VLT/MUSE and ATCA Observations of the Host Galaxy of the Short GRB 080905A at z = 0.122

Short-GRB progenitors could come in various flavors, depending on the nature of the merging compact stellar objects (including a stellar-mass black hole or not) or depending on their ages (millions or billions of years). At a redshift of z = 0.122, the nearly face-on spiral host of the short GRB 080905A is one of the closest short-GRB host galaxies identified so far. This made it a preferred target to explore spatially resolved star formation and to investigate the afterglow position in the context of its star formation structures. We used VLT/MUSE integral-field unit observations, supplemented by ATCA 5.5/9.0 GHz radio-continuum measurements and publicly available HST data, to study the star formation activity in the GRB 080905A host galaxy. The MUSE observations reveal that the entire host is characterized by strong line emission. Using the Hα line flux, we measure for the entire galaxy an SFR of about 1.6 M ⊙ yr−1, consistent with its non-detection by ATCA. Several individual star-forming regions are scattered across the host. The most luminous region has a Hα luminosity that is nearly four times as high as the luminosity of the Tarantula nebula in the Large Magellanic Cloud. Even though star-forming activity can be traced as close to about 3 kpc (in projection) distance to the GRB explosion site, stellar population synthesis calculations show that none of the Hα-bright star-forming regions is a likely birthplace of the short-GRB progenitor.

The diffuse ionized gas (DIG) in star-forming galaxies: the influence of aperture effects on local H ii regions

ABSTRACT The diffuse ionized gas (DIG) contributes to the nebular emission of galaxies, resulting in emission line flux ratios that can be significantly different from those produced by H ii regions. Comparing the emission of [SII]λ6717,31 between pointed observations of H ii regions in nearby galaxies and integrated spectra of more distant galaxies, it has been recently claimed that the DIG can also deeply affect the emission of bright, star-forming galaxies, and that a large correction must be applied to observed line ratios to recover the genuine contribution from H ii regions. Here, we show instead that the e?ect of DIG on the integrated spectra of star-forming galaxies is lower than assumed in previous work. Here we show that, in contrast, aperture effects on the spectroscopy of nearby H ii regions are largely responsible for the observed difference: When spectra of local H ii regions are extracted using large enough apertures while still avoiding the DIG, the observed line ratios are the same as in more distant galaxies. This result is highly relevant for the use of strong-line methods to measure metallicity.

To a question on possibilities of high-resolution NMR spectroscopy in the Earth magnetic field

The low signal-to-noise ratio is a characteristic feature of NMR experiments in the Earth magnetic field. The main problem of such studies is the ineffectiveness of signal accumulation due to fluctuations of the Earth magnetic field because of magnetic interferences from laboratory equipment and other magnetic field sources. Taking into account the fact that generally in the Earth magnetic field proton-containing liquids have spectra with a central strong line, a relatively simple method has been found to neutralize the Larmor frequency fluctuations. The NMR signal processing algorithm is described. The home-built NMR-equipment allows us to clearly register the splitting in proton spectra, for example, due to the J-interaction with such nuclei as 29Si or 13C at their natural abundance (4.7 and 1.1%, respectively).

CFD Analysis of the ESFR Reactor Pit Cooling System in Case of Sodium Leakage

The Decay Heat Removal System (DHRS) for the ESFR Concept consists of three cooling systems, which provide highly reliable, redundant and diversified decay heat removal function. Two of the systems provide strong line of defense, whereas the third system provides a weak line of defense. This third DHR system, DHRS-3, involves separate oil and water cooling loops integrated in the reactor pit, which is installed instead of the safety vessel. It is hoped that the proposed DHR concept enables a robust demonstration of the practical elimination. For its confirmation, detailed numerical analysis is needed as a basis for further investigation. Supporting this approach, the current CFD computation provides a preliminary thermal analysis of the capability of the oil cooling system in the reactor to be used for residual heat removal pit in case of an emergency. For the evaluation, different heat flux values are assumed at the vessel wall to examine the range of the resulting temperatures. The temperature of the main vessel wall should remain below 800°C. Furthermore, a sodium leakage at 500°C into the reactor pit is assumed. The concrete structure should remain below 70°C.

Detecting COVID-19 Related Pneumonia on CT Scans using Hyperdimensional Computing

Pneumonia is a common complication associated with COVID-19 infections. Unlike common versions of pneumonia spread quickly through large lung regions, COVID-19 related pneumonia starts in small localized pockets before spreading over the course of several days. This makes the infection more resilient and with a high probability of developing acute respiratory distress syndrome. Because of the peculiar spread pattern, the use of pulmonary computerized tomography (CT) scans was key in identifying COVID-19 infections. Identifying uncommon pulmonary diseases could be a strong line of defense in early detection of new respiratory infection-causing viruses. In this paper we describe a classification algorithm based on hyperdimensional computing for the detection of COVID-19 pneumonia in CT scans. We test our algorithm using three different datasets. The highest reported accuracy is 95.2\% with an F1 score of 0.90, and all three models had a precision of 1 (0 false positives).

An exercise in detachment: the Council of Europe and sexual minority asylum claims

This contribution explores how the Council of Europe (CoE) – and the European Court of Human Rights (Strasbourg Court), in particular – have addressed the increasing number and complexity of applications involving sexual minority asylum claims (SMACs). The law and policy produced by the CoE and the jurisprudence of the Strasbourg Court immensely influence how domestic authorities address SMACs, so it is crucial to have a thorough understanding of this framework. Indeed, the CoE has acquired a progressively significant role in the field of asylum. Although it does not have an asylum policy as such, several of its bodies have taken a noteworthy role in this field, such as the European Committee for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment (CPT). The Strasbourg Court, above all, along with the now extinct European Commission of Human Rights, developed a strong line of jurisprudence that applies the European Convention on Human Rights (ECHR) to asylum claimants, despite the ECHR not possessing any norm explicitly related to asylum. More specifically, the Strasbourg Court was the first judicial instance at a European level to decide on cases relating to SMACs. It has so far dealt with at least 23 separate cases of asylum on grounds of sexual orientation. Many of these cases led to contentious and inadequate decisions, such as the 2014 judgment in M.E. v. Sweden, which gave legitimacy to the idea that applicants can be sent back to their countries of origin and asked to be ‘discreet’ about their sexuality. This approach reflects a worrying detachment from the realities of sexual minorities in many countries around the world and from their experiences when claiming international protection in Europe. This contribution thus critiques the CoE policy and Court’s jurisprudence in this field, whilst advancing policy and legal recommendations that can adequately address the socio-cultural and sexual diversity of asylum claimants from a queer intersectional perspective.

A reassessment of strong line metallicity conversions in the machine learning era

ABSTRACT Strong line metallicity calibrations are widely used to determine the gas phase metallicities of individual H ii regions and entire galaxies. Over a decade ago, based on the Sloan Digital Sky Survey Data Release 4, Kewley & Ellison published the coefficients of third-order polynomials that can be used to convert between different strong line metallicity calibrations for global galaxy spectra. Here, we update the work of Kewley & Ellison in three ways. First, by using a newer data release, we approximately double the number of galaxies used in polynomial fits, providing statistically improved polynomial coefficients. Second, we include in the calibration suite five additional metallicity diagnostics that have been proposed in the last decade and were not included by Kewley & Ellison. Finally, we develop a new machine learning approach for converting between metallicity calibrations. The random forest (RF) algorithm is non-parametric and therefore more flexible than polynomial conversions, due to its ability to capture non-linear behaviour in the data. The RF method yields the same accuracy as the (updated) polynomial conversions, but has the significant advantage that a single model can be applied over a wide range of metallicities, without the need to distinguish upper and lower branches in R23 calibrations. The trained RF is made publicly available for use in the community.

Note from the Editors

As we posted in January 2021, the Journal of the British Academy is spreading its call for submissions to articles associated with any of the Academy�s own programmes, activities and interests � i.e. beyond just articles arising from the Academy�s programme of public lectures. As part of this, we also welcome responses to, or comments on, articles that have already appeared in the Journal, and we welcome offers of such contributions to academic debate. As a start, we expect to publish responses to Professor Mokyr�s article later in the current volume. The Journal of the British Academy is featuring a strong line-up of thematic supplementary issues in 2021, with three already published. There will be further issues reflecting African perspectives, and a series of issues that relate to the UN Climate Change Conference (COP26) being hosted by the UK in November.

Spatially resolved direct method metallicity in a high-redshift analogue local galaxy: temperature structure impact on metallicity gradients

We investigate how H ii region temperature structure assumptions affect “direct-method” spatially-resolved metallicity observations using multispecies auroral lines in a galaxy from the SAMI Galaxy Survey. SAMI609396B, at redshift z = 0.018, is a low-mass galaxy in a minor merger with intense star formation, analogous to conditions at high redshifts. We use three methods to derive direct metallicities and compare with strong-line diagnostics. The spatial metallicity trends show significant differences among the three direct methods. Our first method is based on the commonly used electron temperature Te([O iii]) from the [O iii]λ4363 auroral line and a traditional Te([O ii]) – Te([O iii]) calibration. The second method applies a recent empirical correction to the O+ abundance from the [O iii]/[O ii] strong-line ratio. The third method infers the Te([O ii]) from the [S ii]λλ4069,76 auroral lines. The first method favours a positive metallicity gradient along SAMI609396B, whereas the second and third methods yield flattened gradients. Strong-line diagnostics produce mostly flat gradients, albeit with unquantified contamination from shocked regions. We conclude that overlooked assumptions about the internal temperature structure of H ii regions in the direct method can lead to large discrepancies in metallicity gradient studies. Our detailed analysis of SAMI609396B underlines that high-accuracy metallicity gradient measurements require a wide array of emission lines and improved spatial resolutions in order to properly constrain excitation sources, physical conditions, and temperature structures of the emitting gas. Integral-field spectroscopic studies with future facilities such as JWST/NIRSpec and ground-based ELTs will be crucial in minimising systematic effects on measured gradients in distant galaxies.