Big Three Dragons: A [N ii] 122 μm Constraint and New Dust-continuum Detection of a z = 7.15 Bright Lyman-break Galaxy with ALMA

We present new Atacama Large Millimeter/submillimeter Array Band 7 observational results of a Lyman-break galaxy at z = 7.15, B14-65666 (“Big Three Dragons”), which is an object detected in [O iii] 88 μm, [C ii] 158 μm, and dust continuum emission during the epoch of reionization. Our targets are the [N ii] 122 μm fine-structure emission line and the underlying 120 μm dust continuum. The dust continuum is detected with a ∼19σ significance. From far-infrared spectral energy distribution sampled at 90, 120, and 160 μm, we obtain a best-fit dust temperature of 40 K (79 K) and an infrared luminosity of log 10 ( L IR / L ⊙ ) = 11.6 (12.1) at the emissivity index β = 2.0 (1.0). The [N ii] 122 μm line is not detected. The 3σ upper limit of the [N ii] luminosity is 8.1 × 107 L ⊙. From the [N ii], [O iii], and [C ii] line luminosities, we use the Cloudy photoionization code to estimate nebular parameters as functions of metallicity. If the metallicity of the galaxy is high (Z > 0.4 Z ⊙), the ionization parameter and hydrogen density are log 10 U ≃ − 2.7 ± 0.1 and n H ≃ 50–250 cm−3, respectively, which are comparable to those measured in low-redshift galaxies. The nitrogen-to-oxygen abundance ratio, N/O, is constrained to be subsolar. At Z < 0.4 Z ⊙, the allowed U drastically increases as the assumed metallicity decreases. For high ionization parameters, the N/O constraint becomes weak. Finally, our Cloudy models predict the location of B14-65666 on the BPT diagram, thereby allowing a comparison with low-redshift galaxies.

Characterizing Extreme Emission-line Galaxies. I. A Four-zone Ionization Model for Very High-ionization Emission*

Stellar population models produce radiation fields that ionize oxygen up to O+2, defining the limit of standard H ii region models (<54.9 eV). Yet, some extreme emission-line galaxies, or EELGs, have surprisingly strong emission originating from much higher ionization potentials. We present UV HST/COS and optical LBT/MODS spectra of two nearby EELGs that have very high-ionization emission lines (e.g., He ii λλ1640,4686 C iv λλ1548,1550, [Fe v]λ4227, [Ar iv]λλ4711,4740). We define a four-zone ionization model that is augmented by a very high-ionization zone, as characterized by He+2 (>54.4 eV). The four-zone model has little to no effect on the measured total nebular abundances, but does change the interpretation of other EELG properties: we measure steeper central ionization gradients; higher volume-averaged ionization parameters; and higher central T e , n e , and log U values. Traditional three-zone estimates of the ionization parameter can underestimate the average log U by up to 0.5 dex. Additionally, we find a model-independent dichotomy in the abundance patterns, where the α/H abundances are consistent but N/H, C/H, and Fe/H are relatively deficient, suggesting these EELGs are α/Fe-enriched by more than three times. However, there still is a high-energy ionizing photon production problem (HEIP3). Even for such α/Fe enrichment and very high log U s, photoionization models cannot reproduce the very high-ionization emission lines observed in EELGs.

Terbium Medical Radioisotope Production: Laser Resonance Ionization Scheme Development

Terbium (Tb) is a promising element for the theranostic approach in nuclear medicine. The new CERN-MEDICIS facility aims for production of its medical radioisotopes to support related R&amp;D projects in biomedicine. The use of laser resonance ionization is essential to provide radioisotopic yields of highest quantity and quality, specifically regarding purity. This paper presents the results of preparation and characterization of a suitable two-step laser resonance ionization process for Tb. By resonance excitation via an auto-ionizing level, the high ionization efficiency of 53% was achieved. To simulate realistic production conditions for Tb radioisotopes, the influence of a surplus of Gd atoms, which is a typical target material for Tb generation, was considered, showing the necessity of radiochemical purification procedures before mass separation. Nevertheless, a 10-fold enhancement of the Tb ion beam using laser resonance ionization was observed even with Gd:Tb atomic ratio of 100:1.

Ionization of NO by superhalogens: DFT and QTAIM approaches

Nitric oxide (NO) is a precursor to NO2, toxic gas, and a major air pollutant. Its ionization has been difficult due to its high ionization energy. We propose here the ionization of NO to NO+ using superhalogens. We study the interaction of NO with superhalogens (X = LiF2, BeF3 and, BF4) using DFT and QTAIM approaches, which lead to the formation of NO-X complexes. These complexes and their isomers are ionic with positively charged NO, which can be stabilized by two F–N bonds and F–O bonds, respectively. This reveals that NO can be ionized by electron transfer to superhalogens. The size of superhalogens has been noticed to play a crucial in the ionization of NO.

Detection of an ionized gas outflow in the extreme UV-luminous star-forming galaxy BOSS-EUVLG1 at z = 2.47

BOSS-EUVLG1 is the most ultraviolet (UV) and Lyα luminous galaxy to be going through a very active starburst phase detected thus far in the Universe. It is forming stars at a rate of 955 ± 118 M⊙ yr−1. We report the detection of a broad Hα component carrying 25% of the total Hα flux. The broad Hα line traces a fast and massive ionized gas outflow characterized by a total mass, log(Mout[M⊙]), of 7.94 ± 0.15, along with an outflowing velocity (Vout) of 573 ± 151 km s−1 and an outflowing mass rate (Ṁout) of 44 ± 20 M⊙ yr−1. The presence of the outflow in BOSS-EUVLG1 is also supported by the identification of blueshifted UV absorption lines in low and high ionization states. The energy involved in the Hα outflow can be explained by the ongoing star formation, without the need for an active galactic nucleus to be included in the scenario. The derived low mass-loading factor (η = 0.05 ± 0.03) indicates that, although it is massive, this phase of the outflow cannot be relevant for the quenching of the star formation, namely, the negative feedback. In addition, only a small fraction (≤15%) of the ionized outflowing material with velocities above 372 km s−1 has the capacity to escape the gravitational potential and to enrich the surrounding circumgalactic medium at distances above several tens of kpc. The ionized phase of the outflow does not carry sufficient mass or energy to play a relevant role in the evolution of the host galaxy nor in the enrichment of the intergalactic medium. As predicted by some recent simulations, other phases of the outflow could be responsible for most of the outflow energy and mass in the form of hot X-ray emitting gas. The expected emission of the extended X-ray emitting halo associated with the outflow in BOSS-EUVLG1 and similar galaxies could be detected with the future ATHENA X-ray observatory, however, there are no methods at present that would assist in their spatial resolution.

Development and Evaluation of an Immuno-MALDI-TOF Mass Spectrometry Approach for Quantification of the Abrin Toxin in Complex Food Matrices

The toxin abrin found in the seeds of Abrus precatorius has attracted much attention regarding criminal and terroristic misuse over the past decade. Progress in analytical methods for a rapid and unambiguous identification of low abrin concentrations in complex matrices is essential. Here, we report on the development and evaluation of a MALDI-TOF mass spectrometry approach for the fast, sensitive and robust abrin isolectin identification, differentiation and quantification in complex food matrices. The method combines immunoaffinity-enrichment with specific abrin antibodies, accelerated trypsin digestion and the subsequent MALDI-TOF analysis of abrin peptides using labeled peptides for quantification purposes. Following the optimization of the workflow, common and isoform-specific peptides were detected resulting in a ~38% sequence coverage of abrin when testing ng-amounts of the toxin. The lower limit of detection was established at 40 ng/mL in milk and apple juice. Isotope-labeled versions of abundant peptides with high ionization efficiency were added. The quantitative evaluation demonstrated an assay variability at or below 22% with a linear range up to 800 ng/mL. MALDI-TOF mass spectrometry allows for a simple and fast (<5 min) analysis of abrin peptides, without a time-consuming peptide chromatographic separation, thus constituting a relevant alternative to liquid chromatography-tandem mass spectrometry.

The five axes of the Turtle: symmetry and asymmetry in NGC 6210

We carry out a comprehensive kinematic and morphological study of the asymmetrical planetary nebula: NGC 6210, known as the Turtle. The nebula’s spectacularly chaotic appearance has led to proposals that it was shaped by mass transfer in a triple star system. We study the three-dimensional structure and kinematics of its shells, lobes, knots, and haloes by combining radial velocity mapping from multiple long-slit spectra with proper motion measurements from multi-epoch imaging. We find that the nebula has five distinct ejection axes. The first is the axis of the bipolar, wind-blown inner shell, while the second is the axis of the lop-sided, elliptical, fainter, but more massive intermediate shell. A further two axes are bipolar flows that form the point symmetric, high-ionization outer lobes, all with inclinations close to the plane of the sky. The final axis, which is inclined close to the line of sight, traces collimated outflows of low-ionization knots. We detect major changes in outflow directions during the planetary nebula phase, starting at or before the initial ionization of the nebula 3500 years ago. Most notably, the majority of redshifted low-ionization knots have kinematic ages greater than 2000 years, whereas the majority of blueshifted knots have ages younger than 2000 years. Such a sudden and permanent 180-degree flip in the ejection axis at a relatively late stage in the nebular evolution is a challenge to models of planetary nebula formation and shaping.

Synthesis and characterization of solution processable, high electron affinity molecular dopants

New organic-soluble dopants have record high electron affinity values and show outstanding doping performance with high ionization energy co-polymers.

Features of modifying properties of chemicals under the action of radiation of different quality: UV light, gamma-radiation and alfa-particles

Modification of the action of ionizing radiation by chemicals, used both to enhance its action and to weaken it’s known and is widely used in medical radiology. The article presents a comparative analysis of the modifying properties of three chemical radioprotectors (cysteamine, cysteine and cysteamine) when they are simultaneously act with to gama-rays, alpha-particles and ultraviolet radiation on yeast cells. The aim of the study was to compare the features of the manifestation of the properties of chemicals in relation to the protection of cells from UV-like damage when exposed to ionizing radiation or from damage caused by ultraviolet radiation. It was demonstrated that the cysteamine protects cells both from the damaging effects of gama-rays and from ultraviolet radiation, unlike cysteamine and cysteine, which protect cells exclusively from the effects of ionizing radiation. Moreover, cystamine does not change the effect of alpha-particles, which have a high ionization density of the substance, but practically do not cause excitation processes in biological objects. The obtained data indicate that cystamine realizes its protective properties against damage caused by ultraviolet radiation and UV-like damage resulting from the action of gama-rays due to the excitation of molecules or, more precisely, the ultraviolet component of Vavilov-Cherenkov luminescence accompanying the action of ionizing radiation.