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PeVatrons are the most powerful naturally occurring particle accelerators in the Universe. The identification of counterparts associated to astrophysical objects such as dying massive stars, molecular gas, star-forming regions, and star clusters is essential to clarify the underlying nature of the PeV emission, i.e., hadronic or leptonic. We present 12,13CO (J= 2→1) observations made with the 1.85 m radio-telescope of the Osaka Prefecture University toward the Cygnus OB7 molecular cloud, which contains the PeVatron candidate LHAASO J2108+5157. We investigate the nature of the sub-PeV (gamma-ray) emission by studying the nucleon density determined from the content of H iand H2, derived from the CO observations. In addition to MML[2017]4607, detected via the observations of the optically thick 12CO (J= 1→0) emission, we infer the presence of an optically thin molecular cloud, named [FKT-MC]2022, whose angular size is 1${_{.}^{\circ}}$1 ± 0${_{.}^{\circ}}$2. We propose this cloud as a new candidate to produce the sub-PeV emission observed in LHAASO J2108+5157. Considering a distance of 1.7 kpc, we estimate a nucleon (H i+ H2) density of 37 ± 14 cm−3, and a total nucleon mass(H i+ H2) of 1.5 ± 0.6 × 104M⊙. On the other hand, we confirm that Kronberger 82 is a molecular clump with an angular size of 0${_{.}^{\circ}}$1, a nucleon density ∼103cm−3, and a mass ∼103M⊙. Although Kronberger 82 hosts the physical conditions to produce the observed emission of LHAASO J2108+5157, [FKT-MC]2022 is located closer to it, suggesting that the latter could be the one associated to the sub-PeV emission. Under this scenario, our results favour a hadronic origin for the emission.

We report the detection of three compact (<0.001 pc) radio sources (CRSs) at the Ka-band (0.9 cm) in the ultra-compact (UC) H iiregions G040.54+2.59 (two CRSs) and G034.13+0.47 (one CRS). These CRSs have weak flux densities and are located at the center of their respective UC H iiregions. We found no clear association between massive ionizing stars and CRSs but some radiative influence on the latter, as suggested by their large emission measures (>107cm−6pc), typical of photo-evaporating neutral objects close to or associated with massive stars. Our modelling of G40.54+2.59 shows that its CRSs supply enough ionized material to shape its morphology while significantly extending its observable lifetime. On the other hand, despite the possible relation of the CRS with the large-scale outflow signatures observed in G034.13+0.47, the influence of this CRS on the evolution of the UC H iiregion is unlikely. Our results show that the presence of CRSs can alleviate the so-called lifetime problem of UC H iiregions. Still, to address the dynamical evolution of these regions adequately, the scenario must include additional mechanisms like ambient confinement, or the role of the kinematics of their associated stellar objects.

We studied the central region of bipolar nebula M 2-9 using radio-continuum observations obtained from the Jansky Very Large Array (JVLA) and the Atacama Large Millimeter Array (ALMA) interferometers. This work presents new images at ∼43 GHz (∼7.0 mm) and ∼345 GHz (∼0.9 mm) with angular resolutions of $\sim {0{^{\prime \prime}_{.}}047}$and ${0{^{\prime \prime}_{.}}09}$, respectively. The continuum emission at ∼43 GHz shows an elongated jet-like structure perpendicular to the ∼345 GHz observation. We conclude that both emissions could correspond to tracing an isothermal collimated fast wind with constant expansion velocity and being driven by the circumstellar ring traced by ALMA. Although this configuration has been discussed within the scope of planetary nebulae models, there is a remarkable fact: the collimated fast wind shows morphological spatial variability. This supports the idea of a symbiotic binary system within the innermost part of M 2-9, which would be composed of a white dwarf and an AGB star. The latter could explain the mirror symmetry observed at larger scales due to their orbital motion.

We observed H2O (616→523) maser emission associated with the high-mass star-forming region IRAS 23139+5959 using the KaVA, a combination of very long baseline interferometry (VLBI) arrays between the Korean VLBI Network and the VLBI Exploration of Radio Astrometry (Japan). Through multi-epoch KaVA observations, we detected three groups of maser features, two of which coincide with those previously detected by the Karl G. Jansky Very Large Array. By determining the maser proper motions, we found that the first of maser groups exhibits an expanding motion that traces a wide-angle outflow almost along the line of sight, while the second one seems to be associated with the envelope of an H iiregion. We discuss the star formation activity in IRAS 23139+5939, which may be reflected in the high variability of H2O masers associated with an outflow seen from the front.

In this article, a broad overview of the current research trends in power-electronic innovations in cyber–physical systems (CPSs) is presented. The recent advances in semiconductor device technologies, control architectures, and communication methodologies have enabled researchers to develop integrated smart CPSs that can cater to the emerging requirements of smart grids, renewable energy, electric vehicles, trains, ships, the Internet of Things (IoT), and so on. The topics presented in this article include novel power-distribution architectures, protection techniques considering large renewable integration in smart grids, wireless charging in electric vehicles, simultaneous power and information transmission, multihop network-based coordination, power technologies for renewable energy and smart transformer, CPS reliability, transactive smart railway grid, and real-time simulation of shipboard power systems. It is anticipated that the research trends presented in this article will provide a timely and useful overview to the power-electronics researchers with broad applications in CPSs.

Stability analysis of micropower networks is gaining importance given the dwindling gap of power generation and demand as well as increasing penetration of intermittent renewable energy sources. Instead of using prevalent small-signal analysis-based approaches, with predictions typically limited to the vicinity of the equilibrium, the outlined approach provides a sense of global/semiglobal stability. With regard to the latter, current approaches to stability analysis are primarily based on time-domain-, energy-function-, and common-Lyapunov-function-based analyses. This paper outlines a stability analysis approach based on polynomial Lyapunov function, which is determined algorithmically using sum-of-squares optimization in order to maximize the region of attraction (ROA) of an equilibrium solution. This procedure precludes the need for prior knowledge of the form of the Lyapunov or energy function. In this paper, the tradeoff between accuracy of determining the ROA of a power-system model and the computation overhead incurred is evaluated.

In the last decade, the development of next-generation electrical smart grids (ESGs) has been one of the priorities in the field of electrical engineering, both for most of the research centers and for the industry. In short, an ESG consists of the integration of information technologies into the electrical system to improve its controllability. In traditional power systems, the control has been carried out only by the power plants and some elements of the grid (transformer tap-changers, compensation capacitors, and reactances), whereas, in the next-generation smart grids, most of the elements can respond to control orders from the system operator, which allows, for instance, for the integration of the distributed generation and the demand into the control schemes of the power system. Because of this improved controllability, ESG technologies promise a significant improvement in the capacity utilization, the reliability of the system, and the energy efficiency of the grid.

This article maps recent developments in social science writing about the arts and argues for seeing this work in terms of the label the `new sociology of art'. It considers four major lines of re-assessment being carried out by sociologists studying the arts: firstly, a reconsideration of the relationship between sociological and other disciplinary approaches to art; secondly, the possibility of an art-sociology as against a sociology of art; thirdly, the application of insights from the sociology of art to non-art `stuff '; and, fourthly, the sociology of the artwork conceived as a contingent social fact. The argument is made that these developments represent an advance on the tendency to limit sociological investigations of the arts to contextual or external factors. The `new sociology of art' is praised for framing questions about the aesthetic properties of art and artworks in a way that is compatible with social constructionsim.

Here we discuss the effects of large ambient pressures and decreasing density gradients on the observed properties of dusty UC hii regions. Dust absorption can effectively reduce the size of the photo ionized region, and density gradients can modify the spectral index of the emission. The effects of the density gradients seem to be present in both galactic and extragalactic HII regions.

Presents the introductory editorial for this issue of the publication.