Central Source Research Articles

Ultradeep ATCA Imaging of 47 Tucanae Reveals a Central Compact Radio Source

We present the results of an ultradeep radio continuum survey, containing ∼480 hr of observations, of the Galactic globular cluster 47 Tucanae with the Australia Telescope Compact Array. This comprehensive coverage of the cluster allows us to reach rms noise levels of 1.19 μJy beam−1 at 5.5 GHz, 940 nJy beam−1 at 9 GHz, and 790 nJy beam−1 in a stacked 7.25 GHz image. This is the deepest radio image of a globular cluster and the deepest image ever made with the Australia Telescope Compact Array. We identify ATCA J002405.702-720452.361, a faint (6.3 ± 1.2 μJy at 5.5 GHz, 5.4 ± 0.9 μJy at 9 GHz), flat-spectrum (α = −0.31 ± 0.54) radio source that is positionally coincident with the cluster center and potentially associated with a faint X-ray source. No convincing optical counterpart was identified. We use radio, X-ray, optical, and UV data to show that explanations involving a background active galactic nucleus, a chromospherically active binary, or a binary involving a white dwarf are unlikely. The most plausible explanations are that the source is an undiscovered millisecond pulsar or a weakly accreting black hole. If the X-ray source is associated with the radio source, the fundamental plane of black-hole activity suggests a black hole mass of ∼54–6000 M ⊙, indicating an intermediate-mass black hole or a heavy stellar-mass black hole.

Effect of topical emollient oil application on weight of preterm newborns: A systematic review and meta-analysis.

Synthesizing current evidence on interventions to improve survival outcomes in preterm infants is crucial for informing programs and policies. The objective of this study is to investigate the impact of topical emollient oil application on the weight of preterm infants. A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted. To identify relevant studies, comprehensive searches were conducted across multiple databases, including PubMed, Cochrane, Scopus, Clinical trials, ProQuest Central, Epistemonikos, and gray literature sources. The inclusion criteria were based on the PICO (Population, Intervention, Comparison, and Outcomes) format. Study quality was assessed using the Cochrane risk of bias tool for randomized trials (RoB 2.0). Data analysis was performed using StataCrop MP V.17 software, which included evaluating heterogeneity, conducting subgroup analysis, sensitivity analysis, and meta-regression. The findings were reported in accordance with the PRISMA checklist, and the review was registered with PROSPERO (CRD42023413770). Out of the initial pool of 2734 articles, a total of 18 studies involving 1454 preterm neonates were included in the final analysis. Fourteen of these studies provided data that contributed to the calculation of the pooled difference in mean weight gain in preterm neonates. The random effects meta-analysis revealed a significant pooled difference in mean weight gain of 52.15 grams (95% CI: 45.96, 58.35), albeit with high heterogeneity (I2 > 93.24%, p 0.000). Subgroup analyses were conducted, revealing that preterm infants who received massages three times daily with either sunflower oil or coconut oil exhibited greater mean differences in weight gain. Meta-regression analysis indicated that the type of emollient oil, duration of therapy, and frequency of application significantly contributed to the observed heterogeneity. A sensitivity analysis was performed, excluding two outlier studies, resulting in a pooled mean weight difference of 78.57grams (95% CI: 52.46, 104.68). Among the nine studies that reported adverse events, only two mentioned occurrences of rash and accidental slippage in the intervention groups. The available evidence suggests that the application of topical emollient oil in preterm neonates is likely to be effective in promoting weight gain, with a moderate-to-high level of certainty. Based on these findings, it is recommended that local policymakers and health planners prioritize the routine use of emollient oils in newborn care for preterm infants. By incorporating emollient oils into standard care protocols, healthcare providers can provide additional support to promote optimal growth and development in preterm infants.

Unravelling the post-collision properties of the Cartwheel galaxy: A MUSE exploration of its bar and inner region

Aims. We aim to investigate the characteristics of the bar and inner disc in the collisional ring galaxy Cartwheel. Methods. We used integral field unit (IFU) observations from the Multi-Unit Spectroscopic Explorer (MUSE) of the Very Large Telescope (VLT) to investigate the stellar kinematics, age, and nature of ionised gas in the inner region of the Cartwheel galaxy. We produced stellar line of sight velocity (V), velocity dispersion (σ), h3 velocity moment, stellar population age, and emission-line maps of the galaxy using the Galaxy IFU Spectroscopy Tool (GIST) pipeline. Results. The observed nature of the intensity, V, and σ profiles together support the existence of a stellar bar, as earlier revealed from near-infrared (NIR) Ks-band imaging. A weak correlation between V/σ and h3 is found within the bar radius, providing more kinematic evidence for a stellar bar that survived the drop-through collision. The overall weak anti-correlation between V/σ and h3 in the disc implies that the stellar orbits in the disc are less stable, which might be due to the impact of the collision. The mass-weighted age map of the galaxy shows that the stellar populations in the bar region are relatively old, with an increasing gradient from the bar edge to the centre, further evidence that the bar was present before the galaxy underwent collision. Using a BPT diagram, we analysed a central unresolved source detected earlier with NIR imaging and do not find evidence of an active galactic nucleus. Our findings signify the preservation of the pre-collisional structures in the inner region of the Cartwheel, an important point to note when attempting to determine the evolution of collisional galaxy systems, particularly when investigating pre-collisional central regions in theoretical studies.

The persistent shadow of the supermassive black hole of M 87

In April 2019, the Event Horizon Telescope (EHT) Collaboration reported the first-ever event-horizon-scale images of a black hole, resolving the central compact radio source in the giant elliptical galaxy M 87. These images reveal a ring with a southerly brightness distribution and a diameter of ∼42 μas, consistent with the predicted size and shape of a shadow produced by the gravitationally lensed emission around a supermassive black hole. These results were obtained as part of the April 2017 EHT observation campaign, using a global very long baseline interferometric radio array operating at a wavelength of 1.3 mm. Here, we present results based on the second EHT observing campaign, taking place in April 2018 with an improved array, wider frequency coverage, and increased bandwidth. In particular, the additional baselines provided by the Greenland telescope improved the coverage of the array. Multiyear EHT observations provide independent snapshots of the horizon-scale emission, allowing us to confirm the persistence, size, and shape of the black hole shadow, and constrain the intrinsic structural variability of the accretion flow. We have confirmed the presence of an asymmetric ring structure, brighter in the southwest, with a median diameter of 43.3−3.1+1.5 μas. The diameter of the 2018 ring is remarkably consistent with the diameter obtained from the previous 2017 observations. On the other hand, the position angle of the brightness asymmetry in 2018 is shifted by about 30° relative to 2017. The perennial persistence of the ring and its diameter robustly support the interpretation that the ring is formed by lensed emission surrounding a Kerr black hole with a mass ∼6.5 × 109 M⊙. The significant change in the ring brightness asymmetry implies a spin axis that is more consistent with the position angle of the large-scale jet.

Re-examining prophylactic cranial irradiation in small cell lung cancer: a systematic review and meta-analysis

Patients with small cell lung cancer (SCLC) are at high risk for brain metastases. Prophylactic cranial irradiation (PCI) is recommended in this population to reduce the incidence of brain metastases and prolong survival. We aimed to assesses the efficacy of PCI in this population in the era of routine brain imaging. To our knowledge, this is the first systematic review and meta-analysis to examine the use among patients who were radiographically confirmed not to have brain metastases after completion of first-line therapy. In this systematic review and meta-analysis, cohort studies and controlled trials reporting on the use of PCI for patients SCLC were identified in EMBASE, MEDLINE, CENTRAL, and grey literature sources. The literature search was conducted on November 12, 2023. Summary data were extracted. Random-effects meta-analyses pooled hazard ratios (HR) for the primary outcome of overall survival between PCI and no intervention groups. This study is registered with the Open Science Framework, DOI:10.17605/OSF.IO/BC359, and PROSPERO, CRD42021249466. Of 4318 identified records, 223 were eligible for inclusion. 109 reported on overall survival in formats amenable to meta-analysis; PCI was associated with longer survival in all patients with SCLC (HR 0.59; 95% CI, 0.55-0.63; p<0.001; n=56,770 patients), patients with limited stage disease (HR 0.60; 95% CI, 0.55-0.65; p<0.001; n=78 studies; n=27,137 patients), and patients with extensive stage disease (HR 0.59; 95% CI, 0.51-0.70; p<0.001; n=28 studies; n=26,467 patients). Between-study heterogeneity was significant when pooled amongst all studies (I2=73.6%; 95% CI 68.4%-77.9%). Subgroup analysis did not reveal sources of heterogeneity. In a subgroup analysis on studies that used magnetic resonance imaging to exclude presence of brain metastases at restaging among all patients, overall survival did not differ significantly between patients who did or did not receive PCI (HR 0.74; 95% CI, 0.52-1.05; p=0.08; n=9 studies; n=1384 patients). Our findings suggested that administration of PCI is associated with a survival benefit, but not when considering studies that radiographically confirmed absence of brain metastases, suggesting that the survival benefit conferred by PCI might be therapeutic rather than prophylactic. No funding.

Impacto de la estrategia de marketing en el rendimiento de las ventas: Un estudio de una muestra de propietarios de microempresas y pequeñas empresas

The marketing strategies (7Ps) are the cornerstone of any enterprise. Therefore, the current research was designed to investigate the impact of marketing strategies on the sales performance of small and micro-scale enterprises in Duhok Province. In this regard, the research aims to test the impact of relationship marketing strategies (product, price, place, promotion, process, people, and physical evidence) on sales performance, as well as how they can be implemented and managed. Undoubtedly, the current research relied on descriptive and analytical method to conduct this research. For this purpose, the data collection technique included a central and secondary source in order to provide a theoretical framework. As for data analysis tools consist of validity and reliability tests, descriptive statistics of participants and variables, correlation analysis, and impact factor analysis via using the most recent version of Statistical Package for Social Sciences (SPSS V. 28). Nevertheless, the present research employed a random sampling that consists of business owners of micro and small scale businesses in Iraq-Kurdistan region, which this research just selected Duhok governorate out of 4 cities. In contrast, the questionnaire survey is the key tool of this research, which was distributed to (150) business leaders (130) questionnaires were gathered, (123) surveys were validated and ready for data analysis and research tests with a response rate valued (82%) of the targeted sample, and reliability factor was (0.928). As a result, several conclusions and suggestions were deduced from this research with an enormous majority of respondents of agreement scales valued (74%). Furthermore, the research concluded that there is a positive significant relationship and impact between marketing strategies (MS) and sales performance (SP) it infers this link is critical to expand profitability, productivity, and growth rates of micro and small areas.

Beneficial and harmful effects of tricyclic antidepressants for adults with major depressive disorder: a systematic review with meta-analysis and trial sequential analysis

QuestionTricyclic antidepressants are used to treat depression worldwide, but the adverse effects have not been systematically assessed. Our objective was to assess the beneficial and harmful effects of all tricyclic...

Analysis of Nuclear Explosion Detection Capability of IMS Hydroacoustic Network

The Comprehensive Nuclear Test Ban Treaty (CTBT) organization has established a hydroacoustic network to ensure the effective detection of nuclear explosions in the vast ocean and in the atmosphere over it in order to effectively guarantee the implementation of the treaty. To assess its effectiveness, according to the reciprocity of underwater acoustic field, this study employs the hydrophone position as the central sound source and utilizes the parabolic equation, along with seabed topography and sound velocity profile data, to estimate the transmission loss. Background noise levels of station evaluation are conducted by using historical data so as to estimate the underwater nuclear explosion sound source level via a passive sonar equation. Utilizing the full ship shock trial (FSST) results of the “Ford” aircraft carrier on June 18, 2021, as a case study, the detection capability of the HA10 station for nuclear explosions is investigated. Subsequently, the network’s overall detection capability was evaluated using the source level at 20 Hz corresponding to a 1 kiloton nuclear explosion yield as a reference. Findings indicate the network’s proficiency in identifying long‐distance propagation signals, particularly those with high explosion source levels within the sound fixing and ranging (SOFAR) channel. The sensitivity analysis demonstrates the network’s ability to detect explosions smaller than 1 kg equivalent in close proximity to a station, and larger explosions exceeding 1 kg or 1 ton at greater distances. This evaluation underscores the network’s significance in detecting and monitoring underwater nuclear explosions across extensive oceanic regions.

Cyberspace and sovereignty in public international law

The paper studies the manifestation of cyberspace in the context of the principle of sovereignty as a fundamental principle of public international law. It is a young phenomenon that is still difficult to define in a clear way in the international community. The author analyzes whether, to what extent, and which formal sources of public international law apply to cyberspace. The analysis focuses on three central sources of public international law - international treaties, international customs and general legal rules. Cyberspace is then analyzed from two angles. The first, external aspect of the analysis seeks an answer to the question of whether, first of all, states as central subjects of international public law, but also the international community and to what extent, have sovereignty over cyberspace. Second, internal segment of the analysis is aimed at determining whether cyberspace has its own sovereignty. The paper briefly reviews the perspectives of the leading world powers, above all the United States of America, the People?s Republic of China and the Russian Federation. The author concludes that it is necessary to continue working on the regulation of cyberspace, primarily through the institutions of the United Nations. Only regulation at this level can provide the necessary legal regulations that will adequately regulate a specific area such as cyberspace.

ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Discovery of an Extremely Dense and Compact Object Embedded in the Prestellar Core G208.68-19.92-N2

The internal structure of the prestellar core G208.68-19.02-N2 (G208-N2) in the Orion Molecular Cloud 3 (OMC-3) region has been studied with the Atacama Large Millimeter/submillimeter Array. The dust continuum emission revealed a filamentary structure with a length of ∼5000 au and an average H2 volume density of ∼6 × 107 cm−3. At the tip of this filamentary structure, there is a compact object, which we call a nucleus, with a radius of ∼150–200 au and a mass of ∼0.1 M ⊙. The nucleus has a central density of ∼2 × 109 cm−3 with a radial density profile of r −1.87±0.11. The density scaling of the nucleus is ∼3.7 times higher than that of the singular isothermal sphere (SIS). This as well as the very low virial parameter of 0.39 suggests that the gravity is dominant over the pressure everywhere in the nucleus. However, there is no sign of CO outflow localized to this nucleus. The filamentary structure is traced by the N2D+ 3–2 emission, but not by the C18O 2–1 emission, implying the significant CO depletion due to high density and cold temperature. Toward the nucleus, the N2D+ also shows the signature of depletion. This could imply either the depletion of the parent molecule, N2, or the presence of the embedded very-low luminosity central source that could sublimate the CO in the very small area. The nucleus in G208-N2 is considered to be a prestellar core on the verge of first hydrostatic core (FHSC) formation or a candidate for the FHSC.

Spectroscopic variability of massive pre-main-sequence stars in M17

Context. It is a challenge to study the formation process of massive stars: their formation time is short, there are only few of them, they are often deeply embedded, and they lie at relatively large distances. Our strategy is to study the outcome of the star formation process and to search for signatures that remain of the formation. We have access to a unique sample of (massive) pre-main-sequence (PMS) stars in the giant H II region M17. These PMS stars can be placed on PMS tracks in the Hertzsprung–Russell diagram (HRD) as we can detect their photospheric spectrum, and they exhibit spectral features indicative of the presence of a circumstellar disk. These stars are most likely in the final stage of formation. Aims. The aim is to use spectroscopic variability as a diagnostic tool to learn about the physical nature of these massive PMS stars. More specifically, we wish to determine the variability properties of the hot gaseous disks to understand the physical origin of the emission lines, identify dominant physical processes in these disks, and to find out about the presence of an accretion flow and/or jet. Methods. We obtained multiple-epoch (four to five epochs) VLT/X-shooter spectra of six young stars in M17 covering about a decade. Four of these stars are intermediate to massive PMS stars with gaseous disks. Using stacked spectra, we updated the spectral classification and searched for the presence of circumstellar features. With the temporal variance method (TVS), we determined the extent and amplitude of the spectral line variations in velocity space. The double-peaked emission lines in the PMS stars with gaseous disks were used to determine peak-to-peak velocities, V/R ratios, and the radial velocity of the systems. Simultaneous photometric variations were studied using VLT acquisition images. Results. From detailed line identification in the PMS stars with gaseous disks, we identify many (double-peaked) disk features, including a new detection of CO bandhead and CI emission. In three of these stars, we detect significant spectral variability, mainly in lines originating in the circumstellar disk, in a velocity range up to 320 km s−1, which exceeds the rotational velocity of the central sources. The shortest variability timescale is about one day. We also detect long-term (months, years) variability. The ratio of the blue and red peaks in two PMS stars shows a correlation with the peak-to-peak velocity, which might be explained by a spiral-arm structure in the disk. Conclusions. The variable PMS stars lie at similar positions in the HRD, but show significant differences in disk lines and variability. The extent and timescale of the variability differs for each star and line (sets), showing the complexity of the region where the lines are formed. We find indications for an accretion flow, slow disk winds, and/or disk structures in the hot gaseous inner disks. We find no evidence for close companions or strong accretion bursts as the cause of the variability in these PMS stars.

Accretion flow in deformed Kerr spacetime: spectral energy distributions from free-free emission

In this paper, we study the properties of accretion flow including its spectral features in Johannsen and Psaltis (JP) non-Kerr spacetime. In doing so, we numerically solve the governing equations that describe the flow motion around the compact objects in a general relativistic framework, where spin (ak ) and deformation parameters (ε) demonstrate the nature of the central source, namely black hole (BH) or naked singularity (NS). With this, we obtain all possible classes of global accretion solutions (i.e., O, A, W and I-type) by varying the energy (E) and angular momentum (λ) of the relativistic accretion flow, and examine the role of thermal bremsstrahlung emission in studying the spectral energy distributions (SEDs) of the accretion disc. We divide the parameter space in λ-E plane in terms of the different classes of accretion solutions for BH and NS models. We further calculate the disc luminosity (L) corresponding to these accretion solutions, and observe that I-type solutions yield higher L and SEDs than the remaining types of solutions for both BH and NS models. For BH model, SEDs for W and I-type solutions differ significantly from the results for O and A-type solutions for low E values. On the contrary, for NS model, SEDs for different accretion solutions are identical in the whole parameter space of λ and E. We also examine the effect of ε on the SEDs and observe that a non-Kerr BH yields higher SEDs than the usual Kerr BH. Finally, for accretion solutions of identical E and λ, we compare the SEDs obtained from BH and NS models, and find that naked singularity objects produce more luminous power spectra than the black holes.

The Effectiveness of Strategies to Improve User Engagement With Digital Health Interventions Targeting Nutrition, Physical Activity, and Overweight and Obesity: Systematic Review and Meta-Analysis.

Digital health interventions (DHIs) are effective in improving poor nutrition, physical inactivity, overweight and obesity. There is evidence suggesting that the impact of DHIs may be enhanced by improving user engagement. However, little is known about the overall effectiveness of strategies on engagement with DHIs. This study aims to assess the overall effectiveness of strategies to improve engagement with DHIs targeting nutrition, physical activity, and overweight or obesity and explore associations between strategies and engagement outcomes. The secondary aim was to explore the impact of these strategies on health risk outcomes. The MEDLINE, Embase, PsycINFO, CINAHL, CENTRAL, Scopus, and Academic Source Complete databases were searched up to July 24, 2023. Eligible studies were randomized controlled trials that evaluated strategies to improve engagement with DHIs and reported on outcomes related to DHI engagement (use or user experience). Strategies were classified according to behavior change techniques (BCTs) and design features (eg, supplementary emails). Multiple-variable meta-analyses of the primary outcomes (usage and user experience) were undertaken to assess the overall effectiveness of strategies. Meta-regressions were conducted to assess associations between strategies and use and user experience outcomes. Synthesis of secondary outcomes followed the "Synthesis Without Meta-Analysis" guidelines. The methodological quality and evidence was assessed using the Cochrane risk-of-bias tool, and the Grading of Recommendations Assessment, Development, and Evaluation tool respectively. Overall, 54 studies (across 62 publications) were included. Pooled analysis found very low-certainty evidence of a small-to-moderate positive effect of the use of strategies to improve DHI use (standardized mean difference=0.33, 95% CI 0.20-0.46; P<.001) and very low-certainty evidence of a small-to-moderate positive effect on user experience (standardized mean difference=0.29, 95% CI 0.07-0.52; P=.01). A significant positive association was found between the BCTs social support (effect size [ES]=0.40, 95% CI 0.14-0.66; P<.001) and shaping knowledge (ES=0.39, 95% CI 0.03-0.74; P=.03) and DHI use. A significant positive association was found among the BCTs social support (ES=0.70, 95% CI 0.18-1.22; P=.01), repetition and substitution (ES=0.29, 95% CI 0.05-0.53; P=.03), and natural consequences (ES=0.29, 95% CI 0.05-0.53; P=.02); the design features email (ES=0.29, 95% CI 0.05-0.53; P=.02) and SMS text messages (ES=0.34, 95% CI 0.11-0.57; P=.01); and DHI user experience. For secondary outcomes, 47% (7/15) of nutrition-related, 73% (24/33) of physical activity-related, and 41% (14/34) of overweight- and obesity-related outcomes reported an improvement in health outcomes. Although findings suggest that the use of strategies may improve engagement with DHIs targeting such health outcomes, the true effect is unknown because of the low quality of evidence. Future research exploring whether specific forms of social support, repetition and substitution, natural consequences, emails, and SMS text messages have a greater impact on DHI engagement is warranted. PROSPERO CRD42018077333; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=77333.

Comparative efficacy and safety of probiotics, prebiotics, and synbiotics for type 2 diabetes management: A systematic review and network meta-analysis

AimsTo compare the effects of probiotics, prebiotics, and synbiotics for type 2 diabetes (T2D) management. MethodsWe searched PubMed, Scopus, CENTRAL, and grey literature sources to December 2022 for randomized trials of the impacts of probiotics, prebiotics, or synbiotics in patients with T2D. We performed network meta-analyses with a Bayesian framework to calculate mean difference [MD] and 95 % credible interval [CrI] and rated the certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results68 randomised trials were included. All results are presented in comparison to the placebo. Supplementation with probiotics (MD: -0.25 %, 95%CrI: -0.42, -0.08; GRADE = moderate) and synbiotics (MD: -0.31 %, 95%CrI: -0.61, -0.04; GRADE = very low) resulted in a trivial/unimportant decrease in glycated hemoglobin. Supplementation with probiotics (MD: -0.69 mmol/L, 95%CrI: -0.98, -0.40; GRADE = very low) and synbiotics (MD: -0.82 mmol/L, 95%CrI: -1.22, -0.43; GRADE = very low) resulted in a trivial/unimportant decrease in fasting plasma glucose. Supplementation with probiotics resulted in a small but important decrease in low-density lipoprotein cholesterol (MD: -0.19 mmol/L; 95%CrI: -0.34, -0.05; GRADE = very low). Supplementations had moderate effects on serum triglyceride (GRADE = low). ConclusionsExisting evidence is uncertain and does not support supplementation with probiotics, prebiotics, and synbiotics for T2D management.

Methods for quantifying rain-splash dispersal of Neonectria ditissima conidia in apple canopies

Many microorganisms can be dispersed by rain-splash, whereby spores become suspended in water and are spread via droplets. The resulting dispersal gradient is dependent on several factors including rainfall intensity, the nature of the plant canopy and its effects on splash, deposition, redistribution (secondary splash) and filtering. Gradients of spore dispersal with distance are important for understanding epidemics, and the primary dispersal gradient can shape an epidemic for several pathogen generations. However, microorganisms are difficult to trap, identify and enumerate efficiently. This makes it difficult to study the spread and dispersal of pathogens to aid in biosecurity responses and management of epidemics. We used macroconidia of Neonectria ditissima, the causal organism of apple canker, to explore patterns of rain-splash dispersal in tree canopies. We investigated the use of a fluorescent tracer dye, PTSA (1,3,6,8-pyrenetetrasulfonic acid), as a surrogate to conidia capture during natural and artificial rain events, and lens tissue as ‘surrogate leaves’ to recapture tracer dye. Conidia and dye were released from central point sources 2.5 m above the ground and recaptured in passive rainwater traps or artificial ‘leaves’. Quantile regression and exponential models were used to explore variation and dispersal gradients derived for both conidia and dye, with and without tree canopy and with natural or artificial precipitation. Estimated dispersal gradients were steeper with a flatter tail when no tree canopy was present, whereas presence of tree canopy resulted in more variation and shallower predicted dispersal gradients, with fatter tails, predicting potential dispersal to further distances from the source. The majority of conidia and dye were recaptured at less than 1 m from the source, but small concentrations of spores were detected up to 3 m and dye more than 6 m. High variation in natural conditions requires further investigation to fully quantify natural dispersal gradients. Nevertheless, these results show the merit of tracer dye, artificial leaves, and quantile regression as tools to estimate potential dispersal patterns of N. ditissima and other rain-splash dispersed microorganisms, considering rain-splash factors in real canopies and natural situations for predicting inoculum dispersal.

Updated Calculations of the Spectral-Line Radiation Force &amp; Mass-Loss Rates for AGN Outflows

AbstractPhoton-driven flows have been studied for almost a century, and a quantitative description of the radiative forces on atoms and ions is important for understanding a wide variety of systems, including active galactic nuclei (AGN). The colloquially-termed “radiation pressure” of line-driven winds plays an important role in driving outflows in these environments. Quantifying the associated forces is crucial to understanding how these flows enable interactive mechanisms within these environments, such as AGN feedback. Here we provide new calculations of the dimensionless line strength parameter due to radiation driving. For representative AGN, we calculate the photoionization balance at each step along the line of sight (LOS) to the proposed wind-launching region above the accretion disk. We then use a recently compiled database of approximately 5.6 million spectral lines to compute the strength of the line-driving force on the gas and the mass-loss rates resulting from these outflows. We also introduce a “shielding factor’’ that increases the magnitude of the accretion disk column density prior to the launch radius. This shielding factor simulates a proposed inner “failed wind” region that is thought to shield the outflowing gas from becoming over-ionized by the central source. We also revisit and formalize the role of the commonly-used ionization parameter in setting the properties of the accelerating gas.

Digging into the Interior of Hot Cores with ALMA: Spiral Accretion into the High-mass Protostellar Core G336.01–0.82

We observed the high-mass star-forming core G336.01–0.82 at 1.3 mm and 0.″05 (∼150 au) angular resolution with the Atacama Large Millimeter/submillimeter Array (ALMA) as part of the Digging into the Interior of Hot Cores with ALMA survey. These high-resolution observations reveal two spiral streamers feeding a circumstellar disk at opposite sides in great detail. Molecular line emission from CH3OH shows velocity gradients along the streamers consistent with infall. Similarly, a flattened envelope model with rotation and infall implies a mass larger than 10 M ☉ for the central source and a centrifugal barrier of 300 au. The location of the centrifugal barrier is consistent with local peaks in the continuum emission. We argue that gas brought by the spiral streamers is accumulating at the centrifugal barrier, which can result in future accretion burst events. A total high infall rate of ∼4 × 10−4 M ☉ yr−1 is derived by matching models to the observed velocity gradient along the streamers. Their contribution accounts for 20%–50% the global infall rate of the core, indicating streamers play an important role in the formation of high-mass stars.

Shock imprints on the radio mini halo in RBS 797

Aims. In this work, we analysed new LOw Frequency ARray observations of the mini halo in the cluster RBS 797, together with archival Very Large Array observations and the recent Chandra results. This cluster is known to host a powerful active galactic nucleus (AGN) at its centre, with two pairs of jets propagating in orthogonal directions. Recent X-ray observations have detected three pairs of shock fronts within 125 kpc from the cluster centre, connected with the activity of the central AGN. Our aim is to investigate the connection between the mini halo emission and the activity of the central source. Methods. We have used different methods to separate the emission of the central source from the diffuse mini halo emission, and we have derived the radial spectral index trend of the mini halo. Results. We find that the diffuse radio emission is elongated in different directions at 144 MHz (east-west) with respect to 1.4 GHz (north-south), tracing the orientation of the two pairs of jets. The mini halo emission is characterised by an average spectral index α = −1.02 ± 0.05. The spectral index profile of the mini halo shows a gradual flattening from the centre to the periphery. Such a trend is unique among the mini halos studied to date, and resembles the spectral index trend typical of particles re-accelerated by shocks. However, the estimated contribution to the radio brightness profile coming from shock re-acceleration is found to be insufficient to account for the radial brightness profile of the mini halo. Conclusions. We propose three scenarios that could explain the observed trend: (i) the AGN-driven shocks are propagating onto an already existing mini halo, re-energising the electrons and leaving clear imprints in the mini halo spectral properties. We estimate that the polarisation induced by the shocks could be detected at 6 GHz and above; (ii) we could be witnessing turbulent re-acceleration in a high magnetic field cluster; and (iii) the mini halo could have a hadronic origin, in which the particles are injected by the central AGN and the diffusion coefficient depends of the cosmic ray proton momentum. Future observations in polarisation would be fundamental to understand the role of shocks and of the magnetic field.

Narrow absorption line outflow in Seyfert 1 galaxy J1429+4518: outflow’s distance from the central source and its energetics

ABSTRACT In the Hubble Space Telescope/Cosmic Origins Spectrograph spectrum of the Seyfert 1 galaxy 2MASX J14292507+4518318, we have identified a narrow absorption line outflow system with a velocity of −151 km s−1. This outflow exhibits absorption troughs from the resonance states of ions like C iv, N v, S iv, and Si ii, as well as excited states from C ii* and Si ii*. Our investigation of the outflow involved measuring ionic column densities and conducting photoionization analysis. These allow the total column density of the outflow to be estimated as log NH = 19.84 cm−2, its ionization parameter to be log UH = −2.0, and its electron number density to be log ne = 2.75 cm−3. These measurements enabled us to determine the mass-loss rate and the kinetic luminosity of the outflow system to be $\dot{M}$ = 0.22 $\mathrm{ M}_{\odot } \, \mathrm{ yr}^{-1}$ and $\log \dot{E_{\mathrm{ K}}}$ = 39.3 erg s−1, respectively. We have also measured the location of the outflow system to be at ∼275 pc from the central source. This outflow does not contribute to the active galactic nucleus (AGN) feedback processes due to the low ratio of the outflow’s kinetic luminosity to the AGN’s Eddington luminosity ($\dot{E_{\mathrm{ K}}}/{L_{\mathrm{ Edd}}}\approx 0.00025 {{\, \rm per\, cent}}$). This outflow is remarkably similar to the two bipolar lobe outflows observed in the Milky Way by XMM–Newton and Chandra.

A Comparison between the Morphologies and Structures of Dwarf Galaxies with and without Active Massive Black Holes

We study the morphologies and structures of 57 dwarf galaxies that are representative of the general population of dwarf galaxies and compare their demographics to a sample of dwarf galaxies hosting optically selected active galactic nuclei (AGNs). The two samples span the same galaxy stellar mass (109 ≲ M ⋆/M ⊙ ≲ 109.5) and color range, and the observations are well-matched in physical resolution. The fractions of irregular galaxies (14%) and early types/ellipticals (∼18%) are nearly identical among the two samples. However, among galaxies with disks (the majority of each sample), the AGN hosts almost always have a detectable (pseudo)bulge, while a large fraction of the non-AGN hosts are pure disk galaxies with no detectable (pseudo)bulge. Central point sources of light consistent with nuclear star clusters are detected in many of the non-AGN hosts. In contrast, central point sources detected in the AGN hosts are, on average, more than 2 orders of magnitude more luminous, suggesting the point sources in these objects are dominated by AGN light. The preference for (pseudo)bulges in dwarf AGN hosts may inform searches for massive black holes in dwarf galaxies and attempts to constrain the black hole occupation fraction, which, in turn, has implications for our understanding of black hole seeding mechanisms.