Miracle-dz/UniFAR-FTUs huggingface dataset:
Self-organized bottleneck in energy relaxation

We study an energy relaxation process after many degrees of freedom are highly excited in a Hamiltonian system with a large number of degrees of freedom. Bottlenecks of relaxation, where relaxation of the excited elements drastically slows down, are discovered. By defining an internal state for the excited elements, it is shown that the drastic slowing-down occurs when the internal state is in a critical state. The relaxation dynamics brings the internal state into the critical state, and the critical bottleneck of relaxation is self-organized.
Two-photon annihilation of Kaluza–Klein dark matter

We investigate the fermionic one-loop cross section for the two-photon annihilation of Kaluza–Klein (KK) dark matter particles in a model of universal extra dimensions (UED). This process gives a nearly mono-energetic gamma-ray line with energy equal to the KK dark matter particle mass. We find that the cross section is large enough that if a continuum signature is detected, the energy distribution of gamma-rays should end at the particle mass with a peak that is visible for an energy resolution of the detector at the per cent level. This would give an unmistakable signature of a dark matter origin of the gamma-rays, and a unique determination of the dark matter particle mass, which in the case studied should be around 800 GeV. Unlike the situation for supersymmetric models where the two-gamma peak may or may not be visible depending on parameters, this feature seems to be quite robust in UED models, and should be similar in other models where annihilation into fermions is not helicity suppressed. The observability of the signal still depends on largely unknown astrophysical parameters related to the structure of the dark matter halo. If the dark matter near the galactic centre is adiabatically contracted by the central star cluster, or if the dark matter halo has substructure surviving tidal effects, prospects for detection look promising.
X-ray Constraints on the Intrinsic Shapes and Baryon Fractions of Five Abell Clusters

We analyzed ROSAT PSPC images of the bright, nearby $(z<0.1)$ galaxy clusters A401, A1656 (Coma), A2029, A2199, and A2256 to constrain their intrinsic shapes and baryon fractions. Following Buote & Tsai we probed the aggregate structure of the clusters on scales $\sim 1.5h^{-1}_{80}$ Mpc to reduce effects of possible substructure on smaller scales ($\lesssim$ a few hundred kpc). The ellipticities of the X-ray isophotes are typically $\epsilon\approx 0.15 - 0.25$ and display negative radial gradients significant (except Coma). By assuming hydrostatic equilibrium and a variety of mass models we obtain ellipticities $\epsilon_{mass} \approx 0.40-0.55$ for isothermal models of the total gravitating matter of the clusters; the $\epsilon_{mass}$ constraints change by $<10%$ upon consideration of the small temperature gradients shown by ASCA to be typical for rich clusters; the observed X-ray ellipticity gradients require that mass models with constant ellipticity have steep density profiles, $\rho\propto r^{-4}$. Estimates of the gas masses are highly insensitive to the ellipticities of the X-ray isophotes. The clusters in our sample have increasing fractions of gas mass to total mass with radius and have $M_{gas}/M_{tot} = (4% - 11%)h^{-3/2}_{80}$ within a radius $1.5h^{-1}_{80}$ Mpc, in excellent agreement with the results of White & Fabian and the Baryon Catastrophe proposed by White et al. (1993). Finally, the ellipticities of the dark matter distributions are essentially identical to $\epsilon_{mass}$ and are consistent with the shapes of dark halos predicted by N-body simulations and the shapes of the galaxy isopleths in the clusters in contrast to our previous conclusions using {\it Einstein} data.
Evidence for adiabatic magnetization of cold Dy N Clusters

Magnetic properties of Dy_N clusters in a molecular beam generated with a liquid helium cooled nozzle are investigated by Stern-Gerlach experiments. The cluster magnetizations \mu_z are measured as a function of magnetic field (B = 0 - 1.6T) and cluster size (16 < N < 56). The most important observation is the saturation of the magnetization \mu_z(B) at large field strengths. The magnetization approaches saturation following the power law |\mu_z-\mu_0| proportional to 1/\sqrt{B}, where \mu_0 denotes the magnetic moment. This gives evidence for adiabatic magnetization.
The Most Massive Black Holes in the Universe: Effects of Mergers in Massive Galaxy Clusters

Recent observations support the idea that nuclear black holes grew by gas accretion while shining as luminous quasars at high redshift, and they establish a relation of the black hole mass with the host galaxy's spheroidal stellar system. We develop an analytic model to calculate the expected impact of mergers on the masses of black holes in massive clusters of galaxies. We use the extended Press-Schechter formalism to generate Monte Carlo merger histories of halos with a mass 1015 h-1 M☉. We assume that the black hole mass function at z = 2 is similar to that inferred from observations at z = 0 (since quasar activity declines markedly at z < 2), and we assign black holes to the progenitor halos assuming a monotonic relation between halo mass and black hole mass. We follow the dynamical evolution of subhalos within larger halos, allowing for tidal stripping, the loss of orbital energy by dynamical friction, and random orbital perturbations in gravitational encounters with subhalos, and we assume that most black holes will efficiently merge after their host galaxies (represented as the nuclei of subhalos in our model) merge. Our analytic model reproduces numerical estimates of the subhalo mass function. We find that mergers can increase the mass of the most massive black holes in massive clusters typically by a factor ~2, after gas accretion has stopped. In our 10 realizations of 1015 h-1 M☉ clusters, the highest initial (z = 2) black hole masses are 5-7 × 109 M☉, but four of the clusters contain black holes in the range 1-1.5 × 1010 M☉ at z = 0. Satellite galaxies may host black holes whose mass is comparable to, or even greater than, that of the central galaxy. Thus, black hole mergers can significantly extend the very high end of the black hole mass function.
Configuration-tree theoretical calculation of the mean-squared displacement of particles in glass formers

We report an analytical evaluation of the mean-squared displacement (MSD) of the particles in glasses based on their coarse grained trajectories, after their vibrations are averaged out. The calculation is conducted by means of a local random configuration-tree theory that was recently proposed by one of us (Lam 2018 J. Stat. Mech. 023301). It assumes that system dynamics is dominated by activated particle hops initiated by voids and that particles are distinguishable with, in general, diverse properties. Results are compared with the numerical simulations of a lattice glass model, and satisfactory agreement has been obtained for various density of particles over a wide range of temperatures in the entire region of time with only two parameters.
Critical behavior of the three-dimensional Ising model with nearest-neighbor, next-nearest-neighbor, and plaquette interactions

The critical and multicritical behavior of the simple cubic Ising model with nearest-neighbor, next-nearest-neighbor and plaquette interactions is studied using the cube and star-cube approximations of the cluster variation method and the recently proposed cluster variation--Pad\'e approximant method. Particular attention is paid to the line of critical end points of the ferromagnetic-paramagnetic phase transition: its (multi)critical exponents are calculated, and their values suggest that the transition belongs to a novel universality class. A rough estimate of the crossover exponent is also given.
The Properties of Poor Groups of Galaxies. III. The Galaxy Luminosity Function

The form of the galaxy luminosity function (GLF) in poor groups—regions of intermediate galaxy density that are common environments for galaxies—is not well understood. Multiobject spectroscopy and wide-field CCD imaging now allow us to measure the GLF of bound group members directly (i.e., without statistical background subtraction) and to compare the group GLF with the GLFs of the field and of rich clusters. We use R-band images in 1.5 × 1.5 degree2 mosaics to obtain photometry for galaxies in the fields of six nearby (2800 < cz < 7700 km s-1) poor groups for which we have extensive spectroscopic data, including 328 new galaxy velocities. For the five groups with luminous X-ray halos, the composite group GLF for group members with -23 + 5 log h < MR < -16 + 5 log h and within projected radii of ≲0.4-0.6 h-1 Mpc from the group center is fit adequately by a Schechter function with M = -21.6 ± 0.4 + 5log h and α = -1.3 ± 0.1. We also find that (1) the ratio of dwarfs (-17 + 5 log h ≥ MR > -19 + 5 log h) to giants (MR ≤ -19 + 5 log h) is significantly larger for the five groups with luminous X-ray halos than for the one marginally X-ray-detected group; (2) the composite GLF for the luminous X-ray groups is consistent in shape with two measures of the composite R-band GLF for rich clusters (Trentham; Driver et al.) and flatter at the faint end than another (α ≈ -1.5; Smith et al.); (3) the composite group GLF rises more steeply at the faint end than the R-band GLF of the Las Campanas Redshift Survey (LCRS; α = -0.7 from Lin et al.), a large volume survey dominated by galaxies in environments more rarefied than luminous X-ray groups; (4) the shape difference between the LCRS field and composite group GLFs results mostly from the population of non-emission line galaxies (EW [O II] < 5 Å), whose dwarf-to-giant ratio is larger in the denser group environment than in the field (cf. Ferguson & Sandage; Bromley et al.); and (5) the non-emission line dwarfs are more concentrated about the group center than the non-emission line giants, except for the central, brightest (MR < M) group elliptical (BGG). This last result indicates that the dwarfs, giants, and BGGs occupy different orbits (i.e., have not mixed completely) and suggests that at least one of these populations formed at a different time. Our results show that the shape of the GLF varies with environment and that this variation is due primarily to an increase in the dwarf-to-giant ratio of quiescent galaxies in higher density regions, at least up to the densities characteristic of X-ray luminous poor groups. This behavior suggests that, in some environments, dwarfs are more biased than giants with respect to dark matter. This trend conflicts with the prediction of standard biased galaxy formation models.
On the dust temperatures of high-redshift galaxies

Dust temperature is an important property of the interstellar medium (ISM) of galaxies. It is required when converting (sub)millimetre broad-band flux to total infrared luminosity (LIR), and hence star formation rate, in high-redshift galaxies. However, different definitions of dust temperatures have been used in the literature, leading to different physical interpretations of how ISM conditions change with, e.g. redshift and star formation rate. In this paper, we analyse the dust temperatures of massive ($M_{\rm star} \gt 10^{10}\, \mathrm{M}_{\odot }$) $z$ = 2–6 galaxies with the help of high-resolution cosmological simulations from the Feedback in Realistic Environments (fire) project. At $z$ ∼ 2, our simulations successfully predict dust temperatures in good agreement with observations. We find that dust temperatures based on the peak emission wavelength increase with redshift, in line with the higher star formation activity at higher redshift, and are strongly correlated with the specific star formation rate. In contrast, the mass-weighted dust temperature, which is required to accurately estimate the total dust mass, does not strongly evolve with redshift over $z$ = 2–6 at fixed IR luminosity but is tightly correlated with LIR at fixed $z$. We also analyse an ‘equivalent’ dust temperature for converting (sub)millimetre flux density to total IR luminosity, and provide a fitting formula as a function of redshift and dust-to-metal ratio. We find that galaxies of higher equivalent (or higher peak) dust temperature (‘warmer dust’) do not necessarily have higher mass-weighted temperatures. A ‘two-phase’ picture for interstellar dust can explain the different scaling relations of the various dust temperatures.
Parsec-Scale Blazar Monitoring: Flux and Polarization Variability

We present analysis of the flux density and polarization variability of parsec-scale radio jets from a dual-frequency, six-epoch, VLBA polarization experiment monitoring 12 blazars. The observations were made at 15 and 22 GHz at bimonthly intervals over 1996. Here we analyze the flux density, fractional polarization, and polarization position angle behavior of core regions and jet features, considering both the linear trends of these quantities with time and more rapid fluctuations about the linear trends. The dual frequency nature of the observations allows us to examine spectral evolution, to separate Faraday effects from changes in magnetic field order, and also to deduce empirical estimates for the uncertainties in measuring properties of VLBI jet features (see the Appendix). Our main results include the following: On timescales ≳1 yr, we find that jet features generally decayed in flux, with older features decaying more slowly than younger features. Using the decay rates of jet features from six sources, we find I ∝ R-1.3±0.1. Short-term fluctuations in flux tended to be fractionally larger in core regions than in jet features, with the more compact core regions having the larger fluctuations. We find significant spectral index changes in the core regions of four sources. Taken together these are consistent with an outburst-ejection cycle for new jet components. Jet features from one source showed a significant spectral flattening over time. Jet features either increased in fractional polarization with time or showed no significant change, with the smallest observed changes in the features at the largest projected radii. Increasing magnetic field order explains most of the increasing fractional polarization we observed. Only in the case of 3C 273 is there evidence of a feature emerging from behind a Faraday depolarizing screen. We find a number of significant polarization angle rotations, including two very large (≳180°) rotations in the core regions of OJ 287 and J1512-09. In general, polarization angle changes were of the same magnitude at both observing bands and cannot be explained by Faraday rotation. The observed polarization angle changes most likely reflect underlying changes in magnetic field structure. In jet features, four of the five observed rotations were in the direction of aligning the magnetic field with the jet axis, and coupled with the tendency of jet features to show a fractional polarization increase, this suggests increasing longitudinal field order.
SINFONI - Integral field spectroscopy at 50 milli-arcsecond resolution with the ESO VLT

SINFONI is an adaptive optics assisted near-infrared integral field spectrometer for the ESO VLT. The Adaptive OPtics Module (built by the ESO Adaptive Optics Group) is a 60-elements curvature-sensor based system, designed for operations with natural or sodium laser guide stars. The near-infrared integral field spectrometer SPIFFI (built by the Infrared Group of MPE) provides simultaneous spectroscopy of 32 x 32 spatial pixels, and a spectral resolving power of up to 3300. The adaptive optics module is in the phase of integration; the spectrometer is presented tested in the laboratory. We provide an overview of the project, with particular emphasis on the problems encountered in designing and building an adaptive optics assisted spectrometer.
On autocorrelation in a Poisson regression model

SUMMARY This paper develops a practical approach to diagnosing the existence of a latent stochastic process in the mean of a Poisson regression model. The asymptotic distribution of standard generalised linear model estimators is derived for the case where an autocorrelated latent process is present. Simple formulae for the effect of autocovariance on standard errors of the regression coefficients are also provided. Methods for adjusting for the severe bias in previously proposed estimators of autocovariance are derived and their behaviour is investigated. Applications of the methods to time series of monthly polio counts in the U.S.A. and daily asthma presentations at a hospital in Sydney are used to illustrate the results and methods.
Finite Percolation at a Multiple of the Threshold

Bond percolation on infinite heavy-tailed power-law random networks lacks a proper phase transition; or one may say, there is a phase transition at {\em zero percolation probability}. Nevertheless, a finite size percolation threshold $q_c(N)$, where $N$ is the network size, can be defined. For such heavy-tailed networks, one can choose a percolation probability $q(N)=\rho q_c(N)$ such that $\displaystyle \lim_{N\to \infty}(q-q_c(N)) =0$, and yet $\rho$ is arbitrarily large (such a scenario does not exist for networks with non-zero percolation threshold). We find that the critical behavior of random power-law networks is best described in terms of $\rho$ as the order parameter, rather than $q$. This paper makes the notion of the phase transition of the size of the largest connected component at $\rho=1$ precise. In particular, using a generating function based approach, we show that for $\rho>1$, and the power-law exponent, $2\leq \tau<3$, the largest connected component scales as $\sim N^{1-1/\tau}$, while for $0<\rho<1$ the scaling is at most $\sim N^{\frac{2-\tau}{\tau}}$; here, the maximum degree of any node, $k_{max}$, has been assumed to scale as N^{1/\tau}$. In general, our approach yields that for large $N$, $\rho \gg 1$, $2\leq \tau<3$, and $k_{max} \sim N^{1/\tau}$, the largest connected component scales as $\sim \rho^{1/(3-\tau)}N^{1-1/\tau}$. Thus, for any fixed but large N, we recover, and make it precise, a recent result that computed a scaling behavior of $q^{1/(3-\tau)}$ for "small $q$". We also provide large-scale simulation results validating some of these scaling predictions, and discuss applications of these scaling results to supporting efficient unstructured queries in peer-to-peer networks.
Computing in String Field Theory Using the Moyal Star Product

Using the Moyal star product, we define open bosonic string field theory carefully, with a cutoff, for any number of string oscillators and any oscillator frequencies. Through detailed computations, such as Neumann coefficients for all string vertices, we show that the Moyal star product is all that is needed to give a precise definition of string field theory. The formulation of the theory as well as the computation techniques are considerably simpler in the Moyal formulation. After identifying a monoid algebra as a fundamental mathematical structure in string field theory, we use it as a tool to compute with ease the field configurations for wedge, sliver, and generalized projectors, as well as all the string interaction vertices for perturbative as well as monoid-type nonperturbative states. Finally, in the context of VSFT we analyze the small fluctuations around any D-brane vacuum. We show quite generally that to obtain nontrivial mass and coupling, as well as a closed strings, there must be an associativity anomaly. We identify the detailed source of the anomaly, but leave its study for future work.
One-dimensional plasmonic hotspots located between silver nanowire dimers evaluated by surface-enhanced resonance Raman scattering

Hotspots of surface-enhanced resonance Raman scattering (SERRS) are localized within 1 nm at gaps or crevices of plasmonic nanoparticle (NP) dimers. We demonstrate SERRS hotspots with volumes that are extended in one dimension tens of thousand times compared to standard zero-dimensional hotspots using gaps or crevices of plasmonic nanowire (NW) dimers.
A NuSTAR study of the 55 ks hard X-ray pulse-phase modulation in the magnetar 4U 0142+61

Archival NuSTAR data of the magnetar 4U0142+61, acquired in 2014 March for a total time span of 258 ks, were analyzed. This is to reconfirm the 55 ks modulation in the hard X-ray pulse phases of this source, found with a Suzaku observation in 2009 (Makishima et al. 2014). Indeed, the 10-70 keV X-ray pulsation, detected with NuSTAR at 8.68917s, was found to be also phase-modulated (at 98 percent confidence or higher) at the same 55 ks period, or half that value. Furthermore, a brief analysis of another Suzaku data set of 4U0142+61, acquired in 2013, reconfirmed the same 55 ks phase modulation in the 15-40 keV pulses. Thus, the hard X-ray pulse-phase modulation was detected with Suzaku (in 2009 and 2013) and NuSTAR (in 2014) at a consistent period. However, the modulation amplitude varied significantly; A=0.17 s with Suzaku (2009), A=1.2 s with Suzaku (2013), and A=0.17 s with NuSTAR. In addition, the phase modulation properties detected with NuSTAR differed considerably between the first 1/3 and the latter 2/3 of the observation. In energies below 10 keV, the pulse-phase modulation was not detected with either Suzaku or NuSTAR. These results reinforce the view of Makishima et al. (2014); the neutron star in 4U0142+61 keeps free precession, under a slight axial deformation due probably to ultra-strong toroidal magnetic fields of 1e16 G. The wobbling angle of precession should remain constant, but the pulse-phase modulation amplitude varies on time scales of months to years, presumably as asymmetry of the hard X-ray emission pattern around the star's axis changes.
Gone after one orbit: How cluster environments quench galaxies

The effect of galactic orbits on a galaxy’s internal evolution within a galaxy cluster environment has been the focus of heated debate in recent years. To understand this connection, we use both the $(0.5 \,$Gpc)3 and the Gpc3 boxes from the cosmological hydrodynamical simulation set Magneticum Pathfinder. We investigate the velocity anisotropy, phase space, and the orbital evolution of up to ∼5 × 105 resolved satellite galaxies within our sample of 6776 clusters with $M_{\mathrm{vir}}\,\, \gt\,\, 10^{14} \, \mathrm{M_{\odot }}$ at low redshift, which we also trace back in time. In agreement with observations, we find that star-forming satellite galaxies inside galaxy clusters are characterized by more radially dominated orbits, independent of cluster mass. Furthermore, the vast majority of star-forming satellite galaxies stop forming stars during their first passage. We find a strong dichotomy both in line-of-sight and radial phase space between star-forming and quiescent galaxies, in line with observations. The tracking of individual orbits shows that the star formation of almost all satellite galaxies drops to zero within $1 \, \mathrm{Gyr}$ after infall. Satellite galaxies that are able to remain star forming longer are characterized by tangential orbits and high stellar mass. All this indicates that in galaxy clusters the dominant quenching mechanism is ram-pressure stripping.