Research Articles (Physics)
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Item Enhancing potential window with ionic liquid/water in salt mixture in co-doped activated carbon electrodes for high-energy supercapacitorsThior, Souleymane; Kitenge, Vianney Ngoyi; Diop, Ndeye Fatou; Otun, Kabir Opeyemi; Maphiri, Vusani Muswa; Adam, Rashed Ali Mohamed; Ngom, Balla Diop; Manyala, Ncholu I. (Elsevier, 2026-01-01)Please read abstract in the article.Item Investigating the Hi distribution and kinematics of ESO444-G084 and [KKS2000]23 : new insights from the MHONGOOSE surveyNamumba, B.; Ianjamasimanana, R.; Koribalski, B.S.; Bosma, A.; Athanassoula, E.; Carignan, C.; Józsa, G.I.G.; Kamphuis, P.; Deane, Roger; Sikhosana, S.P.; Verdes-Montenegro, L.; Sorgho, A.; Ndaliso, X.; Amram, P.; Brinks, E.; Chemin, L.; Combes, F.; De Blok, W.J.G.; Deg, N.; English, J.; Healy, J.; Kurapati, S.; Marasco, A.; Mc Gaugh, S.S.; Oman, K.A.; Spekkens, K.; Veronese, S.; Wong, O.I. (EDP Sciences, 2025-07)We present the HI distribution, kinematics, mass modeling, and disk stability of the dwarf irregular galaxies ESO444-G084 and [KKS2000]23 using high-resolution, high-sensitivity MHONGOOSE survey data from MeerKAT. ESO444-G084 shows centrally concentrated HI emission, while [KKS2000]23 exhibits irregular high-density clumps. Total HI fluxes measured down to 10^19 and 10^18 cm^-2 are nearly identical, indicating that the increased HI diameter at lower column densities results mainly from the larger beam, with no significant extra emission detected. We derive total HI masses of (1.1 +/- 0.1) x 10^8 and (6.1 +/- 0.3) x 10^8 solar masses for ESO444-G084 and [KKS2000]23, respectively. Using PyFAT and TiRiFiC, we extract 3D rotation curves that reveal disk-like kinematics in both galaxies. ESO444-G084 shows a warp beyond ~1.8 kpc and a fast-rising curve consistent with a centrally concentrated dark matter distribution, while [KKS2000]23's more gradual rise suggests a more extended halo. Mass modeling with an isothermal halo and stellar mass-to-light ratios of 0.20 for ESO444-G084 and 0.18 for [KKS2000]23 yields consistent results. We analyze disk stability using spatially resolved Toomre Q and gas-to-critical surface density ratios, linking these with H-alpha and FUV-based star formation. ESO444-G084 supports localized star formation despite global stability, while [KKS2000]23 appears gravitationally unstable yet lacks H-alpha, suggesting that turbulence, gas depletion, or past feedback suppresses star formation. No inflows or outflows are detected, indicating internal processes regulate star formation. This study highlights the interplay between HI morphology, kinematics, dark matter distribution, and disk stability, showing how internal processes shape dwarf galaxy evolution.Item Probing the formation of megaparsec-scale giant radio galaxies. I. Dynamical insights from MHD simulationsGiri, Gourab; Bagchi, Joydeep; Thorat, Kshitij; Deane, Roger; Delhaize, Jacinta; Saikia, D.J. (EDP Sciences, 2025-01)CONTEXT : Giant radio galaxies (GRGs), a minority among the extended-jetted population, form in a wide range of jet and environmental configurations, complicating the identification of the growth factors that facilitate their attainment of megaparsec scales. AIMS : This study aims to numerically investigate the hypothesized formation mechanisms of GRGs extending ≳ Mpc to assess their general applicability. METHODS : We employ triaxial ambient medium settings to generate varying levels of jet frustration and simulate jets with low and high power from different locations in the environment, formulating five representations. RESULTS : The emergence of distinct giant phases in all five simulated scenarios suggests that GRGs may be more common than previously believed, a prediction to be verified with contemporary radio telescopes. We find that different combinations of jet morphology, power, and the evolutionary age of the formed structure hold the potential to elucidate different formation scenarios. The simulated lobes are over-pressured, prompting further investigation into pressure profiles when jet activity ceases, potentially distinguishing between relic and active GRGs. We observed a potential phase transition in giant radio galaxies, marked by differences in lobe expansion speed and pressure variations compared to their smaller evolutionary phases. This suggests the need for further investigation across a broader parameter space to determine if GRGs fundamentally differ from smaller RGs. Axial ratio analysis reveals self-similar expansion in rapidly propagating jets, with notable deviations when the jet forms wider lobes. Overall, this study emphasizes that multiple growth factors at work can better elucidate the current-day population of GRGs, including scenarios e.g., growth of GRGs in dense environments, GRGs of several megaparsecs, GRG development in low-powered jets, and the formation of X-shaped GRGs.Item MeerKAT 1.3 GHz observations of the wide-angle tail radio galaxy J1712-2435Cotton, W.D.; Giri, Gourab; Agnihotri, P.J.; Saikia, D.J.; Thorat, Kshitij; Camilo, F. (IOP Publishing, 2025-08)We present full polarization MeerKAT images of the wide-angle tail, giant radio galaxy J17122435 at 1.3 GHz with 7.\asec5 resolution and an RMS sensitivity of 8 Jy beam. Due to the angular proximity to the Galactic Center (l=359.6, b=+8.5) the immediate environment is not well understood but there are massive clusters nearby. Emission can be traced over an extent of 34.\amin6 which at the redshift of 0.024330 corresponds to a projected length of 1.02 Mpc. The inner jets are quite straight but then bend and completely decollimate into extended plumes nearly orthogonal to the initial jet directions at a projected distance of approximately 100 kpc. The nearly unity brightness ratio of the inner jets suggest that they are orientated within a few degrees of the plane of the sky. The 1400 MHz power is 3.9 W Hz, somewhat below the FRI/FRII divide. The total power emitted is estimated to be 5.6 erg sec over the range 10 MHz to 100 GHz. The source dynamics are modeled with magneto-hydrodynamics simulations; the result is a rough reproduction of the source's radio morphology / appearance. This study further highlights the merit of alternative scenarios, calling for future observational and numerical efforts.Item Low-velocity precessing jets can explain observed morphologies in the Twin Radio Galaxy TRGJ104454+354055Mondal, Santanu; Giri, Gourab; Joshi, Ravi; Wiita, Paul J.; Krishna, Gopal; Ho, Luis C. (IOP Publishing, 2025-07)Our understanding of large-scale radio jets in merger systems has been drastically improved in the era of VLA, VLBA/EVN, uGMRT, and MeerKAT. Twin Radio Galaxies (TRGs) are the rare interacting galaxy pairs where both supermassive black holes host kiloparsec-scale bipolar radio jets. Only recently was a third TRG discovered and it shows significantly different jet morphologies than the previous two. Due to both the extreme paucity and complexity of such systems, the launching of their jets as well as their mutual interaction during the propagation through the ambient medium are not well understood. We have performed 3D hydrodynamic simulations to study the bipolar jets in the third TRG, J104454+354055. Our study indicates that the precession of mutually tilted bipolar jets originating from the two galactic nuclei separated by tens of kiloparsecs and propagating at low velocities can explain the observed morphologies. The simulated jet precession timescales are short compared to the overall dynamical timescale of the jets and could originate from Lense-Thirring effects in the accretion disks. This approach to understanding the TRG jet dynamics could also be applied to other TRG systems with similar helical morphologies that may be discovered in the upcoming era of the SKA and its pathfinder surveys.Item Detection of millimetre-wave coronal emission in a quasar at cosmological distance using microlensingRybak, M.; Sluse, D.; Gupta, K.K.; Millon, M.; Beha, E.; Courbin, F.; McKean, J.P.; Stacey, H.R. (EDP Sciences, 2025-09)Determining the nature of emission processes at the heart of quasars is critical for understanding environments of supermassive black holes. One of the key open questions is the origin of centimetre- to millimetre-wave emission from radio-quiet quasars. The proposed mechanisms range from central star formation to dusty torus, low-power jets, or emission from the accretion-disc corona. Distinguishing between these scenarios requires probing spatial scales of ≤0.01 pc, beyond the reach of any current millimetre-wave telescope. Fortunately, in gravitationally lensed quasars, compact millimetre-wave emission might be microlensed by stars in the foreground galaxy, providing strong constraints on the source size. We report a striking change in rest-frame 1.3 mm flux ratios in RXJ1131−1231, a quadruply lensed quasar at z = 0.658 observed by the Atacama Large Millimeter/submillimeter Array (ALMA) in 2015 and 2020. Over this period, the flux ratios between the three quasar images, A, B, and C, changed by a factor of 1.6 (A/B) and 3.0 (A/C). The observed flux-ratio variability is consistent with the microlensing of a compact source with a half-light radius of ≤50 astronomical units. The compactness of the source leaves coronal emission as the most likely scenario. Furthermore, the inferred millimetre-wave and X-ray luminosities follow the Güdel-Benz relationship for stellar coronae. These observations represent the first unambiguous evidence that coronae are the dominant mechanism for centimetre- to millimetre-wave emission in radio-quiet quasars.Item A nuclear spiral in a dusty star-forming galaxy at z = 2.78Stacey, H.R.; Kaasinen, M.; O’Riordan, C.M.; McKean, J.P.; Powell, D.M.; Rizzo, F. (EDP Sciences, 2025-01)The nuclear structure of dusty star-forming galaxies is largely unexplored but harbours critical information about their structural evolution. Here, we present long-baseline Atacama Large (sub-)Millimetre Array (ALMA) continuum observations of a gravitationally lensed dusty star-forming galaxy at z = 2.78. We use a pixellated lens modelling analysis to reconstruct the rest-frame 230 μm dust emission with a mean resolution of ≈55 pc and demonstrate that the inferred source properties are robust to changes in lens modelling methodology. The central 1 kpc is characterised by an exponential profile, a dual spiral arm morphology and an apparent super-Eddington compact central starburst. We find tentative evidence for a nuclear bar in the central 300 pc. These features may indicate that secular dynamical processes play a role in accumulating a high concentration of cold gas that fuels the rapid formation of a compact stellar spheroid and black hole accretion. We propose that the high spatial resolution provided by long-baseline ALMA observations and strong gravitational lensing will give key insights into the formation mechanisms of massive galaxies.Item Tuning optoelectronic properties of CsPbI2Br perovskite films via octadecyl ammonium iodide substitutionThubane, Sandile Job; Nombona, Nolwazi; Diale, M. (Mmantsae Moche) (Springer, 2025-11)Please read abstract in the article.Item A MeerKAT study of a neutral hydrogen rich grouping of galaxies with megaparsec-scale filamentary-like structureLawrie, G.D.; Deane, Roger; Dave, R. (EDP Sciences, 2025-09)CONTEXT. Environmental effects within cosmological overdensities, such as galaxy groups and clusters, have been shown to impact galaxies and their cold gas reservoirs and thereby provide constraints on galaxy evolution models. Galaxy groups foster frequent galaxy-galaxy interactions, making them rich environments in which to study galaxy transformation. AIMS. In this work, we study a serendipitously discovered large overdensity of neutral hydrogen (H I) galaxies at z ∼ 0.04. The galaxies appear to lie in a filamentary-like structure of megaparsec scale. Using MeerKAT’s angular resolution and field of view, we were able to spatially resolve the H I galaxies while simultaneously probing large-scale structure. METHODS. The H I and sub-arcsec Dark Energy Survey (DES) imaging have revealed a large number of both interacting and disturbed galaxies in this collective group. MeerKAT data enabled us to derive H I masses and investigate interacting galaxies. We used DES and Wide-field Infrared Survey Explorer (WISE) data to quantify the star formation rates, stellar masses, and stellar morphologies of member galaxies and compared these with field scaling relations. To place this discovery and the environmental effects in context, we used the SIMBA cosmological hydrodynamical simulation to investigate the prevalence of qualitatively similar H I overdensities and their large-scale morphological properties. This enabled us to make a prediction of how frequently such structures might be serendipitously discovered with MeerKAT and SKA-Mid H I observations in comparable observation time. RESULTS. The combination of spatially resolved H I data and optical imaging revealed a group rich in interactions, suggesting environmental processes are already shaping galaxy properties within the structure. CONCLUSIONS. More of these serendipitous discoveries are expected, and alongside ongoing targeted programmes, they will provide a rich, unbiased sample to study galaxy transformation and enable a MeerKAT H I perspective on large-scale structure, including filaments.Item Electropolymerization of polyaniline on coated activated carbon derived from human hair as a bilayer electrode for supercapacitor applicationsAdam, Rashed Ali Mohamed; Maphiri, Vusani Muswa; Otun, Kabir Opeyemi; Fasakin, Oladepo; Rutavi, Gift; Thior, Souleymane; Manyala, Ncholu I.; Maphiri, Vusani Muswa; Maphiri, Vusani Muswa; Otun, Kabir Opeyemi; Otun, Kabir Opeyemi; Maphiri, Vusani Muswa; Otun, Kabir Opeyemi; Fasakin, Oladepo; Rutavi, Gift; Thior, Souleymane (Elsevier, 2025-09)In this study, electropolymerization was used to deposit polyaniline (PANI) layer on the surface of coated activated carbon derived from human hair (HH-AC) using nickel foam as conducting substrate via cyclic voltammetry (CV) at different cycle numbers. The bilayer HH-AC/PANI electrode was prepared in a non-acidic medium unlike other conventional electrochemical polymerization methods, and characterized using Raman spectroscopy, UV–visible spectroscopy, scanning electron microscope (SEM), and nitrogen physisorption measurements to determine the chemical composition, electronic structure, surface morphology, and textural properties, respectively. The results showed that a PANI layer was successfully deposited on the surface of HH-AC. The electrochemical evaluation was carried out using CV, galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques in 2.5 M KNO3 neutral electrolyte. The optimal bilayer electrode prepared by 8-cycles and denoted as HH-AC/PANI-8 shows an excellent specific capacitance of 220 F g−1 at a positive potential, which is almost twice of 121 F g−1 for that of pristine HH-AC operated in a three-electrode system. Furthermore, for practical application, a symmetric device comprising HH-AC/PANI-8 bilayer electrode was assembled and tested in a two-electrode system configuration, leading to a specific energy of 28.6 W h kg−1 and a specific power of 800W kg−1, at a specific current of 1 A g−1 and voltage window of 1.6 V. Besides, the capacitance retention of the device remained 83 % after 10,000 cycles at 5 A g−1, indicating a long lifespan. These results suggest that the HH-AC/PANI-8 bilayer electrode is a promising candidate for high-performance supercapacitors.Item Investigating biomimetic coatings on Ti-6Al-4V substratesDockrat, Unaisa; Ntsoane, Tshepo Paul; Malherbe, Johan B.; Bam, Lunga Cleartone; Thabethe, Thabsile Theodora (Elsevier, 2025-08)In this in vitro study, medical grade Ti-6Al-4V (Ti64) substrates, approximately 5 mm thick, were immersed in 1.5 × Simulated Body Fluid (SBF) for 56 days to develop biomimetic apatite coatings. Prior to immersion, the substrates underwent surface pretreatment via sandblasting, polishing, and plasma etching. The resulting morphological changes, surface characteristics, crystal structure, phase composition, and mechanical properties were analysed using AFM, SEM, EDS, Micro-CT, and XRD. The findings revealed that surface pretreatment significantly influenced apatite formation. Plasma-etched and sandblasted substrates exhibited more textured and roughened surfaces, which facilitated the formation of denser, more homogeneous coatings compared to the polished substrates. XRD analysis further confirmed the coating to be the hydroxyapatite phase, while AFM measurements demonstrated a notable increase in surface roughness for the sandblasted and plasma-etched samples. Micro CT analysis revealed that while the surface treatments like sandblasting and plasma etching present an interconnected pore structure, the polished surface creates unconnected porosity. These results emphasize the critical role of surface pretreatment in enhancing biomimetic deposition, with implications for improving osseointegration and mechanical compatibility of Ti64-based biomedical implants. HIGHLIGHTS • Ti-6Al-4V (Ti64) substrates were pretreated by sandblasting, polishing, and plasma etching to alter surface morphology. • Substrates were immersed in 1.5 × Simulated Body Fluid (SBF) in vitro for 56 days to develop biomimetic coatings and assess pretreatment effects. • XRD confirmed hydroxyapatite (HAp) on all samples, and SEM analysis showed rougher surfaces on plasma-etched and sandblasted Ti64. • Sandblasting promoted larger HAp crystallites, improving coating structure and potentional mechanical performance.Item Advanced thermal and magnetic materials for high-power and high-temperature applications : a comprehensive reviewMengesha, Wubshet Getachew; Nagessar, Kaveer (Springer, 2025-09)This comprehensive review explores the advancements, applications, and challenges of advanced thermal and magnetic materials in high-power and high-temperature environments. These materials, including high-temperature superconductors, ferromagnetic materials, and magnetic alloys, are crucial for industries such as energy, aerospace, automotive, and electronics. They are crucial for managing heat, converting energy, and storing it, which boosts the efficiency and dependability of renewable energy systems, electric vehicles, and aerospace technologies. Nonetheless, they encounter major obstacles, such as material breakdown under harsh conditions, expensive production, and sustainability issues. The study explores essential thermal properties like heat capacity, thermal conductivity, thermal expansion, and thermal stress, highlighting the significance of ceramics, composites, metals, carbon nanotubes, and phase-change materials. It also investigates magnetic properties like permeability, coercivity, and remanence, essential for high-power applications. Emerging technologies such as nanotechnology, additive manufacturing, and machine learning offer promising solutions to overcome existing limitations. The review highlights the need for interdisciplinary research to develop sustainable and cost-effective materials capable of withstanding extreme conditions while maintaining performance. It underscores the importance of continuing research and development to address global energy and environmental challenges, paving the way for next-generation technologies. In summary, cutting-edge thermal and magnetic materials are set to transform industries, paving the way for more efficient and dependable technological advancements.Item Evaluation of microstructural evolution of glassy carbon induced by helium implantation and annealingMaepa, Charity E.; Njoroge, Eric Gitau; Ismail, Mahjoub Yagoub Abdalla; Dickinson, Calum; Abdalla, Zaki Adam Yousif; Abdelbagi, Hesham Abdelbagi Ali; Ngongo, S.; Maphiri, Vusani Muswa; Li, Bingsheng; Hlatshwayo, Thulani Thokozani (Elsevier, 2026-01)Please read abstract in the article.Item Insights into the optoelectronic and thermoelectric properties of lead-free Rb2NaIrF6 double perovskite compound : a first-principles studyMbilo, Mwende; Musembi, Robinson; Kachira, John Peter; Onsate, Wisley Nyangau; Keheze, Fanuel Mugwanga; Mapasha, Refilwe Edwin (Elsevier, 2025-08)Please read abstract in the article.Item First Sagittarius A* Event Horizon Telescope results. VIII. Physical interpretation of the polarized ringAkiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Algaba, Juan Carlos; Anantua, Richard; Asada, Keiichi; Azulay, Rebecca; Bach, Uwe; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Bandyopadhyay, Bidisha; Barrett, John; Bauböck, Michi; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Bouman, Katherine L.; Bower, Geoffrey C.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Bustamante, Sandra; Byun, Do-Young; Carlstrom, John E.; Ceccobello, Chiara; Chael, Andrew; Chan, Chi-kwan; Chang, Dominic O.; Chatterjee, Koushik; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cheng, Xiaopeng; Cho, Ilje; Christian, Pierre; Conroy, Nicholas S.; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Dahale, Rohan; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Dhruv, Vedant; Dihingia, Indu K.; Doeleman, Sheperd S.; Dougall, Sean; Dzib, Sergio A.; Eatough, Ralph P.; Emami, Razieh; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Edward; Ford, H. Alyson; Foschi, Marianna; Fraga-Encinas, Raquel; Freeman, William T.; Friberg, Per; Fromm, Christian M.; Fuentes, Antonio; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gómez-Ruiz, Arturo I.; Gómez, José L.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Haworth, Kari; Hecht, Michael H.; Hesper, Ronald; Heumann, Dirk; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Impellizzeri, C.M. Violette; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jiménez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Joshi, Abhishek V.; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kocherlakota, Prashant; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Carsten; Kramer, Joana A.; Kramer, Michael; Krichbaum, Thomas P.; Kuo, Cheng-Yu; La Bella, Noemi; Lauer, Tod R.; Lee, Daeyoung; Lee, Sang-Sung; Leung, Po Kin; Levis, Aviad; Li, Zhiyuan; Lico, Rocco; Lindahl, Greg; Lindqvist, Michael; Lisakov, Mikhail; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin J.; Lowitz, Amy E.; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marchili, Nicola; Markoff, Sera; Marrone, Daniel P.; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Michalik, Daniel; Mizuno, Izumi; Mizuno, Yosuke; Mora, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Mulaudzi, Wanga; Müller, Cornelia; Müller, Hendrik; Mus, Alejandro; Musoke, Gibwa; Myserlis, Ioannis; Nadolski, Andrew; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Navarro Fuentes, Santiago; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Oh, Junghwan; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C.M.; Paraschos, Georgios Filippos; Park, Jongho; Parsons, Harriet; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Pötzl, Felix M.; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ricarte, Angelo; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Romero-Cañizales, Cristina; Ros, Eduardo; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruiz, Ignacio; Ruszczyk, Chet; Rygl, Kazi L.J.; Sánchez, Salvador; Sánchez-Argüelles, David; Sánchez-Portal, Miguel; Sasada, Mahito; Satapathy, Kaushik; Savolainen, Tuomas; Schloerb, F. Peter; Schonfeld, Jonathan; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Sosapanta Salas, León David; Souccar, Kamal; Stanway, Joshua S.; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Torne, Pablo; Toscano, Teresa; Traianou, Efthalia; Trent, Tyler; Trippe, Sascha; Turk, Matthew; Van Bemmel, Ilse; Van Langevelde, Huib Jan; Van Rossum, Daniel R.; Vos, Jesse; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Washington, Jasmin E.; Weintroub, Jonathan; Wharton, Robert; Wielgus, Maciek; Wiik, Kaj; Witzel, Gunther; Wondrak, Michael F.; Wong, George N.; Wu, Qingwen; Yadlapalli, Nitika; Yamaguchi, Paul; Yfantis, Aristomenis; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yu, Wei; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhang, Shuo; Zhao, Guang-Yao; Zhao, Shan-Shan; Najafi-Ziyazi, Mahdi (American Astronomical Society, 2024-04-01)In a companion paper, we present the first spatially resolved polarized image of Sagittarius A* on event horizon scales, captured using the Event Horizon Telescope, a global very long baseline interferometric array operating at a wavelength of 1.3mm. Here we interpret this image using both simple analytic models and numerical general relativistic magnetohydrodynamic (GRMHD) simulations. The large spatially resolved linear polarization fraction (24%–28%, peaking at ∼40%) is the most stringent constraint on parameter space, disfavoring models that are too Faraday depolarized. Similar to our studies of M87*, polarimetric constraints reinforce a preference for GRMHD models with dynamically important magnetic fields. Although the spiral morphology of the polarization pattern is known to constrain the spin and inclination angle, the time-variable rotation measure (RM) of SgrA* (equivalent to ≈46°±12° rotation at 228 GHz) limits its present utility as a constraint. If we attribute the RM to internal Faraday rotation, then the motion of accreting material is inferred to be counterclockwise, contrary to inferences based on historical polarized flares, and no model satisfies all polarimetric and total intensity constraints. On the other hand, if we attribute the mean RM to an external Faraday screen, then the motion of accreting material is inferred to be clockwise, and one model passes all applied total intensity and polarimetric constraints: a model with strong magnetic fields, a spin parameter of 0.94, and an inclination of 150°. We discuss how future 345 GHz and dynamical imaging will mitigate our present uncertainties and provide additional constraints on the black hole and its accretion flow.Item The putative center in NGC1052Baczko, Anne-Kathrin; Kadler, Matthias; Ros, Eduardo; Fromm, Christian M.; Wielgus, Maciek; Perucho, Manel; Krichbaum, Thomas P.; Balokovi´c, Mislav; Blackburn, Lindy; Chan, Chi-kwan; Issaoun, Sara; Janssen, Michael; Ricci, Luca; Akiyama, Kazunori; Albentosa-Ruíz, Ezequiel; Alberdi, Antxon; Alef, Walter; Algaba, Juan Carlos; Anantua, Richard; Asada, Keiichi; Azulay, Rebecca; Bach, Uwe; Ball, David; Bandyopadhyay, Bidisha; Barrett, John; Bauböck, Michi; Benson, Bradford A.; Bintley, Dan; Blundell, Raymond; Bouman, Katherine L.; Bower, Geoffrey C.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Bustamante, Sandra; Byun, Do-Young; Carlstrom , John E.; Ceccobello, Chiara; Chael, Andrew; Chang, Dominic O.; Chatterjee, Koushik; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cheng, Xiaopeng; Cho, Ilje; Christian, Pierre; Conroy , Nicholas S.; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Dahale, Rohan; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Dhruv, Vedant; Dihingia, Indu K.; Doeleman, Sheperd S.; Dougall, Sean Taylor; Dzib, Sergio A.; Eatough, Ralph P.; Emami, Razieh; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Edward; Ford, H. Alyson; Foschi, Marianna; Fraga-Encinas, Raquel; Freeman, William T.; Friberg, Per; Fuentes, Antonio; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gómez-Ruiz, Arturo I.; Gómez, José L.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Haworth, Kari; Hecht, Michael H.; Hesper, Ronald; Heumann, Dirk; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Impellizzeri, C.M. Violette; Inoue, Makoto; James, David J.; Jannuzi, Buell T.; Jeter, Britton; Jiang, Wu; Jiménez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Joshi, Abhishek V.; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kocherlakota, Prashant; Kofuji, Yutaro; Koyama, Shoko; Kramer, Carsten; Kramer, Joana A.; Kramer, Michael; Kuo, Cheng-Yu; La Bella, Noemi; Lauer, Tod R.; Lee, Daeyoung; Lee, Sang-Sung; Leung, Po Kin; Levis, Aviad; Li, Zhiyuan; Lico, Rocco; Lindahl, Greg; Lindqvist, Michael; Lisakov, Mikhail; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Mao , Jirong; Marchili, Nicola; Marko , Sera; Marrone, Daniel P.; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Michalik, Daniel; Mizuno, Izumi; Mizuno, Yosuke; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Mulaudzi, Wanga; Müller, Cornelia; Müller, Hendrik; Mus, Alejandro; Musoke, Gibwa; Myserlis, Ioannis; Nadolski, Andrew; Nagai, Hiroshi; Nagar, Neil M.; Nair, Dhanya G.; Nakamura, Masanori; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Navarro Fuentes, Santiago; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Oh, Junghwan; Okino, Hiroki; Olivares Sánchez, Héctor Raúl; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C.M.; Paraschos, Georgios Filippos; Park, Jongho; Parsons, Harriet; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Piétu3, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Pötzl, Felix M.; Prather, Ben; Preciado-López, Jorge A.; Principe, Giacomo; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Ricarte, Angelo; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Romero-Cañizales, Cristina; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruiz, Ignacio; Ruszczyk, Chet; Rygl, Kazi L.J.; Sánchez, Salvador; Sánchez-Argüelles, David; Sánchez-Portal, Miguel; Sasada, Mahito; Satapathy, Kaushik; Savolainen, Tuomas; Schloerb, F. Peter; Schonfeld, Jonathan; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Sosapanta Salas, León David; Souccar, Kamal; Stanway, Joshua S.; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P.J.; Titus, Michael; Torne, Pablo; Toscano, Teresa; Traianou, Efthalia; Trent, Tyler; Trippe, Sascha; Turk, Matthew; Van Bemmel, Ilse; Van Langevelde, Huib Jan; Van Rossum, Daniel R.; Vos, Jesse; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Washington, Jasmin E.; Weintroub, Jonathan; Wharton, Robert; Wiik, Kaj; Witzel, Gunther; Wondrak, Michael F.; Wong, George N.; Wu, Qingwen; Yadlapalli, Nitika; Yamaguch, Paul; Yfantis, Aristomenis; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yu, Wei; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhang, Shuo; Zhao, Guang-Yao (EDP Sciences, 2024-12)Please read abstract in the article.Item The effects of co-implanting strontium (Sr) and helium (He) into SiC at temperatures exceeding the critical amorphization temperature and annealing above 1000 °CHlatshwayo, Thulani Thokozani; Mokgadi, Thapelo Freddy; Ntshangase, S.S.; Abdalla, Zaki Adam Yousif; Njoroge, Eric Gitau; Nguyen, T.; Sohatsky, A.; Skuratov, V.A. (Elsevier, 2025-07)The structural evolution and migration behaviour of strontium (Sr) in polycrystalline silicon carbide (SiC) co-implanted with helium (He) exceeding 300 °C were investigated at temperatures above 1000 °C. Sr ions were implanted into SiC at 600 °C (denoted as Sr-SiC-600) and co-implanted with He ions at 350 °C (denoted as Sr + He-SiC-600). Both samples were subsequently isochronally annealed at 1100 °C, 1200 °C, and 1300 °C for 5 h. Both as-implanted and annealed were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and Rutherford backscattering spectrometry (RBS). Implantation at 600 °C resulted in a defective layer embedded in the crystalline SiC. Co-implantation led to the formation of He platelets in the defective layer, as well as blisters and large voids on the surface accompanied by slight migration of Sr. Annealing the Sr-SiC-600 samples up to 1300 °C resulted in formation of Sr precipitates accompanied by neither migration nor loss. Contrary annealing Sr + He-SiC-600 samples up to 1300 °C resulted in the formation of Sr precipitates accompanied by some loss of Sr. These results indicate trapping of Sr in both samples. This trapping was influenced by thermally activated cavities in the Sr-SiC-600 samples and by He induced cavities in the Sr + He-SiC-600 samples. These findings have significant implications for the design and performance of TRISO fuel particles.Item Tuning structural and microstrain features in Ni–Co substituted spinel ferrite nanoparticles for high-rate and stable pseudocapacitive energy storageAdewinbi, Saheed A.; Al-Senani, Ghadah M.; Maphiri, Vusani Muswa; Akintayo, Olamide A.; Olaoluwa, Abigail T.; Al-Qahtani, Salhah D.; Animasahun, Lukman O.; Manyala, Ncholu I. (Elsevier, 2025-09)Please read abstract in the article.Item Structural, stability and electronic properties of A7 SbAs rhombohedral phase under pressure variationsNambua, Lengai Julius; Mapasha, Refilwe Edwin; Mwanga, Stanley Ferdinand; Singh, Vijay (Elsevier, 2025-08)Antimony arsenide (SbAs), a bulk 3D binary compound has attracted significant interest since its experimental discovery in 2013. This is due to its potential applications in fields such as electronics, topological insulators, optoelectronics, thermoelectrics, and piezoelectrics. In the A7 rhombohedral phase, SbAs manifests a pseudo-layered structure with interlayer interactions mediated by weak van der Waals forces. In the present work, we have employed first-principles calculations to investigate the pressure-dependent structural, stability, and electronic properties of SbAs in the A7 phase. Our results indicate that the lattice parameter along the a-axis shows a continuous reduction under pressure, whereas, the c-axis evolves with anisotropic compression. Bond lengths and bond angles decrease systematically with a linear trend emerging above 60 GPa like the lattice parameters. Symmetry analysis shows a pressure-induced phase transition from the non-centrosymmetric space group R3m to the centrosymmetric Rm. Phonon dispersion relations show a lack of imaginary modes at ambient pressure, but the onset of instability is observed between 20 and 40 GPa, with the appearance of imaginary modes that decrease in intensity from the former to the latter stated pressure point. However, these modes dissipate from around 60 GPa and above signifying the material's dynamic stability at high pressures. On the electronic front, SbAs exhibits a transition from a semimetallic to a metallic state with increasing pressure accompanied by a rise in the Fermi energy. Furthermore, spin-orbit coupling (SOC) has also been observed to play a significant role in the material's electronic characteristics.Item Designing coin-cell supercapacitors : combining graphene foam with metal oxide composite electrodes for improved energy storage performanceMirghni, Abdulmajid A.; Shuaibu, Abubakar Dahiru; Hardianto, Yuda Prima; AL-Qwairi, Fatima Omar; Hussain, Arshad; Shah, Syed Shaheen; Manyala, Ncholu I.; Aziz, Md. Abdul (Elsevier, 2025-03)Please read abstract in the article.