Miracle-dz/UniFAR-FTUs huggingface dataset:
THE X-RAY ENERGY DEPENDENCE OF THE RELATION BETWEEN OPTICAL AND X-RAY EMISSION IN QUASARS

We develop a new approach to the well-studied anti-correlation between the optical-to-X-ray spectral index, αox, and the monochromatic optical luminosity, lopt. By cross-correlating the Sloan Digital Sky Survey DR5 quasar catalog with the XMM-Newton archive, we create a sample of 327 quasars with X-ray signal-to-noise ratio (S/N) > 6, where both optical and X-ray spectra are available. This allows αox to be defined at arbitrary frequencies, rather than the standard 2500 Å and 2 keV. We find that while the choice of optical wavelength does not strongly influence the αox–lopt relation, the slope of the relation does depend on the choice of X-ray energy. The slope of the relation becomes steeper when αox is defined at low (∼1 keV) X-ray energies. This change is significant when compared to the slope predicted by a decrease in the baseline over which αox is defined. The slopes are also marginally flatter than predicted at high (∼10 keV) X-ray energies. Partial correlation tests show that while the primary driver of αox is lopt, the Eddington ratio correlates strongly with αox when lopt is taken into account, so accretion rate may help explain these results. We combine the αox–lopt and Γ–Lbol/LEdd relations to naturally explain two results: (1) the existence of the Γ–lx relation as reported in Young et al., and (2) the lack of a Γ–lopt relation. The consistency of the optical/X-ray correlations establishes a more complete framework for understanding the relation between quasar emission mechanisms. We also discuss two correlations with the hard X-ray bolometric correction, which we show correlates with both αox and Eddington ratio. This confirms that an increase in accretion rate correlates with a decrease in the fraction of up-scattered disk photons.
THE CONNECTING MOLECULAR RIDGE IN THE GALACTIC CENTER

We report new observations of multiple transitions of the CS molecular lines in the SgrA region of the Galactic center, at an angular resolution of 40″ (=1.5 pc). The objective of this paper is to study the polar arc (PA), which is a molecular ridge near the SgrA region with apparent non-coplanar motions and a velocity gradient perpendicular to the Galactic plane. With our high resolution dense-gas maps, we search for the base and the origin of the PA, which is expected to be embedded in the Galactic disk. We find that the PA is connected to a continuous structure from one of the disk rings/arms in both the spatial and velocity domains. This structure near SgrA* has high CS(J = 4–3)/CS(J = 2–1) ratios ≥ 1 . > The fact that this structure has eluded detection in previous observations is likely due to the combination of high excitation and low surface brightness temperature. We call this new structure the connecting ridge. We discuss the possible mechanism for forming this structure and for lifting the gas above the Galactic plane.
XMM–Newton discovery of mHz quasi-periodic oscillations in the high-mass X-ray binary IGR J19140+0951

We report on the discovery of mHz quasi-periodic oscillations (QPOs) from the high-mass X-ray binary (HMXB) IGR J19140+0951, during a 40 ks XMM–Newton observation performed in 2015, which caught the source in its faintest state ever observed. At the start of the observation, IGR J19140+0951 was at a low flux of 2 × 10−12 erg cm−2 s−1 (2–10 keV; LX = 3 × 1033 erg s−1 at 3.6 kpc), then its emission rose reaching a flux ∼10 times higher, in a flare-like activity. The investigation of the power spectrum reveals the presence of QPOs, detected only in the second part of the observation, with a strong peak at a frequency of 1.46 ± 0.07 mHz, together with higher harmonics. The X-ray spectrum is highly absorbed (NH = 1023 cm−2), well fitted by a power law with a photon index in the range 1.2–1.8. The re-analysis of a Chandra archival observation shows a modulation at ∼0.17 ± 0.05 mHz, very likely the neutron-star spin period (although a QPO cannot be excluded). We discuss the origin of the 1.46 mHz QPO in the framework of both disc-fed and wind-fed HMXBs, favouring the quasi-spherical accretion scenario. The low flux observed by XMM–Newton leads to about three orders of magnitude the source dynamic range, overlapping with the one observed from Supergiant Fast X-ray Transients (SFXTs). However, since its duty cycle is not as low as in SFXTs, IGR J19140+0951 is an intermediate system between persistent supergiant HMXBs and SFXTs, suggesting a smooth transition between these two sub-classes.
Stellar intensity interferometry: optimizing air Cherenkov telescope array layouts

Kilometric-scale optical imagers seem feasible to realize by intensity interferometry, using telescopes primarily erected for measuring Cherenkov light induced by gamma rays. Planned arrays envision 50-100 telescopes, distributed over some 1-4 km2. Although array layouts and telescope sizes will primarily be chosen for gamma-ray observations, also their interferometric performance may be optimized. Observations of stellar objects were numerically simulated for different array geometries, yielding signal-to-noise ratios for different Fourier components of the source images in the interferometric (u, v)-plane. Simulations were made for layouts actually proposed for future Cherenkov telescope arrays, and for subsets with only a fraction of the telescopes. All large arrays provide dense sampling of the (u, v)-plane due to the sheer number of telescopes, irrespective of their geographic orientation or stellar coordinates. However, for improved coverage of the (u, v)-plane and a wider variety of baselines (enabling better image reconstruction), an exact east-west grid should be avoided for the numerous smaller telescopes, and repetitive geometric patterns avoided for the few large ones. Sparse arrays become severely limited by a lack of short baselines, and to cover astrophysically relevant dimensions between 0.1-3 milliarcseconds in visible wavelengths, baselines between pairs of telescopes should cover the whole interval 30-2000 m.
NLO QCD corrections for W^+W^- pair production in association with two jets at hadron colliders

We compute the NLO QCD corrections to the pair production of W-bosons in association with two jets at the Tevatron and the LHC. This process is an important background to heavy Higgs-boson production in association with two jets, either in gluon or weak boson fusion. We consider leptonic decays of W-bosons and include all the spin correlations exactly. For natural choices of the renormalization scale, the NLO QCD corrections to pp(ppbar) -> W^+W^-jj are moderate but different for various values of the center-of-mass collision energy at the LHC and the Tevatron, emphasizing the need to compute them explicitly.
Milliarcsecond properties of 10C sources in the Lockman Hole

We have used recent Very Long Baseline Interferometry (VLBI) observations by Middelberg et al. with a resolution of $\approx 10$ mas to investigate the properties of faint sources selected from the Tenth Cambridge (10C) survey in the Lockman Hole. The 10C survey is complete to 0.5 mJy at 15.7 GHz and has a resolution of 30 arcsec. We have previously shown that this population is dominated by flat-spectrum sources below $\approx 1$ mJy, in disagreement with several models of the faint, high-frequency sky. We find that 33 out of the 51 10C sources in the VLBI field (65 percent) are detected by the VLBI observations. The sources detected by the VLBI observations must have a high brightness temperature, thus ruling out the possibility that this faint, high frequency population is dominated by starbursting or starforming sources and indicating that they must be Active Galactic Nuclei.
SUITES OF DWARFS AROUND NEARBY GIANT GALAXIES

The Updated Nearby Galaxy Catalog (UNGC) contains the most comprehensive summary of distances, radial velocities, and luminosities for 800 galaxies located within 11 Mpc from us. The high density of observables in the UNGC makes this sample indispensable for checking results of N-body simulations of cosmic structures on a ∼1 Mpc scale. The environment of each galaxy in the UNGC was characterized by a tidal index Θ1, depending on the separation and mass of the galaxy's main disturber (MD). We grouped UNGC galaxies with a common MD in suites, and ranked suite members according to their Θ1. All suite members with positive Θ1 are assumed to be physical companions of the MD. About 58% of the sample are members of physical groups. The distribution of suites by the number of members, n, follows a relation N(n) ∼ n−2. The 20 most populated suites contain 468 galaxies, i.e., 59% of the UNGC sample. The fraction of MDs among the brightest galaxies is almost 100% and drops to 50% at MB = −18m. We discuss various properties of MDs, as well as galaxies belonging to their suites. The suite abundance practically does not depend on the morphological type, linear diameter, or hydrogen mass of the MD, the tightest correlation being with the MD dynamical mass. Dwarf galaxies around MDs exhibit well-known segregation effects: the population of the outskirts has later morphological types, richer H i contents, and higher rates of star formation activity. Nevertheless, there are some intriguing cases where dwarf spheroidal galaxies occur at the far periphery of the suites, as well as some late-type dwarfs residing close to MDs. Comparing simulation results with galaxy groups, most studies assume the Local Group is fairly typical. However, we recognize that the nearby groups significantly differ from each other and there is considerable variation in their properties. The suites of companions around the Milky Way and M31, consisting of the Local Group, do not quite seem to be a typical nearby group. The multiplicity of nearby groups of the number of their physical members can be described by the Hirsh-like index hg = 9, indicating that the Local Volume contains nine groups with populations exceeding nine companions to their MDs.
Secular resonant dressed orbital diffusion I : method and WKB limit for tepid discs

The equation describing the secular diffusion of a self-gravitating collisionless system induced by an exterior perturbation is derived while assuming that the time-scale corresponding to secular evolution is much larger than that corresponding to the natural frequencies of the system. Its two-dimensional formulation for a tepid galactic disc is also derived using the epicyclic approximation. Its Wentzel-Kramers-Brillouin (WKB) limit is found while assuming that only tightly wound transient spirals are sustained by the disc. It yields a simple quadrature for the diffusion coefficients which provides a straightforward understanding of the loci of maximal diffusion within the disc.
Photocurrent enhancement of graphene photodetectors by photon tunneling of light into surface plasmons

We demonstrate that surface plasmon resonances excited by photon tunneling through an adjacent dielectric medium enhance the photocurrent detected by a graphene photodetector. The device is created by overlaying a graphene sheet over an etched gap in a gold film deposited on glass. The detected photocurrents are compared for five different excitation wavelengths, ranging from λ 0 = 570 nm to λ 0 = 730 nm . Although the device is not optimized, the photocurrent excited with incident p-polarized light (which excites resonant surface plasmons) is significantly amplified in comparison with that for s-polarized light (without surface plasmon resonances). We observe that the photocurrent is greater for shorter wavelengths (for both s- and p -polarizations) with increased photothermal current. Position-dependent Raman spectroscopic analysis of the optically-excited graphene photodetector indicates the presence of charge carriers in the graphene near the metallic edge. In addition, we show that the polarity of the photocurrent reverses across the gap as the incident light spot moves across the gap. Graphene-based photodetectors offer a simple architecture which can be fabricated on dielectric waveguides to exploit the plasmonic photocurrent enhancement of the evanescent field. Applications for these devices include photodetection, optical sensing and direct plasmonic detection.
Constraining the thermally pulsing asymptotic giant branch phase with resolved stellar populations in the Large Magellanic Cloud

Reliable models of the thermally pulsing asymptotic giant branch (TP-AGB) phase are of critical importance across astrophysics, including our interpretation of the spectral energy distribution of galaxies, cosmic dust production, and enrichment of the interstellar medium. With the aim of improving sets of stellar isochrones that include a detailed description of the TP-AGB phase, we extend our recent calibration of the AGB population in the Small Magellanic Cloud (SMC) to the more metal-rich Large Magellanic Cloud (LMC). We model the LMC stellar populations with the trilegal code, using the spatially resolved star formation history derived from the VISTA survey. We characterize the efficiency of the third dredge-up by matching the star counts and the Ks-band luminosity functions of the AGB stars identified in the LMC. In line with previous findings, we confirm that, compared to the SMC, the third dredge-up in AGB stars of the LMC is somewhat less efficient, as a consequence of the higher metallicity. The predicted range of initial mass of C-rich stars is between Mi ≈ 1.7 and 3 M⊙ at Zi = 0.008. We show how the inclusion of new opacity data in the carbon star spectra will improve the performance of our models. We discuss the predicted lifetimes, integrated luminosities, and mass-loss rate distributions of the calibrated models. The results of our calibration are included in updated stellar isochrones publicly available.
The Pareto Argument for Inequality Revisited 1

: one of the more obscure arguments for Rawls’ difference principle dubbed ‘the Pareto argument for inequality’ has been criticised by G. A. Cohen (1995, 2008) as being inconsistent. In this paper, we examine and clarify the Pareto argument in detail and argue (1) that justification for the Pareto principles derives from rational self-interest and thus the Pareto principles ought to be understood as conditions of individual rationality , (2) that the Pareto argument is not inconsistent, contra Cohen, and (3) that the kind of bargaining model required to arrive at the particular unequal distribution that the difference principle picks out is a model that is not based on bargaining according to one’s threat advantage. The Pareto argument for Inequality is one of the more obscure arguments for Rawls’ difference principle found in A Theory of Justice . Put briefly, the argument justifies a particular deviation from an initial equal distribution of primary social goods that is ultimately unequal so long as everyone is made better off from this deviation. The argument itself is arguably the ‘more fundamental’ and ‘more direct’ argument for the difference principle. 2 In addition, we say, it is one of the ‘strongest’ arguments for the difference principle since by not appealing to the original position it is immune to any objections that are derived from decision-making procedures under conditions of (complete) uncertainty. 3
The contribution of the $\rho^0 - \omega$ interference to the violation of the isospin invariance in the $\pi N$ system

It is generally believed that the $\rho^0 - \omega$ interference is the dominant mechanism underlying the violation of the isospin invariance in the $N N$ system. Assessed in this paper is the role which the mechanism might play in a potential departure from the isospin symmetry in the two $\pi^\pm p$ elastic-scattering reactions.
Wrapping effects in supersymmetric gauge theories

Several perturbative computations of finite‐size effects, performed on the gauge side of the AdS/CFT correspondence by means of superspace techniques, are presented. First, wrapping effects are analyzed in the standard 𝒩 = 4 theory, by means of the calculation of the four‐loop anomalous dimension of the Konishi operator. Then, a similar computation at five loops is described. Afterwards, finite‐size effects are studied in the β‐deformed case, where thanks to the reduced number of supersymmetries the simpler class of single‐impurity operators can be considered, so that the leading corrections to the anomalous dimensions at generic order can be reduced to the computation of a class of integrals. Explicit results are given up to eleven loops. A further chapter is dedicated to the computation of the leading finite‐size effects on operators dual to open strings. In the end, some comments are made and proposals for future developments are discussed.
MULTIPLICITY AND PERIOD DISTRIBUTION OF POPULATION II FIELD STARS IN SOLAR VICINITY

We examine a sample of 223 F, G, and early K metal-poor subdwarfs ([m/H] < −1) with high proper motions (μ>0.″2 yr−1) at distances of up to 250 pc from the Sun. By means of our own speckle interferometric observations conducted on the 6 m Bolshoi Azimuthal Telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences, and the spectroscopic and visual data taken from the literature, we determine the frequency of binary and multiple systems in this sample. The ratio of single, binary, triple, and quadruple systems among 221 primary components of the sample is 147:64:9:1. We show that the distribution of orbital periods of binary and multiple subdwarfs is asymmetric in the range of up to P = 1010 days, and has a maximum at P = 102–103 days, which differs from the distribution, obtained for the thin disk G dwarfs. We estimated the number of undetected companions in our sample. Comparing the frequency of binary subdwarfs in the field and in the globular clusters, we show that the process of halo field star formation by the means of destruction of globular clusters is very unlikely in our Galaxy. We discuss the multiplicity of old metal-poor stars in nearby stellar streams.
Near-infrared [Fe ii] and H2 Emission-line Study of Galactic Supernova Remnants in the First Quadrant

We report the detection of near-infrared (NIR) [Fe ii] (1.644 μm) and H2 1–0 S(1) (2.122 μm) line features associated with Galactic supernova remnants (SNRs) in the first quadrant using two narrowband imaging surveys, UWIFE and UWISH2. Among the total of 79 SNRs fully covered by both surveys, we found 19 [Fe ii]-emitting and 19 H2-emitting SNRs, giving a detection rate of 24% for each. Eleven SNRs show both emission features. The detection rate of [Fe ii] and H2 peaks at the Galactic longitude (l) of 40°–50° and 30°–40°, respectively, and gradually decreases toward smaller/larger l. Five out of the eleven SNRs emitting both emission lines clearly show an “[Fe ii]–H2 reversal,” where H2 emission features are found outside the SNR boundary in [Fe ii] emission. Our NIR spectroscopy shows that the H2 emission originates from collisionally excited H2 gas. The brightest SNR in both [Fe ii] and H2 emissions is W49B, contributing more than 70% and 50% of the total [Fe ii] 1.644 μm (2.0 × 104 L ⊙ ) and H2 2.122 μm (1.2 × 103 L ⊙ ) luminosities of the detected SNRs. The total [Fe ii] 1.644 μm luminosity of our Galaxy is a few times smaller than that expected from the SN rate using the correlation found in nearby starburst galaxies. We discuss possible explanations for this.
Primordial fluctuations from complex AdS saddle points

One proposal for dS/CFT is that the Hartle-Hawking (HH) wave function in the large volume limit is equal to the partition function of a Euclidean CFT deformed by various operators. All saddle points defining the semiclassical HH wave function in cosmology have a representation in which their interior geometry is part of a Euclidean AdS domain wall with complex matter fields. We compute the wave functions of scalar and tensor perturbations around homogeneous isotropic complex saddle points, turning on single scalar field matter only. We compare their predictions for the spectra of CMB perturbations with those of a different dS/CFT proposal based on the analytic continuation of inflationary universes to real asymptotically AdS domain walls. We find the predictions of both bulk calculations agree to first order in the slow roll parameters, but there is a difference at higher order which, we argue, is a signature of the HH state of the fluctuations.
Star formation triggered by galaxy interactions in modified gravity

Together with interstellar turbulence, gravitation is one key player in star formation. It acts both at galactic scales in the assembly of gas into dense clouds, and inside those structures for their collapse and the formation of pre-stellar cores. To understand to what extent the large scale dynamics govern the star formation activity of galaxies, we present hydrodynamical simulations in which we generalise the behaviour of gravity to make it differ from Newtonian dynamics in the low acceleration regime. We focus on the extreme cases of interacting galaxies, and compare the evolution of galaxy pairs in the dark matter paradigm to that in the Milgromian Dynamics (MOND) framework. Following up on the seminal work by Tiret & Combes, this paper documents the first simulations of galaxy encounters in MOND with a detailed Eulerian hydrodynamical treatment of baryonic physics, including star formation and stellar feedback. We show that similar morphologies of the interacting systems can be produced by both the dark matter and MOND formalisms, but require a much slower orbital velocity in the MOND case. Furthermore, we find that the star formation activity and history are significantly more extended in space and time in MOND interactions, in particular in the tidal debris. Such differences could be used as observational diagnostics and make interacting galaxies prime objects in the study of the nature of gravitation at galactic scales.
Measurement of Collins asymmetries in inclusive production of charged pion pairs in e^+e^- annihilation at BABAR

We present measurements of Collins asymmetries in the inclusive process e+e- -->pi pi X, where pi stands for charged pions, at a center-of-mass energy of 10.6 GeV. We use a data sample of 468 fb-1 collected by the BABAR experiment at the PEP-II B factory at SLAC, and consider pairs of charged pions produced in opposite hemispheres of hadronic events. We observe clear asymmetries in the distributions of the azimuthal angles in two distinct reference frames. We study the dependence of the asymmetry on several kinematic variables, finding that it increases with increasing pion momentum and momentum transverse to the analysis axis, and with increasing angle between the thrust and beam axis.
NATURE OF THE WIGGLE INSTABILITY OF GALACTIC SPIRAL SHOCKS

Gas in disk galaxies interacts nonlinearly with an underlying stellar spiral potential to form galactic spiral shocks. While numerical simulations typically show that spiral shocks are unstable to wiggle instability (WI) even in the absence of magnetic fields and self-gravity, its physical nature has remained uncertain. To clarify the mechanism behind the WI, we conduct a normal-mode linear stability analysis and nonlinear simulations assuming that the disk is isothermal and infinitesimally thin. We find that the WI is physical, originating from the generation of potential vorticity at a deformed shock front, rather than Kelvin–Helmholtz instabilities as previously thought. Since gas in galaxy rotation periodically passes through the shocks multiple times, the potential vorticity can accumulate successively, setting up a normal mode that grows exponentially with time. Eigenfunctions of the WI decay exponentially downstream from the shock front. Both shock compression of acoustic waves and a discontinuity of shear across the shock stabilize the WI. The wavelength and growth time of the WI depend on the arm strength quite sensitively. When the stellar-arm forcing is moderate at 5%, the wavelength of the most unstable mode is about 0.07 times the arm-to-arm spacing, with the growth rate comparable to the orbital angular frequency, which is found to be in good agreement with the results of numerical simulations.