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Much remains to be understood about the nature of exoplanets smaller than Neptune, most of which have been discovered in compact multi-planet systems. With its inner ultra-short period planet b aligned with the star and two larger outer planets d-c on polar orbits, the multi-planet system HD 3167 features a peculiar architecture and offers the possibility to investigate both dynamical and atmospheric evolution processes. To this purpose we combined multiple datasets of transit photometry and radial velocimetry (RV) to revise the properties of the system and inform models of its planets. This effort was spearheaded by CHEOPS observations of HD 3167b, which appear inconsistent with a purely rocky composition despite its extreme irradiation. Overall the precision on the planetary orbital periods are improved by an order of magnitude, and the uncertainties on the densities of the transiting planets b and c are decreased by a factor of 3. Internal structure and atmospheric simulations draw a contrasting picture between HD 3167d, likely a rocky super-Earth that lost its atmosphere through photo-evaporation, and HD 3167c, a mini-Neptune that kept a substantial primordial gaseous envelope. We detect a fourth, more massive planet on a larger orbit, likely coplanar with HD 3167d-c. Dynamical simulations indeed show that the outer planetary system d-c-e was tilted, as a whole, early in the system history, when HD 3167b was still dominated by the star influence and maintained its aligned orbit. RV data and direct imaging rule out that the companion that could be responsible for the present-day architecture is still bound to the HD\,3167 system. Similar global studies of multi-planet systems will tell how many share the peculiar properties of the HD3167 system, which remains a target of choice for follow-up observations and simulations., Comment: 22 pages, 23 pages, accepted for publication in A&A (18 August 2022). Updated author list in new version

We present a unified framework for the study of wave propagation in homogeneous linear thermo-visco-elastic (TVE) continua, starting from conservation laws. In free-space such media admit two thermo-compressional modes and a shear mode. We provide asymptotic approximations to the corresponding wavenumbers which facilitate the understanding of dispersion of these modes, and consider common solids and fluids as well as soft materials where creep compliance and stress relaxation are important. We further illustrate how commonly used simpler acoustic/elastic dissipative theories can be derived via particular limits of this framework. Consequently, our framework allows us to: i) simultaneously model interfaces involving both fluids and solids, and ii) easily quantify the influence of thermal or viscous losses in a given configuration of interest. As an example, the general framework is applied to the canonical problem of scattering from an interface between two TVE half spaces in perfect contact. To illustrate, we provide results for fluid-solid interfaces involving air, water, steel and rubber, paying particular attention to the effects of stress relaxation., Comment: Accepted in Proceedings of the Royal Society A

In this review, we discuss various open-source software for modelling the broad-band emission of extragalactic sources from radio up to the highest gamma ray energies. As we provide an overview of the different tools available, we discuss the physical processes such tools implement and detail the computations they can perform. We also examine their conformity with modern good software practices. After considering the currently available software as a first generation of open-source modelling tools, we outline some desirable characteristics for the next generation., Comment: Accepted for publication in Galaxies. Included in the special issue https://www.mdpi.com/journal/galaxies/special_issues/TeVAstronomy

Achieving the regime of single-photon nonlinearities in photonic devices just exploiting the intrinsic high-order susceptibilities of conventional materials would open the door to practical semiconductor-based quantum photonic technologies. Here we show that this regime can be achieved in a triply resonant integrated photonic device made of two coupled ring resonators, without necessarily requiring low volume confinement, in a material platform displaying an intrinsic third-order nonlinearity. By strongly driving one of the three resonances of the system, a weak coherent probe at one of the others results in a strongly suppressed two-photon probability at the output, evidenced by antibunched second-order correlation function at zero-time delay under continuous wave driving.

Microgel particles composed of Interpenetrated Polymer Networks (IPN) of poly(N-isopropylacrylamide) (PNIPAM) and poly(acrylic acid) (PAAc) dispersed in water have been investigated through dynamic light scattering. The study of the temperature, concentration and pH dependence of the relaxation time has highlighted the existence of a thermoreversible transition corresponding to the swollen-shrunken volume phase transition. The presence of PAAc introduces an additional pH-sensitivity with respect to the temperature-sensitivity due to PNIPAM and leads to interesting differences in the transition process at acid and neutral pH.

We revisit Haiman's conjecture on the relations between characters of Kazdhan-Lusztig basis elements of the Hecke algebra over the symmetric group. The conjecture asserts that, for purposes of character evaluation, any Kazhdan-Lusztig basis element is reducible to a sum of the simplest possible ones (those associated to so-called codominant permutations). When the basis element is associated to a smooth permutation, we are able to give a geometric proof of this conjecture. On the other hand, if the permutation is singular, we provide a counterexample., Comment: 14 pages

In this paper, we investigate the electrical evolution of tungsten (W) and tungsten carbide (WC) Schottky contacts on 4H-SiC subjected to thermal treatments at different annealing temperatures from 475 to 700 {\deg} C. For each annealing temperature, the uniformity of the Schottky barrier height (${\phi_B}$) and ideality factor (n) was monitored by current-voltage (I-V) measurements in forward bias, performed over sets of equivalent diodes. Good values of n (below 1.05) were found for both contacts up to thermal annealing at 700 {\deg} C. On the other hand, the barrier of the two contacts behaves differently. For the W/4H-SiC diode, the ${\phi_B}$ increases with the annealing temperature (from 1.14 eV at 475 {\deg} C to 1.25 eV at 700 {\deg} C), whereas the Schottky barrier in WC/4H-SiC features a slight reduction already with thermal annealing at 475 {\deg} C, remaining almost constant at around 1.06 eV up to annealing at 700 {\deg} C. A deeper characterization was performed on the 700 {\deg} C-annealed contacts by studying the temperature-dependence of the Schottky parameters by current-voltage-temperature (I-V-T) characterization. The ${\phi_B}$ and n behaviour with temperature indicates the presence of a nanoscale lateral inhomogeneity for both Schottky contacts, which can be described by Tung's model. Finally, the temperature-dependence of the reverse characteristics could be described by the thermionic field emission model (TFE), accounting for the temperature dependent barrier height determined from forward characterization., Comment: 10 pages, 10 figures

To any element of a connected, simply connected, semisimple complex algebraic group G and a choice of an element of the corresponding Weyl group there is an associated Lusztig variety. When the element of G is regular semisimple, the corresponding variety carries an action of the Weyl group on its (equivariant) intersection cohomology. From this action, we recover the induced characters of an element of the Kazhdan-Lusztig basis of the corresponding Hecke algebra. In type A, we prove a more precise statement: that the Frobenius character of this action is precisely the symmetric function given by the characters of a Kazhdan-Lusztig basis element. The main idea is to find celular decompositions of desingularizations of these varieties and apply the Brosnan-Chow palindromicity criterion for determining when the local invariant cycle map is an isomorphism. This recovers some results of Lusztig about character sheaves and gives a generalization of the Brosnan-Chow solution to the Sharesian-Wachs conjecture to non-codominant permutations, where singularities are involved. We also review the connections between Immanants, Hecke algebras, and Chromatic quasisymmetric functions of indifference graphs., Comment: 70 pages

Using a combination of multipole methods and the method of matched asymptotics, we present a solution procedure for acoustic plane wave scattering by a single Helmholtz resonator in two dimensions. Closed-form representations for the multipole scattering coefficients of the resonator are derived, valid at low frequencies, with three fundamental configurations examined in detail: the thin-walled, moderately thick-walled, and very thick-walled limits. Additionally, we examine the impact of dissipation for very thick-walled resonators, and also numerically evaluate the scattering, absorption, and extinction cross sections (efficiencies) for representative resonators in all three wall thickness regimes. In general, we observe strong enhancement in both the scattered fields and cross sections at the Helmholtz resonance frequencies. As expected, dissipation is shown to shift the resonance frequency, reduce the amplitude of the field, and reduce the extinction efficiency at the fundamental Helmholtz resonance. Finally, we confirm results in the literature on Willis-like coupling effects for this resonator design, and crucially, connect these findings to earlier works by the authors on two-dimensional arrays of resonators, deducing that depolarisability effects (off-diagonal terms) for a single resonator do not ensure the existence of Willis coupling effects (bianisotropy) in bulk., Comment: 24 pages, 7 figures

The phase behaviour of soft colloids has attracted great attention due to the large variety of new phenomenologies emerging from their ability to pack at very high volume fractions. Here we report rheological measurements on interpenetrated polymer network microgels composed of poly(Nisopropylacrylamide) (PNIPAM) and polyacrylic acid (PAAc) at fixed PAAc content as a function of weight concentration. We found three different rheological regimes characteristic of three different states: a Newtonian shear-thinning fluid, an attractive glass characterized by a yield stress, and a jamming state. We discuss the possible molecular mechanisms driving the formation of these states.

Interpenetrated polymer network microgels, composed of crosslinked networks of poly(N-isopropylacrylamide) and polyacrylic acid (PAAc), have been investigated through rheological measurements at four different amounts of polyacrylic acid. Both PAAc content and crosslinking degree modify particle dimensions, mass and softness, thereby strongly affecting the volume fraction and the system viscosity. Here the volume fraction is derived from the flow curves at low concentrations by fitting the zero-shear viscosity with the Einstein-Batchelor equation which provides a parameter k to shift weight concentration to volume fraction. We find that particles with higher PAAc content and crosslinker are characterized by a greater value of k and therefore by larger volume fractions when compared to softer particles. The packing fractions obtained from rheological measurements are compared with those from static light scattering for two PAAc contents revealing a good agreement. Moreover, the behaviour of the viscosity as a function of packing fraction, at room temperature, has highlighted an Arrhenius dependence for microgels synthesized with low PAAc content and a Vogel-Fulcher-Tammann dependence for the highest investigated PAAc concentration. A comparison with the hard spheres behaviour indicates a steepest increase of the viscosity with decreasing particles softness. Finally, the volume fraction dependence of the viscosity at a fixed PAAc and at two different temperatures, below and above the volume phase transition, shows a quantitative agreement with the structural relaxation time measured through dynamic light scattering indicating that IPN microgels softness can be tuned with PAAc and temperature and that, depending on particle softness, two different routes are followed.

Classical novae are cataclysmic binary star systems in which the matter of a companion star is accreted on a white dwarf (WD). Accumulation of hydrogen in a layer eventually causes a thermonuclear explosion on the surface of the WD, brightening the WD to ~10^5 solar luminosities and triggering ejection of the accumulated matter.They provide extreme conditions required to accelerate particles, electrons or protons, to high energies. Here we present the detection of gamma rays by the MAGIC telescopes from the 2021 outburst of RS Ophiuchi (RS Oph), a recurrent nova with a red giant (RG) companion, that allowed us, for the first time, to accurately characterize the emission from a nova in the 60 GeV to 250 GeV energy range. The theoretical interpretation of the combined Fermi-LAT and MAGIC data suggests that protons are accelerated to hundreds of GeV in the nova shock. Such protons should create bubbles of enhanced Cosmic Ray density, on the order of 10 pc, from the recurrent novae., Comment: THIS VERSION IS AFTER THE JOURNAL REVIEW

The blazar TXS 0506+056 got into the spotlight of the astrophysical community in September 2017, when a high-energy neutrino detected by IceCube (IceCube-170922A) was associated at the 3 $\sigma$ level to a $\gamma$-ray flare from this source. This multi-messenger photon-neutrino association remains, as per today, the most significant one ever observed. TXS 0506+056 was a poorly studied object before the IceCube-170922A event. To better characterize its broad-band emission, we organized a multi-wavelength campaign lasting 16 months (November 2017 to February 2019), covering the radio-band (Mets\"ahovi, OVRO), the optical/UV (ASAS-SN, KVA, REM, Swift/UVOT), the X-rays (Swift/XRT, NuSTAR), the high-energy $\gamma$ rays (Fermi/LAT) and the very-high-energy (VHE) $\gamma$ rays (MAGIC). In $\gamma$ rays, the behaviour of the source was significantly different from the 2017 one: MAGIC observations show the presence of flaring activity during December 2018, while the source only shows an excess at the 4$\sigma$ level during the rest of the campaign (74 hours of accumulated exposure); Fermi/LAT observations show several short (days-to-week timescale) flares, different from the long-term brightening of 2017. No significant flares are detected at lower energies. The radio light curve shows an increasing flux trend, not seen in other wavelengths. We model the multi-wavelength spectral energy distributions in a lepto-hadronic scenario, in which the hadronic emission emerges as Bethe-Heitler and pion-decay cascade in the X-rays and VHE $\gamma$ rays. According to the model presented here, the December 2018 $\gamma$-ray flare was connected to a neutrino emission that was too brief and not bright enough to be detected by current neutrino instruments., Comment: 18 pages, 6 figures; V2 to match published version, typo fixed

We investigate the relationship between different transients such as blinkers detected in images taken at 304~{\AA}, extreme ultraviolet coronal bright points (ECBPs) at 193~{\AA}, X-ray coronal bright points (XCBPs) at 94~{\AA} on AIA, and magnetic features observed by HMI during ten years of solar cycle 24. An automatic identification method is applied to detect transients, and the YAFTA algorithm is used to extract the magnetic features. Using ten years of data, we detect in total 7,483,827 blinkers, 2,082,162 ECBPs, and 1,188,839 XCBPs, respectively, with their birthrate of about $1.1\times10^{-18}$ ${\rm m}^{-2}{\rm s}^{-1}$, $3.8\times10^{-19}$ ${\rm m}^{-2}{\rm s}^{-1}$, and $1.5\times10^{-19}$ ${\rm m}^{-2}{\rm s}^{-1}$. We find that about 80\% of blinkers are observed at the boundaries of supergranules, and 57\% (34\%) are associated with ECBPs (XCBPs). We further find that about 61{--}80\% of transients are associated with the isolated magnetic poles in the quiet Sun and that \textbf{the normalized maximum intensities of the transients are correlated with photospheric magnetic flux of poles} via a power law. These results conspicuously show that these transients have a magnetic origin and their synchronized behavior provides further clues towards the understanding of the coupling among the different layers of the solar atmosphere. Our study further reveals that the appearance of these transients is strongly anti-correlated with the sunspots cycle. This finding can be relevant for a better understanding of solar dynamo and magnetic structures at different scales during the solar cycle.

Modelling the broadband emission of jetted active galactic nuclei (AGN) constitutes one of the main research topics of extragalactic astrophysics in the multi-wavelength and multi-messenger domain. We present agnpy, an open-source python package modelling the radiative processes of relativistic particles accelerated in the jets of active galactic nuclei. The package includes classes describing the galaxy components responsible for line and thermal emission and calculates the absorption due to $\gamma\gamma$ pair production on several photon fields. agnpy aims at extending the effort of modelling and interpreting the emission of extragalactic sources to a wide number of astrophysicists. We present the package content and illustrate a few examples of applications of its functionalities. We validate the software by comparing its results against the literature and against other open-source software. We illustrate the utility of agnpy in addressing the most common questions encountered while modelling the emission of jetted active galaxies. When comparing its results against the literature and other modelling tools adopting the same physical assumptions, we achieve an agreement within $10-30\%$. agnpy represents one of the first systematic and validated collection of established radiative processes for jetted active galaxies in an open-source python package. We hope it will stand also among the first endeavours providing reproducible and transparent astrophysical software not only for data reduction and analysis, but also for modelling and interpretation., Comment: Accepted for publication in Astronomy & Astrophysics, online material at: https://github.com/cosimoNigro/agnpy_paper. Updated v2 following A&A language and layout guidelines

The nature of dark matter (DM) is still an open question in Physics. Gamma-ray and neutrino telescopes have been searching for DM signatures for several years and no detection has been obtained so far. In their quest, these telescopes have gathered a wealth of observations that, if properly combined and analyzed, can improve on the constraints to the nature of DM set by individual instruments. In this contribution, we present two open-source analysis tools aimed at performing the before mentioned combined analysis: gLike, a general-purpose ROOT-based code framework for the numerical maximization of joint likelihood functions, and LklCom, a Python-based tool combining likelihoods from different instruments to produce combined exclusion limits on the DM annihilation cross-section., Comment: 4 pages, 3 figures, to appear in the proceedings of the XXXI Astronomical Data Analysis Software and Systems (ADASS) conference (published by ASP)

Majorana bound states (MBS) and Andreev bound states (ABS) in realistic Majorana nanowires setups have similar experimental signatures which make them hard to distinguishing one from the other. Here, we characterize the continuous Majorana/Andreev crossover interpolating between fully-separated, partially-separated, and fully-overlapping Majorana modes, in terms of global and local topological invariants, fermion parity, quasiparticle densities, Majorana pseudospin and spin polarizations, density overlaps and transition probabilities between opposite Majorana components. We found that in inhomogeneous wires, the transition between fully-overlapping trivial ABS and nontrivial MBS does not necessarily mandate the closing of the bulk gap of quasiparticle excitations, but a simple parity crossing of partially-separated Majorana modes (ps-MM) from trivial to nontrivial regimes. We demonstrate that fully-separated and fully-overlapping Majorana modes correspond to the two limiting cases at the opposite sides of a continuous crossover: the only distinction between the two can be obtained by estimating the degree of separations of the Majorana components. This result does not contradict the bulk-edge correspondence: Indeed, the field inhomogeneities driving the Majorana/Andreev crossover have a length scale comparable with the nanowire length, and therefore correspond to a nonlocal perturbation which breaks the topological protection of the MBS., Comment: 18 pages, 10 figures, updated references