Miracle-dz/UniFAR-FTUs huggingface dataset:
AKARI near-infrared background fluctuations arise from normal galaxy populations

We show that measurements of the fluctuations in the near-infrared background (NIRB) from the AKARI satellite can be explained by faint galaxy populations at low redshifts. We demonstrate this using reconstructed images from deep galaxy catalogs (HUGS/S-CANDELS) and two independent galaxy population models. In all cases, we find that the NIRB fluctuations measured by AKARI are consistent with faint galaxies and there is no need for a contribution from unknown populations. We find no evidence for a steep Rayleigh-Jeans spectrum for the underlying sources as previously reported. The apparent Rayleigh-Jeans spectrum at large angular scales is likely a consequence of galaxies being removed systematically to deeper levels in the longer wavelength channels.
Magnetic cluster excitations

Magnetic cluster systems can be considered as nanomagnets consisting of a small number of interacting spins that are magnetically isolated from the neighboring clusters of the compound by nonmagnetic ligands. Inelastic neutron scattering is a powerful experimental tool for the study of magnetic clusters, since it provides direct access to energy splittings. The present work presents the underlying concepts, which are illustrated for some representative examples such as single-molecule magnets, diluted magnets and magnetic polarons. It is shown that - besides the dominant Heisenberg interaction - higher-order exchange terms are often needed to rationalize the experimental data.
RADIO-TO-TeV PHASE-RESOLVED EMISSION FROM THE CRAB PULSAR: THE ANNULAR GAP MODEL

The Crab pulsar is a quite young, famous pulsar that radiates multi-wavelength pulsed photons. The latest detection of GeV and TeV pulsed emission with an unprecedented signal-to-noise ratio, supplied by the powerful telescopes Fermi, MAGIC, and VERITAS, challenges the current popular pulsar models, and can be a valuable discriminator to justify the pulsar high-energy-emission models. Our work is divided into two steps. First, taking reasonable parameters (the magnetic inclination angle α = 45° and the view angle ζ = 63°), we use the latest high-energy data to calculate radio, X-ray, γ-ray, and TeV light curves from a geometric view to obtain crucial information on emission locations. Second, we calculate the phase-averaged spectrum and phase-resolved spectra for the Crab pulsar and take a theoretical justification from a physical view for the emission properties as found in the first step. It is found that a Gaussian emissivity distribution with the peak emission near the null charge surface in the so-called annular gap (AG) region gives the best modeled light curves. The pulsed radio, X-ray, γ-ray, and TeV emission are mainly generated from the emission of primary particles or secondary particles with different emission mechanisms in the nearly similar region of the AG located in the only magnetic pole, which leads to the nearly “phase-aligned” multi-wavelength light curves. The emission of peak 1 and peak 2 originates from the AG region near the null charge surface, while the emission of the bridge primarily originates from the core gap (CG) region. The charged particles cannot co-rotate with the pulsar and escape from the magnetosphere, which determines the original flowing primary particles. The acceleration electric field and potential in the AG and CG are huge enough and are in the several tens of neutron star radii. Thus, the primary particles are accelerated to ultra-relativistic energies and produce numerous secondary particles (pairs) in the inner regions of the AG and CG. We emphasize that there are mainly two types of pairs: one is curvature-radiation induced (CR-induced) and the other is inverse-Compton-scattering induced (ICS-induced). The phase-averaged spectrum and phase-resolved spectra from soft X-ray to TeV bands are produced by four components: synchrotron radiation from CR- and ICS-induced pairs dominates the X-ray band to soft γ-ray band (100 eV to 10 MeV); curvature radiation and synchrotron radiation from the primary particles mainly contribute to the γ-ray band (10 MeV to ∼20 GeV); ICS from the pairs significantly contributes to the TeV γ-ray band (∼20–400 GeV). The multi-wavelength pulsed emission from the Crab pulsar can be well modeled with the AG and CG model. To distinguish our single magnetic pole model from two-pole models, the convincing values of the magnetic inclination angle and the viewing angle will play a key role.
ON THE ROLE AND ORIGIN OF NONTHERMAL ELECTRONS IN HOT ACCRETION FLOWS

We study the X-ray spectra of tenuous, two-temperature accretion flows using a model involving an exact, Monte Carlo computation of the global Comptonization effect as well as a general relativistic description of both the flow structure and radiative processes. In our previous work, we found that in flows surrounding supermassive black holes, thermal synchrotron radiation is not capable of providing a sufficient seed photon flux to explain the X-ray spectral indices as well as the cut-off energies measured in several best-studied active galactic nuclei (AGNs). In this work, we complete the model by including seed photons provided by nonthermal synchrotron radiation and we find that it allows us to reconcile the hot flow model with the AGN data. We take into account two possible sources of nonthermal electrons. First, we consider e± produced by charged-pion decay, which should always be present in the innermost part of a two-temperature flow due to proton–proton interactions. We find that for a weak heating of thermal electrons (small δ) the synchrotron emission of pion-decay e± is much stronger than the thermal synchrotron emission in the considered range of bolometric luminosities, L ∼ (10−4–10−2) LEdd. The small-δ model including hadronic effects, in general, agrees with the AGN data, except for the case of a slowly rotating black hole and a thermal distribution of protons. For large δ, the pion-decay e± have a negligible effect and, in this model, we consider nonthermal electrons produced by direct acceleration. We find an approximate agreement with the AGN data for the fraction of the heating power of electrons, which is used for the nonthermal acceleration η ∼ 0.1. However, for constant η and δ, the model predicts a positive correlation of the X-ray spectral index with the Eddington ratio, and hence a fine tuning of η and/or δ with the accretion rate is required to explain the negative correlation observed at low luminosities. We note a significant difference between the dependence of plasma parameters, Te and τ, on the Eddington ratio that is predicted by the large- and small-δ models. This may be the key property allowing for the estimation of the value of δ. However, a precise measurement of the spectral cut-off is required, and we note that differences between results available in the literature are similar in magnitude to the difference between the model predictions. In flows surrounding stellar-mass black holes, the synchrotron emission of pion-decay e± exceeds the thermal synchrotron only above ∼0.01 LEdd. Furthermore, in such flows, the nonthermal synchrotron radiation is emitted at energies of ≳ 1 keV, and therefore the Compton cooling is less efficient than in flows surrounding supermassive black holes. This may explain spectral differences between AGNs and black-hole transients around ∼0.01 LEdd (the latter being typically much harder).
ON THE RADIAL VELOCITY DETECTION OF ADDITIONAL PLANETS IN TRANSITING, SLOWLY ROTATING M-DWARF SYSTEMS: THE CASE OF GJ 1132

M-dwarfs are known to commonly host high-multiplicity planetary systems. Therefore, M-dwarf planetary systems with a known transiting planet are expected to contain additional small planets (rp ≤ 4 R⊕, mp ≲ 20 M⊕) that are not seen in transit. In this study, we investigate the effort required to detect such planets using precision velocimetry around the sizable subset of M-dwarfs that are slowly rotating (Prot ≳ 40 days), and hence more likely to be inactive. We focus on the test case of GJ 1132. Specifically, we perform a suite of Monte-Carlo simulations of the star’s radial velocity signal, featuring astrophysical contributions from stellar jitter due to rotationally modulated active regions, as well as Keplerian signals from the known transiting planet and hypothetical additional planets not seen in transit. We then compute the detection completeness of non-transiting planets around GJ 1132 and consequently estimate the number of RV measurements required to detect those planets. We show that, with 1 m s−1 precision per measurement, only ∼50 measurements are required to achieve a 50% detection completeness for all non-transiting planets in the system, as well as planets that are potentially habitable. Throughout this work, we advocate the use of Gaussian process regression as an effective tool for mitigating the effects of stellar jitter including stars with high activity. Given that GJ 1132 is representative of a large population of slowly rotating M-dwarfs, we conclude with a discussion of how our results may be extended to other systems with known transiting planets, such as those that will be discovered with TESS.
Universality of transport properties of ultrathin oxide films

We report low-temperature measurements of current–voltage characteristics for highly conductive Nb/Al–AlOx–Nb junctions with thicknesses of the Al interlayer ranging from 40 to 150 nm and ultrathin barriers formed by diffusive oxidation of the Al surface. In a superconducting state these devices have revealed a strong subgap current leakage. Analyzing Cooper-pair and quasiparticle currents across the devices, we conclude that the strong suppression of the subgap resistance compared with conventional tunnel junctions is not related to technologically derived pinholes in the barrier but rather has more fundamental grounds. We argue that it originates from a universal bimodal distribution of transparencies across the aluminum oxide barrier proposed earlier by Schep and Bauer (1997 Phys. Rev. Lett. 78 3015). We suggest a simple physical explanation of its source in the nanometer-thick oxide films relating it to strong local barrier-height fluctuations in the nearest to conducting electrode layers of the insulator which are generated by oxygen vacancies in thin aluminum oxide tunnel barriers formed by thermal oxidation.
MODELING THE AFTERGLOW OF THE POSSIBLE FERMI-GBM EVENT ASSOCIATED WITH GW150914

We model the possible afterglow of the Fermi Gamma-ray Burst Monitor (GBM) event associated with LIGO detection GW150914, under the assumption that the gamma-rays are produced by a short GRB-like relativistic outflow. We model GW150914-GBM as both a weak, on-axis short GRB and normal short GRB seen far off-axis. Given the large uncertainty in the position of GW150914, we determine that the best chance of finding the afterglow is with ASKAP or possibly the Murchinson Widefield Array (MWA), with the flux from an off-axis short GRB reaching 0.2–4 mJy (0.12–16 mJy) at 150 MHz (863.5 MHz) by 1–12 months after the initial event. At low frequencies, the source would evolve from a hard to soft spectrum over several months. The radio afterglow would be detectable for several months to years after it peaks, meaning the afterglow may still be detectable and increasing in brightness NOW (2016 mid-July). With a localization from the MWA or ASKAP, the afterglow would be detectable at higher radio frequencies with the ATCA and in X-rays with Chandra or XMM.
EXCLUSION OF COSMIC RAYS IN PROTOPLANETARY DISKS. II. CHEMICAL GRADIENTS AND OBSERVATIONAL SIGNATURES

The chemical properties of protoplanetary disks are especially sensitive to their ionization environment. Sources of molecular gas ionization include cosmic rays (CRs), stellar X-rays, and short-lived radionuclides, each of which varies with location in the disk. This behavior leads to a significant amount of chemical structure, especially in molecular ion abundances, which is imprinted in their submillimeter rotational line emission. Using an observationally motivated disk model, we make predictions for the dependence of chemical abundances on the assumed properties of the ionizing field. We calculate the emergent line intensity for abundant molecular ions and simulate sensitive observations with the Atacama Large Millimeter/Sub-millimeter Array (ALMA) for a disk at D = 100 pc. The models readily distinguish between high ionization rates (ζ ≳ 10−17 s−1 per H2) and below, but it becomes difficult to distinguish between low ionization models when ζ ≲ 10−19 s−1. We find that H2D+ emission is not detectable for sub-interstellar CR rates with ALMA (6h integration), and that N2D+ emission may be a more sensitive tracer of midplane ionization. HCO+ traces X-rays and high CR rates (ζCR ≳ 10−17 s−1), and provides a handle on the warm molecular ionization properties where CO is present in the gas. Furthermore, species like HCO+, which emits from a wide radial region and samples a large gradient in temperature, can exhibit ring-like emission as a consequence of low-lying rotational level de-excitation near the star. This finding highlights a scenario where rings are not necessarily structural or chemical in nature, but simply a result of the underlying line excitation properties.
Fundamental properties of Fanaroff-Riley type II radio galaxies investigated via Monte Carlo simulations

Radio galaxies and quasars are among the largest and most powerful single objects known and are believed to have had a significant impact on the evolving Universe and its large-scale structure. We explore the intrinsic and extrinsic properties of the population of Fanaroff–Riley type II (FR II) objects, i.e. their kinetic luminosities, lifetimes and the central densities of their environments. In particular, the radio and kinetic luminosity functions of these powerful radio sources are investigated using the complete, flux-limited radio catalogues of the Third Cambridge Revised Revised Catalogue (3CRR) and Best et al. We construct multidimensional Monte Carlo simulations using semi-analytical models of FR II source time evolution to create artificial samples of radio galaxies. Unlike previous studies, we compare radio luminosity functions found with both the observed and simulated data to explore the best-fitting fundamental source parameters. The new Monte Carlo method we present here allows us to (i) set better limits on the predicted fundamental parameters of which confidence intervals estimated over broad ranges are presented and (ii) generate the most plausible underlying parent populations of these radio sources. Moreover, as has not been done before, we allow the source physical properties (kinetic luminosities, lifetimes and central densities) to co-evolve with redshift, and we find that all the investigated parameters most likely undergo cosmological evolution. Strikingly, we find that the break in the kinetic luminosity function must undergo redshift evolution of at least (1 + z) 3 . The fundamental parameters are strongly degenerate, and independent constraints are necessary to draw more precise conclusions. We use the estimated kinetic luminosity functions to set constraints on the duty cycles of these powerful radio sources. A comparison of the duty cycles of powerful FR IIs with those determined from radiative luminosities of active galactic nuclei of comparable black hole mass suggests a transition in behaviour from high to low redshifts, corresponding to either a drop in the typical black hole mass of powerful FR IIs at low redshifts, or a transition to a kinetically dominated, radiatively inefficient FR II population.
ON THE STABILITY OF A GALACTIC DISK IN MODIFIED GRAVITY

We find the dispersion relation for tightly wound spiral density waves in the surface of rotating, self-gravitating disks in the framework of Modified Gravity (MOG). Also, the Toomre-like stability criterion for differentially rotating disks has been derived for both fluid and stellar disks. More specifically, the stability criterion can be expressed in terms of a matter density threshold over which the instability occurs. In other words the local stability criterion can be written as &Sgr; 0 < &Sgr; crit ( v s , κ , &agr; , &mgr; 0 ) ? > , where &Sgr; crit ? > is a function of vs (sound speed), κ (epicycle frequency) and α and &mgr; 0 ? > are the free parameters of the theory. In the case of a stellar disk the radial velocity dispersion &sgr; r ? > appears in &Sgr; crit ? > instead of vs. We find the exact form of the function &Sgr; crit ? > for both stellar and fluid self-gravitating disks. Also, we use a sub-sample of THINGS catalog of spiral galaxies in order to compare the local stability criteria. In this perspective, we have compared MOG with Newtonian gravity and investigated the possible and detectable differences between these theories.
IMPLEMENTATION OF SINK PARTICLES IN THE ATHENA CODE

We describe the implementation and tests of sink particle algorithms in the Eulerian grid-based code Athena. The introduction of sink particles enables the long-term evolution of systems in which localized collapse occurs, and it is impractical (or unnecessary) to resolve the accretion shocks at the centers of collapsing regions. We discuss the similarities and differences of our methods compared to other implementations of sink particles. Our criteria for sink creation are motivated by the properties of the Larson–Penston collapse solution. We use standard particle-mesh methods to compute particle and gas gravity together. Accretion of mass and momenta onto sinks is computed using fluxes returned by the Riemann solver. A series of tests based on previous analytic and numerical collapse solutions is used to validate our method and implementation. We demonstrate use of our code for applications with a simulation of planar converging supersonic turbulent flow, in which multiple cores form and collapse to create sinks; these sinks continue to interact and accrete from their surroundings over several Myr.
Large-scale behavior of the partial duplication random graph

The following random graph model was introduced for the evolution of protein-protein interaction networks: Let $\mathcal G = (G_n)_{n=n_0, n_0+1,. }$ be a sequence of random graphs, where $G_n = (V_n, E_n)$ is a graph with $|V_n|=n$ vertices, $n=n_0,n_0+1,. $ In state $G_n = (V_n, E_n)$, a vertex $v\in V_n$ is chosen from $V_n$ uniformly at random and is partially duplicated. Upon such an event, a new vertex $v'\notin V_n$ is created and every edge $\{v,w\} \in E_n$ is copied with probability~$p$, i.e.\ $E_{n+1}$ has an edge $\{v',w\}$ with probability~$p$, independently of all other edges. Within this graph, we study several aspects for large~$n$. (i) The frequency of isolated vertices converges to~1 if $p\leq p^* \approx 0.567143$, the unique solution of $pe^p=1$. (ii) The number $C_k$ of $k$-cliques behaves like $n^{kp^{k-1}}$ in the sense that $n^{-kp^{k-1}}C_k$ converges against a non-trivial limit, if the starting graph has at least one $k$-clique. In particular, the average degree of a vertex (which equals the number of edges -- or 2-cliques -- divided by the size of the graph) converges to $0$ iff $p<0.5$ and we obtain that the transitivity ratio of the random graph is of the order $n^{-2p(1-p)}$. (iii) The evolution of the degrees of the vertices in the initial graph can be described explicitly. Here, we obtain the full distribution as well as convergence results.
Truths and Myths About the Finance-Growth Nexus in China: A Meta-Analysis

ABSTRACT Drawing on a unique dataset of 520 estimates from 32 studies, we analyze the effect of financial development on economic growth in China quantitatively using a meta-regression analysis. We find that the effect of financial development on economic growth, corrected for publication biases, is positive and statistically significant and that banking-sector development plays a dominant role in the economic growth of China. Moreover, there is weak evidence of the existence of Type-I publication bias and strong evidence of the existence of Type-II publication bias. We also find that sample size, the language of the studies, the empirical model, and the use of data from different regions are the sources of the heterogeneity of the estimates.
INVESTIGATION OF THE PUZZLING ABUNDANCE PATTERN IN THE STARS OF THE FORNAX DWARF SPHEROIDAL GALAXY

Many works have found unusual characteristics of elemental abundances in nearby dwarf galaxies. This implies that there is a key factor of galactic evolution that is different from that of the Milky Way (MW). The chemical abundances of the stars in the Fornax dwarf spheroidal galaxy (Fornax dSph) provide excellent information for setting constraints on the models of galactic chemical evolution. In this work, adopting the five-component approach, we fit the abundances of the Fornax dSph stars, including α elements, iron group elements, and neutron-capture elements. For most sample stars, the relative contributions from the various processes to the elemental abundances are not usually in the MW proportions. We find that the contributions from massive stars to the primary α elements and iron group elements increase monotonically with increasing [Fe/H]. This means that the effect of the galactic wind is not strong enough to halt star formation and the contributions from the massive stars to α elements did not halt for [Fe/H] ≲ −0.5. The average contribution ratios of various processes between the dSph stars and the MW stars monotonically decrease with increasing progenitor mass. This is important evidence of a bottom-heavy initial mass function (IMF) for the Fornax dSph, compared to the MW. Considering a bottom-heavy IMF for the dSph, the observed relations of [α/Fe] versus [Fe/H], [iron group/Fe] versus [Fe/H], and [neutron-capture/Fe] versus [Fe/H] for the dSph stars can be explained.
Accretion-driven turbulence as universal process: galaxies, molecular clouds, and protostellar disks

Context. Even though turbulent motions are found everywhere in astrophysical systems, the origin of this turbulence is poorly understood. When cosmic structures form, they grow in mass via accretion from their surrounding environment. Aims. We propose that accretion is able to drive internal turbulent motions in a wide range of astrophysical objects and study this process in the case of galaxies, molecular clouds, and protoplanetary disks. Methods. We use a combination of numerical simulations and analytical arguments to predict the level of turbulence as a function of the accretion rate, the dissipation scale, and the density contrast, and compare our models with observational data. Results. We find that in Milky Way type galaxies the observed level of turbulence in the interstellar medium can be explained by accretion, provided that the galaxies gain mass at a rate comparable to the rate at which they form stars. This process is particularly relevant in the extended outer disks beyond the star-forming radius. For it to drive turbulence in dwarf galaxies, the accretion rate needs to exceed the star formation rate by a large factor, so we expect other sources to dominate. We also calculate the rate at which molecular clouds grow in mass when they build up from the atomic component of the galactic gas and find that their internal turbulence is likely to be driven by accretion as well. It is the very process of cloud formation that excites turbulent motions on small scales by establishing the turbulent cascade. In the case of T Tauri disks, we show that accretion can drive subsonic turbulence if the rate at which gas falls onto the disk is comparable to the rate at which disk material accretes onto the central star. This also explains the observed relation of accretion rate and stellar mass, u M ∝ M 1.8 � . T he efficiency required to convert infall motion into turbulence is a few percent in all three cases. Conclusions. We conclude that accretion-driven turbulence is a universal concept with far-reaching implications for a wide range of astrophysical objects.