Miracle-dz/UniFAR-FTUs huggingface dataset:
Planetary Camera observations of the M87 stellar cusp

Analysis of V and I band HST Planetary Camera images of the giant elliptical galaxy M87 show that its central starlight distribution is consistent with the black hole M_• = 2.6 X 10^9 M_☉ cusp model proposed for M87 by Young et al. [ApJ, 221, 721 (1978)]. A combined approach of image deconvolution and modeling is used to investigate the starlight distribution into limiting radii of ≈0". 04 (3 pc at 16 Mpc). The central structure of M87 can be described by three components: a power-law starlight profile of the form µ(r)∝a:r^(-1/4) for r<3", a central nonthermal point source, and optical counterparts of the jet knots N1 and M identified by VLBI observations. M87 lacks a constant surface brightness core, and its central starlight luminosity density exceeds 10^3L_☉ pc^(-3) (I band) for r< 10 pc. The profile strongly resembles a stellar cusp associated with a massive black hole. A review of existing velocity dispersion observations suggests that the Young et al. black hole mass can be accommodated to the observations with minor adjustments of dynamical models. The central luminosity spike itself remains unresolved at HST resolution, with r_c < 1 pc. The spike has optical spectral index ɑ= -0.46 ± 0.20 and is at least as blue if not bluer than the rest of the M87 jet. The total nonthermal flux in the inner 1" of M87 agrees well with the central radio flux and the radio-optical spectral index of the rest of the jet. It is also consistent with the spectral-line dilution seen by Dressler & Richstone [ApJ, 348, 120 ( 1990)]; we thus argue that the spike is completely nonthermal.
X-Ray-Extreme-Ultraviolet Simultaneous Observations of NGC 5548: Fast Extreme-Ultraviolet Dip without X-Ray Variation

The bright Seyfert 1 galaxy NGC 5548 was monitored in X-rays by ASCA for 9 days and in EUV by EUVE for 12 days continuously in 1996. The periods of X-ray observations were really simultaneously covered by EUV observations. The 0.1-10 keV combined continuum of X-ray and EUV is well presented by a simple power law with a photon index Γ = 1.78 plus the Wien part of a disk blackbody with kT = 17 eV. On long timescales of days, the variability of the EUV flux is in good accordance with that of the X-rays. Furthermore, there is a clear positive correlation between Γ and the 2-10 keV flux. These results are consistent with the scenario that the X-rays are produced by inverse Compton scattering of soft photons in hot electron clouds. On the other hand, focusing on the short-term variability, we found that the EUV flux shows 20,000 s variability with 40% amplitude with neither X-ray flux nor spectral changes when the source is at its maximum flux state. This seems to conflict with the ordinary framework of the inverse Compton model. To explain such fast variability of the EUV flux accompanied by no X-ray change, we suggest that the EUV emission consists of two components; relatively stable disk emission and a variable component that is dominant at EUV flares.
INFLUENCE FUNCTIONS IN FUNCTIONAL MEASUREMENT ERROR MODELS WITH REPLICATED DATA

We consider the construction and properties of influence functions in the context of functional measurement error models with replicated data. In these models estimates of the parameters can be affected both by the individual observations and the means of replicated observations. We show that influence function of the means of replicates on the estimate of regression coefficients can be only derived under the assumption that the variances of the errors are known, while one for the individual observations can be only derived simultaneously with their influence function on the estimators of the variances of the errors.
Heat Transfer of Compressed Air Flow in a Spanwise Rotating Four-Pass Serpentine Channel

Convective heat transfer of compressed air flow in a radially rotating four-pass serpentine channel is investigated experimentally in the present study. The coolant air was compressed at 5 atmospheric pressure to achieve a high rotation number and Reynolds number simultaneously. The main governing parameters are the Prandtl number, the Reynolds number for forced convection, and the rotation number for the Coriolis-force-induced cross-stream secondary flow and the Grashof number for centrifugal buoyancy. To simulate the operating conditions of a real gas turbine, the present study kept the parameters in the test rig approximately the same as those in a real engine. The air in the present serpentine channel was pressurized to increase the air density for making up the low rotational speed in the experiment. The air flow was also cooled to increase the density ratio before entering the rotating ducts. Consequently, the order of magnitude of Grashof number in the present study was the same as that in real operating conditions. The local heat transfer rate on the walls of the four-pass serpentine channel are correlated and compared with that in the existing literature
The Initiation of Precipitation in Updrafts

Abstract The initial stages of the formation of precipitation in uniform updrafts under natural and seeded conditions are examined using a detailed microphysical model of parcel ascent. The effects of seeding are related to the initiation of precipitation which is considered to be the rate-limiting step in the precipitation process. The times required to reach a 20 dBZ radar reflectivity factor are compared between natural and seeded cases. Three regions of ice-nucleant seedability are defined on the bases of cloud-base temperature and updraft velocity. These are 1) no precipitation under natural or seeded conditions, 2) easy to overseed, and 3) difficult to overseed. It is suggested that these regions define a physically valid stratification for the analysis of cloud seeding projects. The optimal ice crystal concentration which yields the minimum time to form precipitation is estimated to be between 100 and 1000 crystals per liter. Seeding with large drops is shown to produce precipitation more efficient.
Dynamic pressure loads associated with twin supersonic plume resonance

The phenomenon of twin supersonic plume resonance is defined and studied as it pertains to high level dynamic loads in the inter-nozzle region of aircraft like the F-15 and B1-A. Using a 1/40th scale model twin jet nacelle with powered choked nozzles, it is found that intense internozzle dynamic pressures are associated with the synchrophased coupling of each plume's jet flapping mode. This condition is found most prevalent when each plume's jet flapping mode has constituent elements composed of the B-type helical instability. Suppression of these fatigue bearing loads was accomplished by simple geometric modifications to only one plume's nozzle. These modifications disrupt the natural selection of the B-type mode and thereby decouple the plumes.
Different regimes of light localization in a disordered photonic crystal

A. F. Ioffe Physical-Technical Institute, 194021 St. Petersburg, Russia~Received 2 December 1998! It is known that photonic Bloch states can become strongly localized near the band edges in a disorderedphotonic crystal. We show that Bloch states are disrupted and another localization regime establishes whenlocal ﬂuctuations of the band-edge frequency caused by randomization of refractive index proﬁle becomes aslarge as the band-gap width. Transmission experiments performed on opal photonic crystal have shown theexponential decay of light throughout the gap region, which is ascribed to building up of the second regime oflight localization. @S0163-1829~99! 11027-0#I. INTRODUCTION
A Survey of Neutral Hydrogen Absorption in the Nuclei of Active Spiral Galaxies

Nineteen spiral and irregular galaxies with bright continuum nuclei were observed with the VLA to search for absorption at 21 cm by cool atomic hydrogen in or in front of the nuclei. Fifteen absorption lines were detected, and six tentatively identified, in 15 of these galaxies. Equivalent widths are much larger than for a spiral disk like that of the Milky Way; it is suggested that absorption arises not in the disks but in circumstellar clouds, or in some cases in an intervening system falling toward the active nucleus. Simple order-of-magnitude calculations suggest accretion rates of about 1 solar mass of H I per year onto the nucleus. 85 references.
Fractal dewetting of a viscous adhesive film between separating parallel plates

A dewetting cylindrical film between two separating plates is observed to produce fractal finger patterns that penetrate radially inward. In lieu of the classical tip splitting, this fractal is generated by successive shielding of alternating fingers. By analyzing this key shielding dynamics via a forced two-dimensional Hele–Shaw model with global force balance, a self-similar scaling for the shielding distance and shielding time were obtained for every generation of shielding events. The theory predicts that the plate detach time is reduced by a factor of 12 due to the fractal fingers. This is confirmed experimentally for large Bond numbers when there are sufficient fingers to justify a continuum approximation in the theory. A cumulative node number density, which is not a power law, is also predicted but not confirmed experimentally.
The polynomial method in the study of zero-sum theorems

Here we try to have a glimpse of the polynomial method used in the study of some zero-sum problems in additive combinatorics. While the first few sections of this paper are of an expository nature, in the last section we present some new results on bounds of some zero-sum constants obtained by generalizing a polynomial method. We also mention some open questions.
Bifurcation of vortex breakdown patterns in a circular cylinder with two rotating covers

We analyse the topology of vortex breakdown in a closed cylindrical container in the steady domain under variation of three parameters, the aspect ratio of the cylinder, the Reynolds number, and the ratio of the angular velocities of the covers. We develop a general post-processing method to obtain topological bifurcation diagrams from a database of simulations of two-dimensional flows and apply the method to axisymmetric simulations of the flow in the cylinder. Interpreting the diagrams with the aid of bifurcation theory, we obtain complete topological bifurcation diagrams for the rotation ratio in the interval [−0.04, 0.075]. In this narrow range we identify three codimension-3 bifurcation points which act as organising centres for the entire bifurcation diagram.
Study of Pressure Wave Propagation in a Two-Phase Bubbly Mixture

Background: Bubbly flows are used in a wide variety of applications and require accurate modeling. In this paper three modeling approaches are investigated using the geometrically simple configuration of a gas bubble strongly oscillating in a bubbly medium. Method of Approach: A coupled Eulerian-Lagrangian, a multi-component compressible, and an analytical approach are compared for different void fractions. Results: While the homogeneous mixture models (analytical and multi-component) compare well with each other, the Eulerian-Lagrangian model captures additional features and inhomogeneities. The discrete bubbles appear to introduce localized perturbations in the void fraction and the pressure distributions not captured by homogeneous mixture models. Conclusion: The bubbly mixture impedes the growth and collapse of the primary bubble while wavy patterns in the velocity, pressure, and void fraction fields propagate in space and time.
OPACOS: OVRO POST-AGB CO (1–0) EMISSION SURVEY. I. DATA AND DERIVED NEBULAR PARAMETERS

We have performed interferometric observations of the 12CO (J = 1–0) emission in a sample of 27 objects spanning different evolutionary stages from the late asymptotic giant branch (late-AGB), through the post-AGB (pAGB) phase, and to the planetary nebula (PN) stage, but dominated by pAGB objects and young PNs (⩾81%). In this paper (the first in a series) we present our maps and main nebular properties derived for the whole sample. Observations were performed with the Caltech Millimeter Array at the Owens Valley Radio Observatory. The angular resolution obtained in our survey ranges between 2. ″3 and 10. ″7. The 13CO and C18O (J = 1–0) transitions as well as the 2.6 mm continuum emission have also been observed in several objects. The detection statistics in the 12CO, 13CO, C18O transitions and 2.6 mm continuum are 89%, 83%, 0%, and 37%, respectively. We report first detections of 12CO (J = 1–0) emission in 13 targets and confirm emission from several previous marginal detections. The molecular envelope probed by 12CO (J = 1–0) emission is extended for 18 (out of 24) sources; envelope asymmetries and/or velocity gradients are found in most extended objects. Our data have been used to derive accurate target coordinates and systemic velocities and to characterize the envelope size, morphology, and kinematics. We also provide an estimate of the total molecular mass and the fraction of it contained in fast flows, lower limits to the linear momentum and to the isotopic 12C/13C ratio, as well as the AGB mass-loss rate and timescale for sources with extended CO emission.
An estimate for the resolvent of a non-selfadjoint differential operator on an unbounded domain

Abstract. We consider the operator T defined by , , where is an unbounded domain, S is a positive definite selfadjoint operator defined on a domain and is a bounded complex measurable function with the property for a . We derive an estimate for the norm of the resolvent of T. In addition, we prove that T is invertible, and the inverse operator is a sum of a normal operator and a quasinilpotent one, having the same invariant subspaces. By the derived estimate, spectrum perturbations are investigated. Moreover, a representation for the resolvent of T by the multiplicative integral is established. As examples, we consider the Schrödinger operators on the positive half-line and orthant.
Asymptotically Optimal Tests Using Limited Information and Testing for Exogeneity

By appropriately partitioning the joint hypothesis of weak exogeneity and the maintained overidentifying restrictions in the linear dynamic simultaneous equations model and showing that the component subhypotheses are separable, asymptotically optimal tests for the weak exogeneity hypothesis may be constructed using limited information statistics. A necessary and sufficient condition for the separability of parametric hypotheses of the mixed implicit function and constraint equation type is derived which generalizes conditions previously obtained in the literature. Consequently, limited and full information procedures for testing the weak exogeneity hypothesis are asymptotically equivalent. The impact of these results for testing strong exogeneity in the linear dynamic simultaneous equations model is also explored.
The determination of dust cloud altitudes from a satellite using hyperspectral measurements in the gaseous absorption band

An approach to derive dust layer optical thickness and top height using top-of-atmosphere (TOA) reflectance in the oxygen A-band is introduced. The algorithm is similar to that developed by the authors for the case of water clouds. It is based on the fitting of spectral TOA reflectance measurements in the narrow band around 760 nm using results of the exact radiative transfer calculations for a given dust layer model. The accuracy of the technique with respect to the uncertainty in a priori assumption of the dust single-scattering albedo is discussed. The algorithm is applied to satellite hyperspectral measurements over the Atlantic Ocean.
Treatment of Solar Radiation by Spatial and Temporal Discretization for Modeling the Thermal Response of Arch Dams

AbstractA methodology for computing thermal loads in arch dams is proposed. The methodology considers the nonuniform distribution of solar insolation over dam faces because of shading, curvature of dam faces, orientation, and slopes. Because, in most cases, the mean daily global solar radiation is the only type available, a methodology for estimating hourly solar energy reaching dam faces is described. The methodology is applied to a case study where observations from 21 thermometers embedded in the concrete and data of climatic variables are available. The concrete temperature field is successfully computed, with good agreement between observations and predictions. The proposed methodology is compared with other approaches, and the consequences on the stress calculations are analyzed.
A simple formulation for the eddy‐diffusivity parameterization of cloud‐topped boundary layers

A new formulation for the eddy‐diffusivity parameterization of the cloudy boundary layer is presented. The new aspects of the scheme are: (i) two prognostic turbulent kinetic energies (TKE), for the clear and cloudy air; (ii) in each region, the mixing length is formulated in terms of the TKE and a time scale. Additionally a statistical cloud scheme is used. The model is evaluated in a decoupling stratocumulus case and in a cumulus case, using a single‐column mode. The model realistically simulates the overall cloud properties. The in‐cloud mixing length formulation qualitatively matches the typical eddy size (as diagnosed from large eddy simulations). Consistent interactions between the sub‐cloud and the cloud layers are achieved through a realistic in‐cloud mixing. In the cumulus case, the conditionally unstable layer is maintained. These results show that boundary layer clouds and associated mixing can be represented consistently in the context of the eddy‐diffusivity approach.
Market Making and Reversal on the Stock Exchange

Abstract The accurate record of stock market ticker prices displays striking properties of dependence. We find for example that after a decline of 1/8 of a point between transactions, an advance on the next transaction is three times as likely as a decline. Further examinations disclose that after two price changes in the same direction, the odds in favor of a continuation in that direction are almost twice as great as after two changes in opposite directions. The dealer (specialist) in a stock typically quotes the market by announcing the highest buy order and lowest sell order carried on his book. But these orders tend to be concentrated at integers (26, 43), halves , quarters and odd eighths in descending preference. This non-uniform distribution of orders produces some non-random effects in stock price motion. These properties of the stock market are typical of markets in many second-hand goods.
The α-effect in 2D fast dynamos

We look at the large-scale dynamo properties of spatially periodic, time dependent, helical 2D flows of the form u(x, t) = (∂ y ψ (x, y, t), −∂ x ψ (x, y, t), −ψ (x, y, t). These flows act as kinematic fast dynamos and are able to generate a mean magnetic field uniform and constant in the xy-plane but whose direction varies periodically along z with wavenumber k. Using Mean Field Electrodynamics, the generation mechanism can be understood in terms of a k-dependent α-effect, which depends on the magnetic Reynolds number, R m . We calculate this effect for different motions and investigate how its limit as k → 0 depends on R m and on the properties of the flows such as their spatial structure or correlation time. This work generalises earlier studies based on 2D steady flows to motions with time dependence.
Rheology of random foams

The computational study of the rheology of two‐dimensional random cellular systems such as foam or concentrated emulsion systems is presented. The numerical simulations are performed under homogeneous shear using a computationally efficient model in which effects of viscous dissipation inside the liquid films are taken into consideration. It is shown that the system possesses a finite yield stress and behaves like Bingham plastics. The role of the topological change of the cellular structure is also examined.
A uniqueness theorem and reconstruction of singularities for a two-dimensional nonlinear Schrödinger equation

This work deals with the inverse scattering problem for a two-dimensional Schrödinger equation with a saturation-like nonlinearity, where the real-valued unknown functions q and α belong to with certain special behaviour at infinity. We prove Saito's formula which implies a uniqueness result and a representation formula for a certain combination of the functions q and α in the sense of tempered distributions. What is more, we prove that the leading order singularities of this combination can be obtained exactly by the inverse Born approximation method from general scattering data at arbitrarily large energies.
Dependence of domain wall pinning potential landscapes on domain wall chirality and pinning site geometry in planar nanowires

We report on domain wall pinning behavior and the potential-energy landscapes created by notches of two different geometries in planar Permalloy nanowires. Domain wall depinning was probed experimentally using spatially resolved magneto-optical Kerr effect measurements. The spin structure of pinned domain walls was determined using Lorentz microscopy, and domain wall pinning behavior was also analyzed using micromagnetic simulations, which are in good qualitative agreement with experimental results. All notch structures have dimensions that are comparable with the domain wall length scales. For the notch structures investigated, the depinning field experienced by a domain wall is found to be relatively insensitive to notch geometry although the pinning behavior is highly sensitive to both the wall type and the wall chirality spin structure. Energetically, the notches present both potential barriers and/or potential wells depending on the micromagnetic structure of the domain wall, and we find that the chirality of the domain wall is a key determinant of the pinning potential landscape. The pinning behavior of domain walls is discussed in detail, and direct quantitative measurements of the width and depth of the potential wells and/or barriers responsible for domain wall pinning are given for vortex walls pinned in triangular and rectangular notches.
Effect of pump fluctuations on line shapes in coherent anti-Stokes Raman scattering

The theory of coherent anti-Stokes Raman scattering (CARS) is extended to include the effect of pump fluctuations. The intensities and spectra of lines in resonant CARS are calculated to all orders in fields assuming a phase-diffusion model for waves at the two pump frequencies. The bandwidth of the two lasers enters in a much more complicated way than following a simple scaling of ${T}_{1}$ or ${T}_{2}$. Various resonances in CARS spectra due to dynamic splitting of the energy levels are discussed for a range of detunings, field intensities, and bandwidths. In contrast to the usual spectra in strong fields, the Rabi sidebands appear as dispersion-shaped structures. The laser linewidth is shown to change dramatically the CARS line shape. The case of no saturation is also treated, thus allowing for the inclusion of more general line shapes and fluctuations of the pump waves and the nonlinear susceptibility tensor ${\ensuremath{\chi}}^{(3)}$. Gaussian statistics of the pump field are shown to lead to enhancement factors in CARS intensity, similar to those appearing in the context of multiphoton absorption processes.
Hopping conductivity in amorphous antimony

Amorphous Sb films ranging in thickness between 170 and 14 000 \AA{} were prepared at 77\ifmmode^\circ\else\textdegree\fi{}K in three different ways: getter sputtering, evaporation from Sb, and evaporation from PtSb. The electrical resistivity of these various films is well fitted between 30 and 160 \ifmmode^\circ\else\textdegree\fi{}K by the relation $\ensuremath{\rho}={\ensuremath{\rho}}_{0}\mathrm{exp}[{(\frac{{T}_{0}}{T})}^{\frac{1}{4}}]$ with ${T}_{0}\ensuremath{\simeq}{10}^{7}$ \ifmmode^\circ\else\textdegree\fi{}K.