bluuebunny/crossref_metadata_2025 huggingface dataset:
Minimum detection velocity performance analysis for air moving target detection in a spaceborne surveillance radar system
Authors: Ma Jingtao , Wang Lingyu , Huang Penghui , Liao Guisheng , Zhang Xuepan
Published: October 2023

Due to the advantages of wide coverage, continuous remote monitoring, and high measurement accuracy, the spaceborne multi‐channel surveillance radar has been widely used for the air moving target detection and tracking. In this paper, the minimum detection velocity (MDV) definition for the aerial target detection performance evaluation in a spaceborne multi‐channel radar system is analysed, where three kinds of MDV definitions based on empirical formula, output signal‐to‐clutter‐plus‐noise ratio (SCNR) loss criterion, and output SCNR criterion are discussed in detail based on theoretical analysis and simulation verification. The analysis results will provide valuable reference for the practical spaceborne radar system designment with the air target detection mode.
Security‐constrained active power curtailment considering line temperature and thermal inertia
Authors: Bolgaryn Roman , Wiemer Jan , Scheidler Alexander , Braun Martin
Published: October 2023

A novel method is introduced to determine cost‐optimized active power curtailment (APC) of renewable energy sources (RES) considering weather‐dependent dynamic line rating (DLR). A new formulation of the security‐constrained optimal power flow (SC‐OPF) is developed and applied in a case study. The reduction of the required preventive APC in the case for secure grid operation due to the consideration of thermal inertia of overhead power lines is demonstrated. Considering thermal inertia allows relying on curative APC that is activated only after an situation occurs. The overhead power line temperature, calculated with the temperature‐dependent power flow (TDPF), acts as a new limit for line loading and releases unused transmission reserves. The TDPF algorithm is integrated in the open‐source Python library pandapower, providing access to it to the broader community. The power system can be utilized to a greater extent, with a reduced demand for congestion management.
ADFF: Adaptive de‐morphing factor framework for restoring accomplice's facial image
Authors: Long Min , Zhou Jun , Zhang Le‐Bing , Peng Fei , Zhang Dengyong
Published: October 2023

Morphing attacks (MAs) pose a substantial security threat to the Automatic Border Control (ABC) system. While a few morphing attack detection (MAD) methods have been proposed, the face morphing accomplice's facial restoration has not received sufficient attention. Due to the inability to foresee the morphing factor used for a particular morphed image, selecting the appropriate de‐morphing factor becomes a challenging problem in the restoration of the accomplice's facial image. If the morphing factor cannot be chosen reasonably, achieving the desired restoration effect is difficult. Therefore, this paper presents an adaptive de‐morphing factor framework (ADFF) architecture for restoring the accomplice's facial image. By exploiting the morphed images stored in the electronic passport system and the real‐time captured criminal's images, ADFF can effectively restore the accomplice's facial image. Experimental results and analysis show that ADFF can significantly reduce the security threats of MAs on ABC.
Constitutional Morality: An Indian Framework
Authors: Nayak Nakul
Published: October 2023

Over the last dozen years, Indian courts have formulated the idea that, inherent in the Indian Constitution, lies a type of morality referred to as constitutional morality (CM). CM acts as an interpretive device to help courts ascertain the meaning of the Constitution’s text in contested cases. Fundamental questions around CM, however, remain unaddressed: What are the methodological moves that courts have adopted to deploy CM in case law? What judicial premises and logics are at work in CM? And, given CM’s path dependence, what implications does CM have for Indian constitutional law and theory? This Article attempts to address these questions, using three levels of analysis. First, it explores the intellectual history of CM to ascertain how B.R. Ambedkar—the chief draftsperson of India’s Constitution—conceptualized it. Second, it develops a framework that situates CM as understood by Indian courts. Courts have given two distinct meanings to CM: (i) CM as a fiction that anchors the meaning of “morality” understood as a restriction to fundamental rights, and (ii) as an obligation on institutional actors to follow ethical political practices even when the law does not guide their conduct. This Article charts out both accounts and analyzes them on their own terms. Finally, it sketches two problems that the development of CM presents for Indian constitutional theory. As the Indian Supreme Court gears up to commence hearings on whether courts may continue to use CM as an interpretive device, the normative attractiveness of CM will be under the scanner. The framework and analyses I have developed can act as a foundation on which critiques and defenses of CM can take place.
Predicting enzymatic function of protein sequences with attention
Authors: Buton Nicolas , Coste François , Le Cunff Yann
Published: October 2023

Motivation

There is a growing number of available protein sequences, but only a limited amount has been manually annotated. For example, only 0.25% of all entries of UniProtKB are reviewed by human annotators. Further developing automatic tools to infer protein function from sequence alone can alleviate part of this gap. In this article, we investigate the potential of Transformer deep neural networks on a specific case of functional sequence annotation: the prediction of enzymatic classes.

Results

We show that our EnzBert transformer models, trained to predict Enzyme Commission (EC) numbers by specialization of a protein language model, outperforms state-of-the-art tools for monofunctional enzyme class prediction based on sequences only. Accuracy is improved from 84% to 95% on the prediction of EC numbers at level two on the EC40 benchmark. To evaluate the prediction quality at level four, the most detailed level of EC numbers, we built two new time-based benchmarks for comparison with state-of-the-art methods ECPred and DeepEC: the macro-F1 score is respectively improved from 41% to 54% and from 20% to 26%. Finally, we also show that using a simple combination of attention maps is on par with, or better than, other classical interpretability methods on the EC prediction task. More specifically, important residues identified by attention maps tend to correspond to known catalytic sites. Quantitatively, we report a max F-Gain score of 96.05%, while classical interpretability methods reach 91.44% at best.

Availability and implementation

Source code and datasets are respectively available at https://gitlab.inria.fr/nbuton/tfpc and https://doi.org/10.5281/zenodo.7253910
Vertical effects of cervical headgear in growing patients with Class II malocclusion: a systematic review and meta-analysis
Authors: Hussain Umar , Shah Ahsan Memood , Rabi Fazli , Campobasso Alessandra , Papageorgiou Spyridon N
Published: October 2023

Background

Cervical headgear (cHG) has been shown to be effective in Class II correction both with dental and orthopaedic effects but has traditionally been associated with vertical adverse effects in terms of posterior mandibular rotation.

Objective

To assess the treatment effects of cHG treatment in the vertical dimension.

Search methods

Unrestricted literature search of five databases up to May 2023.

Selection criteria

Randomized/non-randomized clinical studies comparing cHG to untreated controls, high-pull headgear (hp-HG), cHG adjuncts, or other Class II treatment alternatives (functional appliances or distalisers).

Data collection and analysis

After duplicate study selection, data extraction, and risk-of-bias assessment according to Cochrane, random-effects meta-analyses of mean differences (MD)/standardized mean diffences (SMD) and their 95% confidence intervals (CIs) were performed, followed by meta-regressions, sensitivity analyses, and assessment of certainty on existed evidence.

Results

Two randomized/16 non-randomized studies (12 retrospective/4 prospective) involving 1094 patients (mean age 10.9 years and 46% male) were included. Compared to natural growth, cHG treatment was not associated on average with increases in mandibular (eight studies; SMD 0.22; 95% CI −0.06, 0.49; P = 0.11) or maxillary plane angle (seven studies; SMD 0.81; 95% CI −0.34, 1.95; P=0.14). Observed changes translate to MDs of 0.48° (95% CI −0.13, 1.07°) and 1.22° (95% CI −0.51, 2.94°) in the SN-ML and SN-NL angles, respectively. No significant differences were seen in y-axis, facial axis angle, or posterior face height (P > 0.05). Similarly, no significant differences were found between cHG treatment and (i) addition of a lower utility arch, (ii) hp-HG treatment, and (iii) removable functional appliance treatment (P > 0.05 for all). Meta-regressions of patient age, sex, or duration and sensitivity analyses showed relative robustness, while our confidence in these estimates was low to very low due to the risk of bias, inconsistency, and imprecision.

Conclusions

cHG on average is not consistently associated with posterior rotation of the jaws or a consistent increase in vertical facial dimensions among Class II patients.

Registration

PROSPERO registration (CRD42022374603).
An isolated subcutaneous paraspinal pseudo-tumor—more to it than meets the eye—a case report and review of literature
Authors: Keny Swapnil , Modi Nihar , Keny Aryan , Gokhale Nikhil , Yadav Saurabh , Azad Kalpana
Published: October 2023

A 4-year-old male child presented to us with a paraspinal pseudo-tumor over the mid-back region with pain being his only symptom. On initial ultrasonography, it was presumed to be a nerve sheath tumor, but on an excision biopsy and histopathology, it proved to be a subcutaneous cysticercosis. Furthermore, an MRI of the brain showed a ring enhancing lesion with vasogenic edema, which confirmed the diagnosis of a neurologically symptomless neurocysticercosis. We treated the patient with albendazole and a short course of dexamethasone. There was complete resolution of the painful subcutaneous swelling, and the patient remained neurologically symptomless at all subsequent follow-ups. Resolution of the brain lesions was seen in the 6-month MRI follow-up. Although rare, orthopedic surgeons should consider the possibility of parasitic infections when dealing with small near-asymptomatic soft tissue paraspinal swellings of uncertain etiology. A thorough investigation in such cases can be lifesaving.
Gastric adenocarcinoma metastasis to the rectum causing complete obstruction, a case report
Authors: Bolliet Marine , Green Mary , Damadi Amir
Published: October 2023

Gastric adenocarcinoma is a leading cause of mortality worldwide. The most common sites of metastases are the liver, peritoneum, lungs, and bones. Cases have been described in the colon and rectum, but are very rare. This case report describes a patient in remission from diffuse signet ring cell type gastric adenocarcinoma with resection and chemoradiation close to 10 years prior to presenting with a near-obstructing rectal mass that was consistent with metastatic gastric adenocarcinoma. Gastric cancer spreads via hematogenous, lymphatic, peritoneal seeding, or local recurrence pathways. Given the length of time between initial presentation and eventual metastasis, the theory of dormancy is discussed and proposed as a possible cause in the delay of metastasis to the rectum. This highlights the importance of maintaining a high index of suspicion for recurrence and metastasis in a patient with a history of gastric cancer, who presents with a new obstructing rectal mass.
Undifferentiated embryonal sarcoma of the liver: a case report of a rare case in an adult patient
Authors: Marques Ana M , Fontinha Guilherme , Ferreira Maria João , Sá Milene , Constantino Júlio , Pereira Jorge
Published: October 2023

Undifferentiated embryonal sarcoma of the liver is a rare primary mesenchymal hepatic tumor that usually occurs in pediatric patients. In adulthood, this aggressive neoplasm represents only 7% of the liver sarcomas. This case reports a liver sarcoma occurring in a 49-year-old female patient. The patient was admitted in the emergency room with abdominal pain. Computerized tomography scan and magnetic resonance imaging showed a giant lobulated cystic mass in the right hepatic lobe, suggesting an atypical hemangioma. Right hepatectomy was performed. This rare case promotes a review of the differential diagnosis of liver primary neoplasms including sarcoma. The histological examination revealed an undifferentiated embryonal sarcoma. The patient underwent adjuvant chemotherapy. Currently, our patient is in complete sustained remission 4 years after chemotherapy.
Follicular thyroid carcinoma within a struma ovarii: a case report
Authors: Almnashef Rasha , Menchaf Ruba , Idres Fatima A , Aljammal Ghina , Mansour Marah , Farho Mohamad Ali , Ibrahim Zain A , Abbassi Haitham
Published: October 2023

Struma ovarii comprises 1% of all ovarian tumors and 3% of ovarian teratomas. It occurs in older females. Struma ovarii is often asymptomatic, unilateral, and accidentally detected through abdominal ultrasound or computed tomography. It presents with palpable abdominal pain or irregular menstrual cycles. Generally, it is treated with surgical resection, even though the best procedure in these cases remains under discussion. In this study, we present a case of a 28-year-old female with severe pain in the right iliac fossa. Physical examination and radiological images showed a large mass. A bilateral salpingo-oophorectomy with omentectomy, a total mass resection, and an abdominal hysterectomy were performed. A biopsy confirmed the diagnosis of a follicular thyroid tumor. The management decision is based on clinical and pathological data. This is particularly challenging due to its rarity and the insufficient guidelines regarding the management of this type of cancer.
Pediatric laryngeal schwannoma: a case report
Authors: Hamam Yaser A , Alqeeq Basel F , Hamam Mohammed , Abuhelal Ahmed M , Saqer Saleh A
Published: October 2023

Schwannomas are benign tumors originating from Schwann cells in the peripheral nervous system. They mostly occur in the head and neck region but are rare in the larynx, and present with various symptoms. Surgical removal is the recommended treatment. This study presents a 12-year-old female with sudden onset hemoptysis, snoring, difficulty breathing, dysphagia, and voice changes. On examination, she was conscious and had muffled voice while speaking, without signs of respiratory distress. Endoscopic laryngoscopy revealed a large laryngeal mass obstructing the vocal cords. Endoscopic excision and biopsy confirmed the presence of the laryngeal schwannoma. Postoperative recovery was uneventful, with normal vocal cord function and no recurrence at follow-up.
A feasibility randomized controlled trial testing the use of indocyanine green fluorescence image-guidance in liver surgery compared to standard liver surgery alone in reducing microscopic positive tumor margin resection rate with an embedded qualitative study: the I-FIGS study protocol
Authors: Karmarkar Rahi , Latour Jos , Hosking Joanne , Jayaraj Pavith , Aroori Somaiah
Published: October 2023

Indocyanine green fluorescence image-guidance (I-FIGS) is gaining global popularity in liver surgery for various applications. However, its true clinical value in reducing microscopic positive margins (R1-resection rate) remains uncertain. To address this, a multi-center randomized controlled trial (RCT) comparing I-FIGS with standard liver surgery is needed. However, due to a lack of essential information on potential R1 reduction rate, sample size, methodology, intervention delivery and patient experience, a feasibility RCT protocol has been developed to determine the viability of conducting a full-scale RCT. The aim of the study is to conduct a feasibility RCT (fRCT) with an embedded qualitative study to gather all the necessary information for a full-scale RCT. Adult patients undergoing elective liver surgery for colorectal liver metastasis (CRLMs), hepatocellular carcinoma (HCC) or peripheral cholangiocarcinoma will be eligible for the study. Forty patients will be randomly assigned to either the control group (standard liver surgery) or the intervention group (standard liver surgery + I-FIGS). Patients in the I-FIGS group will receive intravenous injection of 0.03–0.05 mg/kg indocyanine green (ICG) dye 2–4 hours before the surgery. Data will be collected on demographics, screening, recruitment and retention rates, adherence to study methods, intraoperative details, postoperative histology, and experiences of both surgeons and patients. Interviews will be conducted with selected patients and surgeons to explore their experiences with the intervention. The protocol has been approved by the West-Midlands-Solihull Research Ethics Committee and registered with ClinicalTrials.gov (NCT05616039). The results will be disseminated through academic publications, congresses, newsletters and other platforms.
The Charge of God: Laudato Si’ read through Chesterton, Wordsworth, and Hopkins
Authors: Hurley Michael D
Published: October 2023

G. K. Chesterton, William Wordsworth, and Gerard Manley Hopkins are set in conversation with Pope Francis’s Laudato Si’ (2015), to show how far those writers anticipate its animus against technocratic capitalism, but also, more surprisingly, how far Laudato Si’ challenges the progressive assumptions of contemporary eco-activism. Chesterton, Wordsworth, and Hopkins do not merely foreshadow and clarify the theological stakes of a papal document. By making even single words expressive of a whole worldview (achieving what William Empson called a ‘compacted doctrine’), their writings prove more imaginatively affective, as well as more theologically adequate than the communicative formalities available to the theological treatise as a genre.
Rotational excitation of interstellar benzonitrile by helium atoms
Authors: Ben Khalifa M , Loreau J
Published: October 2023

Interstellar aromatic molecules such as polycyclic aromatic hydrocarbons and polycyclic nitrogen and oxygen bearing molecules are thought to be abundant in the interstellar medium (ISM). In this class of molecules, benzonitrile (c-C6H5CN) plays an important role as a proxy for benzene. It has been detected through rotational emission in several astrophysical sources and is one of the simplest N-bearing polar aromatic molecules. Even in the cold ISM, the population of the rotational levels of benzonitrile might not be at equilibrium. Consequently, modelling its detected emission lines requires a prior computation of its quenching rate coefficients by the most abundant species in the ISM (He or H2). In this paper, we focus on the excitation of c-C6H5CN by collision with He. We compute the first potential energy surface (PES) using the explicitly correlated coupled cluster method in conjunction with large basis sets. The PES obtained is characterized by a potential well depth of −97.2 cm−1 and an important anisotropy. Scattering computations of the rotational (de-)excitation of c-C6H5CN by He atoms are performed by means of the coupled states approximation that allow to obtain collisional rates for rotational states up to j = 9 and temperatures up to 40 K. These rate coefficients are then used to examine the effect of C6H5CN excitation induced by collisions with para-H2 in molecular clouds by carrying out simple radiative transfer calculations of the excitation temperatures and show that non-equilibrium effects can be expected for H2 densities up to 105–106 cm−3.
Quasi-periodic oscillations during magnetar giant flares in the strangeon star model
Authors: Li Hong-Bo , Kang Yacheng , Hu Zexin , Shao Lijing , Xia Cheng-Jun , Xu Ren-Xin
Published: October 2023

Soft gamma-ray repeaters (SGRs) are widely understood as slowly rotating isolated neutron stars. Their generally large spin-down rates, high magnetic fields, and strong outburst energies render them different from ordinary pulsars. In a few giant flares (GFs) and short bursts of SGRs, high-confidence quasi-periodic oscillations (QPOs) were observed. Although remaining an open question, many theoretical studies suggest that the torsional oscillations caused by starquakes could explain QPOs. Motivated by this scenario, we systematically investigate torsional oscillation frequencies based on the strangeon star (SS) model with various values of harmonic indices and overtones. To characterize the strong-repulsive interaction at short distances and the non-relativistic nature of strangeons, a phenomenological Lennard–Jones model is adopted. We show that, attributing to the large shear modulus of SSs, our results explain well the high-frequency QPOs (≳150 Hz) during the GFs. The low-frequency QPOs (≲150 Hz) can also be interpreted when the ocean–crust interface modes are included. We also discuss possible effects of the magnetic field on the torsional mode frequencies. Considering realistic models with general-relativistic corrections and magnetic fields, we further calculate torsional oscillation frequencies for quark stars. We show that it would be difficult for quark stars to explain all QPOs in GFs. Our work advances the understanding of the nature of QPOs and magnetar asteroseismology.
The localization of galaxy groups in close proximity to galaxy clusters using cosmic web nodes
Authors: Cornwell Daniel J , Kuchner Ulrike , Gray Meghan E , Aragón-Salamanca Alfonso , Pearce Frazer R , Cui Weiguang , Knebe Alexander
Published: October 2023

We investigate the efficacy of using the cosmic web nodes identified by the DisPerSE topological filament finder to systematically identify galaxy groups in the infall regions around massive clusters. The large random motions and infall velocities of galaxies in the regions around clusters complicate the detection and characterisation of substructures through normal group-finding algorithms. Yet understanding the co-location of galaxies within filaments and/or groups is a key part of understanding the role of environment on galaxy evolution, particularly in light of next-generation wide-field spectroscopic surveys. Here we use simulated massive clusters from TheThreeHundred collaboration and compare the derived group catalogues, (haloes with σv > 300 h−1 km s−1) with the critical points from DisPerSE, ran on haloes with more than 100 particles. We find that in 3D, 56 per cent of DisPerSE nodes are correctly identified as groups (purity) while 68  per cent of groups are identified as nodes (completeness). The fraction of matches increases with group mass and with distance from the host cluster centre. This rises to a completeness of 100 per cent for the most massive galaxy groups (M > 1014 M⊙) in 3D, or 63 per cent when considering the projected 2D galaxy distribution. When a perfect match occurs between a cosmic web node and a galaxy group, the DisPerSE node density (δ) serves as an estimate of the group’s mass, albeit with significant scatter. We conclude that the use of a cosmic filament finder shows promise as a useful and straightforward observational tool for disentangling substructure within the infall regions of massive clusters.
The acoustic size of the Sun
Authors: Takata M , Gough D O
Published: October 2023

Analysis of f-mode frequencies has provided a measure of the radius of the Sun which is lower, by a few hundredths per cent, than the photospheric radius determined by direct optical measurement. Part of this difference can be understood by recognizing that it is primarily the variation of density well beneath the photosphere of the star that determines the structure of these essentially adiabatic oscillation modes, not some aspect of radiative intensity. In this paper we attempt to shed further light on the matter, by considering a differently defined, and dynamically more robust, seismic radius, namely one determined from p-mode frequencies. This radius is calibrated by the distance from the centre of the Sun to the position in the subphotospheric layers where the first derivative of the density scale height changes essentially discontinuously. We find that radius is more-or-less consistent with what is suggested by the f modes. In addition, the interpretation of the radius inferred from p modes leads us to understand more deeply the role of the total mass constraint in the structure inversions. This enables us to reinterpret the sound-speed inversion, suggesting that the positions of the photosphere and the adiabatically stratified layers in the convective envelope differ non-homologously from those of the standard solar model.
Making hot Jupiters in stellar clusters – II. Efficient formation in binary systems
Authors: Li Daohai , Mustill Alexander J , Davies Melvyn B , Gong Yan-Xiang
Published: October 2023

Observations suggested that the occurrence rate of hot Jupiters (HJs) in open clusters is largely consistent with the field ($\sim 1{{\ \rm per\ cent}}$) but in the binary-rich cluster M67, the rate is $\sim 5{{\ \rm per\ cent}}$. How does the cluster environment boost HJ formation via the high-eccentricity tidal migration initiated by the extreme-amplitude von Zeipel–Lidov–Kozai (XZKL) mechanism forced by a companion star? Our analytical treatment shows that the cluster’s collective gravitational potential alters the companion’s orbit slowly, which may render the star–planet–companion configuration XZKL-favourable. We have also performed direct Gyr N-body simulations of the star cluster evolution and XZKL of planets’ orbit around member stars. We find that an initially single star may acquire a companion star via stellar scattering and the companion may enable XZKL in the planets’ orbit. Planets around an initially binary star may also be XZKL-activated by the companion. In both scenarios, the companion’s orbit has likely been significantly changed by stellar scattering and the cluster potential before XZKL occurs. Across different cluster models, 0.8–3 per cent of the planets orbiting initially single stars have experienced XZKL while the fraction is 2–26 per cent for initially binary stars. Around a star that is binary at 1 Gyr, 13–32 per cent of its planets have undergone XZKL, and combined with single stars, the overall XZKL fraction is 3–21 per cent, most affected by the cluster binarity. If 10 per cent of the stars in M67 host a giant planet, our model predicts an HJ occurrence rate of $\sim 1{{\ \rm per\ cent}}$. We suggest that HJ surveys target old, high-binarity, not-too-dense open clusters and prioritize wide binaries to maximize HJ yield.
The three hundred project: thermodynamical properties, shocks, and gas dynamics in simulated galaxy cluster filaments and their surroundings
Authors: Rost Agustín M , Nuza Sebastián E , Stasyszyn Federico , Kuchner Ulrike , Hoeft Matthias , Welker Charlotte , Pearce Frazer , Gray Meghan , Knebe Alexander , Cui Weiguang , Yepes Gustavo
Published: October 2023

Using cosmological simulations of galaxy cluster regions from The Three Hundred project, we study the nature of gas in filaments feeding massive clusters. By stacking the diffuse material of filaments throughout the cluster sample, we measure average gas properties such as density, temperature, pressure, entropy and Mach number and construct one-dimensional profiles for a sample of larger, radially oriented filaments to determine their characteristic features as cosmological objects. Despite the similarity in velocity space between the gas and dark matter accretion patterns on to filaments and their central clusters, we confirm some differences, especially concerning the more ordered radial velocity dispersion of dark matter around the cluster and the larger accretion velocity of gas relative to dark matter in filaments. We also study the distribution of shocked gas around filaments and galaxy clusters, showing that the surrounding shocks allow an efficient internal transport of material, suggesting a laminar infall. The stacked temperature profile of filaments is typically colder towards the spine, in line with the cosmological rarefaction of matter. Therefore, filaments are able to isolate their inner regions, maintaining lower gas temperatures and entropy. Finally, we study the evolution of the gas density–temperature phase diagram of our stacked filament, showing that filamentary gas does not behave fully adiabatically through time but it is subject to shocks during its evolution, establishing a characteristic z = 0, entropy-enhanced distribution at intermediate distances from the spine of about $1{-}2\, h^{-1}\,$ Mpc for a typical galaxy cluster in our sample.
An empirical connection between line-emitting regions and X-rays heating the accretion disc in BH-LMXB MAXI J1820+070
Authors: Tetarenko B E , Shaw A W , Charles P A
Published: October 2023

The recurring transient outbursts in low-mass X-ray binaries (LMXBs) provide ideal laboratories to study the accretion process. Unlike their supermassive relatives, LMXBs are far too small and distant to be imaged directly. Fortunately, phase-resolved spectroscopy can provide an alternative diagnostic to study their highly complex, time-dependent accretion discs. The primary spectral signature of LMXBs are strong, disc-formed emission lines detected at optical wavelengths. The shape, profile, and appearance/disappearance of these lines change throughout a binary orbit, and thus, can be used to trace how matter in these discs behaves and evolves over time. By combining a Swift multiwavelength monitoring campaign, phase-resolved spectroscopy from the Gran Telescopio Canarias (GTC) and Liverpool Telescope, and modern astrotomography techniques, we find a clear empirical connection between the line emitting regions and physical properties of the X-rays heating the disc in the black hole LMXB MAXI J1820+070 during its 2018 outburst. In this paper, we show how these empirical correlations can be used as an effective observational tool for understanding the geometry and structure of a LMXB accretion disc and present further evidence for an irradiation-driven warped accretion disc present in this system.
MaNGA DynPop – III. Stellar dynamics versus stellar population relations in 6000 early-type and spiral galaxies: Fundamental Plane, mass-to-light ratios, total density slopes, and dark matter fractions
Authors: Zhu Kai , Lu Shengdong , Cappellari Michele , Li Ran , Mao Shude , Gao Liang , Ge Junqiang
Published: October 2023

We present dynamical scaling relations, combined with the stellar population properties, for a subsample of about 6000 nearby galaxies with the most reliable dynamical models extracted from the full Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) sample of 10 000 galaxies. We show that the inclination-corrected mass plane for both early-type galaxies (ETGs) and late-type galaxies (LTGs), which links dynamical mass, projected half-light radius Re, and the second stellar velocity moment σe within Re, satisfies the virial theorem and is even tighter than the uncorrected one. We find a clear parabolic relation between $\lg (M/L)_{\rm e}$, the total mass-to-light ratio (M/L) within a sphere of radius Re, and $\lg \sigma _{\rm e}$, with the M/L increasing with σe and for older stellar populations. However, the relation for ETGs is linear and the one for the youngest galaxies is constant. We confirm and improve the relation between mass-weighted total density slopes $\overline{\gamma _{_{\rm T}}}$ and σe: $\overline{\gamma _{_{\rm T}}}$ become steeper with increasing σe until $\lg (\sigma _{\rm e}/{\rm km\, s^{-1}})\approx 2.2$ and then remain constant around $\overline{\gamma _{_{\rm T}}}\approx 2.2$. The $\overline{\gamma _{_{\rm T}}}\!-\!\sigma _{\rm e}$ variation is larger for LTGs than ETGs. At fixed σe the total density profiles steepen with galaxy age and for ETGs. We find generally low dark matter fractions, median fDM(<Re) = 8 per cent, within a sphere of radius Re. However, we find that fDM(<Re) depends on σe better than stellar mass: dark matter increases to a median fDM(<Re) = 33 per cent for galaxies with $\sigma _{\rm e}\lesssim 100$ km s−1. The increased fDM(<Re) at low σe explains the parabolic $\lg (M/L)_{\rm e}\!-\!\lg \sigma _{\rm e}$ relation.
Constraining the formation history of the TOI-1338/BEBOP-1 circumbinary planetary system
Authors: Coleman Gavin A L , Nelson Richard P , Triaud Amaury H M J , Standing Matthew R
Published: October 2023

The recent discovery of multiple planets in the circumbinary system TOI-1338/BEBOP-1 raises questions about how such a system formed. The formation of the system was briefly explored in the discovery paper, but only to answer the question do current pebble accretion models have the potential to explain the origin of the system? We use a global model of circumbinary planet formation that utilizes N-body simulations, including prescriptions for planet migration, gas and pebble accretion, and interactions with a circumbinary disc, to explore the disc parameters that could have led to the formation of the TOI-1338/BEBOP-1 system. With the disc lifetime being the main factor in determining how planets form, we limit our parameter space to those that determine the disc lifetime. These are: the strength of turbulence in the disc, the initial disc mass, and the strength of the external radiation field that launches photoevaporative winds. When comparing the simulated systems to TOI-1338/BEBOP-1, we find that only discs with low levels of turbulence are able to produce similar systems. The radiation environment has a large effect on the types of planetary systems that form, whilst the initial disc mass only has limited impact since the majority of planetary growth occurs early in the disc lifetime. With the most TOI-1338/BEBOP-1 like systems all occupying similar regions of parameter space, our study shows that observed circumbinary planetary systems can potentially constrain the properties of planet forming discs.
On the correlations of galaxy peculiar velocities and their covariance
Authors: Blake Chris , Turner Ryan J
Published: October 2023

Measurements of the peculiar velocities of large samples of galaxies enable new tests of the standard cosmological model, including determination of the growth rate of cosmic structure that encodes gravitational physics. With the size of such samples now approaching hundreds of thousands of galaxies, complex statistical analysis techniques and models are required to extract cosmological information. In this paper, we summarize how correlation functions between galaxy velocities, and with the surrounding large-scale structure, may be utilized to test cosmological models. We present new determinations of the analytical covariance between such correlation functions, which may be useful for cosmological likelihood analyses. The statistical model we use to determine these covariances includes the sample selection functions, observational noise, curved-sky effects, and redshift-space distortions. By comparing these covariance determinations with corresponding estimates from large suites of cosmological simulations, we demonstrate that these analytical models recover the key features of the covariance between different statistics and separations, and produce similar measurements of the growth rate of structure.
Accretion flows in the hard state of black hole X-ray binaries: the effect of hot gas condensation
Authors: Wang Yilong , Liu B F , Qiao Erlin , Cheng Huaqing
Published: October 2023

It is commonly believed that accretion discs are truncated and their inner regions are described by advection dominated accretion flows (ADAFs) in the hard spectral state of black hole X-ray binaries. However, the increasing occurrence of a relativistically blurred Fe K α line together with a hard continuum points to the existence of a thin disc located near the innermost stable circular orbit (ISCO). Assuming the accretion in the hard state is via an ADAF extending to near 100 Schwarzschild radii, which is supplied by either a stellar wind from a companion star or resulting from an evaporated disc, we study the possible condensation of the hot gas during its accretion towards the black hole. It is found that a small fraction of the ADAF condenses into a cold disc as a consequence of efficient radiative cooling at small distances, forming a disc-corona configuration near the ISCO. This takes place for low accretion rates corresponding to luminosities ranging from ∼10−3 to a few per cent of the Eddington luminosity. The coexistence of the weak inner disc and the dominant hot accretion flow provides a natural explanation of the broad K α line in the hard state. Detailed computations demonstrate that such accretion flows produce a hard X-ray spectrum accompanied by a weak disc component with a negative correlation between the 2 and 10 keV photon index and the Eddington ratio. The predicted spectrum of Cygnus X-1 and the correlation between the photon index and the Eddington ratio are in good agreement with observations.
ExoMol line lists – LIII: empirical rovibronic spectra of yttrium oxide
Authors: Yurchenko Sergei N , Brady Ryan P , Tennyson Jonathan , Smirnov Alexander N , Vasilyev Oleg A , Solomonik Victor G
Published: October 2023

Empirical line lists BRYTS for the open shell molecule 89Y16O (yttrium oxide) and its isotopologues are presented. The line lists cover the six lowest electronic states: $X\, {}^{2}\Sigma ^{+}$, $A\, {}^{2}\Pi$, $A^{\prime }\, {}^{2}\Delta$, $B\, {}^{2}\Sigma ^{+}$, $C\, {}^{2}\Pi$, and $D\, {}^{2}\Sigma ^{+}$ up to 60 000 cm−1 (<0.167 $\mu$m) for rotational excitation up to J = 400.5. An ab initio spectroscopic model consisting of potential energy curves (PECs), spin–orbit, and electronic angular momentum couplings is refined by fitting to experimentally determined energies of YO, derived from published YO experimental transition frequency data. The model is complemented by empirical spin-rotation and Λ-doubling curves and ab initio dipole moment and transition dipole moment curves computed using multireference configuration interaction (MRCI). The ab initio PECs computed using the complete basis set limit extrapolation and the coupled-cluster CCSD(T) method with its higher quality provide an excellent initial approximation for the refinement. Non-adiabatic coupling curves for two pairs of states of the same symmetry A/C and B/D are computed using a state-averaged complete active space self-consistant field theory (CASSCF) and used to build diabatic representations for the $A\, {}^{2}\Pi$, $C\, {}^{2}\Pi$, $B\, {}^{2}\Sigma ^{+}$, and $D\, {}^{2}\Sigma ^{+}$ curves. The experimentally derived energies of 89Y16O utilized in the fit are used to replace the corresponding calculated energy values in the BRYTS line list. Simulated spectra of YO show excellent agreement with the experiment, where it is available. Calculated lifetimes of YO are tuned to agree well with the experiment, where available. The BRYTS YO line lists are available from the ExoMol database (www.exomol.com).
ExoMol line lists – LI. Molecular line lists for lithium hydroxide (LiOH)
Authors: Owens Alec , Wright Sam O M , Pavlenko Yakiv , Mitrushchenkov Alexander , Koput Jacek , Yurchenko Sergei N , Tennyson Jonathan
Published: October 2023

New molecular line lists for lithium hydroxide (6Li16O1H and 7Li16O1H isotopologues) covering wavelengths λ > 1 $\mu$m (0–10 000 cm−1 range) are presented. Each line list contains around 300 million transitions between rotation–vibration energy levels with total angular momentum up to J = 95, applicable for temperatures up to T ≈ 3500 K. Line list calculations were based on a previously published, high-level ab initio potential energy surface and a newly computed dipole moment surface of the ground $\tilde{X}\, ^1\Sigma ^+$ electronic state. Lithium-containing molecules are important in a variety of stellar objects and there is potential for LiOH to be observed in the atmospheres of exoplanets. Transit spectra are simulated using the rocky super-Earth 55 Cancri e as an example with two different atmospheric scenarios including LiOH. This work provides the first, comprehensive line lists of LiOH to facilitate its future molecular detection. The OYT7 line lists along with the associated temperature- and pressure-dependent molecular opacities can be downloaded from the ExoMol database at www.exomol.com and the CDS astronomical database.
Rotation periods and colours of 10-m-scale near-Earth asteroids from CFHT target of opportunity streak photometry
Authors: Bolin B T , Ghosal M , Jedicke R
Published: October 2023

The rotational properties of ∼10-m-scale asteroids are poorly understood with only a few measurements. Additionally, collisions or thermal recoil can spin their rotations to periods less than a few seconds obfuscating their study due to the observational cadence imposed by the long read-out times of charge-coupled device imagers. We present a method to measure the rotation periods of 10-m-scale asteroids using the target of opportunity capability of the Canada–France–Hawaii Telescope (CFHT) and its MegaCam imager by intentionally streaking their detections in single exposures when they are at their brightest. Periodic changes in brightness as small as ∼0.05 mag along the streak can be measured as short as a few seconds. Additionally, the streak photometry is taken in multiple g, r, and i filter exposures enabling the measurement of asteroid colours. The streak photometry method was tested on CFHT observations of three 10-m-scale asteroids, 2016 GE1, 2016 CG18, and 2016 EV84. Our three targets are among the smallest known asteroids with measured rotation periods/colours having some of the shortest known rotation periods. We compare our rotation period and taxonomic results with independent data from the literature and discuss applications of the method to future small asteroid observations.
Sulphur X-ray absorption in the local ISM
Authors: Gatuzz Efrain , Gorczyca T W , Hasoglu M F , Costantini E , García Javier A , Kallman Timothy R
Published: October 2023

We present a study S K-edge using high-resolution HETGS Chandra spectra of 36 low-mass X-ray binaries. For each source, we have estimated column densities for S i, S ii, S iii, S xiv, S xv, and S xvi ionic species, which trace the neutral, warm, and hot phases of the Galactic interstellar medium. We also estimated column densities for a sample of interstellar dust analogues. We measured their distribution as a function of Galactic latitude, longitude, and distances to the sources. While the cold-warm column densities tend to decrease with the Galactic latitude, we found no correlation with distances or Galactic longitude. This is the first detailed analysis of the sulphur K-edge absorption due to ISM using high-resolution X-ray spectra.
Characterization of black hole accretion through image moment invariants
Authors: Jiménez-Rosales A , Yfantis A I , Mościbrodzka M , Dexter J
Published: October 2023

We apply image moment invariant analysis to total intensity and polarimetric images calculated from general relativistic magnetohydrodynamic simulations of accreting black holes. We characterize different properties of the models in our library by their invariant distributions and their evolution in time. We show that they are highly sensitive to different physical effects present in the system which allow for model discrimination. We propose a new model scoring method based on image moment invariants that is uniformly applicable to total intensity and polarimetric images simultaneously. The method does not depend on the type of images considered and its application to other non-ring like images (e.g. jets) is straight forward.
Testing the surface brightness fluctuation method on dwarf galaxies in the COSMOS field
Authors: Foster Lauren M , Taylor James E , Blakeslee John P
Published: October 2023

Dwarf galaxies are important tracers of small-scale cosmological structure, yet much of our knowledge about these systems comes from the limited sample of dwarf galaxies within the Local Group. To make a comprehensive inventory of dwarf populations in the local Universe, we require effective methods for deriving distance estimates for large numbers of faint, low surface brightness objects. Here we test the surface brightness fluctuation (SBF) method, traditionally applied to brighter early-type galaxies, on a sample of 20 nearby dwarf galaxies detected in the Cosmological Evolution Survey (COSMOS) field. These objects are partially resolved in the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) images and have confirmed redshift distances in the range 17–130 Mpc. We discuss the many model choices required in applying the SBF method and explore how these affect the final distance estimates. Amongst other variations on the method, when applying the SBF method, we alter the standard equation to include a term accounting for the power spectrum of the background, greatly improving our results. For the most robust modelling choices, we find a roughly Gaussian SBF signal that correlates linearly with distance out to distances of 50–100 Mpc, but with only a fraction of the power expected. At larger distances, there is excess power relative to that predicted, probably from undetected point sources. Overall, obtaining accurate SBF distances to faint, irregular galaxies remains challenging, but may yet prove possible with the inclusion of more information about galaxy properties and point source populations, and the use of more advanced techniques.
Light curve and hardness tests for millilensing in GRB 950830, GRB 090717A, and GRB 200716C
Authors: Mukherjee Oindabi , Nemiroff Robert
Published: October 2023

Two different temporal sections of a single gamma-ray burst (GRB) must be statistically similar to show an internal gravitational lensing signature. Here, two straightforward gravitational lensing tests are defined and applied: a light curve similarity test and a hardness similarity test. Gravitational millilensing has been claimed to be detected within several individual GRBs that contain two emission episodes separated by a time-delay. However, our analyses indicate that none of those claims satisfy both tests. The hardness similarity test performed on GRB 950830 and GRB 090717A found that the ratio between the second and the first emission episodes in each energy channel differed from the same ratio averaged over all detected energy channels at around 90 per cent confidence level. Also, a light curve similarity test performed on GRB 950830, GRB 090717A, and GRB 200716C separately found that it is unlikely that the two emission episodes in each GRB were drawn from a single parent emission episode for that GRB, with differences at the 3.0σ, 5.84σ, and 9.35σ confidence levels, respectively.