Assessing the sources of reionisation: a spectroscopic case study of a 30× lensed galaxy at z ∼ 5 with Lyα, C iv, Mg ii, and [Ne iii]

We present a detailed spectroscopic analysis of a galaxy at z ≃ 4.88 that is, by chance, magnified ∼30 × by gravitational lensing. Only three sources at z ≳ 5 are known with such high magnification. This particular source has been shown to exhibit widespread, high equivalent width ${\rm C\, {\small IV}}\, \lambda \, 1549$ emission, implying it is a unique example of a metal-poor galaxy with a hard radiation field, likely representing the galaxy population responsible for cosmic reionisation. Using UV nebular line ratio diagnostics, VLT/X-shooter observations rule out strong AGN activity, indicating a stellar origin of the hard radiation field instead. We present a new detection of ${[\rm Ne\, {\small III}]}\, \lambda \, 3870$ and use the [Ne iii]/[O ii] line ratio to constrain the ionisation parameter and gas-phase metallicity. Closely related to the commonly used [O iii]/[O ii] ratio, our [Ne iii]/[O ii] measurement shows this source is similar to local “Green Pea” galaxies and Lyman-continuum leakers. It furthermore suggests this galaxy is more metal poor than expected from the Fundamental Metallicity Relation, possibly as a consequence of excess gas accretion diluting the metallicity. Finally, we present the highest redshift detection of ${\rm Mg\, {\small II}}\, \lambda \, 2796$, observed at high equivalent width in emission, in contrast to more evolved systems predominantly exhibiting Mg ii absorption. Strong Mg ii emission has been observed in most z ∼ 0 Lyman-continuum leakers known and has recently been proposed as an indirect tracer of escaping ionising radiation. In conclusion, this strongly lensed galaxy, observed just 300 Myr after reionisation ends, enables testing of observational diagnostics proposed to constrain the physical properties of distant galaxies in the JWST/ELT era.

Hardness of ionizing radiation fields in MaNGA star-forming galaxies

We investigate radiation hardness within a representative sample of 67 nearby (0.02 ≲ z ≲ 0.06) star-forming (SF) galaxies using the integral field spectroscopic data from the MaNGA survey. The softness parameter η = $\frac{O^{+}/O^{2+}}{S^{+}/S^{2+}}$ is sensitive to the spectral energy distribution of the ionizing radiation. We study η via the observable quantity η′ ($=\frac{[O\rm \small {II}]/[O\rm \small {III}]}{[S\rm \small {II}][S\rm \small {III}]}$) We analyse the relation between radiation hardness (traced by η and η′) and diagnostics sensitive to gas-phase metallicity, electron temperature, density, ionization parameter, effective temperature and age of ionizing populations. It is evident that low metallicity is accompanied by low log η′, i.e. hard radiation field. No direct relation is found between radiation hardness and other nebular parameters though such relations can not be ruled out. We provide empirical relations between log $\rm \eta$ and strong emission line ratios N2, O3N2 and Ar3O3 which will allow future studies of radiation hardness in SF galaxies where weak auroral lines are undetected. We compare the variation of [O iii]/[O ii] and [S iii]/[S ii] for MaNGA data with SF galaxies and H ii regions within spiral galaxies from literature, and find that the similarity and differences between different data set is mainly due to the metallicity. We find that predictions from photoionizaion models considering young and evolved stellar populations as ionizing sources in good agreement with the MaNGA data. This comparison also suggests that hard radiation fields from hot and old low-mass stars within or around SF regions might significantly contribute to the observed η values.

From soft to hard radiation: the role of multiple scatterings in medium-induced gluon emissions

A proper understanding of the physics of medium-induced gluon emissions is known to be of critical importance to describe the properties of strongly interacting matter under extreme conditions. In this regard, many theoretical efforts have been directed towards obtaining analytical calculations which might help us discerning the underlying physical picture and the dominant dynamics for different regimes. These analytical approaches rely on approximations whose validity is analyzed here by comparing their results with a recently developed numerical evaluation which includes all-order resummation of multiple scatterings. More specifically, by quantitatively comparing the energy spectrum and rates, we observe that three different regimes — each with its corresponding physical picture — emerge naturally from the equations: the high-energy regime where the emission process is dominated by a single hard scattering, the intermediate-energy regime where coherence effects among multiple scatterings become fundamental, and the low-energy regime where the dynamics is again dominated by a single scattering but where one must include the suppression factor due to the probability of not having any further scatterings (which is obtained through the resummation of virtual terms).

InPAs Alloys Use for Electrical Engineering in Hard-radiation Environment

Effective functioning of electronics in high- radiation environment requires developing of novel semiconductor systems with radiation-tolerant properties. In given work, in search of semiconductor materials with immunity to radiation, investigations have been focused on InPxAs1-x alloys. Investigating of electrical and optical characteristics and physical processes, flowing in heavily irradiated InPxAs1-x alloys under high fluences of high-energy electrons and fast neutrons, let us create new generation of radiation-resistant semiconductor materials for electrical engineering application in hard-radiation environment.

Output of the dependence of the torque on theangleof rotation of the half couplings of the rope hyperbolic coupling «MAMSAR»

Виброизолирующие муфты приводов с упругими канатными элементами являются относительно новым направлением и в литературных источниках малоизвестны [1-14]. Они имеют несколько неоспоримых преимуществ перед другими типами муфт. Их характеристики практически не зависят от температурных режимов эксплуатации (температурные диапазоны эксплуатации – от –200 и вплоть до +370 С); они пожаробезопасны, инертны к агрессивным средам; это практически единственный тип муфт, способный долго работать в зонах повышенной и жесткой радиации. Такая нечувствительность к агрессивным средам и условиям эксплуатации позволяет до минимума сократить трудозатраты на их техническое обслуживание. Статья является логическим продолжением работ авторов о возможности использования канатных опор «MAMSAR» [1-4] в качестве отдельных или сборных муфт приводов. В данной работе в качестве объекта исследования рассматривается муфта с гиперболическим канатным элементом [1]. Целью настоящей статьи является вывод зависимости крутящего момента от смещения для муфт приводов с упругими канатными элементами в виде гиперболы «MAMSAR» [1]. Поставленная цель достигается реализацией следующих задач: 1.Получить формулу зависимости крутящего момента от смещения для гиперболической канатной муфты. 2. Экспериментально определить зависимость крутящего момента от смещения для гиперболической канатной муфты 3. Уточнить формулу – зависимость крутящего момента от смещения для гиперболической канатной муфты с использованием коэффициента поправки на основе экспериментальных данных. Vibration-isolating drive couplings with elastic rope elements are a relatively new direction and are little known in the literature [1-14]. They have several undeniable advantages over other types of couplings. Their characteristics practically do not depend on operating temperature conditions (operating temperature ranges – from -200 and up to +370 C); they are fire-safe, inert to aggressive environments; this is almost the only type of couplings that can work for a long time in areas of high and hard radiation. This insensitivity to aggressive environments and operating conditions allows you to minimize the labor costs for their maintenance. The article is a logical continuation of the authors work on the possibility of using "MAMSAR" rope supports [1-4] as separate or combined drive couplings. In this paper, a coupling with a hyperbolic rope element is considered as an object of research [1]. The purpose of this article is to derive the dependence of torque on displacement for drive couplings with elastic rope elements in the form of a "MAMSAR" hyperbola [1]. This goal is achieved by implementing the following tasks: 1. Get the formula for the dependence of torque on displacement for a hyperbolic cable coupling. 2. Experimentally determine the dependence of torque on displacement for a hyperbolic cable coupling 3. Refine the formula-the dependence of torque on displacement for a hyperbolic cable coupling using the correction coefficient based on experimental data.

Chemodynamics of green pea galaxies – I. Outflows and turbulence driving the escape of ionizing photons and chemical enrichment

ABSTRACT We investigate the ionized gas kinematics, physical properties, and chemical abundances of Sloan Digital Sky Survey J142947, a Green Pea galaxy at redshift z∼ 0.17 with strong, double-peak Ly α emission and indirect evidence of Lyman continuum (LyC) leakage. Using high-dispersion spectroscopy, we perform a multicomponent analysis of emission-line profiles. Our model consistently fits all lines as a narrow component with intrinsic velocity dispersion σ ∼ 40 km s−1, and two broader blue-shifted components with σ ∼ 90 and ∼ 250 km s−1. We find electron densities and temperatures, ionization conditions, and direct O/H and N/O abundances for each component. A highly ionized, metal-poor, young and compact starburst dominates narrow emission, showing evidence of hard radiation fields and elevated N/O. The blue-shifted broader components are consistent with highly turbulent, possibly clumpy ionized gas at the base of a strong photoionized outflow, which accounts for ≳50 per cent of the integrated emission-line fluxes. The outflow is dense and metal-enriched compared to the H ii regions, with expansion velocities larger than those obtained from UV interstellar absorption lines under standard assumptions. Some of these metals may be able to escape, with outflows loading factors comparable to those found in high-z galaxies of similar SFR/Area. Our findings depict a two-stage starburst picture; hard radiation fields from young star clusters illuminate a turbulent and clumpy ISM that has been eroded by SNe feedback. Whilst UV data suggest an extended Ly α halo with high average H i column density, LyC photons could only escape from SDSS J142947 through low H i density channels or filaments in the ISM approaching density-bounded conditions, traced by outflowing gas.