bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of transient electromagnetic fields excited by single- and double-line grounded-wire sources on land
Authors: Zhou Nan-nan , Xue Guoqiang , Li Hai , Kangxin Lei , Chen Wen
Published: January 2022

The lack of a systematic comparison of field surveys on land makes it challenging to select a suitable grounded-wire transient electromagnetic (TEM) source. Therefore, in this study, we compare land-based TEM methods with single- and double-line grounded-wire sources in the broadside direction. The comparison results indicate that the amplitude of the electric field from the double-line source is one or two orders weaker than that of the single-line source in the same time range. Further, we compare the detectability of horizontal electric fields for resistive or conductive targets by analysing the root mean square misfit and decay curves. According to the decay curve analysis, the double-line source shows better detectability for resistive targets, whereas the single-line source has a larger depth of investigation in the broadside direction. In the presence of a resistive target, sign reversal is more likely in the broadside direction for the double-line source than for the single-line source. In the field survey over Kalatongke Ni-Cu sulphide deposits in Xinjiang, China, both single- and double-line configurations can locate the resistive target; however, the latter configuration outperforms the former in discriminating the different values of the resistive rocks in the broadside direction. The double-line source will be the preferred choice for exploring resistive targets in the broadside direction.
Intruders in the Scottish church: clerical allegiance and English clergymen in Scotland during the Second War of Independence, 1332–57
Authors: McHugh Jenny M
Published: January 2022

Ecclesiastics on both sides of the Anglo-Scottish border have often been forgotten in discussions of allegiance and political identity during the Scottish Wars of Independence. This article explores the careers and loyalties of English clergymen working in Scotland, their relationship to their Scottish counterparts, and their influence on the political landscape of the Anglo-Scottish border. It argues that the lives of these men can offer unique insights into the English administration of Scotland between 1332 and 1357, and challenges claims that the English sought to incorporate the regions of Berwickshire and Roxburghshire into the kingdom of England.
A molecular map of long non-coding RNA expression, isoform switching and alternative splicing in osteoarthritis
Authors: Katsoula Georgia , Steinberg Julia , Tuerlings Margo , Coutinho de Almeida Rodrigo , Southam Lorraine , Swift Diane , Meulenbelt Ingrid , Wilkinson J Mark , Zeggini Eleftheria
Published: January 2022

Osteoarthritis is a prevalent joint disease and a major cause of disability worldwide with no curative therapy. Development of disease-modifying therapies requires a better understanding of the molecular mechanisms underpinning disease. A hallmark of osteoarthritis is cartilage degradation. To define molecular events characterizing osteoarthritis at the whole transcriptome level, we performed deep RNA sequencing in paired samples of low- and high-osteoarthritis grade knee cartilage derived from 124 patients undergoing total joint replacement. We detected differential expression between low- and high-osteoarthritis grade articular cartilage for 365 genes and identified a 38-gene signature in osteoarthritis cartilage by replicating our findings in an independent dataset. We also found differential expression for 25 novel long non-coding RNA genes (lncRNAs) and identified potential lncRNA interactions with RNA-binding proteins in osteoarthritis. We assessed alterations in the relative usage of individual gene transcripts and identified differential transcript usage for 82 genes, including ABI3BP, coding for an extracellular matrix protein, AKT1S1, a negative regulator of the mTOR pathway and TPRM4, coding for a transient receptor potential channel. We further assessed genome-wide differential splicing, for the first time in osteoarthritis, and detected differential splicing for 209 genes, which were enriched for extracellular matrix, proteoglycans and integrin surface interactions terms. In the largest study of its kind in osteoarthritis, we find that isoform and splicing changes, in addition to extensive differences in both coding and non-coding sequence expression, are associated with disease and demonstrate a novel layer of genomic complexity to osteoarthritis pathogenesis.
Maximal Hörmander Functional Calculus onLpSpaces and UMD Lattices
Authors: Deleaval Luc , Kriegler Christoph
Published: January 2022

Let $A$ be a generator of an analytic semigroup having a Hörmander functional calculus on $X = L^p(\Omega ,Y)$, where $Y$ is a UMD lattice. Using methods from Banach space geometry in connection with functional calculus, we show that for Hörmander spectral multipliers decaying sufficiently fast at $\infty $, there holds a maximal estimate $\| \sup _{t> 0} |m(tA)f|\, \|_{L^p(\Omega ,Y)} \lesssim \|f\|_{L^p(\Omega ,Y)}$. We also show square function estimates $\left \| \left ( \sum _k \sup _{t> 0} |m_k(tA)f_k|^2 \right )^{\frac 12} \right \|_{L^p(\Omega ,Y)} \lesssim \left \| \left ( \sum _k |f_k|^2 \right )^{\frac 12} \right \|_{L^p(\Omega ,Y)}$ for suitable families of spectral multipliers $m_k$, which are even new for the euclidean Laplacian on scalar valued $L^p(\ensuremath {{\mathbb {R}}}^d)$. As corollaries, we obtain maximal estimates for wave propagators and Bochner–Riesz means. Finally, we illustrate the results by giving several examples of operators $A$ that admit a Hörmander functional calculus on some $L^p(\Omega ,Y)$ and discuss examples of lattices $Y$ and non-self-adjoint operators $A$ fitting our context.
Offline Context Affects Online Reviews: The Effect of Post-Consumption Weather
Authors: Brandes Leif , Dover Yaniv
Published: January 2022

This empirical study investigates whether unpleasant weather—a prominent aspect of a consumer’s offline environment—influences online review provision and content. It uses a unique dataset that combines 12 years of data on hotel bookings and reviews, with weather condition information at a consumer’s home and hotel address. The results show that bad weather increases review provision and reduces rating scores for past consumption experiences. Moreover, 6.5% more reviews are written on rainy days and that these reviews are 0.1 points lower, accounting for 59% of the difference in average rating scores between four- and five-star hotels in our data. These results are consistent with a scenario in which bad weather (i) induces negative consumer mood, lowering rating scores, and (ii) makes consumers less time-constrained, which increases review provision. Additional analyses with various automated sentiment measures for almost 300,000 review texts support this scenario: reviews on rainy days show a significant reduction in reviewer positivity and happiness, yet are longer and more detailed. This study demonstrates that offline context influences online reviews, and discusses how platforms and businesses should include contextual information in their review management approaches.
COVID-19 and Older Persons—In Need of a Comprehensive Human Rights Approach
Authors: Bílková Veronika
Published: January 2022

The COVID-19 crisis has had a severe and disproportionate impact on older persons—due both to the effects of the virus itself and to the effects of the measures adopted to counter its spread, including some of those specifically designed to ensure better protection of the elderly. This impact has not gone unnoticed but most of the reports and statements that pertain to it either simply describe what has happened or explain the situation by pointing to the natural frailty of older persons and the unprecedented nature of the emergency. This article argues that such an explanation is incomplete. The problems that older persons have experienced in the recent months are neither natural nor coincidental. They reflect certain gaps that have existed in the protection of the human rights of older persons for a long time and that the current crisis has solely made more acute and more visible. The article introduces these gaps (normative, implementation, monitoring, institutional, information and societal gaps) and shows that they are all closely interrelated. To improve the protection of the human rights of older persons during COVID-19 and beyond, it is necessary to address all these gaps simultaneously. This, moreover, may not be done by legal means only. Other, non-legal means must be put in place as well. A comprehensive approach to the human rights of older persons should therefore replace the non-comprehensive approach that has prevailed so far.
Pain that only she must bear: on the invisibility of women in judicial abortion rhetoric
Authors: Laguardia F
Published: January 2022

The graphic and bodily facts of a legal question of rights are relevant to the courts, particularly in questions that directly implicate physical bodies and pain, such as right to die cases, or what level of search may be allowable and when. However, in the case of abortion, or more specifically the bodily ramifications of pregnancy and childbirth, this detail is conspicuously absent. This article, relying on a content analysis of over 220 legal opinions on abortion rights, documents this absence of rhetoric. Particularly in the context of other discussions of pain and physical health risks in these very same cases, the complete absence of an acknowledgement of the bodily ramifications of pregnancy and childbirth appears purposeful, if perhaps not conscious. Reviewing prior literature on abortion rights and abortion rhetoric, it is likely that this lack of language both reflects and reinforces an assumption of women’s roles as mothers, a general reluctance to acknowledge the totality of the sacrifices women make in giving birth, and the refusal to acknowledge women’s individual interests as whole persons.
Pattern and timing of mitochondrial divergence of island spotted skunks on the California Channel Islands
Authors: Bolas Ellen C , Quinn Cate B , Van Vuren Dirk H , Lee Andy , Vanderzwan Stevi L , Floyd Chris H , Jones Krista L , Shaskey Laura , Sacks Benjamin N
Published: January 2022

Island spotted skunks (Spilogale gracilis amphiala) are a rare subspecies endemic to the California Channel Islands, currently extant on Santa Cruz and Santa Rosa islands. How and when skunks arrived on the islands is unknown, hindering decision-making about their taxonomic status and conservation priority. We investigated these questions by sequencing the complete mitochondrial genomes of 55 skunks from the two islands and mainland (California and Arizona) and examining phylogenetic patterns and estimations of isolation times among populations. Island spotted skunks grouped in a single monophyletic clade distinct from mainland spotted skunks. A haplotype network analysis had the most recent common ancestral haplotype sampled from an individual on Santa Rosa, suggesting both islands were colonized by a single matriline. Additionally, no haplotypes were shared between skunk populations on the two islands. These patterns imply that both island populations were derived from a common ancestral population shortly after establishment and have remained isolated from each other ever since. Together with divergence estimates from three methods, this topology is consistent with colonization of the super-island, Santarosae, by a single ancestral population of spotted skunks in the early Holocene, followed by divergence as the sea level rose and split Santarosae into Santa Cruz and Santa Rosa islands 9,400–9,700 years ago. Such a scenario of colonization could be explained either by rafting or one-time transport by Native Americans. Given their distinct evolutionary history, high levels of endemism, and current population status, island spotted skunks may warrant management as distinct evolutionarily significant units.
Warming and grazing enhance litter decomposition and nutrient release independent of litter quality in an alpine meadow
Authors: Li Bowen , Lv Wangwang , Sun Jianping , Zhang Lirong , Jiang Lili , Zhou Yang , Liu Peipei , Hong Huan , Wang Qi , A Wang , Zhang Suren , Xia Lu , Wang Zongsong , Dorji Tsechoe , Su Ailing , Luo Caiyun , Zhang Zhenhua , Wang Shiping
Published: January 2022

Warming and grazing, and litter quality jointly determine litter decomposition and nutrient releases in grazing ecosystems. However, their effects have previously been studied in isolation. We conducted a two factorial experiment with asymmetric warming using infrared heaters and moderate grazing in an alpine meadow. Litter samples were collected from all plots in each treatment, among which some subsamples were placed in their original plots and other samples were translocated to other treatment plots to test the relative effects of each treatment on litter decomposition and nutrient releases. We found that warming rather than grazing alone significantly increased total losses of litter mass, total organic carbon, total nitrogen (TN) and total phosphorus (TP) per unit area due to increases in both mass loss rates and litter biomass. However, grazing with warming did not affect their total mass losses because increased mass loss was offset by decreased litter biomass compared with the control. Seasonal mean soil temperature better predicted litter decomposition than litter lignin content or carbon to nitrogen ratio. There were interactions between warming and grazing, but there were no interactions between them and litter quality on litter decomposition. The temperature sensitivity of TN loss was higher than that of TP loss per unit area. Our results suggest that increased temperature has a greater effect on litter decomposition and nutrient release than change in litter quality, and that more N release from litter could result in greater P deficiency in the alpine meadow.
No longer second-class citizens: Redefining organizational identity as a response to digitalization in accounting shared services
Authors: Klimkeit Dirk , Reihlen Markus
Published: January 2022

New technologies can become an identity-challenging threat for organizations. While there is a growing literature on how new technologies challenge fundamental questions of organizational existence such as ‘who are we?’, ‘what do we do?’, and ‘what do we want to be?’, this literature has largely overlooked how new technologies can become drivers of organizational identity change. In this article, we investigate the impact of digitalization, especially Robotic Process Automation, on organizational identity. Drawing on the analysis of shared service centers in Asia and Eastern Europe, we explored how these organizations respond to identity-challenging technologies. While traditionally, work in shared services has been characterized by a combination of standardization, controlling the labor process, and deskilling, we found in this study that shared service organizations are responding to the digital challenges by moving up the value chain to more complex, knowledge-intensive work. As a result, shared service organizations in our study began to redefine their organizational identity by, among others, professionalizing their workforce.
The Physicality of Virtue in Job 31: The Use of Bodily Terms in Job’s Depiction of Moral Integrity
Authors: Vesely Patricia
Published: January 2022

Job’s appeal of innocence in Job 31 may be the most comprehensive depiction of moral goodness found in the Hebrew Bible. In these verses, Job professes his innocence with respect to his relationships in both private and public realms, to God, and to the land. This essay assesses Job’s vision of moral integrity in Job 31:1–12, focusing on Job’s use of bodily language, including the terms ‘heart’, ‘eyes’, ‘feet’, and ‘hands’. The use of such language in Job 31 suggests that moral integrity, for Job, includes both ‘interior’ (unseen) and ‘exterior’ (visible) components of his being. This essay brings Job’s depiction of moral goodness in conversation with an Aristotelian virtue ethics and demonstrates that, while biblical Hebrew does not contain terms for ‘virtue’ or ‘character’, similar notions are present in the biblical text’s use of bodily language. Unlike some modern conceptions of virtue or character, however, the biblical text does not depict these concepts as abstract or intangible but as physical and inseparable from the environment of which the moral agent is a part.
Auxin analog-induced Ca2+ signaling is independent of inhibition of endosomal aggregation in Arabidopsis roots
Authors: Wang Ren , Himschoot Ellie , Grenzi Matteo , Chen Jian , Safi Alaeddine , Krebs Melanie , Schumacher Karin , Nowack Moritz K , Moeder Wolfgang , Yoshioka Keiko , Van Damme Daniël , De Smet Ive , Geelen Danny , Beeckman Tom , Friml Jiří , Costa Alex , Vanneste Steffen
Published: January 2022

Much of what we know about the role of auxin in plant development derives from exogenous manipulations of auxin distribution and signaling, using inhibitors, auxins, and auxin analogs. In this context, synthetic auxin analogs, such as 1-naphthalene acetic acid (1-NAA), are often favored over the endogenous auxin, indole-3-acetic acid (IAA), in part due to their higher stability. While such auxin analogs have proven instrumental in revealing the various faces of auxin, they display in some cases bioactivities distinct from IAA. Here, we focused on the effect of auxin analogs on the accumulation of PIN proteins in brefeldin A-sensitive endosomal aggregations (BFA bodies), and correlation with the ability to elicit Ca2+ responses. For a set of commonly used auxin analogs, we evaluated if auxin analog-induced Ca2+ signaling inhibits PIN accumulation. Not all auxin analogs elicited a Ca2+ response, and their differential ability to elicit Ca2+ responses correlated partially with their ability to inhibit BFA-body formation. However, in tir1/afb and cngc14, 1-NAA-induced Ca2+ signaling was strongly impaired, yet 1-NAA still could inhibit PIN accumulation in BFA bodies. This demonstrates that TIR1/AFB–CNGC14-dependent Ca2+ signaling does not inhibit BFA body formation in Arabidopsis roots.
Beyond Criminalisation: Abortion Law Reform in Aotearoa New Zealand
Authors: Snelling Jeanne M
Published: January 2022

With the enactment of the Abortion Legislation Act 2020, New Zealand radically transformed its approach to abortion. Abortion is no longer a crime, and is instead regulated under general health law, adopting a gestational model. Whilst some claim that reform was overdue, critics have described the new legislation as the ‘world’s most extreme abortion law’. This article investigates these claims through the lens of reproductive justice, a movement that emerged alongside the global campaign for recognition of reproductive rights. First, it outlines the tenets of reproductive justice, before critiquing New Zealand’s previous law, and considering arguments for its modernisation. It then describes how a growing number of jurisdictions have decriminalised abortion, with increasing pressure on other countries, including England and Wales, to similarly undertake law reform. Finally, it examines the main provisions of New Zealand’s law. It concludes that, to the extent that the new law enables access to timely, equitable, and publicly funded abortion services, it is consistent with the tenets of reproductive justice. By placing women at the centre of the law, it improves the welfare of women, but particularly marginalised women. However, it suggests that the current 20-week gestational test is arbitrary, with the originally proposed 22-week threshold preferable.
Adaboost-DSNN: an adaptive boosting algorithm based on deep self normalized neural network for pulsar identification
Authors: Tariq Irfan , Meng Qiao , Yao Shunyu , Liu Wei , Zhou Chenye , Ahmed Adnan , Spanakis-Misirlis Apostolos
Published: January 2022

A modern pulsar survey generates a large number of pulsar candidates. Filtering these pulsar candidates in a large astronomical data set is an important step towards discovering new pulsars. In this paper, a novel adaptive boosting algorithm based on deep self normalized neural network (Adaboost-DSNN) is proposed to accurately classify pulsar and non-pulsar signals. To train the proposed method on a highly imbalanced data set, the Synthetic Minority Oversampling TEchnique (SMOTE) was initially employed for balancing the data set. Then, a deep ensemble network combined with a deep self-normalized neural network and adaptive boosting was developed to train and learn the processed pulsar data. The design of the proposed Adaboost-DSNN method significantly reduced the computational time when dealing with large astronomical data sets, while also improving the classification performance. The scaled exponential liner units activation function was used to normalize the data. Considering their neighbour information and the special dropout technique (α-dropout), Adaboost-DSNN displayed good pulsar classification performance, while preserving the data properties across subsequent layers. The proposed Adaboost-DSNN method was tested on the High Time Resolution Universe Survey data sets (HTRU-1 and HTRU-2). According to experimental results, Adaboost-DSNN outperform other state-of-the-art methods with respect to training time and F1-score. The training time of the Adaboost-DSNN model is 10x times faster compared to other models of this kind.
Realistic galaxy image simulation via score-based generative models
Authors: Smith Michael J , Geach James E , Jackson Ryan A , Arora Nikhil , Stone Connor , Courteau Stéphane
Published: January 2022

We show that a denoising diffusion probabilistic model (DDPM), a class of score-based generative model, can be used to produce realistic mock images that mimic observations of galaxies. Our method is tested with Dark Energy Spectroscopic Instrument (DESI) grz imaging of galaxies from the Photometry and Rotation curve OBservations from Extragalactic Surveys (PROBES) sample and galaxies selected from the Sloan Digital Sky Survey. Subjectively, the generated galaxies are highly realistic when compared with samples from the real data set. We quantify the similarity by borrowing from the deep generative learning literature, using the ‘Fréchet inception distance’ to test for subjective and morphological similarity. We also introduce the ‘synthetic galaxy distance’ metric to compare the emergent physical properties (such as total magnitude, colour, and half-light radius) of a ground truth parent and synthesized child data set. We argue that the DDPM approach produces sharper and more realistic images than other generative methods such as adversarial networks (with the downside of more costly inference), and could be used to produce large samples of synthetic observations tailored to a specific imaging survey. We demonstrate two potential uses of the DDPM: (1) accurate inpainting of occluded data, such as satellite trails, and (2) domain transfer, where new input images can be processed to mimic the properties of the DDPM training set. Here we ‘DESI-fy’ cartoon images as a proof of concept for domain transfer. Finally, we suggest potential applications for score-based approaches that could motivate further research on this topic within the astronomical community.
Systematic biases in determining dust attenuation curves through galaxy SED fitting
Authors: Qin Jianbo , Zheng Xian Zhong , Fang Min , Pan Zhizheng , Wuyts Stijn , Shi Yong , Peng Yingjie , Gonzalez Valentino , Bian Fuyan , Huang Jia-Sheng , Gu Qiu-Sheng , Liu Wenhao , Tan Qinghua , Shi Dong Dong , Ren Jian , Zhang Yuheng , Qiao Man , Wen Run , Liu Shuang
Published: January 2022

While the slope of the dust attenuation curve (δ) is found to correlate with effective dust attenuation (AV) as obtained through spectral energy distribution (SED) fitting, it remains unknown how the fitting degeneracies shape this relation. We examine the degeneracy effects by fitting SEDs of a sample of local star-forming galaxies (SFGs) selected from the Galaxy And Mass Assembly survey, in conjunction with mock galaxy SEDs of known attenuation parameters. A well-designed declining starburst star formation history is adopted to generate model SED templates with intrinsic UV slope (β0) spanning over a reasonably wide range. The best-fitting β0 for our sample SFGs shows a wide coverage, dramatically differing from the limited range of β0 < −2.2 for a starburst of constant star formation. Our results show that strong degeneracies between β0, δ, and AV in the SED fitting induce systematic biases leading to a false AV–δ correlation. Our simulation tests reveal that this relationship can be well reproduced even when a flat AV–δ relation is taken to build the input model galaxy SEDs. The variations in best-fitting δ are dominated by the fitting errors. We show that assuming a starburst with constant star formation in SED fitting will result in a steeper attenuation curve, smaller degeneracy errors, and a stronger AV–δ relation. Our findings confirm that the AV–δ relation obtained through SED fitting is likely driven by the systematic biases induced by the fitting degeneracies between β0, δ, and AV.
Non-linear density–velocity dynamics in f(R) gravity from spherical collapse
Authors: Nadkarni-Ghosh Sharvari , Chowdhury Sandip
Published: January 2022

We investigate the joint density–velocity evolution in f(R) gravity using smooth, compensated spherical top-hats as a proxy for the non-linear regime. Using the Hu-Sawicki model as a working example, we solve the coupled continuity, Euler, and Einstein equations using an iterative hybrid Lagrangian–Eulerian scheme. The novel aspect of this scheme is that the metric potentials are solved for analytically in the Eulerian frame. The evolution is assumed to follow GR at very early epochs and switches to f(R) at a pre-determined epoch. Choosing the ‘switching epoch’ too early is computationally expensive because of high frequency oscillations; choosing it too late potentially destroys consistency with ΛCDM. To make an informed choice, we perform an eigenvalue analysis of the background model which gives a ballpark estimate of the magnitude of oscillations. There are two length scales in the problem: the comoving Compton wavelength of the associated scalar field and the width of the top-hat. The evolution is determined by their ratio. When the ratio is large, the evolution is scale-independent and the density–velocity divergence relation (DVDR) is unique. When the ratio is small, the evolution is very close to GR, except for the formation of a spike near the top-hat edge, a feature which has been noted in earlier literature. We are able to qualitatively explain this feature in terms of the analytic solution for the metric potentials, in the absence of the chameleon mechanism. In the intermediate regime, the evolution is profile-dependent and no unique DVDR exists.
COD: an algorithm for shape reconstruction of transiting celestial bodies through topological optimization
Authors: Nachmani G , Mazeh T , Sochen N
Published: January 2022

We introduce a novel algorithm, COD – Compact Opacity Distribution, for shape reconstruction of a celestial body that has been observed to occult a star, using the photometric time-series observations of the occultation. COD finds a solution to the light-curve inversion problem for an optically thick occulter having an approximately convex shape, together with an estimate of its size, impact parameter and velocity, relative to the occulted star. The algorithm is based on an optimization scheme that uses topological constraints and an objective function for the geometry of the occulter. The constraints of the problem follow linear relations, which enable the use of linear programming optimization as the mathematical framework. Multiple tests of the algorithm were performed, all of which resulted in high correlations between the simulated and obtained shapes of the occulting objects, with errors within $5{{\ \rm per\ cent}}$ in their projected velocities and horizontal sizes, and within 0.1 in their impact parameters. These tests include a video of a solar eclipse by Phobos, as seen by NASA’s Curiosity rover, which was collapsed into its corresponding light curve and reconstructed afterwards. We applied COD to the mysterious case of VVV-WIT-08 – a single deep occultation ($\sim 96 {{\ \rm per\ cent}}$) of a giant star lasting for over 200 d. The analysis, which did not assume any specific shape of the occulter, suggested an object with a projected opacity distribution resembling an ellipse with an eccentricity of ∼0.5, tilted at ∼30 degrees relative to the direction of motion, with a semi-minor axis similar to the stellar radius.
Constraints on the abundance of primordial black holes with different mass distributions from lensing of fast radio bursts
Authors: Zhou Huan , Li Zhengxiang , Huang Zhiqi , Gao He , Huang Lu
Published: January 2022

Primordial black holes (PBHs) has been considered to form a part of dark matter for a long time but the possibility has been poorly constrained over a wide mass range, including the stellar mass range ($1{-}100\ {\rm M}_{\odot }$). However, due to the discovery of merger events of black hole binaries by LIGO-Virgo gravitational wave observatories, the interest for PBHs in the stellar mass window has been aroused again. Fast radio bursts (FRBs) are bright radio transients with millisecond duration and very high all-sky occurrence rate. Lensing effect of these bursts has been proposed as one of the optimal probes for constraining the abundance of PBHs in the stellar mass range. In this paper, we first investigate constraints on the abundance of PBHs from the latest 593 FRB observations for both the monochromatic mass distribution and three other popular extended mass distributions related to different formation mechanisms of PBHs. It is found that constraints from currently public FRB observations are relatively weaker than those from existing gravitational wave detections. Furthermore, we forecast constraining power of future FRB observations on the abundance of PBHs with different mass distributions of PBHs and different redshift distributions of FRBs taken into account. Finally, We find that constraints of parameter space on extended mass distributions from ∼105 FRBs with $\overline{\Delta t}\le 1 ~\rm ms$ would be comparable with what can be constrained from gravitational wave events. It is foreseen that upcoming complementary multimessenger observations will yield considerable constraints on the possibilities of PBHs in this intriguing mass window.
A Chandra Virgo cluster survey of spiral galaxies – I. Introduction to the survey and a new ULX sample
Authors: Soria Roberto , Kolehmainen Mari , Graham Alister W , Swartz Douglas A , Yukita Mihoko , Motch Christian , Jarrett Thomas H , Miller-Jones James C A , Plotkin Richard M , Maccarone Thomas J , Ferrarese Laura , Guest Alexander , Lançon Ariane
Published: January 2022

We present an analysis of the ultraluminous X-ray source (ULX) population in 75 Virgo cluster late-type galaxies, including all those with a star formation rate ≳1 M⊙ yr−1 and a representative sample of the less star forming ones. This study is based on 110 observations obtained over 20 yr with the Chandra X-ray Observatory Advanced Camera for Imaging Spectroscopy. As part of a Large Chandra Program, new observations were obtained for 52 of these 75 galaxies. The data are complete to a sensitivity of ≈1039 erg s−1, with a typical detection limit of ≈3 × 1038 erg s−1 for the majority of the sources. The catalogue contains about 80 ULXs (0.3–10 keV luminosity >1039 erg s−1), and provides their location, observed flux, de-absorbed luminosity, and (for the 25 most luminous ones) simple X-ray spectral properties. We discuss the ULX luminosity function in relation to the mass and star formation rate of the sample galaxies. We show that recent models of low-mass plus high-mass X-ray binary populations (scaling with stellar mass and star formation rate, respectively) are mostly consistent with our observational results. We tentatively identify the most luminous X-ray source in the sample (a source in IC 3322A with LX ≈ 6 × 1040 erg s−1) as a recent supernova or its young remnant. The properties of the sample galaxies (morphologies, stellar masses, star formation rates, total X-ray luminosities from their point-source population) are also summarized.
Seismic modelling of a very young SPB star – KIC 8264293
Authors: Szewczuk Wojciech , Walczak Przemysław , Daszyńska-Daszkiewicz Jadwiga , Moździerski Dawid
Published: January 2022

KIC 8264293 is a fast-rotating B-type pulsator observed by Kepler satellite. Its photometric variability is mainly due to pulsations in high-order g modes. Besides, we detected a weak Hα emission. Thus, the second source of variability is the fluctuation in a disc around the star. The pulsational spectrum of KIC 8264293 reveals a frequency grouping and period spacing pattern. Here, we present the thorough seismic analysis of the star based on these features. Taking into account the position of the star in the HR diagram and fitting the 14 frequencies that form the period spacing, we constrain the internal structure of the star. We conclude that the star barely left the zero-age main sequence and the best seismic model has $M = 3.54\, \mathrm{M}_{\odot }$, $V_\mathrm{rot}=248\, \mathrm{km\, s}^{-1}$, and Z = 0.0112. We found the upper limit on the mixing at the edge of the convective core, with the overshooting parameter up to fov = 0.03. On the other hand, we were not able to constrain the envelope mixing for the star. To excite the modes in the observed frequency range, we had to modify the opacity data. Our best seismic model with an opacity increase by 100 per cent at the ‘nickel’ bump log T = 5.46 explains the whole instability. KIC 8264293 is the unique, very young star pulsating in high-order g modes with the Be feature. However, it is not obvious whether the source of this circumstellar matter is the ejection of mass from the underlying star or whether the star has retained its protostellar disc.
Detecting intermediate-mass black holes in midiquasars with current and future surveys
Authors: Liodakis I
Published: January 2022

The lack of detected intermediate-mass black holes poses a gap in our understanding of the growth and evolution of the most exotic of astrophysical objects. Here, we investigate the possibility of low-luminosity relativistic jets launched by intermediate-mass black holes in the centres of dwarf galaxies. We built population models that allow us to make predictions for their radio emission and quantify their detectability by current and future surveys. We find that the upcoming instruments in optical and radio like the SKA, ngVLA, and the Vera C. Rubin Observatory will likely be able to detect a significant fraction ($\gt 38{{\,\rm per\,cent}}$) of such sources population if they exist. In addition, our results suggest that it is not unlikely that a small number of midiquasars, possibly masquerading as low-luminosity active galactic nuclei, may have already been detected by existing surveys.
Globally optimal shape and spin pole determination with light-curve inversion
Authors: Chng Chee-Kheng , Sasdelli Michele , Chin Tat-Jun
Published: January 2022

Light-curve inversion is an established technique in determining the shape and spin states of an asteroid. However, the front part of the processing pipeline, which recovers the spin pole and area of each facet, is a non-convex optimization problem. Hence, any local iterative optimization scheme can only promise a locally optimal solution. Apart from the obvious downsides of getting a non-optimal solution and the need for an initialization scheme, another major implication is that it creates an ambiguous scenario – which is to be blamed for the remaining residual? The inaccuracy of the modelling, the integrity of the data, or the non-global algorithm? We address the last uncertainty in this paper by embedding the spin pole and area vector determination module in a deterministic global optimization framework. To the best of our knowledge, this is the first attempt to solve these parameters globally. Specifically, given calibrated light-curve data, a scattering model for the object, and spin period, our method outputs the globally optimal spin pole and area vector solutions. One theoretical contribution of this paper is the introduction of a lower bound error function that is derived based on (1) the geometric relationship between the incident and scattered light on a surface and (2) the uncertainty of the gap between the observed and estimated brightness at a particular epoch in a light curve. We validated our method’s ability in achieving global minimum with both simulated and real light-curve data. We also tested our method on the real light curves of four asteroids.
The large-scale structure from non-Gaussian primordial perturbations
Authors: Peña G A , Candlish G N
Published: January 2022

The late-time effect of primordial non-Gaussianity offers a window into the physics of inflation and the very early Universe. In this work, we study the consequences of a particular class of primordial non-Gaussianity that is fully characterized by initial density fluctuations drawn from a non-Gaussian probability density function, rather than by construction of a particular form for the primordial bispectrum. We numerically generate multiple realizations of cosmological structure and use the late-time matter power spectrum, bispectrum, and trispectrum to determine the effect of these modified initial conditions. We show that the initial non-Gaussianity has only a small imprint on the first three polyspectra, when compared to a standard Gaussian cosmology. Furthermore, some of our models present an interesting scale-dependent deviation from the Gaussian case in the bispectrum and trispectrum, although the signal is at most at the per cent level. The majority of our models are consistent with cosmic microwave background constraints on the trispectrum, while the others are only marginally excluded. Finally, we discuss further possible extensions of our study.
Properties and evolutions of starspots on three detached eclipsing binaries in the LAMOST–Kepler survey
Authors: Wang Jiaxin , Fu Jianning , Zong Weikai , Pan Yang , Niu Hubiao , Zhang Bo , Zhang Yong
Published: January 2022

Spotted detached eclipsing binaries (DEBs) offer insights into starspots on binaries. In this work, we study three spotted DEBs, KIC 8097825, KIC 6859813 and KIC 5527172, which have been observed using Kepler photometry and Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) spectroscopy. The physical parameters of binaries are determined by binary modelling. The size, lifetime and single/-double-dip ratio (SDR) of starspots are derived by starspot analysis. KIC 8097825 has large starspots. KIC 6859813 has a spot rotation period shorter than its orbital period but the system should be synchronized by inference from time-scale estimation. The difference may be the result of the surface differential rotation. KIC 5527172 has a long spot lifetime and an M-dwarf component with an inflation radius. The primaries of these binaries and the secondary of KIC 8097825 have spots. Adding spotted DEBs from the literature, we compare the starspots on binaries with those on the single stars. The spot sizes of starspots on 65 per cent of binaries are smaller than the median of those on single stars. The lifetimes of starspots on binaries are consistent with those on single stars when the rotation periods are larger than 3 d. SDRs for half of the binaries are consistent with those of single-star systems, while the other half are smaller. The relative lifetime positively correlates with the rms and SDR but negatively correlates with the rotation period. These relations are similar to those of spots on single-star systems. Binaries with luminosity ratios close to the unit tend to have more double dips.
A large catalogue of molecular clouds in the Southern sky
Authors: Guo H-L , Chen B-Q , Liu X-W
Published: January 2022

We present a large catalogue of molecular clouds with accurate distance estimates in the Southern sky. Based on the three-dimensional dust extinction map and the best-fitting extinction and distance information of over 17 million stars presented in Guo et al. (2021, ApJ, 906, 47), we have identified 250 dust/molecular clouds in the Southern sky using a hierarchical structure identification algorithm. Amongst these are 71 clouds located at high Galactic latitudes (b < −10°). We have estimated the distances to the clouds by fitting the extinction versus distance profiles of the lines of sight overlapping with the clouds, using a simple Gaussian dust distribution model. The typical uncertainties of the distances are less than 7 per cent. We also provide the physical properties of the individual clouds, including the linear radius, mass and surface mass density.
The spatially resolved PAH characteristics in the Whirlpool Galaxy (M51a)
Authors: Zang Rong Xuan , Maragkoudakis Alexandros , Peeters Els
Published: January 2022

We present a detailed study on the spatially resolved polycyclic aromatic hydrocarbon (PAH) emission properties in the (circum)nuclear region (NR) and extranuclear regions (ENRs) of M51a using Spitzer-IRS (infrared spectrograph) observations. Correlations among PAH intensity ratios are examined with respect to each other, local physical parameters, galactocentric distance (Rg), and very small grain (VSG) emission. Additional comparison is performed with the mid-infrared emission features in the H ii regions of M33 and M83. The NR exhibits the strongest correlation among the PAH intensity ratios, whereas ENRs are showing increased scatter attributed to interstellar medium emission. Overall, the radiation field hardness has a higher impact on PAH emission than metallicity, with the latter regulating PAH variance as a function of Rg. Specifically, the variance of PAH emission with respect to the different physical parameters suggests a higher rate of small/medium PAH processing compared to large PAHs and a higher ratio of small-to-large PAHs formed with increasing galactocentric distance. We find similarities between the 7.7 $\mu$m carriers in M51a’s NR and M83’s H ii regions, the 8.6 $\mu$m carriers in M51a’s NR and M33 H ii regions, and both types of carriers between M51a’s ENRs, M33’s, and M83’s H ii regions. We have identified a positive correlation between PAH/VSG and the PAH intensity ratios. We conclude that the relative abundance of PAHs and VSG is not solely driven by the hardness of the radiation field.
Inferring astrophysics and dark matter properties from 21 cm tomography using deep learning
Authors: Neutsch Steffen , Heneka Caroline , Brüggen Marcus
Published: January 2022

21 cm tomography opens a window to directly study astrophysics and fundamental physics of early epochs in our Universe’s history, the Epoch of Reionization (EoR) and Cosmic Dawn (CD). Summary statistics such as the power spectrum omit information encoded in this signal due to its highly non-Gaussian nature. Here, we adopt a network-based approach for direct inference of CD and EoR astrophysics jointly with fundamental physics from 21 cm tomography. We showcase a warm dark matter (WDM) universe, where dark matter density parameter Ωm and WDM mass mWDM strongly influence both CD and EoR. Reflecting the three-dimensional nature of 21 cm light-cones, we present a new, albeit simple, 3D convolutional neural network (3D-21cmPIE-Net) for efficient parameter recovery at moderate training cost. On simulations we observe high-fidelity parameter recovery for CD and EoR astrophysics (R2 > 0.78–0.99), together with DM density Ωm (R2 > 0.97) and WDM mass (R2 > 0.61, significantly better for $m_\mathrm{WDM}\lt 3\!-\!4\,$ keV). For realistic mock observed light-cones that include noise and foreground levels expected for the Square Kilometre Array, we note that in an optimistic foreground scenario parameter recovery is unaffected, while for moderate, less optimistic foreground levels (occupying the so-called wedge) the recovery of the WDM mass deteriorates, while other parameters remain robust against increased foreground levels at R2 > 0.9. We further test the robustness of our network-based inference against modelling uncertainties and systematics by transfer learning between bare simulations and mock observations; we find robust recovery of specific X-ray luminosity and ionizing efficiency, while DM density and WDM mass come with increased bias and scatter.
Probing infrared excess connection with Li enhancement among red clump giants
Authors: Mallick Anohita , Reddy Bacham E , Muthumariappan C
Published: January 2022

We have performed a search among low-mass red giants for finding evidence for merger scenario for triggering He-flash and subsequent Li enhancement. We chose a sample of red giants from GALAH survey with well-measured Li abundances, and near- and mid-IR fluxes from 2MASS and WISE surveys, respectively. The sample contains 418 cool red clump giants and 359 upper red giant branch (RGB) giants. Most of the giants and majority of super Li-rich giants show no IR excess. Only five red clump giants and one RGB giant show IR excess. Notably, of the five red clump giants with IR excess, three are super Li-rich (A(Li) ≥ 3.2 dex) and two are Li-rich (A(Li) ≥ 1.0 dex). Results suggest that Li enhancement among red clump giants may be due to two channels: one resulting from in situ He-flash in single-star evolution and the other due to He-flash triggered by events like merger of He-white dwarfs with giants’ He-inert core on RGB. In the latter case, IR excess, as a result of mass-loss, is expected from merger events. We have modelled IR excess in all six giants using dusty code and derived dust parameters. The estimated kinematic ages and time-scales of dust envelopes of the super Li-rich phase suggest that Li enhancement took place very recently. Further, the analysis shows a significantly higher proportion (four out of five red clump giants) of rapid rotators (vsini ≥ 8 km s−1) among Li-rich giants with IR excess compared to Li-normal and Li-rich giants with no IR excess.
The edge-on Galaxies in the Pan-STARRS survey (EGIPS)
Authors: Makarov D , Savchenko S , Mosenkov A , Bizyaev D , Reshetnikov V , Antipova A , Tikhonenko I , Usachev P , Borisov S , Makarova L , Kautsch S , Marchuk A , Rubtsov E
Published: January 2022

We present a catalogue of 16 551 edge-on galaxies created using the public DR2 data of the Pan-STARRS survey. The catalogue covers the three quarters of the sky above Dec. = −30°. The galaxies were selected using a convolutional neural network, trained on a sample of edge-on galaxies identified earlier in the SDSS survey. This approach allows us to dramatically improve the quality of the candidate selection and perform a thorough visual inspection in a reasonable amount of time. The catalogue provides homogeneous information on astrometry, SExtractor photometry, and non-parametric morphological statistics of the galaxies. The photometry is reliably for objects in the 13.8–17.4 r-band magnitude range. According to the HyperLeda data base, redshifts are known for about 63 per cent of the galaxies in the catalogue. Our sample is well separated into the red sequence and blue cloud galaxy populations. The edge-on galaxies of the red sequence are systematically Δ(g − i) ≈ 0.1 mag redder than galaxies oriented at an arbitrary angle to the observer. We found a variation of the galaxy thickness with the galaxy colour. The red sequence galaxies are thicker than the galaxies of the blue cloud. In the blue cloud, on average, thinner galaxies turn out to be bluer. In the future, based on this catalogue it is intended to explore the three-dimensional structure of galaxies of different morphologies, as well as to study the scaling relations for discs and bulges.