no evidence that these sources really are the pre-merger nuclei. They are compact, extreme starburst regions containing 10^9 Msun of dense molecular gas and new stars, but no old stars. Most of the dust emission and HCN emission arises in the two extreme starbursts. The entire bolometric luminosity of Arp~220 comes from starbursts, not an AGN. In Mrk231, the disk geometry shows that the molecular disk cannot be heated by the AGN; the far IR luminosity of Mrk~231 is powered by a starburst, not the AGN. (Abridged)
Uniformly Rotating Rings in General Relativity  [PDF]
Thomas Fischer,Stefan Horatschek,Marcus Ansorg
Physics , 2005, DOI: 10.1111/j.1365-2966.2005.09629.x
Abstract: In this paper, we discuss general relativistic, self-gravitating and uniformly rotating perfect fluid bodies with a toroidal topology (without central object). For the equations of state describing the fluid matter we consider polytropic as well as completely degenerate, perfect Fermi gas models. We find that the corresponding configurations possess similar properties to the homogeneous relativistic Dyson rings. On the one hand, there exists no limit to the mass for a given maximal mass-density inside the body. On the other hand, each model permits a quasistationary transition to the extreme Kerr black hole.
Multi-satellite aerosol observations in the vicinity of clouds
T. Várnai, A. Marshak,W. Yang
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2013,
Abstract: Improved characterization of aerosol properties in the vicinity of clouds is important for better understanding two critical aspects of climate: aerosol–cloud interactions and the direct radiative effect of aerosols. Satellite measurements have provided important insights into aerosol properties near clouds, but also suggested that the observations can be affected by 3-D radiative processes and instrument blurring not considered in current data interpretation methods. This study examines systematic cloud-related changes in particle properties and radiation fields that influence satellite measurements of aerosols in the vicinity of low-level maritime clouds. For this, the paper presents a statistical analysis of a yearlong global dataset of co-located MODIS and CALIOP observations and theoretical simulations. The results reveal that CALIOP-observed aerosol particle size and optical thickness, and MODIS-observed solar reflectance increase systematically in a wide transition zone around clouds. It is estimated that near-cloud changes in particle populations – including both aerosols and undetected cloud particles – are responsible for roughly two thirds of the observed increase in 0.55 μm MODIS reflectance. The results also indicate that 3-D radiative processes significantly contribute to near-cloud reflectance enhancements, while instrument blurring contributes significantly only within 1 km from clouds and then quickly diminishes with distance from clouds.
Stationary Scalar Clouds Around Rotating Black Holes  [PDF]
Shahar Hod
Physics , 2012, DOI: 10.1103/PhysRevD.86.104026
Abstract: Motivated by novel results in the theory of wave dynamics in black-hole spacetimes, we analyze the dynamics of a massive scalar field surrounding a rapidly rotating Kerr black hole. In particular, we report on the existence of stationary (infinitely long-lived) regular field configurations in the background of maximally rotating black holes. The effective height of these scalar "clouds" above the central black hole is determined analytically. Our results support the possible existence of stationary scalar field dark matter distributions surrounding rapidly rotating black holes.
A Roche Model for Uniformly Rotating Rings  [PDF]
Stefan Horatschek,David Petroff
Physics , 2008, DOI: 10.1111/j.1365-2966.2008.14122.x
Abstract: A Roche model for describing uniformly rotating rings is presented and the results are compared with numerical solutions to the full problem for polytropic rings. In the thin ring limit, the surfaces of constant pressure including the surface of the ring itself are given in analytic terms, even in the mass-shedding case.
Multi-satellite aerosol observations in the vicinity of clouds  [PDF]
T. Várnai,A. Marshak,W. Yang
Atmospheric Chemistry and Physics Discussions , 2012, DOI: 10.5194/acpd-12-32039-2012
Abstract: Improved characterization of aerosol properties in the vicinity of clouds is important for better understanding two critical aspects of climate: aerosol-cloud interactions and the direct radiative effect of aerosols. Satellite measurements have provided important insights into aerosol properties near clouds, but also suggested that the observations can be affected by 3-D radiative processes and instrument blurring not considered in current data interpretation methods. This study examines systematic changes in particle properties and radiation fields that influence satellite measurements of aerosols in the vicinity of clouds. For this, the paper presents a statistical analysis of a yearlong global dataset of co-located MODIS and CALIOP observations and theoretical simulations. The results reveal that CALIOP-observed aerosol particle size and optical thickness, and MODIS-observed solar reflectance increase systematically in a wide transition zone around clouds. It is estimated that near-cloud changes in particle populations – including both aerosols and undetected cloud particles – are responsible for roughly two thirds of the observed increase in 0.55 μm MODIS reflectance. The results also indicate that 3-D radiative processes significantly contribute to near-cloud reflectance enhancements, while instrument blurring does not.
Rotating black rings on Taub-NUT  [PDF]
Yu Chen,Edward Teo
Physics , 2012, DOI: 10.1007/JHEP06(2012)068
Abstract: In this paper, we construct new solutions describing rotating black rings on Taub-NUT using the inverse-scattering method. These are five-dimensional vacuum space-times, generalising the Emparan-Reall and extremal Pomeransky-Sen'kov black rings to a Taub-NUT background space. When reduced to four dimensions in Kaluza-Klein theory, these solutions describe (possibly rotating) electrically charged black holes in superposition with a finitely separated magnetic monopole. Various properties of these solutions are studied, from both a five- and four-dimensional perspective.
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