Research Articles (Physics)

Permanent URI for this collectionhttp://hdl.handle.net/2263/1725

A collection containing some of the full text peer-reviewed/ refereed articles published by researchers from
the Department of Physics

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Millimeter-wave observations of Euclid Deep Field South using the South Pole Telescope : a data release of temperature maps and catalogs
Archipley, M.; Hryciuk, A.; Bleem, L.E.; Kornoelje, K.; Klein, M.; Anderson, A. J.;; Ansarinejad, B.; Aravena, M.; Balkenhol, L.; Barry, P.S.; Benabed, K.; Bender, A.N.; Benson, B.A.; Bianchini, F.; Bocquet, S.; Bouchet, F.R.; Camphuis, E.; Campitiello, M.G.; Carlstrom, J.E.; Cathey, J.; Chang, C.L.; Chapman, S.C.; Chaubal, P.; Chichura, P.M.; Chokshi, A.; Chou, T. -l.; Coerver, A.; Crawford, T.M.; Daley, C.; De Haan, T.; Deane, Roger; Dibert, K.R.; Dobbs, M.A.; Doohan, M.; Doussot, A.; Dutcher, D.; Everett, W.; Feng, C.; Ferguson, K.R.; Fichman, K.; Floyd, B.; Foster, A.; Galli, S.; Gambrel, A.E.; Gardner, R.W.; Ge, F.; Goeckner-Wald, N.; Gonzalez, A.; Grandis, S.; Greve, T.R.; Gualtieri, R.; Guidi, F.; Guns, S.; Halverson, N.W.; Hill, R.; Hivon, E.; Holder, G.P.; Holzapfel, W.L.; Hood, J.C.; Huang, N.; Keruzore, F.; Khalife, A.R.; Knox, L.; Korman, M.; Kuo, C.-l.; Levy, K.; Lowitz, A.E.; Lu, C.; Lynch, G.P.; Maniyar, A.; Martsen, E.S.; Menanteau, F.; Millea, M.; Montgomery, J.; Nakato, Y.; Natoli, T.; Noble, G.I.; Omori, Y.; Ouellette, A.; Pan, Z.; Phadke, K.A.; Pollak, A.W.; Prabhu, K.; Quan, W.; Raghunathan, S.; Rahimi, M.; Rahlin, A.; Reichardt, C.L.; Reuter, C.; Rouble, M.; Ruhl, J.E.; Schiappucci, E.; Simpson, A.; Sobrin, J.A.; Stalder, B.; Stark, A.A.; Sulzenauer, N.; Tandoi, C.; Thorne, B.; Trendafilova, C.; Umilta, C.; Vieira, J.D.; Vitrier, A.; Vizgan, D.; Wan, Y.; Weiss, A.; Whitehorn, N.; Wu, W.L.K.; Young, M.R.; Zebrowski, J.A.; Zhou, D. (EDP Sciences, 2026-02)
CONTEXT : The South Pole Telescope third-generation camera (SPT-3G) has observed over 10 000 square degrees of sky at 95, 150, and 220 GHz (3.3, 2.0, 1.4 mm, respectively) and will significantly overlap the ongoing 14 000 square-degree Euclid Wide Survey. The Euclid collaboration recently released Euclid Deep Field South (EDF-S) observations of 23 square degrees at wide field depths in the first quick data release (Q1). AIMS : With the goal of releasing complementary millimeter-wave data and encouraging legacy science, we performed dedicated observations of a 57-square-degree field overlapping the EDF-S. METHODS : The observing time totaled 20 days, and we reached noise depths of 4.3, 3.8, and 13.2 μK-arcmin at 95, 150, and 220 GHz, respectively. RESULTS : In this work we present the temperature maps and two catalogs constructed from these data. The emissive source catalog contains 601 objects (334 inside EDF-S) with 54% synchrotron-dominated sources and 46% thermal dust emission-dominated sources. The 5σ detection thresholds are 1.7, 2.0, and 6.5 mJy in the three bands. The cluster catalog contains 217 cluster candidates (121 inside EDF-S) with median mass M500c = 2.12 × 1014 M⊙/h70 and median redshift z = 0.70, corresponding to an order-of-magnitude improvement in cluster density over previous tSZ-selected catalogs in this region (3.81 clusters per square degree). CONCLUSIONS : The overlap between SPT and Euclid data will enable a range of multiwavelength studies of the aforementioned source populations. This work serves as the first step toward joint projects between SPT and Euclid and provides a rich dataset containing information on galaxies, clusters, and their environments.
Raspberry Pi multispectral imaging camera system (PiMICS) : a low-cost, skills-based physics educational tool
Howell, John C.; Flores, Brian; Naranjo, Juan Javier; Mendez, Angel; Costa-Vera, Cesar; Koumriqian, Chris; Taormina, Nathan; Jordan, Juliana; Neethling, Pieter H.; Groenewald, Calvin; Lovemore, Michael A.C.; Kinsey, Patrick A.T.; Kruger, T.P.J. (Tjaart) (American Association of Physics Teachers, 2026-02)
Here, we report on a skills-building 3D-printable, Raspberry Pi-based multispectral camera (15–25 spectral channels in the visible and near-IR) for as little as $150–$300. The cameras rely on measuring the reflectance spectra of various objects using both active and passive illumination. The cameras were used in a successful pilot program designed such that students could learn 3D modeling, 3D printing, feedback, control, image analysis, Python programming, systems integration, and machine learning, as well as spectroscopy. The students in the pilot program studied a wide array of target spectra upon completion of their cameras, showing their aid as valuable research tools. We believe this can be an important instructional tool in introductory or advanced STEM laboratory courses.
Radio activity from the rapidly rotating T dwarf 2MASS 2228-4310
Wandia, Kelvin; Garrett, Michael A.; Golden, Aaron; Hallinan, Gregg; Williams-Baldwin, David; Lucatelli, Geferson; Beswick, Robert J.; Radcliffe, Jack Frederick; Siemion, Andrew; Myburgh, Talon (Oxford University Press, 2026-03)
Please read abstract in the article.
Probing jet base emission of M87* with the 2021 Event Horizon Telescope observations
Saurabh; Müller, Hendrik; Von Fellenberg, Sebastiano D.; Tiede, Paul; Janssen, Michael; Blackburn, Lindy L.; Broderick, Avery E.; Chavez, Erandi; Georgiev, Boris; Krichbaum, Thomas P.; Moriyama, Kotaro; Nair, Dhanya G.; Natarajan, Iniyan; Park, Jongho; West, Andrew Thomas; Wielgus, MacIek Iej; Akiyama, Kazunori; Albentosa-Ruíz, Ezequiel; Alberdi, A.; Alef, Walter; Algaba Marcos, Juan Carlos; Anantua, Richard J.; Asada, Keiich; Azulay, Rebecca; Bach, Uwe; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Bandyopadhyay, Bidisha; Barrett, John; Bauböck, Michi; Benson, Bradford A.; Bintley, Dan; Blundell, Raymond; Bouman, Katherine L.; Bower, Geoffrey C.; Bremer, Michael; Brissenden, Roger; Britze, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Bustamante, Sandra; Carlos, Douglas F.; Carlstrom, John E.; Chael, Andrew; Chan, Chi-kwan; Chang, Dominic O.; Chatterjee, Koushik; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cheng, Xiaopeng; Chichura, Paul; Cho, Ilje; Christian, Pierre; Conroy, Nicholas S.; Conway, John E.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Curd, Brandon; Dahale, Rohan; Jordy, Davelaar; De Laurentis, Mariafelicia; Deane, Roger; Desvignes, Gregory; Dexter, Jason; Dhru, Vedant; Dihingia, Indu K.; Doeleman, Sheperd S.; Dzib, Sergio A.; Eatough, Ralph P.; Emami, Razieh; Falcke, Heino; Farah, Joseph; 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; Goddi, Ciriaco; Gold, Roman; Gómez-Ruiz, Arturo I.; Gómez, José L.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Hesper, Ronald; Heumann, Dirk; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Impellizzer, C.M. Violette; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Jeter, Britton; Jiang, Wu; Jiménez-Rosales, Alejandra; Johnson , Svetlana; Jorstad, Michael D.; Jones, Adam C.; Joshi, Abhishek V.; Jung, Taehyun; 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; Kuo, Cheng-Yu; La Bella, Noemi; Lee, Deokhyeong; Lee, Sang-Sung; Levis, Aviad; Li, Shaoliang; 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.; Messias, Hugo; Mizuno, Izumi; Mizuno, Yosuke; Montgomery, Joshua; Moran, James M.; Moscibrodzka, Monika; Mulaudzi, Wanga; Müller, Cornelia; Mus, Alejandro; Musoke, Gibwa; Myserlis, Ioannis; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayanan, Gopal; Nathanail, Antonios; Navarro Fuentes, Santiago; Neilsen, Joey; Ni, Chunchong; Nowak, Michael A.; Oh, Junghwan; Okino, Hiroki; Olivares Sánchez, Héctor Raúl; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C.M.; Paraschos, Georgios Filippos; Parsons, Harriet; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plavin, Alexander; PopStefanija, Aleksandar; Porth, Oliver; Prather, Ben; Principe, Giacomo; Psaltis, Dimitrios; Pu, Hung-Yi; Rahlin, Alexandra; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Rezzolla, Luciano; Ricarte, Angelo; Ricci, Luca; Ripperda, Bart; Röder, Jan; Roelofs, Freek; Romero-Cañizales, Cristina; Ros, Eduardo; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruiz, Ignacio; Ruszczyk, Chet; Rygl, Kazi L.J.; Salas, León D.S.; 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; Silpa, Sasikumar; Small, Des; Smith, Randall; Sohn, Bong Won; SooHoo, Jason; Souccar, Kamal; Stanway, Joshua S.; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tilanus, Remo P.J.; Titus, Michael; Toma, Kenji; 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.; Wongphexhauxsorn, Jompoj; Wu, Qingwen; Yadlapalli, Nitika; Yamaguchi, Paul; Yfantis, Aristomenis; Yoon, Doosoo; Young, André; Younsi, Ziri; Yu, Wei; Yuan, Feng; Yuan, Ye-Fei; Zeng, Ai-Ling; Zensu, J. Anton; Zhang, Shuo; Zhao, Guang-Yao; Zhao, Shan-Shan (EDP Sciences, 2026-02)
We investigate the presence and spatial characteristics of the jet base emission in M87* at 230 GHz, enabled by the significantly enhanced (u,v) coverage in the 2021 Event Horizon Telescope (EHT) observations. The integration of the 12−m Kitt Peak Telescope (USA) and NOEMA (France) stations into the array introduces two critical intermediate-length baselines to SMT (USA) and IRAM 30−m (Spain), providing sensitivity to emission structures at spatial scales of ∼250 μas and ∼2500 μas (∼ 0.02 pc and ∼ 0.02 pc). Without these new baselines, previous EHT observations of the source in 2017 and 2018 lacked the capability to constrain emission on large scales, where a “missing flux” of order ∼1 Jy is expected to reside. To probe these scales, we analyzed closure phases–robust against station-based gain calibration errors–and model the jet base emission using a simple Gaussian component offset from the compact ring emission at spatial separations > 100 μas. Our analysis revealed a Gaussian feature centered at (ΔRA ≈ 320 μas, ΔDec. ≈ 60 μ as), projected separation of ≈ 5500 AU, with an estimated flux density of only ∼60 mJy, implying that most of the missing flux identified in previous EHT studies had to originate from different, larger scales. Brighter emission at the relevant spatial scales is firmly ruled out, and the data do not favor more complex models. This component aligns with the inferred position of the large-scale jet and is therefore physically consistent with the emission of the jet base. While our findings point to detectable jet base emission at 230 GHz, the limited coverage provided by only two intermediate baselines limits our ability to robustly reconstruct its morphology. Consequently, we treated the recovered Gaussian as an upper limit on the jet base flux density. Future EHT observations with expanded intermediate baseline coverage will be essential to constrain the structure and nature of this component with higher precision.
Biosynthesized nickel oxide honeycomb nanostructures for DSSC counter electrode : a joint experimental and density functional theory study
Nasejje, Stella; Mushebo, Emmanuel; Birabwa, Denise Joanitah; Diale, M. (Mmantsae Moche); Mukhokosi, Emma Panzi (IOP Publishing, 2026-01-05)
The urgent need to address fossil fuel challenges has led to a surge in green energy technologies, including solar cells. Nanodimensional particles, particularly 2D nanostructures, have shown great potential in these technologies due to their high surface area-to-volume ratio. Nickel oxide (NiO) is a promising p-type semiconductor for solar cell photo-cathodes, offering remarkable physical and chemical properties at a relatively low cost. However, its surface morphology, area, and pores have a significant impact on performance. Traditional chemical synthesis methods for NiO nanostructures have several drawbacks, including the use of hazardous precursors. To address this, we present for the first time a novel bioengineering method using bamboo shoot extract to produce 2D NiO nanostructures. The results have been supported by Density Functional Theory (DFT) calculations. The DFT calculations revealed that NiO is a p-type semiconductor with direct band gap for spin-down at Г. The results show that the bioengineered NiO nanostructures exhibit high crystallinity and a honeycomb-like morphology. We successfully integrated these nanoparticles into a dye-sensitized solar cell (DSSC), demonstrating their viability as a counter electrode. The cell exhibits promising performance, with a short-circuit current density of 0.113 mA cm−2 and an efficiency of 0.0057%. This study presents a straightforward, cost-effective, and environmentally friendly method for bioengineering NiO honeycomb-like nanostructures, thereby paving the way for sustainable energy solutions.
An overabundance of radio active galactic nuclei in the SPT2349-56 protocluster : preheating the intracluster medium
Chapman, Scott C.; Deane, Roger; Zhou, Dazhi; Aravena, Manuel; Rasakanya, William; Archipley, Melanie; Burgoyne, James; Cathey, Jared; Gonzalez, Anthony H.; Hill, Ryley; Hughes, Chayce; Llave, Monica Natalia Isla; Malkan, Matt; Phadke, Kedar A.; Pillai, Vismaya; Posses, Ana; Slocombe, Bonnie; Solimano, Manuel; Spilker, Justin; Sulzenauer, Nikolaus; Vito, Fabio; Vieira, Joaquin D.; Vizgan, David; Wang, George; Weiss, Axel (IOP Publishing, 2026-03-11)
Following the detection of a radio-loud active galactic nucleus (AGN) in the z = 4.3 protocluster SPT2349−56, we have obtained additional observations with the South African MeerKAT radio telescope in the S band (2.4 GHz) with the aim of further characterizing radio emission from amongst the ∼30 submillimeter galaxies (SMGs) identified in the structure. In addition to the previous radio-AGN, we newly identify two of the protocluster SMGs individually at 2.4 GHz as having a radio excess. Two of these radio-AGN are now known to be X-ray luminous AGN. Two additional members are also detected with radio emission consistent with their star formation rate (SFR). Archival MeerKAT Ultra-High Frequency (UHF; 816 MHz) observations further constrain luminosities and radio spectral indices of these five galaxies. The Australia Telescope Compact Array is used to detect and resolve the central two sources at 5.5 and 9.0 GHz finding elongated, bipolar jet-like morphologies. The excess radio luminosities range from L _1.4,rest = (1–20) × 10 ^25 W Hz ^−1 , ∼10–100× higher than expected from the SFRs, assuming the usual far-infrared–radio correlation. Of the known cluster members, only the SMG “N1” shows signs of AGN in any other diagnostics, namely a large and compact excess in ^12 CO(11–10) line emission. We compare these results to field samples of radio sources and SMGs. The overdensity of radio-loud AGN in the compact core region of the cluster may be providing significant heating to the recently discovered nascent intracluster medium in SPT2349−56.
Spatially resolved polarization swings in the supermassive binary black hole candidate OJ 287 with first Event Horizon Telescope observations
Gómez, Jose L.; Cho, Ilje; Traianou, Efthalia; Krichbaum, Thomas P.; Zhao, Guangyao; Lico, Rocco; Fuentes, Antonio; Foschi, Marianna; Dahale, Rohan; Georgiev, Boris; Moriyama, Kotaro; Wielgus, MacIek Iej; Gold, Roman; Pesce, Dominic W.; Müller, Hendrik; Jorstad, Svetlana G.; Toscano, Teresa; Röder, Jan; Martí, Josep María; Perucho, Manuel; Kovalev, Y.Y.; Komossa, Stefanie; Gopakumar, Achamveedu; Valtonen, Mauri J.; Bruni, Gabriele; Chandra, Sunil; Akiyama, Kazunori; Albentosa-Ruíz, Ezequiel; Alberdi, A.; Alef, Walter; Algaba Marcos, Juan Carlos; Anantua, Richard J.; Asada, Keiichi; Azulay, Rebecca; Bach, Uwe; Baczko, Anne Kathrin; Ball, David; Baloković, Mislav; Bandyopadhyay, Bidisha; Barrett, John P.; Bauböck, Michi; Benson, Bradford A.; Bintley, Dan I.; Blackburn, Lindy L.; Blundell, Raymond; Bouman, Katherine L.; Bower, Geoffrey C.; Bremer, Michael A.R.; Brissenden, Roger J.V.; Britzen, Silke; Broderick, Avery E.; Broguière, Dominique; Bronzwaer, Thomas; Bustamante, Sandra; Carlos, Douglas Ferreira; Carlstrom, John E.; Chael, Andrew A.; Chan, Chikwan; Chang, Dominic O.; Chatterjee, Koushik; Chatterjee, S.; Chen, Mingtang; Chen, Yongjun; Cheng, Xiaopeng; Christian, Pierre; Conroy, Nicholas S.; Conway, John E.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, A.; Cui, Yuzhu; Curd, Brandon; Davelaar, Jordy R.J.; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica T.; Desvignes, Grégory; Dexter, Jason; Dhruv, Vedant; Dihingia, Indu Kalpa; Doeleman, Sheperd S.; Dzib, Sergio Abraham; Eatough, Ralph P.; Emami, Razieh; Falcke, Heino D.; Farah, Joseph R.; Fish, Vincent L.; Fomalont, Edward B.; Ford, H. Alyson; Fraga-Encinas, Raquel; Freeman, William T.; Friberg, Per; Fromm, Christian M.; Galison, Peter Louis; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Geertsema, Gertie T.; Goddi, Ciriaco; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; 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.; Jones, Adam C.; Joshi, Abhishek V.; Jung, Taehyun; 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; Kuo, Cheng-Yu; La Bella, Noemi; Lee, Sang-Sung; Levis, Aviad; Li, Zhiyuan; 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, Ivàn; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Izumi; Mizuno, Yosuke; Montgomery, Joshua; Moran, James M.; Moscibrodzka, Monika; Mulaudzi, Wanga; Müller, Cornelia; Mus, Alejandro; Musok, Gibwa; Myserlis, Ioannis; Nagai, Hiroshi; Nagar, Neil M.; Nai, Dhanya G.; Nakamura, Masanori; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Navarro Fuentes, Santiago; Neilsen, Joey; Ni, Chunchong; Nowak, Michael A.; Oh, Junghwan; Okino, Hiroki; Olivares Sánchez, Héctor Raúl; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C.M.; Paraschos, Georgios Filippos; Park, Jongho; Parsons, Harriet; Patel, Nimesh; Pen, Ue-Li; Piétu, Vincent; PopStefanija, Aleksandar; Porth, Oliver; Prather, Ben; Principe, Giacomo; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Rezzolla, Luciano; Ricarte, Angelo; Ripperda, Bart; Roelofs, Freek; 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; Saurabh; Savolainen, Tuomas; Schloerb, F. Peter; Schonfeld, Jonathan; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Silpa, Sasikumar; Small, Des; Sohn, Bong Won; SooHoo, Jason; Salas, León D.S.; Souccar, Kamal; Stanway,; Sun, He Joshua S.; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P.J.; Titus, Michael; Toma, Kenji; Torne, Pablo; 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; Yamaguchi, Paul; Yfantis, Aristomenis; Yoon, Doosoo; Young, André; Younsi, Ziri; Yu, Wei; Yuan, Feng; Yuan, Ye-Fei; Zeng, Ai-Ling; Zensus, J. Anton; Zhang, Shuo; Zhao, Shan-Shan (EDP Sciences, 2026-01)
We present the first Event Horizon Telescope 1.3 mm observations of the supermassive binary black hole candidate OJ 287. The observations achieved an unprecedented angular resolution of 18 μas and reveal significant structural and polarization variability over just five days, marking the shortest timescale on which such changes have been directly imaged in this source. The inner jet exhibits a twisted ridgeline structure, with features displaying apparent superluminal motions up to about 22 c. The linear polarization maps reveal three main polarized features whose electric-vector position angles (EVPAs) change substantially over the time span of our observations, including a component with a radial polarization consistent with being produced by a recollimation shock. Most notably, we directly resolved two innermost jet components whose EVPAs rotate in opposite directions. The faster component, moving at 2.4 ± 0.9 μas/day (17.4 ± 6.5 c), exhibits counterclockwise EVPA swings of roughly 3.7° per day, while the slower component, with a proper motion of 1.4 ± 0.3 μas/day (10.2 ± 2.2 c), rotates clockwise at approximately 2.5° per day. Previous studies inferred helical magnetic fields in AGN jets from time-resolved or integrated polarization variability but lacked the angular resolution to directly image this effect. Our results provide spatially resolved evidence that a helical magnetic field threads the jet’s collimation and acceleration zone, ruling out models based on the superposition of unresolved components. Our analysis suggests that propagating shocks interact with a Kelvin–Helmholtz plasma instability, illuminating different phases of the helical magnetic field and producing the observed polarization spatial and temporal variability. Moreover, our model naturally accounts for the more rapid polarization rotation observed in the faster moving component. Our model predicts even more rapid swings in polarization, which could be tested with future observations featuring a more densely sampled time coverage.
A possible challenge for cold and warm dark matter
Vegetti, Simona; White, Simon D.M.; McKean, John P.; Powell, Devon M.; Spingola, Cristiana; Massari, Davide; Despali, Giulia; Fassnacht, Christopher D. (Nature Research, 2026)
Measuring the density profile and mass concentration of dark-matter haloes is a key test of the standard cold dark matter paradigm. Such objects are dark and thus challenging to characterize, but they can be studied via gravitational lensing. Recently, a million-solar-mass object was discovered superposed on an extended and extremely thin gravitational arc. Here we report on extensive tests of various assumptions for the mass density profile and redshift of this object. We find that models that best describe the data have two components: an unresolved point mass of radius ≤10 pc centred on an extended mass distribution with an almost constant surface density out to a truncation radius of 139 pc. These properties do not resemble any known astronomical object. However, if the object is dark matter dominated, its structure is incompatible with cold dark matter models but may be compatible with a self-interacting dark-matter halo where the central region has collapsed to form a black hole. This detection could thus carry substantial implications for our current understanding of dark matter.
Investigating the influence of radio-faint active galactic nuclei on the infrared-radio correlation of massive galaxies
Peluso, Giorgia; Delvecchio, Ivan; Radcliffe, Jack Frederick; Daddi, Emanuele; Deane, Roger; Jarvis, Matt; Zamorani, Giovanni; Prandoni, Isabella; Gitti, Myriam; Spingola, Cristiana; Ubertosi, Francesco; Sargent, Mark; Smolcic, Vernesa; Wang, Wuji; Delhaize, Jacinta; Jin, Shuowen; Deller, Adam (EDP Sciences, 2026-02)
Please read abstract in the article.
Therapeutic switching of metformin using heteroleptic Cu(II) and Zn(II) complexes : a combined experimental and computational study
Alem, Mamaru B.; Koobotse, Moses O.; Demissie, Taye B.; Desalegn, Tegene; Kruger, T.P.J. (Tjaart); Damena, Tadewos; Mmereki, Baagi T.; Ngwira, Kennedy J.; Zachariah, Matshediso (American Chemical Society, 2026-02-02)
Please read abstract in the article.
Spectral modelling of Cygnus A between 110 and 250 MHz : impact on the LOFAR 21-cm signal power spectrum
Ceccotti, E.; Offringa, A.R.; Koopmans, L.V.E.; Mertens, F.G.; Mevius, M.; Acharya, A.; Brackenho, S.A.; Ciardi, B.; Gehlot, B.K.; Ghara, R.; Chege, J.K.; Ghosh, S.; Höfer, C.; Hothi, I.; Iliev, I.T.; McKean, John P.; Munshi, S.; Zaroubi, S. (EDP Sciences, 2025-04)
Studying the redshifted 21-cm signal from the neutral hydrogen during the Epoch of Reionisation and Cosmic Dawn is fundamental for understanding the physics of the early universe. One of the challenges that 21-cm experiments face is the contamination by bright foreground sources, such as Cygnus A, for which accurate spatial and spectral models are needed to minimise the residual contamination after their removal. In this work, we develop a new, high-resolution model of Cygnus A using Low Frequency Array (LOFAR) observations in the 110–250 MHz range, improving upon previous models by incorporating physical spectral information through the forced-spectrum method during multi-frequency deconvolution. This approach addresses the limitations of earlier models by providing a more accurate representation of the complex structure and spectral behaviour of Cygnus A, including the spectral turnover in its brightest hotspots. The impact of this new model on the LOFAR 21-cm signal power spectrum is assessed by comparing it with both simulated and observed North Celestial Pole datasets. Significant improvements are observed in the cylindrical power spectrum along the Cygnus A direction, highlighting the importance of having spectrally accurate models of the brightest foreground sources. However, this improvement is washed out in the spherical power spectrum, where we measure differences of a few hundred mK at k < 0.63 h cMpc−1, but not statistically significant. The results suggest that other systematic effects must be mitigated before a substantial impact on 21-cm power spectrum can be achieved.
Investigation of mass substructure in gravitational lens system SDP 81 with ALMA long-baseline observations
Stacey, H.R.; Powell, D.M.; Vegetti, S.; McKean, John P.; Wen, D. (EDP Sciences, 2025-11)
The prevalence and properties of low-mass dark matter haloes serve as a crucial test for understanding the nature of dark matter, and may be constrained through the gravitational deflection of strongly lensed arcs. Previous studies found evidence for the presence of low-mass dark matter haloes in observations of the gravitationally lensed, dusty star-forming galaxy SDP.81, using the Atacama Large Millimetre/sub-millimetre Array (ALMA). In this work, we analyse these observations to assess the robustness of these reported results. While our analysis indicates that the data support additional angular structure in the lensing mass distribution beyond an elliptical power-law density profile, we do not find evidence for two previously reported sub-halo detections. However, we verify with realistic mock data that we could have found evidence in favour of a previously reported sub-halo with a log Bayes factor of 29, should it exist in the real data. After testing various systematics, we find that this previous sub-halo inference was most likely spurious and resulted from an inadequate smooth model, specifically, poorly fitting multipoles. While we do not find evidence in favour of any individual sub-halo, we find evidence for similarity in the lensing signatures of multipoles () and single massive sub-haloes, consistent with other recent work. We suggest that future searches for low-mass haloes in lensed arcs include lens angular structure in the form of multipoles up to 4th order and require a good-fitting smooth model as a prerequisite. Overall, our findings demonstrate the suitability of ALMA data of this quality to simultaneously constrain the abundance of low-mass haloes and lens angular structure.
Discovery of a z ∼ 0.8 ultra steep spectrum radio halo in the MeerKAT-South Pole Telescope Survey
Magolego, Isaac; Deane, Roger; Thorat, Kshitij; Heywood, Ian; Rasakanya, William; Aravena, Manuel; Bleem, Lindsey E.; Campitiello, Maria Giulia; Phadke, Kedar A.; Spilker, Justin S.; Vieira, Joaquin D.; Zhou, Dazhi; Benson, Bradford A.; Chapman, Scott C.; Posses, Ana C.; Schrabback, Tim; Stark, Anthony A.; Vizgan, David (Oxford University Press, 2026-01)
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The effect of Y element on the properties of cobalt-based full-Heusler ZrCo2Y (Y=Sb, Bi, As) as a potential thermoelectric contact electrode
Allan, Lynet; Mulwa, Winfred M.; Mapasha, Refilwe Edwin; Mwabora, Julius M.; Musembi, Robinson J. (Elsevier, 2025-12)
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Controlling the migration of implanted cesium in silicon carbide using zirconium nanolayer
Abdelbagi, Hesham Abdelbagi Ali; Mtshali, Christopher B.; Hossain, M.K.; Ronning, C.; Jafer, Tasabeeh A.O.; Ismail, Mahjoub Yagoub Abdalla; Abdalla, Zaki Adam Yousif; Malherbe, Johan B.; El-Said, A.S.; Hlatshwayo, Thulani Thokozani; Ntshangase, S.S. (Elsevier, 2025-12)
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Growth and characterization of orthorhombic cesium lead tri-iodide perovskite thin-films by sequential physical vapor deposition for solar cells
Sibiya, Sizwe Bhekithemba (Elsevier, 2025-12)
This study used the sequential physical vapor deposition (SPVD) technique to grow poly-crystalline yellow phase cesium lead triiodide (γ-CsPbI3). The effect of CsI thickness on structural, optical, morphological, and electrical properties of γ-CsPbI3 was investigated. Crystallographic parameters of γ-CsPbI3 as-deposited and 100 °C annealed pure-phase were determined using X-ray diffraction (XRD). Computed lattice constants were a = 4.88, b = 9.96, and c = 16.5 Å, with an average crystallite size increasing from 170 − 243 nm, and micro-strain decreasing with an increase of cesium iodide (CsI) thickness from 200 to 500 nm. Field-emission scanning electron microscopy (FE-SEM) images showed uniform surface coverage with polycrystalline grains. Average grain size increased from 168 to 235 nm with increasing CsI thickness, resulting in large, pinhole-free, and tightly packed grains. Furthermore, atomic force microscopy (AFM) surface analysis demonstrated a reduction in surface roughness from 44.0 to 38.3 nm as CsI thickness increased from 200 to 500 nm. The ultraviolet–visible (UV–Vis) spectra showed an increase in bandgap from 2.24 to 2.38 eV for as-deposited and a decrease from 2.37 to 2.05 eV for annealed films as the thickness of CsI increased. Current–voltage (J-V) measurements revealed a correlation between the trap-filled limit voltage (VTFL) and defect density. For electron-only devices with film thicknesses of 300, 400, 500, and 600 nm, the trap state densities were found to be 1.40 × 1015, 1.95 × 1015, 2.12 × 1015, and 2.39 × 1015 cm−3, respectively. The corresponding electron mobilities were 2.34 × 101, 6.30 × 101, 4.72 × 102, and 1.07 × 102 cm2/V·s. Additionally, perovskite solar cells (PSCs) fabricated under ambient air conditions revealed an improvement in power conversion efficiency (PCE) from 2.0 to 4.93 % for the FTO/c-TiO2/CsPbI3/Au architecture. This work suggests a way of improving precursor’s reaction using SPVD by controlling the film thickness, reducing defect density through SPVD, and therefore highlighting film thickness optimization in perovskites.
Effects of the physisorption properties of human hair-derived activated carbon as a potential electrode for symmetric supercapacitor
Adam, Rashed Ali Mohamed; Tarimo, Delvina Japhet; Maphiri, Vusani Muswa; Mirghni, Abdulmajid Abdallah; Fasakin, Oladepo; Manyala, Ncholu I. (Springer, 2025-04)
Herein, human hair-derived activated carbon (HH-AC) with remarkable physisorption properties such as high surface area and well-balanced micro- and mesopores, is synthesized by chemical activation method using potassium hydroxide (KOH). The activated carbon is synthesized at different ratio of charred human hair and activator as 1:1, 1:2 and 1:3 for HH AC(11), HH-AC(12) and HH-AC(13), respectively. These activated materials are characterized by a powder X-ray diffraction (XRD), Laser Raman spectroscopy, Scanning electron microscope (SEM), and N2 adsorption/desorption isotherms. To examine the influence of the micro-mesopore ratio with high surface area on supercapacitor behavior, all samples are tested in a three-electrode using 2.5 moles of potassium nitrate (2.5 M KNO3) as electrolyte solution. The results show that HH-AC(12) sample which has micro to mesopore-balanced (50 : 50) exhibited superior electrochemical performance with specific capacitance of 215 F g−1 and 125.8 F g−1 in the negative and positive potential, respectively at 1A g−1. The sample HH-AC(11), which is dominated by micropores, showed lower rate capability and specific capacitance despite the huge surface area. Whereas the HH-AC(13) sample with mostly mesopores achieved higher rate capability compared to the others. The HH-AC(12) is further examined in a 2-electrode setup to form a symmetric device. The results show a specific energy of 16Wh kg−1 and a specific power of 375Wkg−1 at 0.5 A g−1. The device demonstrates outstanding capacitance retention of 97% after 10,000 cycles. Thus, ACs with micro to mesopores-balanced are potential candidates for supercapacitor applications.
Sunyaev–Zeldovich detection of hot intracluster gas at redshift 4.3
Zhou, Dazhi; Chapman, Scott C.; Aravena, Manuel; Araya-Araya, Pablo; Archipley, Melanie; Cathey, Jared; Deane, Roger; Di Mascolo, Luca; Gobat, Raphael; Greve, Thomas R.; Hill, Ryley; Kim, Seonwoo; Phadke, Kedar A.; Pillai, Vismaya R.; Posses, Ana C.; Reichardt, Christian L.; Solimano, Manuel; Spilker, Justin S.; Sulzenauer, Nikolaus; Dike, Veronica J.; Vieira, Joaquin D.; Vizgan, David; Wang, George C.P.; Weiss, Axel (Nature Research, 2026-01-29)
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Interface engineering of activated carbon via nitrogen and nitrogen-sulfur doping for high-performance supercapacitors and dye adsorption
Kitenge, Vianney Ngoyi; Baloyi, T.; Diop, Ndeye Fatou; Mohamed, H.E.A.; Botha, N.; Thior, Souleymane; ShamsKhameneh, A.; Madiba, I.; Manyala, Ncholu I.; Chaker, M.; Maaza, M. (Elsevier, 2026-02)
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A critical review on electronic materials properties and multifunctional applications
Mengesha, Wubshet Getachew; Nagessar, Kaveer (Springer, 2026-01)
The rapid advancement of electronic technologies necessitates the development of materials with tailored properties for multifunctional applications. However, there are significant challenges include a fundamental gap in connecting quantum-level behavior to macroscopic properties, data scarcity, and difficulties in integrating multidisciplinary datasets. This paper aims to analyze recent advancements and propose integrated frameworks to bridge these gaps by leveraging artificial intelligence (AI) and machine learning (ML) with a comprehensive review methodology and critical analysis of properties, types, their diverse applications coupled with AI-driven approaches, including generative models, physics-informed neural networks, and autonomous laboratories, for predicting and optimizing electronic materials. Key findings highlight their diverse applications and discovery such as perovskites, 2D mate- rials, and high-temperature superconductors—and in optimizing electronic, thermal, and magnetic characteristics. Recent studies indicate that AI-driven approaches can improve prediction accuracy and enable inverse design in selected systems. These approaches have the potential for significant impact on materials discovery and integration, potentially leading to a transformation of the electronic materials landscape. This paper underscores the future potential of AI-driven paradigms to revolutionize the electronic materials landscape by integrating computational prediction with experimental validation for multifunctional real-world applications.

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