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16,946 results on '"Agudo, A"'

1. Universal mechanistic rules for de novo design of enzymes

Author

Chatzittofi, Michalis, Agudo-Canalejo, Jaime, and Golestanian, Ramin

Subjects
Condensed Matter - Soft Condensed Matter, Condensed Matter - Statistical Mechanics, Physics - Biological Physics, Physics - Chemical Physics
Abstract

Enzymes are nano-scale machines that have evolved to drive chemical reactions out of equilibrium in the right place at the right time. Thermodynamically favourable reactions such as ATP hydrolysis are used by the cell to convert chemical energy into useful structure, function, and mechanical work. This includes the `fuelled' catalysis of chemical reactions that would otherwise be thermodynamically unfavourable. Given the complexity and specificity of enzymatic function, bottom-up design of enzymes presents a daunting task that is far more challenging than making passive molecules with specific binding affinities or building nano-scale mechanically active devices. Here, we present a thermodynamically-consistent model for the operation of such a fuelled enzyme, which uses the energy from a favourable reaction to undergo non-equilibrium conformational changes that in turn catalyze a chemical reaction on an attached substrate molecule. We show that enzymatic function can emerge through a bifurcation upon appropriate implementation of momentum conservation on the effective reaction coordinates of the low dimensional description of the enzyme, and thanks to a generically present dissipative coupling. By considering the different aspects of the dynamics, such as the interplay of the non-equilibrium drive and the geometry of the enzyme-substrate complex, we propose three golden rules that should be universally applicable for de novo design of enzymes, as they are based on generic ingredients and physical constraints. These rules lead to optimal combinations of parameters, which can vastly accelerate reactions, while at the same time decreasing the energy dissipation of the combined reaction process, or, in other words, to an efficient enzyme. Our results can complement the recently developed strategies for de novo enzyme design based on machine learning approaches.

Published
2024

2. Thermodynamic inference of correlations in nonequilibrium collective dynamics

Author

Chatzittofi, Michalis, Golestanian, Ramin, and Agudo-Canalejo, Jaime

Subjects
Condensed Matter - Statistical Mechanics, Physics - Biological Physics
Abstract

The theory of stochastic thermodynamics has revealed many useful fluctuation relations, with the thermodynamic uncertainty relation (TUR) being a theorem of major interest. When many nonequilibrium currents interact with each other, a naive application of the TUR to an individual current can result in an apparent violation of the TUR bound. Here, we explore how such an apparent violation can be used to put a lower bound on the strength of correlations as well as the number of interacting currents in collective dynamics. Our proposed protocol allows for the inference of hidden correlations in experiment, for example when a team of molecular motors pulls on the same cargo but only one or a subset of them is fluorescently tagged. By solving analytically and numerically several models of many-body nonequilibrium dynamics, we ascertain under which conditions this strategy can be applied and the inferred bound on correlations becomes tight.

Published
2024

3. iSee: Advancing Multi-Shot Explainable AI Using Case-based Recommendations

Author

Wijekoon, Anjana, Wiratunga, Nirmalie, Corsar, David, Martin, Kyle, Nkisi-Orji, Ikechukwu, Palihawadana, Chamath, Caro-Martínez, Marta, Díaz-Agudo, Belen, Bridge, Derek, and Liret, Anne

Subjects
Computer Science - Artificial Intelligence, Computer Science - Human-Computer Interaction, Computer Science - Information Retrieval
Abstract

Explainable AI (XAI) can greatly enhance user trust and satisfaction in AI-assisted decision-making processes. Recent findings suggest that a single explainer may not meet the diverse needs of multiple users in an AI system; indeed, even individual users may require multiple explanations. This highlights the necessity for a "multi-shot" approach, employing a combination of explainers to form what we introduce as an "explanation strategy". Tailored to a specific user or a user group, an "explanation experience" describes interactions with personalised strategies designed to enhance their AI decision-making processes. The iSee platform is designed for the intelligent sharing and reuse of explanation experiences, using Case-based Reasoning to advance best practices in XAI. The platform provides tools that enable AI system designers, i.e. design users, to design and iteratively revise the most suitable explanation strategy for their AI system to satisfy end-user needs. All knowledge generated within the iSee platform is formalised by the iSee ontology for interoperability. We use a summative mixed methods study protocol to evaluate the usability and utility of the iSee platform with six design users across varying levels of AI and XAI expertise. Our findings confirm that the iSee platform effectively generalises across applications and its potential to promote the adoption of XAI best practices., Comment: Accepted to appear at the ECAI-PAIS 2024 main conference proceedings

Published
2024

4. Electron-beam-induced modification of gold microparticles in an SEM

Author

Weinel, Kristina, Hahn, Marc Benjamin, Lubk, Axel, Feng, Wen, Martinez, Ignacio Gonzalez, Büchner, Bernd, and Jácome, Leonardo Agudo

Subjects
Condensed Matter - Materials Science
Abstract

Electron-beam-induced conversion of materials in a transmission electron microscope uses the high power density of a localized electron beam of acceleration voltages above 100 kV as an energy source to transform matter at the sub-micron scale. Here, the e-beam-induced transformation of precursor microparticles employing a low-energy e-beam with an acceleration voltage of 30 kV in a scanning electron microscope is developed to increase the versatility and efficiency of the technique. Under these conditions, the technique can be classified between e-beam lithography, where the e-beam is used to mill holes in or grow some different material onto a substrate, and e-beam welding, where matter can be welded together when overcoming the melting phase. Modifying gold microparticles on an amorphous SiOx substrate reveals the dominant role of inelastic electron-matter interaction and subsequent localized heating for the observed melting and vaporization of the precursor microparticles under the electron beam. Monte-Carlo scattering simulations and thermodynamic modeling further support the findings.

Published
2024

5. Analysis of Crab X-ray Polarization using Deeper IXPE Observations

Author

Wong, Josephine, Mizuno, Tsunefumi, Bucciantini, Niccoló, Romani, Roger W., Yang, Yi-Jung, Liu, Kuan, Deng, Wei, Goya, Kazuho, Xie, Fei, Pilia, Maura, Kaaret, Philip, Weisskopf, Martin C., Silvestri, Stefano, Ng, C. -Y., Chen, Chien-Ting, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccoló, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Negro, Michela, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel Lawrence, Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Sgró, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey, Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Zane, Silvia

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present Crab X-ray polarization measurements using IXPE data with a total exposure of 300ks, three times more than the initial 2022 discovery paper. Polarization is detected in three times more pulsar phase bins, revealing an S-shaped $+40^\circ$ polarization angle sweep in the main pulse and ${>}1\sigma$ departures from the OPTIMA optical polarization in both pulses, suggesting different radiation mechanisms or sites for the polarized emission at the two wavebands. Our polarization map of the inner nebula reveals a toroidal magnetic field, as seen in prior IXPE analyses. Along the southern jet, the magnetic field orientation relative to the jet axis changes from perpendicular to parallel and the polarization degree decreases by ${\sim}6\%$. These observations may be explained by kink instabilities along the jet or a collision with a dense, jet-deflecting medium at the tip. Using spectropolarimetric analysis, we find asymmetric polarization in the four quadrants of the inner nebula, as expected for a toroidal field geometry, and a spatial correlation between polarization degree and photon index., Comment: 14 pages, 7 figures, 3 tables. Accepted by The Astrophysical Journal

Published
2024

6. X-ray and multiwavelength polarization of Mrk 501 from 2022 to 2023

Author

Chen, Chien-Ting J., Liodakis, Ioannis, Middei, Riccardo, Kim, Dawoon E., Di Gesu, Laura, Di Marco, Alessandro, Ehlert, Steven R., Errando, Manel, Negro, Michela, Jorstad, Svetlana G., Marscher, Alan P., Wu, Kinwah, Agudo, Iván, Poutanen, Juri, Mizuno, Tsunefumi, Kouch, Pouya M., Lindfors, Elina, Borman, George A., Grishina, Tatiana S., Kopatskaya, Evgenia N., Larionova, Elena G., Morozova, Daria A., Savchenko, Sergey S., Troitsky, Ivan S., Troitskaya, Yulia V., Vasilyev, Andrey A., Zhovtan, Alexey V., Aceituno, Francisco José, Bonnoli, Giacomo, Casanova, Víctor, Escudero, Juan, Agís-González, Beatriz, Husillos, César, Santos, Jorge Otero, Sota, Alfredo, Piirola, Vilppu, Myserlis, Ioannis, Angelakis, Emmanouil, Kraus, Alexander, Gurwell, Mark, Keating, Garrett, Rao, Ramprasad, Kang, Sincheol, Lee, Sang-Sung, Kim, Sang-Hyun, Cheong, Whee Yeon, Jeong, Hyeon-Woo, Song, Chanwoo, Berdyugin, Andrei V., Kagitani, Masato, Kravtsov, Vadim, Nitindala, Anagha P., Sakanoi, Takeshi, Imazawa, Ryo, Sasada, Mahito, Fukazawa, Yasushi, Kawabata, Koji S., Uemura, Makoto, Nakaoka, Tatsuya, Akitaya, Hiroshi, Casadio, Carolina, Sievers, Albrecht, Antonelli, Lucio Angelo, Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccoló, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Lalla, Niccoló, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel Lawrence, Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgró, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Xie, Fei, and Zane, Silvia

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

We present multiwavelength polarization measurements of the luminous blazar Mrk~501 over a 14-month period. The 2--8 keV X-ray polarization was measured with the Imaging X-ray Polarimetry Explorer (IXPE) with six 100-ks observations spanning from 2022 March to 2023 April. Each IXPE observation was accompanied by simultaneous X-ray data from NuSTAR, Swift/XRT, and/or XMM-Newton. Complementary optical-infrared polarization measurements were also available in the B, V, R, I, and J bands, as were radio polarization measurements from 4.85 GHz to 225.5 GHz. Among the first five IXPE observations, we did not find significant variability in the X-ray polarization degree and angle with IXPE. However, the most recent sixth observation found an elevated polarization degree at $>3\sigma$ above the average of the other five observations. The optical and radio measurements show no apparent correlations with the X-ray polarization properties. Throughout the six IXPE observations, the X-ray polarization degree remained higher than, or similar to, the R-band optical polarization degree, which remained higher than the radio value. This is consistent with the energy-stratified shock scenario proposed to explain the first two IXPE observations, in which the polarized X-ray, optical, and radio emission arises from different regions., Comment: Accepted for publication in ApJ

Published
2024

7. XEQ Scale for Evaluating XAI Experience Quality Grounded in Psychometric Theory

Author

Wijekoon, Anjana, Wiratunga, Nirmalie, Corsar, David, Martin, Kyle, Nkisi-Orji, Ikechukwu, Díaz-Agudo, Belen, and Bridge, Derek

Subjects
Computer Science - Artificial Intelligence, Computer Science - Human-Computer Interaction
Abstract

Explainable Artificial Intelligence (XAI) aims to improve the transparency of autonomous decision-making through explanations. Recent literature has emphasised users' need for holistic "multi-shot" explanations and the ability to personalise their engagement with XAI systems. We refer to this user-centred interaction as an XAI Experience. Despite advances in creating XAI experiences, evaluating them in a user-centred manner has remained challenging. To address this, we introduce the XAI Experience Quality (XEQ) Scale (pronounced "Seek" Scale), for evaluating the user-centred quality of XAI experiences. Furthermore, XEQ quantifies the quality of experiences across four evaluation dimensions: learning, utility, fulfilment and engagement. These contributions extend the state-of-the-art of XAI evaluation, moving beyond the one-dimensional metrics frequently developed to assess single-shot explanations. In this paper, we present the XEQ scale development and validation process, including content validation with XAI experts as well as discriminant and construct validation through a large-scale pilot study. Out pilot study results offer strong evidence that establishes the XEQ Scale as a comprehensive framework for evaluating user-centred XAI experiences.

Published
2024

8. A detailed study of the very-high-energy Crab pulsar emission with the LST-1

Author

Project, CTA-LST, Abe, K., Abe, S., Abhishek, A., Acero, F., Aguasca-Cabot, A., Agudo, I., Crespo, N. Alvarez, Antonelli, L. A., Aramo, C., Arbet-Engels, A., Arcaro, C., Artero, M., Asano, K., Aubert, P., Baktash, A., Bamba, A., Larriva, A. Baquero, Baroncelli, L., de Almeida, U. Barres, Barrio, J. A., Batkovic, I., Baxter, J., González, J. Becerra, Bernardini, E., Medrano, J. Bernete, Berti, A., Bhattacharjee, P., Bigongiari, C., Bissaldi, E., Blanch, O., Bonnoli, G., Bordas, P., Brunelli, G., Bulgarelli, A., Burelli, I., Burmistrov, L., Buscemi, M., Cardillo, M., Caroff, S., Carosi, A., Carrasco, M. S., Cassol, F., Castrejón, N., Cauz, D., Cerasole, D., Ceribella, G., Chai, Y., Cheng, K., Chiavassa, A., Chikawa, M., Chon, G., Chytka, L., Cicciari, G. M., Cifuentes, A., Contreras, J. L., Cortina, J., Costantini, H., Da Vela, P., Dalchenko, M., Dazzi, F., De Angelis, A., de Lavergne, M. de Bony, De Lotto, B., de Menezes, R., Del Peral, L., Delgado, C., Mengual, J. Delgado, della Volpe, D., Dellaiera, M., Di Piano, A., Di Pierro, F., Di Tria, R., Di Venere, L., Díaz, C., Dominik, R. M., Prester, D. Dominis, Donini, A., Dorner, D., Doro, M., Eisenberger, L., Elsässer, D., Emery, G., Escudero, J., Ramazani, V. Fallah, Ferrarotto, F., Fiasson, A., Foffano, L., Coromina, L. Freixas, Fröse, S., Fukazawa, Y., López, R. Garcia, Gasbarra, C., Gasparrini, D., Gavira, L., Geyer, D., Paiva, J. Giesbrecht, Giglietto, N., Giordano, F., Gliwny, P., Godinovic, N., Grau, R., Green, D., Green, J., Gunji, S., Günther, P., Hackfeld, J., Hadasch, D., Hahn, A., Hassan, T., Hayashi, K., Heckmann, L., Heller, M., Llorente, J. Herrera, Hirotani, K., Hoffmann, D., Horns, D., Houles, J., Hrabovsky, M., Hrupec, D., Hui, D., Iarlori, M., Imazawa, R., Inada, T., Inome, Y., Ioka, K., Iori, M., Martinez, I. Jimenez, Quiles, J. Jiménez, Jurysek, J., Kagaya, M., Karas, V., Katagiri, H., Kataoka, J., Kerszberg, D., Kobayashi, Y., Kohri, K., Kong, A., Kubo, H., Kushida, J., Lainez, M., Lamanna, G., Lamastra, A., Lemoigne, L., Linhoff, M., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., Bahilo, J. Lozano, Luque-Escamilla, P. L., Majumdar, P., Makariev, M., Mallamaci, M., Mandat, D., Manganaro, M., Manicò, G., Mannheim, K., Marchesi, S., Mariotti, M., Marquez, P., Marsella, G., Martí, J., Martinez, O., Martínez, G., Martínez, M., Mas-Aguilar, A., Maurin, G., Mazin, D., Guillen, E. Mestre, Micanovic, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., Mizuno, T., Gonzalez, M. Molero, Molina, E., Montaruli, T., Moralejo, A., Morcuende, D., Morselli, A., Moya, V., Muraishi, H., Nagataki, S., Nakamori, T., Neronov, A., Nickel, L., Rosillo, M. Nievas, Nikolic, L., Nishijima, K., Noda, K., Nosek, D., Novotny, V., Nozaki, S., Ohishi, M., Ohtani, Y., Oka, T., Okumura, A., Orito, R., Otero-Santos, J., Ottanelli, P., Owen, E., Palatiello, M., Paneque, D., Pantaleo, F. R., Paoletti, R., Paredes, J. M., Pech, M., Pecimotika, M., Peresano, M., Pfeiffle, F., Pietropaolo, E., Pihet, M., Pirola, G., Plard, C., Podobnik, F., Pons, E., Prandini, E., Priyadarshi, C., Prouza, M., Rando, R., Rhode, W., Ribó, M., Righi, C., Rizi, V., Fernandez, G. Rodriguez, Frías, M. D. Rodríguez, Saito, T., Sakurai, S., Sanchez, D. A., Sano, H., Šarić, T., Sato, Y., Saturni, F. G., Savchenko, V., Schiavone, F., Schleicher, B., Schmuckermaier, F., Schubert, J. L., Schussler, F., Schweizer, T., Arroyo, M. Seglar, Siegert, T., Silvia, R., Sitarek, J., Sliusar, V., Strišković, J., Strzys, M., Suda, Y., Tajima, H., Takahashi, H., Takahashi, M., Takata, J., Takeishi, R., Tam, P. H. T., Tanaka, S. J., Tateishi, D., Tavernier, T., Temnikov, P., Terada, Y., Terauchi, K., Terzic, T., Teshima, M., Tluczykont, M., Tokanai, F., Torres, D. F., Travnicek, P., Truzzi, S., Tutone, A., Vacula, M., Vallania, P., van Scherpenberg, J., Acosta, M. Vázquez, Verna, G., Viale, I., Vigliano, A., Vigorito, C. F., Visentin, E., Vitale, V., Voitsekhovskyi, V., Voutsinas, G., Vovk, I., Vuillaume, T., Walter, R., Wan, L., Will, M., Yamamoto, T., Yamazaki, R., Yeung, P. K. H., Yoshida, T., Yoshikoshi, T., Zhang, W., and Zywucka, N.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Context: There are currently three pulsars firmly detected by imaging atmospheric Cherenkov telescopes (IACTs), two of them reaching TeV energies, challenging models of very-high-energy (VHE) emission in pulsars. More precise observations are needed to better characterize pulsar emission at these energies. The LST-1 is the prototype of the Large-Sized Telescope, that will be part of the Cherenkov Telescope Array Observatory (CTAO). Its improved performance over previous IACTs makes it well suited for studying pulsars. Aims: To study the Crab pulsar emission with the LST-1, improving and complementing the results from other telescopes. These observations can also be used to characterize the potential of the LST-1 to study other pulsars and detect new ones. Methods: We analyzed a total of $\sim$103 hours of gamma-ray observations of the Crab pulsar conducted with the LST-1 in the period from September 2020 to January 2023. The observations were carried out at zenith angles less than 50 degrees. A new analysis of the Fermi-LAT data was also performed, including $\sim$14 years of observations. Results: The Crab pulsar phaseogram, long-term light-curve, and phase-resolved spectra are reconstructed with the LST-1 from 20 GeV to 450 GeV for P1 and up to 700 GeV for P2. The pulsed emission is detected with a significance of 15.2$\sigma$. The two characteristic emission peaks of the Crab pulsar are clearly detected (>10$\sigma$), as well as the so-called bridge emission (5.7$\sigma$). We find that both peaks are well described by power laws, with spectral indices of $\sim$3.44 and $\sim$3.03 respectively. The joint analysis of Fermi-LAT and LST-1 data shows a good agreement between both instruments in the overlapping energy range. The detailed results obtained in the first observations of the Crab pulsar with LST-1 show the potential that CTAO will have to study this type of sources., Comment: Accepted by A&A

Published
2024

9. The Impact of Different Uses of the Internet on Students' Performance Progression throughout Primary Education

Author

María Ladrón de Guevara Rodríguez, Luis Alejandro Lopez-Agudo, and Oscar David Marcenaro-Gutierrez

Abstract

The present research analyses the impact that the time spent on the Internet by primary school (3rd and 6th grade) students may have on their academic progression in terms of test scores. In order to go beyond a correlational analysis, we have applied a time fixed-effects estimation using a recent longitudinal database of 15,974 students from the Spanish region of the Canary Islands. Our results show that, in general, an increasingly frequent use of the Internet has a negative influence on students' academic achievement progression, with higher use of instant messaging applications being particularly linked to girls' poorer mathematics academic performance progression. This negative influence may be a consequence of replacing time to academic activities (e.g., reading books or homework) with time using the Internet, which can also ultimately lead students to adopt unhealthy study habits that can affect their future academic success. Furthermore, we find that there is not a negative impact of playing videogames on the mathematics competence, as the development of spatial-visual (digital) skills possibly counterbalances the negative influence of time substitution between academically oriented tasks and the Internet.

Published
2024
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10. FootBots: A Transformer-based Architecture for Motion Prediction in Soccer

Author

Capellera, Guillem, Ferraz, Luis, Rubio, Antonio, Agudo, Antonio, and Moreno-Noguer, Francesc

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Multiagent Systems
Abstract

Motion prediction in soccer involves capturing complex dynamics from player and ball interactions. We present FootBots, an encoder-decoder transformer-based architecture addressing motion prediction and conditioned motion prediction through equivariance properties. FootBots captures temporal and social dynamics using set attention blocks and multi-attention block decoder. Our evaluation utilizes two datasets: a real soccer dataset and a tailored synthetic one. Insights from the synthetic dataset highlight the effectiveness of FootBots' social attention mechanism and the significance of conditioned motion prediction. Empirical results on real soccer data demonstrate that FootBots outperforms baselines in motion prediction and excels in conditioned tasks, such as predicting the players based on the ball position, predicting the offensive (defensive) team based on the ball and the defensive (offensive) team, and predicting the ball position based on all players. Our evaluation connects quantitative and qualitative findings. https://youtu.be/9kaEkfzG3L8, Comment: Published as a conference paper at IEEE ICIP 2024

Published
2024

11. Testing particle acceleration in blazar jets with continuous high-cadence optical polarization observations

Author

Liodakis, Ioannis, Kiehlmann, Sebastian, Marscher, Alan P., Zhang, Haocheng, Blinov, Dmitry, Jorstad, Svetlana G., Agudo, Iván, Benítez, Erika, Berdyugin, Andrei, Bonnoli, Giacomo, Casadio, Carolina, Chen, Chien-Ting, Chen, Wen-Ping, Ehlert, Steven R., Escudero, Juan, Grishina, Tatiana S., Hiriart, David, Hsu, Angela, Imazawa, Ryo, Jermak, Helen E., Jose, Jincen, Kaaret, Philip, Kopatskaya, Evgenia N., Lalchand, Bhavana, Larionova, Elena G., Lindfors, Elina, López, José M., McCall, Callum, Morozova, Daria A., Palaiologou, Efthymios, Pandey, Shivangi, Poutanen, Juri, Rakshit, Suvendu, Reig, Pablo, Sasada, Mahito, Savchenko, Sergey S., Shablovinskaya, Elena, Neha, Sharma, Shrestha, Manisha, Steele, Iain A., Troitskiy, Ivan S., Troitskaya, Yulia V., Uemura, Makoto, Vasilyev, Andrey A., Weaver, Zachary, Wiersema, Klaas, and Weisskopf, Martin C.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Variability can be the pathway to understanding the physical processes in astrophysical jets, however, the high-cadence observations required to test particle acceleration models are still missing. Here we report on the first attempt to produce continuous, >24 hour polarization light curves of blazars using telescopes distributed across the globe and the rotation of the Earth to avoid the rising Sun. Our campaign involved 16 telescopes in Asia, Europe, and North America. We observed BL Lacertae and CGRaBS J0211+1051 for a combined 685 telescope hours. We find large variations in the polarization degree and angle for both sources in sub-hour timescales as well as a ~180 degree rotation of the polarization angle in CGRaBS J0211+1051 in less than two days. We compared our high-cadence observations to Particle-In-Cell magnetic reconnection and turbulent plasma simulations. We find that although the state of the art simulation frameworks can produce a large fraction of the polarization properties, they do not account for the entirety of the observed polarization behavior in blazar jets., Comment: 20 pages, 15 figures, 2 tables, accepted for publication in A&A. The data used in the paper are available here: https://doi.org/10.7910/DVN/IETSXS

Published
2024

12. An IXPE-Led X-ray Spectro-Polarimetric Campaign on the Soft State of Cygnus X-1: X-ray Polarimetric Evidence for Strong Gravitational Lensing

Author

Steiner, James F., Nathan, Edward, Hu, Kun, Krawczynski, Henric, Dovciak, Michal, Veledina, Alexandra, Muleri, Fabio, Svoboda, Jiri, Alabarta, Kevin, Parra, Maxime, Bhargava, Yash, Matt, Giorgio, Poutanen, Juri, Petrucci, Pierre-Olivier, Tennant, Allyn F., Baglio, M. Cristina, Baldini, Luca, Barnier, Samuel, Bhattacharyya, Sudip, Bianchi, Stefano, Brigitte, Maimouna, Cabezas, Mauricio, Cangemi, Floriane, Capitanio, Fiamma, Casey, Jacob, Cavero, Nicole Rodriguez, Castellano, Simone, Cavazzuti, Elisabetta, Chun, Sohee, Churazov, Eugene, Costa, Enrico, Di Lalla, Niccolo, Di Marco, Alessandro, Egron, Elise, Ewing, Melissa, Fabiani, Sergio, Garcia, Javier A., Green, David A., Grinberg, Victoria, Hadrava, Petr, Ingram, Adam, Kaaret, Philip, Kislat, Fabian, Kitaguchi, Takao, Kravtsov, Vadim, Kubatova, Brankica, La Monaca, Fabio, Latronico, Luca, Loktev, Vladislav, Malacaria, Christian, Marin, Frederic, Marinucci, Andrea, Maryeva, Olga, Mastroserio, Guglielmo, Mizuno, Tsunefumi, Negro, Michela, Omodei, Nicola, Podgorny, Jakub, Rankin, John, Ratheesh, Ajay, Rhodes, Lauren, Russell, David M., Slechta, Miroslav, Soffitta, Paolo, Spooner, Sean, Suleimanov, Valery, Tombesi, Francesco, Trushkin, Sergei A., Weisskopf, Martin C., Zane, Silvia, Zdziarski, Andrzej A., Zhang, Sixuan, Zhang, Wenda, Zhou, Menglei, Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kolodziejczak, Jeffery J., Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Ng, Chi-Yung, O'Dell, Stephen L., Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Thomas, Nicholas E., Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Xie, Fei

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the first X-ray spectropolarimetric results for Cygnus X-1 in its soft state from a campaign of five IXPE observations conducted during 2023 May-June. Companion multiwavelength data during the campaign are likewise shown. The 2-8 keV X-rays exhibit a net polarization degree PD=1.99%+/-0.13% (68% confidence). The polarization signal is found to increase with energy across IXPE's 2-8 keV bandpass. The polarized X-rays exhibit an energy-independent polarization angle of PA=-25.7+/-1.8 deg. East of North (68% confidence). This is consistent with being aligned to Cyg X-1's AU-scale compact radio jet and its pc-scale radio lobes. In comparison to earlier hard-state observations, the soft state exhibits a factor of 2 lower polarization degree, but a similar trend with energy and a similar (also energy-independent) position angle. When scaling by the natural unit of the disk temperature, we find the appearance of a consistent trendline in the polarization degree between soft and hard states. Our favored polarimetric model indicates Cyg X-1's spin is likely high (a* above ~0.96). The substantial X-ray polarization in Cyg X-1's soft state is most readily explained as resulting from a large portion of X-rays emitted from the disk returning and reflecting off the disk surface, generating a high polarization degree and a polarization direction parallel to the black hole spin axis and radio jet. In IXPE's bandpass, the polarization signal is dominated by the returning reflection emission. This constitutes polarimetric evidence for strong gravitational lensing of X-rays close to the black hole., Comment: 20 pages, accepted for publication in ApJL

Published
2024

13. Probing the polarized emission from SMC X-1: the brightest X-ray pulsar observed by IXPE

Author

Forsblom, Sofia V., Tsygankov, Sergey S., Poutanen, Juri, Doroshenko, Victor, Mushtukov, Alexander A., Ng, Mason, Ravi, Swati, Marshall, Herman L., Di Marco, Alessandro, La Monaca, Fabio, Malacaria, Christian, Mastroserio, Guglielmo, Loktev, Vladislav, Possenti, Andrea, Suleimanov, Valery F., Taverna, Roberto, Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Dovciak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Recent observations of X-ray pulsars (XRPs) performed by the Imaging X-ray Polarimetry Explorer (IXPE) have made it possible to investigate the intricate details of these objects in a new way, thanks to the added value of X-ray polarimetry. Here we present the results of the IXPE observations of SMC X-1, a member of the small group of XRPs displaying super-orbital variability. SMC X-1 was observed by IXPE three separate times during the high state of its super-orbital period. The observed luminosity in the 2-8 keV energy band of $L=2\times10^{38}$ erg/s makes SMC X-1 the brightest XRP ever observed by IXPE. We detect significant polarization in all three observations, with values of the phase-averaged polarization degree (PD) and polarization angle (PA) of $3.2\pm0.8$% and $97\deg\pm8\deg$ for Observation 1, $3.0\pm0.9$% and $90\deg\pm8\deg$ for Observation 2, and $5.5\pm1.1$% and $80\deg\pm6\deg$ for Observation 3, for the spectro-polarimetric analysis. The observed PD shows an increase over time with decreasing luminosity, while the PA decreases in decrements of 10\deg. The phase-resolved spectro-polarimetric analysis reveals significant detection of polarization in three out of seven phase bins, with the PD ranging between 2% and 10%, and a corresponding range in the PA from $\sim$70\deg\ to $\sim$100\deg. The pulse-phase resolved PD displays an apparent anti-correlation with the flux. Using the rotating vector model, we obtain constraints on the pulsar's geometrical properties for the individual observations. The position angle of the pulsar displays an evolution over time supporting the idea that we observe changes related to different super-orbital phases. Scattering in the wind of the precessing accretion disk may be responsible for the behavior of the polarimetric properties observed during the high-state of SMC X-1's super-orbital period., Comment: 11 pages, 11 figures, submitted to A&A

Published
2024

14. Constraints on Lorentz invariance violation from the extraordinary Mrk 421 flare of 2014 using a novel analysis method

Author

MAGIC Collaboration, Abe, S., Abhir, J., Abhishek, A., Acciari, V. A., Aguasca-Cabot, A., Agudo, I., Aniello, T., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Arcaro, C., Artero, M., Asano, K., Babić, A., Baquero, A., de Almeida, U. Barres, Barrio, J. A., Batković, I., Bautista, A., Baxter, J., González, J. Becerra, Bednarek, W., Bernardini, E., Bernete, J., Berti, A., Besenrieder, J., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bošnjak, Ž., Bronzini, E., Burelli, I., Busetto, G., Campoy-Ordaz, A., Carosi, A., Carosi, R., Carretero-Castrillo, M., Castro-Tirado, A. J., Cerasole, D., Ceribella, G., Chai, Y., Cifuentes, A., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., de Menezes, R., Del Popolo, A., Delfino, M., Delgado, J., Mendez, C. Delgado, Di Pierro, F., Di Tria, R., Di Venere, L., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Emery, G., Escudero, J., Fariña, L., Fattorini, A., Foffano, L., Font, L., Fröse, S., Fukami, S., Fukazawa, Y., López, R. J. García, Garczarczyk, M., Gasparyan, S., Gaug, M., Paiva, J. G. Giesbrecht, Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Gradetzke, T., Grau, R., Green, D., Green, J. G., Günther, P., Hadasch, D., Hahn, A., Hassan, T., Heckmann, L., Llorente, J. Herrera, Hrupec, D., Hütten, M., Imazawa, R., Ishio, K., Martínez, I. Jiménez, Jormanainen, J., Kankkunen, S., Kayanoki, T., Kerszberg, D., Kluge, G. W., Kobayashi, Y., Kouch, P. M., Kubo, H., Kushida, J., Láinez, M., Lamastra, A., Leone, F., Lindfors, E., Linhoff, L., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., Lyard, E., Fraga, B. Machado de Oliveira, Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mangano, S., Mannheim, K., Mariotti, M., Martínez, M., Martínez-Chicharro, M., Mas-Aguilar, A., Mazin, D., Menchiari, S., Mender, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., González, M. Molero, Molina, E., Mondal, H. A., Moralejo, A., Morcuende, D., Nakamori, T., Nanci, C., Neustroev, V., Nickel, L., Rosillo, M. Nievas, Nigro, C., Nikolić, L., Nilsson, K., Nishijima, K., Ekoume, T. Njoh, Noda, K., Nogues, L., Nozaki, S., Ohtani, Y., Okumura, A., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Peresano, M., Persic, M., Pihet, M., Pirola, G., Podobnik, F., Moroni, P. G. Prada, Prandini, E., Principe, G., Priyadarshi, C., Rhode, W., Ribó, M., Rico, J., Righi, C., Sahakyan, N., Saito, T., Saturni, F. G., Schleicher, B., Schmidt, K., Schmuckermaier, F., Schubert, J. L., Schweizer, T., Sciaccaluga, A., Silvestri, G., Sitarek, J., Sliusar, V., Sobczynska, D., Stamerra, A., Strišković, J., Strom, D., Suda, Y., Tajima, H., Takahashi, M., Takeishi, R., Tavecchio, F., Temnikov, P., Terauchi, K., Terzić, T., Teshima, M., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Acosta, M. Vazquez, Ventura, S., Viale, I., Vigorito, C. F., Vitale, V., Vovk, I., Walter, R., Will, M., Wunderlich, C., and Yamamoto, T.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Phenomenology
Abstract

The Lorentz Invariance Violation (LIV), a proposed consequence of certain quantum gravity (QG) scenarios, could instigate an energy-dependent group velocity for ultra-relativistic particles. This energy dependence, although suppressed by the massive QG energy scale $E_\mathrm{QG}$, expected to be on the level of the Planck energy $1.22 \times 10^{19}$ GeV, is potentially detectable in astrophysical observations. In this scenario, the cosmological distances traversed by photons act as an amplifier for this effect. By leveraging the observation of a remarkable flare from the blazar Mrk\,421, recorded at energies above 100 GeV by the MAGIC telescopes on the night of April 25 to 26, 2014, we look for time delays scaling linearly and quadratically with the photon energies. Using for the first time in LIV studies a binned-likelihood approach we set constraints on the QG energy scale. For the linear scenario, we set $95\%$ lower limits $E_\mathrm{QG}>2.7\times10^{17}$ GeV for the subluminal case and $E_\mathrm{QG}> 3.6 \times10^{17}$ GeV for the superluminal case. For the quadratic scenario, the $95\%$ lower limits for the subluminal and superluminal cases are $E_\mathrm{QG}>2.6 \times10^{10}$ GeV and $E_\mathrm{QG}>2.5\times10^{10}$ GeV, respectively.

Published
2024

15. Generalized Nested Latent Variable Models for Lossy Coding applied to Wind Turbine Scenarios

Author

Pérez-Gonzalo, Raül, Espersen, Andreas, and Agudo, Antonio

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Artificial Intelligence, Computer Science - Information Theory, Computer Science - Machine Learning
Abstract

Rate-distortion optimization through neural networks has accomplished competitive results in compression efficiency and image quality. This learning-based approach seeks to minimize the compromise between compression rate and reconstructed image quality by automatically extracting and retaining crucial information, while discarding less critical details. A successful technique consists in introducing a deep hyperprior that operates within a 2-level nested latent variable model, enhancing compression by capturing complex data dependencies. This paper extends this concept by designing a generalized L-level nested generative model with a Markov chain structure. We demonstrate as L increases that a trainable prior is detrimental and explore a common dimensionality along the distinct latent variables to boost compression performance. As this structured framework can represent autoregressive coders, we outperform the hyperprior model and achieve state-of-the-art performance while reducing substantially the computational cost. Our experimental evaluation is performed on wind turbine scenarios to study its application on visual inspections, Comment: Accepted to ICIP 2024

Published
2024

16. Topological phases in discrete stochastic systems

Author

Agudo-Canalejo, Jaime and Tang, Evelyn

Subjects
Condensed Matter - Statistical Mechanics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Soft Condensed Matter, Physics - Biological Physics
Abstract

Topological invariants have proved useful for analyzing emergent function as they characterize a property of the entire system, and are insensitive to local details, disorder, and noise. They support edge states, which reduce the system response to a lower dimensional space and offer a mechanism for the emergence of global cycles within a large phase space. Topological invariants have been heavily studied in quantum electronic systems and been observed in other classical platforms such as mechanical lattices. However, this framework largely describes equilibrium systems within an ordered crystalline lattice, whereas biological systems are often strongly non-equilibrium with stochastic components. We review recent developments in topological states in discrete stochastic models in 1d and 2d systems, and initial progress in identifying testable signature of topological states in molecular systems and ecology. These models further provide simple principles for targeted dynamics in synthetic systems or in the engineering of reconfigurable materials. Lastly, we describe novel theoretical properties of these systems such as the necessity for non-Hermiticity in permitting edge states, as well as new analytical tools to reveal these properties. The emerging developments shed light on fundamental principles for non-equilibrium systems and topological protection enabling robust biological function., Comment: Invited review for Reports on Progress in Physics, submitted. Comments welcome

Published
2024

17. IXPE observation of PKS 2155-304 reveals the most highly polarized blazar

Author

Kouch, Pouya M., Liodakis, Ioannis, Middei, Riccardo, Kim, Dawoon E., Tavecchio, Fabrizio, Marscher, Alan P., Marshall, Herman L., Ehlert, Steven R., Di Gesu, Laura, Jorstad, Svetlana G., Agudo, Iván, Madejski, Grzegorz M., Romani, Roger W., Errando, Manel, Lindfors, Elina, Nilsson, Kari, Toppari, Ella, Potter, Stephen B., Imazawa, Ryo, Sasada, Mahito, Fukazawa, Yasushi, Kawabata, Koji S., Uemura, Makoto, Mizuno, Tsunefumi, Nakaoka, Tatsuya, Akitaya, Hiroshi, McCall, Callum, Jermak, Helen E., Steele, Iain A., Myserlis, Ioannis, Gurwell, Mark, Keating, Garrett K., Rao, Ramprasad, Kang, Sincheol, Lee, Sang-Sung, Kim, Sang-Hyun, Cheong, Whee Yeon, Jeong, Hyeon-Woo, Angelakis, Emmanouil, Kraus, Alexander, Aceituno, Francisco José, Bonnoli, Giacomo, Casanova, Víctor, Escudero, Juan, Agís-González, Beatriz, Husillos, César, Morcuende, Daniel, Otero-Santos, Jorge, Sota, Alfredo, Bachev, Rumen, Antonelli, Lucio Angelo, Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Lalla, Niccolò, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Negro, Michela, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel Lawrence, Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the X-ray polarization properties of the high-synchrotron-peaked (HSP) blazar PKS 2155$-$304 based on observations with the Imaging X-ray Polarimetry Explorer (IXPE). We observed the source between Oct 27 and Nov 7, 2023. We also conducted an extensive contemporaneous multiwavelength (MW) campaign. We find that during the first half ($T_1$) of the IXPE pointing, the source exhibited the highest X-ray polarization degree detected for an HSP blazar thus far, (30.7$\pm$2.0)%, which dropped to (15.3$\pm$2.1)% during the second half ($T_2$). The X-ray polarization angle remained stable during the IXPE pointing at 129.4$^\circ$$\pm$1.8$^\circ$ and 125.4$^\circ$$\pm$3.9$^\circ$ during $T_1$ and $T_2$, respectively. Meanwhile, the optical polarization degree remained stable during the IXPE pointing, with average host-galaxy-corrected values of (4.3$\pm$0.7)% and (3.8$\pm$0.9)% during the $T_1$ and $T_2$, respectively. During the IXPE pointing, the optical polarization angle changed achromatically from $\sim$140$^\circ$ to $\sim$90$^\circ$ and back to $\sim$130$^\circ$. Despite several attempts, we only detected (99.7% conf.) the radio polarization once (during $T_2$, at 225.5 GHz): with degree (1.7$\pm$0.4)% and angle 112.5$^\circ$$\pm$5.5$^\circ$. The direction of the broad pc-scale jet is rather ambiguous and has been found to point to the east and south at different epochs; however, on larger scales (> 1.5 pc) the jet points toward the southeast ($\sim$135$^\circ$), similar to all of the MW polarization angles. Moreover, the X-ray to optical polarization degree ratios of $\sim$7 and $\sim$4 during $T_1$ and $T_2$, respectively, are similar to previous IXPE results for several HSP blazars. These findings, combined with the lack of correlation of temporal variability between the MW polarization properties, agree with an energy-stratified shock-acceleration scenario in HSP blazars., Comment: 17 pages, 10 figures, 4 tables, Accepted for publication in A&A

Published
2024

18. IOP4, the Interactive Optical Photo-Polarimetric Python Pipeline

Author

Pedrosa, Juan Escudero, Agudo, Ivan, Morcuende, Daniel, Otero-Santos, Jorge, Bonnoli, Giacomo, Piirola, Vilppu, Husillos, César, Bernardos, Mabel, López-Coto, Rubén, Sota, Alfredo, Casanova, Víctor, Aceituno, Francisco, and Santos-Sanz, Pablo

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

IOP4 is a pipeline to perform photometry and polarimetry analysis of optical data from Calar Alto (CAHA) and Sierra Nevada (OSN) observatories. IOP4 implements Object Relational Mapping (ORM) to seamlessly integrate all information about the reduction and results in a database which can be used to query and plot results, flag data and inspect the reduction process in an integrated fashion with the whole pipeline. It also ships with an already built-in web interface which can be used out of the box to browse the database and supervise all pipeline processes. It is built to ease debugging and inspection of data. Reduction from five different instruments are already implemented: RoperT90, AndorT90 and DIPOL (at OSN 0.9m telescope), AndorT150 (OSN 1.5m telescope) and CAFOS (CAHA 2.2m telescope). IOP4's modular design allows for easy integration of new observatories and instruments, and its results have already featured in several high-impact refereed publications. In this paper we describe the implementation and characteristics of IOP4., Comment: Submitted April 23, 2024

Published
2024

19. Nonlinear Response Theory of Molecular Machines

Author

Chatzittofi, Michalis, Agudo-Canalejo, Jaime, and Golestanian, Ramin

Subjects
Condensed Matter - Soft Condensed Matter, Condensed Matter - Statistical Mechanics, Physics - Biological Physics
Abstract

Chemical affinities are responsible for driving active matter systems out of equilibrium. At the nano-scale, molecular machines interact with the surrounding environment and are subjected to external forces. The mechano-chemical coupling which arises naturally in these systems reveals a complex interplay between chemical and mechanical degrees of freedom with strong impact on their active mechanism. By considering various models far from equilibrium, we show that the tuning of applied forces give rise to a nonlinear response that causes a non-monotonic behaviour in the machines' activity. Our findings have implications in understanding, designing, and triggering such processes by controlled application of external fields, including the collective dynamics of larger non-equilibrium systems where the total dissipation and performance might be affected by internal and inter-particle interactions.

Published
2024
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20. The flaring activity of blazar AO 0235+164 during year 2021

Author

Pedrosa, Juan Escudero, Agudo, Iván, Moritz, Till, Marscher, Alan P., Jorstad, Svetlana, Tramacere, Andrea, Casadio, Carolina, Thum, Clemens, Myserlis, Ioannis, Sievers, Albrecht, Otero-Santos, Jorge, Morcuende, Daniel, López-Coto, Rubén, D'Ammando, Filippo, Bonnoli, Giacomo, Gurwell, Mark, Gómez, José Luis, Rao, Ramprasad, and Keating, Garrett

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Context. The blazar AO 0235+164, located at redshift $z=0.94$, has displayed interesting and repeating flaring activity in the past, the latest episodes occurring in 2008 and 2015. In 2020, the source brightened again, starting a new flaring episode that peaked in 2021. Aims. We study the origin and properties of the 2021 flare in relation to previous studies and the historical behavior of the source, in particular to the 2008 and 2015 flaring episodes. Methods. We analyze the multi-wavelength photo-polarimetric evolution of the source. From Very Long Baseline Array images, we derive the kinematic parameters of new components associated with the 2021 flare. We use this information to constrain a model for the spectral energy distribution of the emission during the flaring period. We propose an analytical geometric model to test whether the observed wobbling of the jet is consistent with precession. Results. We report the appearance of two new components that are ejected in a different direction than previously, confirming the wobbling of the jet. We find that the direction of ejection is consistent with that of a precessing jet.The derived period independently agrees with the values commonly found in the literature. Modeling of the spectral energy distribution further confirm that the differences between flares can be attributed to geometrical effects., Comment: Accepted 15 May 2024

Published
2024
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21. Studying geometry of the ultraluminous X-ray pulsar Swift J0243.6+6124 using X-ray and optical polarimetry

Author

Poutanen, Juri, Tsygankov, Sergey S., Doroshenko, Victor, Forsblom, Sofia V., Jenke, Peter, Kaaret, Philip, Berdyugin, Andrei V., Blinov, Dmitry, Kravtsov, Vadim, Liodakis, Ioannis, Tzouvanou, Anastasia, Di Marco, Alessandro, Heyl, Jeremy, La Monaca, Fabio, Mushtukov, Alexander A., Pavlov, George G., Salganik, Alexander, Veledina, Alexandra, Weisskopf, Martin C., Zane, Silvia, Loktev, Vladislav, Suleimanov, Valery F., Wilson-Hodge, Colleen, Berdyugina, Svetlana V., Kagitani, Masato, Piirola, Vilppu, Sakanoi, Takeshi, Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Dovciak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Xie, Fei

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract

Discovery of pulsations from a number of ultra-luminous X-ray (ULX) sources proved that accretion onto neutron stars can produce luminosities exceeding the Eddington limit by a couple of orders of magnitude. The conditions necessary to achieve such high luminosities as well as the exact geometry of the accretion flow in the neutron star vicinity are, however, a matter of debate. The pulse phase-resolved polarization measurements that became possible with the launch of the IXPE can be used to determine the pulsar geometry and its orientation relative to the orbital plane. They provide an avenue to test different theoretical models of ULX pulsars. In this paper we present the results of three IXPE observations of the first Galactic ULX pulsar Swift J0243.6+6124 during its 2023 outburst. We find strong variations of the polarization characteristics with the pulsar phase. The average polarization degree increases from about 5% to 15% as the flux dropped by a factor of three in the course of the outburst. The polarization angle (PA) as function of the pulsar phase shows two peaks in the first two observations, but changes to a characteristic sawtooth pattern in the remaining data set. This is not consistent with a simple rotating vector model. Assuming the existence of an additional constant polarized component, we were able to fit the three observations with a common rotating vector model and obtain constraints on the pulsar geometry. In particular, we find the pulsar angular momentum inclination with respect to the line-of-sight of 15-40 deg, the magnetic obliquity of 60-80 deg, and the pulsar spin position angle of -50 deg, which differs from the constant component PA of about 10 deg. Combining these X-ray measurements with the optical PA, we find evidence for a 30 deg misalignment between the pulsar spin and the binary orbital axis., Comment: 13 pages, 10 figures, submitted to A&A

Published
2024

22. Discovery of a shock-compressed magnetic field in the north-western rim of the young supernova remnant RX J1713.7-3946 with X-ray polarimetry

Author

Ferrazzoli, Riccardo, Prokhorov, Dmitry, Bucciantini, Niccolò, Slane, Patrick, Vink, Jacco, Cardillo, Martina, Yang, Yi-Jung, Silvestri, Stefano, Zhou, Ping, Costa, Enrico, Omodei, Nicola, Ng, C. -Y., Soffitta, Paolo, Weisskopf, Martin C., Baldini, Luca, Di Marco, Alessandro, Doroshenko, Victor, Heyl, Jeremy, Kaaret, Philip, Kim, Dawoon E., Marin, Frédéric, Mizuno, Tsunefumi, Pesce-Rollins, Melissa, Sgrò, Carmelo, Swartz, Douglas A., Tamagawa, Toru, Xie, Fei, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Donnarumma, Immacolata, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Negro, Michela, O'Dell, Stephen L., Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Spandre, Gloria, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Wu, Kinwah, and Zane, Silvia

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

Supernova remnants (SNRs) provide insights into cosmic-ray acceleration and magnetic field dynamics at shock fronts. Recent X-ray polarimetric measurements by the Imaging X-ray Polarimetry Explorer (IXPE) have revealed radial magnetic fields near particle acceleration sites in young SNRs, including Cassiopeia A, Tycho, and SN 1006. We present here the spatially-resolved IXPE X-ray polarimetric observation of the northwestern rim of SNR RX J1713.7-3946. For the first time, our analysis shows that the magnetic field in particle acceleration sites of this SNR is oriented tangentially with respect to the shock front. Because of the lack of precise Faraday-rotation measurements in the radio band, this was not possible before. The average measured polarization degree (PD) of the synchtrotron emission is 12.5 {\pm} 3.3%, lower than the one measured by IXPE in SN 1006, comparable to the Tycho one, but notably higher than the one in Cassiopeia A. On sub-parsec scales, localized patches within RX J1713.7-3946 display PD up to 41.5 {\pm} 9.5%. These results are compatible with a shock-compressed magnetic field. However, in order to explain the observed PD, either the presence of a radial net magnetic field upstream of the shock, or partial reisotropization of the turbulence downstream by radial magneto-hydrodynamical instabilities, can be invoked. From comparison of PD and magnetic field distribution with {\gamma}-rays and 12 CO data, our results provide new inputs in favor of a leptonic origin of the {\gamma}-ray emission., Comment: 18 pages, 6 figures, 2 tables, published in ApJ Letters

Published
2024
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23. Distinguishing radiation mechanisms and particle populations in blazar jets through long-term multi-band monitoring with RINGO3 and Fermi

Author

McCall, Callum, Jermak, Helen, Steele, Iain A., Agudo, Iván, de Almeida, Ulisses Barres, Hovatta, Talvikki, Lamb, Gavin P., Lindfors, Elina, and Mundell, Carole

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the results of seven years of multicolour photometric monitoring of a sample of 31 $\gamma$-ray bright blazars using the RINGO3 polarimeter on the Liverpool Telescope from 2013--2020. We explore the relationships between simultaneous observations of flux in three optical wavebands along with Fermi $\gamma$-ray data in order to explore the radiation mechanisms and particle populations in blazar jets. We find significant correlations between optical and $\gamma$-ray flux with no detectable time lag, suggesting leptonic emission processes in the jets of these sources. Furthermore, we find the spectral behaviour against optical and $\gamma$-ray flux for many sources is best fit logarithmically. This is suggestive of a transition between bluer-/redder-when-brighter into stable-when-brighter behaviour during high activity states; a behaviour that might be missed in poorly sampled data, resulting in apparent linear relationships., Comment: 32 pages, 35 figures

Published
2024
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24. No Bells, Just Whistles: Sports Field Registration by Leveraging Geometric Properties

Author

Gutiérrez-Pérez, Marc and Agudo, Antonio

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Artificial Intelligence
Abstract

Broadcast sports field registration is traditionally addressed as a homography estimation task, mapping the visible image area to a planar field model, predominantly focusing on the main camera shot. Addressing the shortcomings of previous approaches, we propose a novel calibration pipeline enabling camera calibration using a 3D soccer field model and extending the process to assess the multiple-view nature of broadcast videos. Our approach begins with a keypoint generation pipeline derived from SoccerNet dataset annotations, leveraging the geometric properties of the court. Subsequently, we execute classical camera calibration through DLT algorithm in a minimalist fashion, without further refinement. Through extensive experimentation on real-world soccer broadcast datasets such as SoccerNet-Calibration, WorldCup 2014 and TS- WorldCup, our method demonstrates superior performance in both multiple- and single-view 3D camera calibration while maintaining competitive results in homography estimation compared to state-of-the-art techniques., Comment: Accepted in CVPRW 2024

Published
2024

25. BIN1K358R suppresses glial response to plaques in mouse model of Alzheimer's disease

Author

Garcia‐Agudo, Laura Fernandez, Shi, Zechuan, Smith, Ian F, Kramár, Enikö A, Tran, Katelynn, Kawauchi, Shimako, Wang, Shuling, Collins, Sherilyn, Walker, Amber, Shi, Kai‐Xuan, Neumann, Jonathan, Liang, Heidi Yahan, Da Cunha, Celia, Milinkeviciute, Giedre, Morabito, Samuel, Miyoshi, Emily, Rezaie, Narges, Gomez‐Arboledas, Angela, Arvilla, Adrian Mendoza, Ghaemi, Daryan Iman, Tenner, Andrea J, LaFerla, Frank M, Wood, Marcelo A, Mortazavi, Ali, Swarup, Vivek, MacGregor, Grant R, and Green, Kim N

Subjects
Biomedical and Clinical Sciences, Neurosciences, Clinical Sciences, Alzheimer's Disease including Alzheimer's Disease Related Dementias (AD/ADRD), Alzheimer's Disease, Brain Disorders, Neurodegenerative, Dementia, Acquired Cognitive Impairment, Aging, 2.1 Biological and endogenous factors, Aetiology, Neurological, Mice, Animals, Alzheimer Disease, Plaque, Amyloid, Amyloid beta-Peptides, Neuroglia, Mice, Transgenic, Disease Models, Animal, Alzheimer's disease, astrocytes, BIN1 K358R, inflammation, MODEL-AD, oligodendrocytes, MODEL‐AD, Geriatrics, Clinical sciences, Biological psychology
Abstract

IntroductionThe BIN1 coding variant rs138047593 (K358R) is linked to Late-Onset Alzheimer's Disease (LOAD) via targeted exome sequencing.MethodsTo elucidate the functional consequences of this rare coding variant on brain amyloidosis and neuroinflammation, we generated BIN1K358R knock-in mice using CRISPR/Cas9 technology. These mice were subsequently bred with 5xFAD transgenic mice, which serve as a model for Alzheimer's pathology.ResultsThe presence of the BIN1K358R variant leads to increased cerebral amyloid deposition, with a dampened response of astrocytes and oligodendrocytes, but not microglia, at both the cellular and transcriptional levels. This correlates with decreased neurofilament light chain in both plasma and brain tissue. Synaptic densities are significantly increased in both wild-type and 5xFAD backgrounds homozygous for the BIN1K358R variant.DiscussionThe BIN1 K358R variant modulates amyloid pathology in 5xFAD mice, attenuates the astrocytic and oligodendrocytic responses to amyloid plaques, decreases damage markers, and elevates synaptic densities.HighlightsBIN1 rs138047593 (K358R) coding variant is associated with increased risk of LOAD. BIN1 K358R variant increases amyloid plaque load in 12-month-old 5xFAD mice. BIN1 K358R variant dampens astrocytic and oligodendrocytic response to plaques. BIN1 K358R variant decreases neuronal damage in 5xFAD mice. BIN1 K358R upregulates synaptic densities and modulates synaptic transmission.

Published
2024

26. Dark Matter Line Searches with the Cherenkov Telescope Array

Author

Abe, S., Abhir, J., Abhishek, A., Acero, F., Acharyya, A., Adam, R., Aguasca-Cabot, A., Agudo, I., Aguirre-Santaella, A., Alfaro, J., Alfaro, R., Alvarez-Crespo, N., Batista, R. Alves, Amans, J. -P., Amato, E., Ambrosi, G., Angel, L., Aramo, C., Arcaro, C., Arnesen, T. T. H., Arrabito, L., Asano, K., Ascasibar, Y., Aschersleben, J., Ashkar, H., Backes, M., Baktash, A., Balazs, C., Balbo, M., Larriva, A. Baquero, Martins, V. Barbosa, de Almeida, U. Barres, Barrio, J. A., Batković, I., Batzofin, R., Baxter, J., González, J. Becerra, Beck, G., Benbow, W., Berge, D., Bernardini, E., Bernete, J., Bernlöhr, K., Berti, A., Bertucci, B., Bhattacharjee, P., Bhattacharyya, S., Bigongiari, C., Biland, A., Bissaldi, E., Biteau, J., Blanch, O., Blazek, J., Bocchino, F., Boisson, C., Bolmont, J., Bonnoli, G., Bonollo, A., Bordas, P., Bosnjak, Z., Bottacini, E., Böttcher, M., Bringmann, T., Bronzini, E., Brose, R., Brown, A. M., Brunelli, G., Bulgarelli, A., Bulik, T., Burelli, I., Burmistrov, L., Burton, M., Buscemi, M., Bylund, T., Cailleux, J., Campoy-Ordaz, A., Cantlay, B. K., Capasso, G., Caproni, A., Capuzzo-Dolcetta, R., Caraveo, P., Caroff, S., Carosi, A., Carosi, R., Carquin, E., Carrasco, M. -S., Cassol, F., Castaldini, L., Castrejon, N., Castro-Tirado, A. J., Cerasole, D., Cerruti, M., Chadwick, P. M., Chaty, S., Chen, A. W., Chernyakova, M., Chiavassa, A., Chudoba, J., Chytka, L., Cicciari, G. M., Cifuentes, A., Araujo, C. H. Coimbra, Colapietro, M., Conforti, V., Conte, F., Contreras, J. L., Costa, A., Costantini, H., Cotter, G., Cristofari, P., Cuevas, O., Curtis-Ginsberg, Z., D'Amico, G., D'Ammando, F., Dai, S., Dalchenko, M., Dazzi, F., De Angelis, A., de Lavergne, M. de Bony, De Caprio, V., Pino, E. M. de Gouveia Dal, De Lotto, B., De Lucia, M., de Menezes, R., de Naurois, M., de Souza, V., del Peral, L., del Valle, M. V., Giler, A. G. Delgado, Mengual, J. Delgado, Delgado, C., Dell'aiera, M., della Volpe, D., Depaoli, D., Di Girolamo, T., Di Piano, A., Di Pierro, F., Di Tria, R., Di Venere, L., Díaz, C., Diebold, S., Dinesh, A., Djuvsland, J., Dominik, R. M., Prester, D. Dominis, Donini, A., Dorner, D., Dörner, J., Doro, M., Dournaux, J. -L., Duangchan, C., Dubos, C., Ducci, L., Dwarkadas, V. V., Ebr, J., Eckner, C., Egberts, K., Einecke, S., Elsässer, D., Emery, G., Errando, M., Escanuela, C., Escarate, P., Godoy, M. Escobar, Escudero, J., Esposito, P., Ettori, S., Falceta-Goncalves, D., Fedorova, E., Fegan, S., Feng, Q., Ferrand, G., Ferrarotto, F., Fiandrini, E., Fiasson, A., Filipovic, M., Fioretti, V., Fiori, M., Foffano, L., Guiteras, L. Font, Fontaine, G., Fröse, S., Fukazawa, Y., Fukui, Y., Furniss, A., Galanti, G., Galaz, G., Galelli, C., Gallozzi, S., Gammaldi, V., Garczarczyk, M., Gasbarra, C., Gasparrini, D., Ghalumyan, A., Gianotti, F., Giarrusso, M., Paiva, J. G. Giesbrecht Formiga, Giglietto, N., Giordano, F., Giuffrida, R., Glicenstein, J. -F., Glombitza, J., Goldoni, P., González, J. M., González, M. M., Coelho, J. Goulart, Gradetzke, T., Granot, J., Grasso, D., Grau, R., Gréaux, L., Green, D., Green, J. G., Grolleron, G., Guedes, L. M. V., Gueta, O., Hackfeld, J., Hadasch, D., Hamal, P., Hanlon, W., Hara, S., Harvey, V. M., Hassan, T., Hayashi, K., Heß, B., Heckmann, L., Heller, M., Cadena, S. Hernández, Hervet, O., Hinton, J., Hiroshima, N., Hnatyk, B., Hnatyk, R., Hofmann, W., Holder, J., Horan, D., Horvath, P., Hovatta, T., Hrabovsky, M., Hrupec, D., Iarlori, M., Inada, T., Incardona, F., Inoue, S., Inoue, Y., Iocco, F., Iori, M., Ishio, K., Jamrozy, M., Janecek, P., Jankowsky, F., Jean, P., Quiles, J. Jimenez, Jin, W., Juramy-Gilles, C., Jurysek, J., Kagaya, M., Kalekin, O., Karas, V., Katagiri, H., Kataoka, J., Kaufmann, S., Kazanas, D., Kerszberg, D., Kieda, D. B., Kleiner, T., Kluge, G., Kobayashi, Y., Kohri, K., Komin, N., Kornecki, P., Kosack, K., Kowal, G., Kubo, H., Kushida, J., La Barbera, A., La Palombara, N., Láinez, M., Lamastra, A., Lapington, J., Laporte, P., Lazarević, S., Lazendic-Galloway, J., Lemoine-Goumard, M., Lenain, J. -P., Leone, F., Leonora, E., Leto, G., Lindfors, E., Linhoff, M., Liodakis, I., Lipniacka, A., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Bahilo, J. Lozano, Luque-Escamilla, P. L., Macias, O., Majumdar, P., Mallamaci, M., Malyshev, D., Mandat, D., Manicò, G., Mariotti, M., Márquez, I., Marquez, P., Marsella, G., Martí, J., Martínez, G. A., Martínez, M., Martinez, O., Marty, C., Mas-Aguilar, A., Mastropietro, M., Mazin, D., Menchiari, S., Mestre, E., Meunier, J. -L., Meyer, D. M. -A., Meyer, M., Miceli, D., Miceli, M., Michailidis, M., Michałowski, J., Miener, T., Miranda, J. M., Mitchell, A., Mizote, M., Mizuno, T., Moderski, R., Molero, M., Molfese, C., Molina, E., Montaruli, T., Moralejo, A., Morcuende, D., Morselli, A., Moulin, E., Zamanillo, V. Moya, Munari, K., Murach, T., Muraczewski, A., Muraishi, H., Nakamori, T., Nayak, A., Nemmen, R., Neto, J. P., Nickel, L., Niemiec, J., Nieto, D., Rosillo, M. Nievas, Nikołajuk, M., Nikolić, L., Nishijima, K., Noda, K., Nosek, D., Novotny, V., Nozaki, S., Ohishi, M., Ohtani, Y., Okumura, A., Olive, J. -F., Ong, R. A., Orienti, M., Orito, R., Orlandini, M., Orlando, E., Orlando, S., Ostrowski, M., Otero-Santos, J., Oya, I., Pagano, I., Pagliaro, A., Palatiello, M., Panebianco, G., Paneque, D., Pantaleo, F. R., Paredes, J. M., Parmiggiani, N., Patricelli, B., Pe'er, A., Pech, M., Pecimotika, M., Pensec, U., Peresano, M., Pérez-Romero, J., Persic, M., Peters, K. P., Petruk, O., Piano, G., Pierre, E., Pietropaolo, E., Pihet, M., Pinchbeck, L., Pirola, G., Pittori, C., Plard, C., Podobnik, F., Pohl, M., Pollet, V., Ponti, G., Prandini, E., Principe, G., Priyadarshi, C., Produit, N., Prouza, M., Pueschel, E., Pühlhofer, G., Pumo, M. L., Queiroz, F., Quirrenbach, A., Rainò, S., Rando, R., Razzaque, S., Regeard, M., Reimer, A., Reimer, O., Reisenegger, A., Rhode, W., Ribeiro, D., Ribó, M., Ricci, C., Richtler, T., Rico, J., Rieger, F., Riitano, L., Rizi, V., Roache, E., Fernandez, G. Rodriguez, Frías, M. D. Rodríguez, Rodríguez-Vázquez, J. J., Romano, P., Romeo, G., Rosado, J., de Leon, A. Rosales, Rowell, G., Rudak, B., Ruiter, A. J., Rulten, C. B., Sadeh, I., Saha, L., Saito, T., Salzmann, H., Sánchez-Conde, M., Sandaker, H., Sangiorgi, P., Sano, H., Santander, M., Santos-Lima, R., Sapienza, V., Šarić, T., Sarkar, A., Sarkar, S., Saturni, F. G., Savarese, S., Scherer, A., Schiavone, F., Schipani, P., Schleicher, B., Schovanek, P., Schubert, J. L., Schwanke, U., Arroyo, M. Seglar, Seitenzahl, I. R., Sergijenko, O., Servillat, M., Siegert, T., Siejkowski, H., Siqueira, C., Sliusar, V., Slowikowska, A., Sol, H., Spencer, S. T., Spiga, D., Stamerra, A., Stanič, S., Starecki, T., Starling, R., Stawarz, Ł., Steppa, C., Hatlen, E. Sæther, Stolarczyk, T., Strišković, J., Suda, Y., Świerk, P., Tajima, H., Tak, D., Takahashi, M., Takeishi, R., Tavernier, T., Tejedor, L. A., Terauchi, K., Teshima, M., Testa, V., Tian, W. W., Tibaldo, L., Tibolla, O., Peixoto, C. J. Todero, Torradeflot, F., Torres, D. F., Tosti, G., Tothill, N., Toussenel, F., Tramacere, A., Travnicek, P., Tripodo, G., Trois, A., Truzzi, S., Tutone, A., Vaclavek, L., Vacula, M., Vallania, P., Vallés, R., van Eldik, C., van Scherpenberg, J., Vandenbroucke, J., Vassiliev, V., Acosta, M. Vázquez, Vecchi, M., Ventura, S., Vercellone, S., Verna, G., Viana, A., Viaux, N., Vigliano, A., Vignatti, J., Vigorito, C. F., Villanueva, J., Visentin, E., Vitale, V., Vodeb, V., Voisin, V., Voitsekhovskyi, V., Vorobiov, S., Voutsinas, G., Vovk, I., Vuillaume, T., Wagner, S. J., Walter, R., White, M., White, R., Wierzcholska, A., Will, M., Williams, D. A., Wohlleben, F., Wolter, A., Yamamoto, T., Yang, L., Yoshida, T., Yoshikoshi, T., Zaharijas, G., Zampieri, L., Sanchez, R. Zanmar, Zavrtanik, D., Zavrtanik, M., Zdziarski, A. A., Zech, A., Zhang, W., Zhdanov, V. I., Ziętara, K., Živec, M., and Zuriaga-Puig, J.

Subjects
High Energy Physics - Phenomenology, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

Monochromatic gamma-ray signals constitute a potential smoking gun signature for annihilating or decaying dark matter particles that could relatively easily be distinguished from astrophysical or instrumental backgrounds. We provide an updated assessment of the sensitivity of the Cherenkov Telescope Array (CTA) to such signals, based on observations of the Galactic centre region as well as of selected dwarf spheroidal galaxies. We find that current limits and detection prospects for dark matter masses above 300 GeV will be significantly improved, by up to an order of magnitude in the multi-TeV range. This demonstrates that CTA will set a new standard for gamma-ray astronomy also in this respect, as the world's largest and most sensitive high-energy gamma-ray observatory, in particular due to its exquisite energy resolution at TeV energies and the adopted observational strategy focussing on regions with large dark matter densities. Throughout our analysis, we use up-to-date instrument response functions, and we thoroughly model the effect of instrumental systematic uncertainties in our statistical treatment. We further present results for other potential signatures with sharp spectral features, e.g.~box-shaped spectra, that would likewise very clearly point to a particle dark matter origin., Comment: 44 pages JCAP style (excluding author list and references), 19 figures; minor changes to match published version

Published
2024
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27. The variability patterns of the TeV blazar PG 1553+113 from a decade of MAGIC and multi-band observations

Author

MAGIC Collaboration, Abe, H., Abe, S., Abhir, J., Acciari, V. A., Agudo, I., Aniello, T., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Arcaro, C., Artero, M., Asano, K., Baack, D., Babić, A., Baquero, A., de Almeida, U. Barres, Batković, I., Baxter, J., González, J. Becerra, Bernardini, E., Bernete, J., Berti, A., Besenrieder, J., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bošnjak, Ž., Burelli, I., Busetto, G., Campoy-Ordaz, A., Carosi, A., Carosi, R., Carretero-Castrillo, M., Castro-Tirado, A. J., Chai, Y., Cifuentes, A., Cikota, S., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Del Popolo, A., Delfino, M., Delgado, J., Mendez, C. Delgado, Depaoli, D., Di Pierro, F., Di Venere, L., Prester, D. Dominis, Donini, A., Dorner, D., Doro, M., Elsaesser, D., Emery, G., Escudero, J., Fariña, L., Fattorini, A., Foffano, L., Font, L., Fukami, S., Fukazawa, Y., López, R. J. García, Gasparyan, S., Gaug, M., Paiva, J. G. Giesbrecht, Giglietto, N., Giordano, F., Gliwny, P., Grau, R., Green, J. G., Hadasch, D., Hahn, A., Heckmann, L., Herrera, J., Hovatta, T., Hrupec, D., Hütten, M., Imazawa, R., Inada, T., Iotov, R., Ishio, K., Martínez, I. Jiménez, Jormanainen, J., Kerszberg, D., Kluge, G. W., Kobayashi, Y., Kouch, P. M., Kubo, H., Kushida, J., Lezáun, M. Láinez, Lamastra, A., Leone, F., Lindfors, E., Liodakis, I., Lombardi, S., Longo, F., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., Fraga, B. Machado de Oliveira, Majumdar, P., Makariev, M., Maneva, G., Mang, N., Manganaro, M., Mannheim, K., Mariotti, M., Martínez, M., Martínez-Chicharro, M., Mas-Aguilar, A., Mazin, D., Menchiari, S., Mender, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., González, M. Molero, Molina, E., Mondal, H. A., Moralejo, A., Morcuende, D., Nakamori, T., Nanci, C., Neustroev, V., Nigro, C., Nikolić, L., Nilsson, K., Nishijima, K., Ekoume, T. Njoh, Noda, K., Nozaki, S., Ohtani, Y., Okumura, A., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavlović, D., Persic, M., Pihet, M., Pirola, G., Podobnik, F., Moroni, P. G. Prada, Prandini, E., Principe, G., Priyadarshi, C., Rhode, W., Ribó, M., Rico, J., Righi, C., Sahakyan, N., Saito, T., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schmuckermaier, F., Schubert, J. L., Schweizer, T., Sciaccaluga, A., Sitarek, J., Spolon, A., Stamerra, A., Strišković, J., Strom, D., Suda, Y., Suutarinen, S., Tajima, H., Takeishi, R., Tavecchio, F., Temnikov, P., Terauchi, K., Terzić, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Ventura, S., Verguilov, V., Viale, I., Vigorito, C. F., Vitale, V., Walter, R., Wunderlich, C., Yamamoto, T., collaborators, MWL, Jermak, H., Steele, I. A., Smith, P. S., Blinov, D., Raiteri, C. M., Villata, M., Mirzaqulov, D. O., Kurtanidze, S. O., Carosati, D., Savchenko, S. S., Acosta-Pulido, J. A., Borman, G. A., Bozhilov, V., Carnerero, M. I., Chigladze, R. A., Damljanovic, G., Ehgamberdiev, S. A., Feige, M., Grishina, T. S., Gupta, A. C., Hagen-Thorn, V. A., Ibryamov, S., Ivanidze, R. Z., Jorstad, S. G., Kania, J., Kimeridze, G. N., Kopatskaya, E. N., Kopp, M., Kunkel, L., Kurtanidze, O. M., Larionov, V. M., Larionova, E. G., Larionova, L. V., Lorey, C., Marchini, A., Marscher, A. P., Minev, M., Morozova, D. A., Nikolashvili, M. G., Ovcharov, E., Reinhart, D., Sadun, A. C., Scherbantin, A., Schneider, L., Semkov, E., Sigua, L. A., Steineke, R., Troitskaya, Yu. V., Troitskiy, I. S., Valcheva, A., Vasilyev, A. A., Vince, O., Zaharieva, E., Zottmann, N., Kiehlmann, S., Readhead, A., Max-Moerbeck, W., Reeves, R. A., Sandrinelli, A., Ramazani, V. Fallah, Giroletti, M., Righini, S., Marchili, N., Patricelli, B., Ghirlanda, G., and Lico, R.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

PG 1553+113 is one of the few blazars with a convincing quasi-periodic emission in the gamma-ray band. The source is also a very high-energy (VHE; >100 GeV) gamma-ray emitter. To better understand its properties and identify the underlying physical processes driving its variability, the MAGIC Collaboration initiated a multiyear, multiwavelength monitoring campaign in 2015 involving the OVRO 40-m and Medicina radio telescopes, REM, KVA, and the MAGIC telescopes, Swift and Fermi satellites, and the WEBT network. The analysis presented in this paper uses data until 2017 and focuses on the characterization of the variability. The gamma-ray data show a (hint of a) periodic signal compatible with literature, but the X-ray and VHE gamma-ray data do not show statistical evidence for a periodic signal. In other bands, the data are compatible with the gamma-ray period, but with a relatively high p-value. The complex connection between the low and high-energy emission and the non-monochromatic modulation and changes in flux suggests that a simple one-zone model is unable to explain all the variability. Instead, a model including a periodic component along with multiple emission zones is required., Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society. 19 pages, 9 figures. Corresponding authors: Elisa Prandini, Antonio Stamerra, Talvikki Hovatta

Published
2024
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28. X-ray polarization measurement of the gold standard of radio-quiet active galactic nuclei : NGC 1068

Author

Marin, F., Marinucci, A., Laurenti, M., Kim, D. E., Barnouin, T., Di Marco, A., Ursini, F., Bianchi, S., Ravi, S., Marshall, H. L., Matt, G., Chen, C. -T., Gianolli, V. E., Ingram, A., Maksym, W. P., Panagiotou, C., Podgorny, J., Puccetti, S., Ratheesh, A., Tombesi, F., Agudo, I., Antonelli, L. A., Bachetti, M., Baldini, L., Baumgartner, W., Bellazzini, R., Bongiorno, S., Bonino, R., Brez, A., Bucciantini, N., Capitanio, F., Castellano, S., Cavazzuti, E., Ciprini, S., Costa, E., De Rosa, A., Del Monte, E., Di Gesu, L., Di Lalla, N., Donnarumma, I., Doroshenko, V., Dovciak, M., Ehlert, S., Enoto, T., Evangelista, Y., Fabiani, S., Ferrazzoli, R., Garcia, J., Gunji, S., Heyl, J., Iwakiri, W., Jorstad, S., Kaaret, P., Karas, V., Kislat, F., Kitaguchi, T., Kolodziejczak, J., Krawczynski, H., La Monaca, F., Latronico, L., Liodakis, I., Madejski, G., Maldera, S., Manfreda, A., Marscher, A., Massaro, F., Mitsuishi, I., Mizuno, T., Muleri, F., Negro, M., Ng, S., O'Dell, S., Omodei, N., Oppedisano, C., Papitto, A., Pavlov, G., Perri, M., Pesce-Rollins, M., Petrucci, P. -O., Pilia, M., Possenti, A., Poutanen, J., Ramsey, B., Rankin, J., Roberts, O., Romani, R., Sgro, C., Slane, P., Soffitta, P., Spandre, G., Swartz, D., Tamagawa, T., Tavecchio, F., Taverna, R., Tawara, Y., Tennant, A., Thomas, N., Trois, A., Tsygankov, S., Turolla, R., Vink, J., Weisskopf, M., Wu, K., Xie, F., and Zane, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, J.2.3, J.2.9
Abstract

We used the Imaging X-ray Polarimetry Explorer (IXPE) satellite to measure, for the first time, the 2-8 keV polarization of NGC 1068. We pointed IXPE for a net exposure time of 1.15 Ms on the target, in addition to two ~ 10 ks each Chandra snapshots in order to account for the potential impact of several ultraluminous X-ray source (ULXs) within IXPE's field-of-view. We measured a 2 - 8 keV polarization degree of 12.4% +/- 3.6% and an electric vector polarization angle of 101{\deg} +/- 8{\deg} at 68% confidence level. If we exclude the spectral region containing the bright Fe K lines and other soft X-ray lines where depolarization occurs, the polarization fraction rises up to 21.3% +/- 6.7% in the 3.5 - 6.0 keV band, with a similar polarization angle. The observed polarization angle is found to be perpendicular to the parsec scale radio jet. Using a combined Chandra and IXPE analysis plus multi-wavelength constraints, we estimated that the circumnuclear "torus" may sustain a half-opening angle of 50{\deg} - 55{\deg} (from the vertical axis of the system). Thanks to IXPE, we have measured the X-ray polarization of NGC 1068 and found comparable results, both in terms of polarization angle orientation with respect to the radio-jet and torus half-opening angle, to the X-ray polarimetric measurement achieved for the other archetypal Compton-thick AGN : the Circinus galaxy. Probing the geometric arrangement of parsec-scale matter in extragalactic object is now feasible thanks to X-ray polarimetry., Comment: 9 pages, 5 figures, 2 tables, submited to A&A

Published
2024

29. Morphological Symmetries in Robotics

Author

Ordoñez-Apraez, Daniel, Turrisi, Giulio, Kostic, Vladimir, Martin, Mario, Agudo, Antonio, Moreno-Noguer, Francesc, Pontil, Massimiliano, Semini, Claudio, and Mastalli, Carlos

Subjects
Computer Science - Robotics, Computer Science - Artificial Intelligence, Electrical Engineering and Systems Science - Systems and Control
Abstract

We present a comprehensive framework for studying and leveraging morphological symmetries in robotic systems. These are intrinsic properties of the robot's morphology, frequently observed in animal biology and robotics, which stem from the replication of kinematic structures and the symmetrical distribution of mass. We illustrate how these symmetries extend to the robot's state space and both proprioceptive and exteroceptive sensor measurements, resulting in the equivariance of the robot's equations of motion and optimal control policies. Thus, we recognize morphological symmetries as a relevant and previously unexplored physics-informed geometric prior, with significant implications for both data-driven and analytical methods used in modeling, control, estimation and design in robotics. For data-driven methods, we demonstrate that morphological symmetries can enhance the sample efficiency and generalization of machine learning models through data augmentation, or by applying equivariant/invariant constraints on the model's architecture. In the context of analytical methods, we employ abstract harmonic analysis to decompose the robot's dynamics into a superposition of lower-dimensional, independent dynamics. We substantiate our claims with both synthetic and real-world experiments conducted on bipedal and quadrupedal robots. Lastly, we introduce the repository MorphoSymm to facilitate the practical use of the theory and applications outlined in this work., Comment: 18 pages, 11 figures

Published
2024

30. Performance and first measurements of the MAGIC Stellar Intensity Interferometer

Author

MAGIC Collaboration, Abe, S., Abhir, J., Acciari, V. A., Aguasca-Cabot, A., Agudo, I., Aniello, T., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Arcaro, C., Artero, M., Asano, K., Babić, A., Baquero, A., de Almeida, U. Barres, Barrio, J. A., Batković, I., Bautista, A., Baxter, J., González, J. Becerra, Bernardini, E., Bernardos, M., Bernete, J., Berti, A., Besenrieder, J., Bigongiari, C., Biland, A., Blanch, O., Bošnjak, Ž., Burelli, I., Busetto, G., Campoy-Ordaz, A., Carosi, A., Carosi, R., Carretero-Castrillo, M., Ceribella, G., Chai, Y., Cifuentes, A., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., de Menezes, R., Del Popolo, A., Delfino, M., Delgado, J., Mendez, C. Delgado, Di Pierro, F., Di Venere, L., Prester, D. Dominis, Donini, A., Dorner, D., Doro, M., Elsaesser, D., Emery, G., Escudero, J., na, L. Fari, Fattorini, A., Foffano, L., Font, L., Fröse, S., Fukami, S., Fukazawa, Y., López, R. J. García, Garczarczyk, M., Gasparyan, S., Gaug, M., Paiva, J. G. Giesbrecht, Giglietto, N., Giordano, F., Gliwny, P., Gradetzke, T., Grau, R., Green, D., Green, J. G., Günther, P., Hadasch, D., Hahn, A., Hassan, T., Heckmann, L., Herrera, J., Hrupec, D., Hütten, M., Imazawa, R., Ishio, K., Martínez, I. Jiménez, Jormanainen, J., Kayanoki, T., Kerszberg, D., Kluge, G. W., Kobayashi, Y., Kouch, P. M., Kubo, H., Kushida, J., Láinez, M., Lamastra, A., Leone, F., Lindfors, E., Linhoff, L., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., Lyard, E., Fraga, B. Machado de Oliveira, Majumdar, P., Makariev, M., Maneva, G., Mang, N., Manganaro, M., Mangano, S., Mannheim, K., Mariotti, M., Martínez, M., Martínez-Chicharro, M., Mas-Aguilar, A., Mazin, D., Menchiari, S., Mender, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., González, M. Molero, Molina, E., Mondal, H. A., Moralejo, A., Morcuende, D., Nakamori, T., Nanci, C., Neustroev, V., Nickel, L., Rosillo, M. Nievas, Nigro, C., Nikolić, L., Nilsson, K., Nishijima, K., Ekoume, T. Njoh, Noda, K., Nozaki, S., Ohtani, Y., Okumura, A., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Peresano, M., Persic, M., Pihet, M., Pirola, G., Podobnik, F., Moroni, P. G. Prada, Prandini, E., Principe, G., Priyadarshi, C., Rhode, W., Ribó, M., Rico, J., Righi, C., Sahakyan, N., Saito, T., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schmuckermaier, F., Schubert, J. L., Schweizer, T., Sciaccaluga, A., Silvestri, G., Sitarek, J., Sliusar, V., Sobczynska, D., Spolon, A., Stamerra, A., Strišković, J., Strom, D., Strzys, M., Suda, Y., Surić, T., Suutarinen, S., Tajima, H., Takahashi, M., Takeishi, R., Temnikov, P., Terauchi, K., Terzić, T., Truzzi, M. Teshima S., Tutone, A., Ubach, S., van Scherpenberg, J., Acosta, M. Vazquez, Ventura, S., Viale, I., Vigorito, C. F., Vitale, V., Walter, R., Will, M., Wunderlich, C., Yamamoto, T., Díaz, G. Chon C., Fiori, M., Lobo, M., Naletto, G., Polo, M., Rodríguez-Vázquez, J. J., Saha, P., and Zampieri, L.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

In recent years, a new generation of optical intensity interferometers has emerged, leveraging the existing infrastructure of Imaging Atmospheric Cherenkov Telescopes (IACTs). The MAGIC telescopes host the MAGIC-SII system (Stellar Intensity Interferometer), implemented to investigate the feasibility and potential of this technique on IACTs. After the first successful measurements in 2019, the system was upgraded and now features a real-time, dead-time-free, 4-channel, GPU-based correlator. These hardware modifications allow seamless transitions between MAGIC's standard very-high-energy gamma-ray observations and optical interferometry measurements within seconds. We establish the feasibility and potential of employing IACTs as competitive optical Intensity Interferometers with minimal hardware adjustments. The measurement of a total of 22 stellar diameters are reported, 9 corresponding to reference stars with previous comparable measurements, and 13 with no prior measurements. A prospective implementation involving telescopes from the forthcoming Cherenkov Telescope Array Observatory's northern hemisphere array, such as the first prototype of its Large-Sized Telescopes, LST-1, is technically viable. This integration would significantly enhance the sensitivity of the current system and broaden the UV-plane coverage. This advancement would enable the system to achieve competitive sensitivity with the current generation of long-baseline optical interferometers over blue wavelengths., Comment: 18 pages, 13 figures, submitted to MNRAS

Published
2024
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31. First detection of polarization in X-rays for PSR B0540-69 and its nebula

Author

Xie, Fei, Wong, Josephine, La Monaca, Fabio, Romani, Roger W., Heyl, Jeremy, Kaaret, Philip, Di Marco, Alessandro, Bucciantini, Niccolò, Liu, Kuan, Ng, Chi-Yung, Di Lalla, Niccolò, Weisskopf, Martin C., Costa, Enrico, Soffitta, Paolo, Muleri, Fabio, Bachetti, Matteo, Pilia, Maura, Rankin, John, Fabiani, Sergio, Agudo, Iván, Antonelli, Lucio A., Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Ratheesh, Ajay, Roberts, Oliver J., Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, Zane, Silvia, Wadiasingh, Zorawar, Ho, Wynn C. G., Harding, Alice K., Gendreau, Keith C., and Arzoumanian, Zaven

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report on X-ray polarization measurements of the extra-galactic Crab-like PSR B0540-69 and its Pulsar Wind Nebula (PWN) in the Large Magellanic Cloud (LMC), using a ~850 ks Imaging X-ray Polarimetry Explorer (IXPE) exposure. The PWN is unresolved by IXPE. No statistically significant polarization is detected for the image-averaged data, giving a 99% confidence polarization upper limit (MDP99) of 5.3% in 2-8 keV energy range. However, a phase-resolved analysis detects polarization for both the nebula and pulsar in the 4-6 keV energy range. For the PWN defined as the off-pulse phases, the polarization degree (PD) of (24.5 ${\pm}$ 5.3)% and polarization angle (PA) of (78.1 ${\pm}$ 6.2){\deg} is detected at 4.6${\sigma}$ significance level, consistent with the PA observed in the optical band. In a single on-pulse window, a hint of polarization is measured at 3.8${\sigma}$ with polarization degree of (50.0 ${\pm}$ 13.1)% and polarization angle of (6.2 ${\pm}$ 7.4){\deg}. A 'simultaneous' PSR/PWN analysis finds two bins at the edges of the pulse exceeding 3${\sigma}$ PD significance, with PD of (68 ${\pm}$ 20)% and (62 ${\pm}$ 20)%; intervening bins at 2-3${\sigma}$ significance have lower PD, hinting at additional polarization structure., Comment: 10 pages, 7 figures, 4 tables, author's version of the paper accepted for publication in ApJ

Published
2024

32. Ordered magnetic fields around the 3C 84 central black hole

Author

Paraschos, G. F., Kim, J. -Y., Wielgus, M., Röder, J., Krichbaum, T. P., Ros, E., Agudo, I., Myserlis, I., Moscibrodzka, M., Traianou, E., Zensus, J. A., Blackburn, L., Chan, C. -K., Issaoun, S., Janssen, M., Johnson, M. D., Fish, V. L., Akiyama, K., Alberdi, A., Alef, W., Algaba, J. C., Anantua, R., Asada, K., Azulay, R., Bach, U., Baczko, A. -K., Ball, D., Baloković, M., Barrett, J., Bauböck, M., Benson, B. A., Bintley, D., Blundell, R., Bouman, K. L., Bower, G. C., Boyce, H., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Bustamante, S., Byun, D. -Y., Carlstrom, J. E., Ceccobello, C., Chael, A., Chang, D. O., Chatterjee, K., Chatterjee, S., Chen, M. T., Chen, Y., Cheng, X., Cho, I., Christian, P., Conroy, N. S., Conway, J. E., Cordes, J. M., Crawford, T. M., Crew, G. B., Cruz-Osorio, A., Cui, Y., Dahale, R., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Dhruv, V., Doeleman, S. S., Dougal, S., Dzib, S. A., Eatough, R. P., Emami, R., Falcke, H., Farah, J., Fomalont, E., Ford, H. A., Foschi, M., Fraga-Encinas, R., Freeman, W. T., Friberg, P., Fromm, C. M., Fuentes, A., Galison, P., Gammie, C. F., García, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gómez-Ruiz, A. I., Gómez, J. L., Gu, M., Gurwell, M., Hada, K., Haggard, D., Haworth, K., Hecht, M. H., Hesper, R., Heumann, D., Ho, L. C., Ho, P., Honma, M., Huang, C. L., Huang, L., Hughes, D. H., Ikeda, S., Impellizzeri, C. M. V., Inoue, M., James, D. J., Jannuzi, B. T., Jeter, B., Jaing, W., Jiménez-Rosales, A., Jorstad, S., Joshi, A. V., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, D. -J., Kim, J., Kino, M., Koay, J. Y., Kocherlakota, P., Kofuji, Y., Koch, P. M., Koyama, S., Kramer, C., Kramer, J. A., Kramer, M., Kuo, C. -Y., La Bella, N., Lauer, T. R., Lee, D., Lee, S. -S., Leung, P. K., Levis, A., Li, Z., Lico, R., Lindahl, G., Lindqvist, M., Lisakov, M., Liu, J., Liu, K., Liuzzo, E., Lo, W. -P., Lobanov, A. P., Loinard, L., Lonsdale, C. J., Lowitz, A. E., Lu, R. -S., MacDonald, N. R., Mao, J., Marchili, N., Markoff, S., Marrone, D. P., Marscher, A. P., Martí-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Michalik, D., Mizuno, I., Mizuno, Y., Moran, J. M., Moriyama, K., Mulaudzi, W., Müller, C., Müller, H., Mus, A., Musoke, G., Nadolski, A., Nagai, H., Nagar, N. M., Nakamura, M., Narayanan, G., Natarajan, I., Nathanail, A., Fuentes, S. Navarro, Neilsen, J., Neri, R., Ni, C., Noutsos, A., Nowak, M. A., Oh, J., Okino, H., Olivares, H., Ortiz-León, G. N., Oyama, T., Özel, F., Palumbo, D. C. M., Park, J., Parsons, H., Patel, N., Pen, U. -L., Piétu, V., Plambeck, R., PopStefanija, A., Porth, O., Pötzl, F. M., Prather, B., Preciado-López, J. A., Psaltis, D., Pu, H. -Y., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ricarte, A., Ripperda, B., Roelofs, F., Rogers, A., Romero-Cañizales, C., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruiz, I., Ruszczyk, C., Rygl, K. L. J., Sánchez, S., Sánchez-Argüelles, D., Sánchez-Portal, M., Sasada, M., Satapathy, K., Savolainen, T., Schloerb, F. P., Schonfeld, J., Schuster, K., Shao, L., Shen, Z., Small, D., Sohn, B. W., SooHoo, J., Salas, L. D. Sosapanta, Souccar, K., Sun, H., Tazaki, F., Tetarenko, A. J., Tiede, P., Tilanus, R. P. J., Titus, M., Torne, P., Toscano, T., Trent, T., Trippe, S., Turk, M., van Bemmel, I., van Langevelde, H. J., van Rossum, D. R., Vos, J., Wagner, J., Ward-Thompson, D., Wardle, J., Washington, J. E., Weintroub, J., Wharton, R., Wiik, K., Witzel, G., Wondrak, M. F., Wong, G. N., Wu, Q., Yadlapalli, N., Yamaguchi, P., Yfantis, A., Yoon, D., Young, A., Young, K., Younsi, Z., Yu, W., Yuan, F., Yuan, Y. -F., Zhang, S., Zhao, G. Y., and Zhao, S. -S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract

3C84 is a nearby radio source with a complex total intensity structure, showing linear polarisation and spectral patterns. A detailed investigation of the central engine region necessitates the use of VLBI above the hitherto available maximum frequency of 86GHz. Using ultrahigh resolution VLBI observations at the highest available frequency of 228GHz, we aim to directly detect compact structures and understand the physical conditions in the compact region of 3C84. We used EHT 228GHz observations and, given the limited (u,v)-coverage, applied geometric model fitting to the data. We also employed quasi-simultaneously observed, multi-frequency VLBI data for the source in order to carry out a comprehensive analysis of the core structure. We report the detection of a highly ordered, strong magnetic field around the central, SMBH of 3C84. The brightness temperature analysis suggests that the system is in equipartition. We determined a turnover frequency of $\nu_m=(113\pm4)$GHz, a corresponding synchrotron self-absorbed magnetic field of $B_{SSA}=(2.9\pm1.6)$G, and an equipartition magnetic field of $B_{eq}=(5.2\pm0.6)$G. Three components are resolved with the highest fractional polarisation detected for this object ($m_\textrm{net}=(17.0\pm3.9)$%). The positions of the components are compatible with those seen in low-frequency VLBI observations since 2017-2018. We report a steeply negative slope of the spectrum at 228GHz. We used these findings to test models of jet formation, propagation, and Faraday rotation in 3C84. The findings of our investigation into different flow geometries and black hole spins support an advection-dominated accretion flow in a magnetically arrested state around a rapidly rotating supermassive black hole as a model of the jet-launching system in the core of 3C84. However, systematic uncertainties due to the limited (u,v)-coverage, however, cannot be ignored., Comment: 15 pages, 6 figures, published in A&A

Published
2024
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33. Discovery of a strong rotation of the X-ray polarization angle in the galactic burster GX 13+1

Author

Bobrikova, Anna, Forsblom, Sofia V., Di Marco, Alessandro, La Monaca, Fabio, Poutanen, Juri, Ng, Mason, Ravi, Swati, Loktev, Vladislav, Kajava, Jari J. E., Ursini, Francesco, Veledina, Alexandra, Rogantini, Daniele, Salmi, Tuomo, Bianchi, Stefano, Capitanio, Fiamma, Done, Chris, Fabiani, Sergio, Gnarini, Andrea, Heyl, Jeremy, Kaaret, Philip, Matt, Giorgio, Muleri, Fabio, Nitindala, Anagha P., Rankin, John, Weisskopf, Martin C., Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Doroshenko, Victor, Dovciak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Ratheesh, Ajay J., Roberts, Oliver, Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, Xie, Fei, and Zane, Silvia

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Weakly magnetized neutron stars in X-ray binaries show complex phenomenology with several spectral components that can be associated with the accretion disk, boundary and/or spreading layer, a corona, and a wind. Spectroscopic information alone is, however, not enough to disentangle these components. Additional information about the nature of the spectral components and in particular the geometry of the emission region can be provided by X-ray polarimetry. One of the objects of the class, a bright, persistent, and rather peculiar galactic Type I X-ray burster was observed with the Imaging X-ray Polarimetry Explorer (IXPE) and the X-ray Multi-Mirror Mission Newton (XMM-Newton). Using the XMM-Newton data we estimated the current state of the source as well as detected strong absorption lines associated with the accretion disk wind. IXPE data showed the source to be significantly polarized in the 2-8 keV energy band with the overall polarization degree (PD) of 1.4% at a polarization angle (PA) of -2 degrees (errors at 68% confidence level). During the two-day long observation, we detected rotation of the PA by about 70 degrees with the corresponding changes in the PD from 2% to non-detectable and then up to 5%. These variations in polarization properties are not accompanied by visible changes in spectroscopic characteristics. The energy-resolved polarimetric analysis showed a significant change in polarization, from being strongly dependent on energy at the beginning of the observation to being almost constant with energy in the later parts of the observation. As a possible interpretation, we suggest the presence of a constant component of polarization, strong wind scattering, or different polarization of the two main spectral components with individually peculiar behavior. The rotation of the PA suggests a 30-degree misalignment of the neutron star spin from the orbital axis., Comment: 12 pages, 12 figures

Published
2024
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34. Constraints on axion-like particles with the Perseus Galaxy Cluster with MAGIC

Author

MAGIC Collaboration, Abe, H., Abe, S., Abhir, J., Acciari, V. A., Agudo, I., Aniello, T., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Arcaro, C., Artero, M., Asano, K., Baack, D., Babić, A., Baquero, A., de Almeida, U. Barres, Barrio, J. A., Batković, I., Baxter, J., González, J. Becerra, Bednarek, W., Bernardini, E., Bernete, J., Berti, A., Besenrieder, J., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bošnjak, Ž., Burelli, I., Busetto, G., Campoy-Ordaz, A., Carosi, A., Carosi, R., Carretero-Castrillo, M., Castro-Tirado, A. J., Ceribella, G., Chai, Y., Cifuentes, A., Cikota, S., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Del Popolo, A., Delgado, J., Mendez, C. Delgado, Depaoli, D., Di Pierro, F., Di Venere, L., Donini, A., Dorner, D., Doro, M., Elsaesser, D., Emery, G., Escudero, J., Fariña, L., Fattorini, A., Foffano, L., Font, L., Fukami, S., Fukazawa, Y., López, R. J. García, Garczarczyk, M., Gasparyan, S., Gaug, M., Paiva, J. G. Giesbrecht, Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Grau, R., Green, D., Green, J. G., Hadasch, D., Hahn, A., Hassan, T., Heckmann, L., Herrera, J., Hrupec, D., Hütten, M., Imazawa, R., Inada, T., Iotov, R., Ishio, K., Martínez, I. Jiménez, Jormanainen, J., Kerszberg, D., Kluge, G. W., Kobayashi, Y., Kouch, P. M., Kubo, H., Kushida, J., Láinez, M., Lamastra, A., Leone, F., Lindfors, E., Linhoff, L., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., Fraga, B. Machado de Oliveira, Majumdar, P., Makariev, M., Maneva, G., Mang, N., Manganaro, M., Mangano, S., Mannheim, K., Mariotti, M., Martínez, M., Martínez-Chicharro, M., Mas-Aguilar, A., Mazin, D., Menchiari, S., Mender, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., González, M. Molero, Molina, E., Mondal, H. A., Moralejo, A., Morcuende, D., Nakamori, T., Nanci, C., Nava, L., Neustroev, V., Nickel, L., Rosillo, M. Nievas, Nigro, C., Nikolić, L., Nilsson, K., Nishijima, K., Ekoume, T. Njoh, Noda, K., Nozaki, S., Ohtani, Y., Okumura, A., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavlović, D., Persic, M., Pihet, M., Pirola, G., Podobnik, F., Moroni, P. G. Prada, Prandini, E., Principe, G., Priyadarshi, C., Rhode, W., Ribó, M., Rico, J., Righi, C., Sahakyan, N., Saito, T., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schmuckermaier, F., Schubert, J. L., Schweizer, T., Sciaccaluga, A., Sitarek, J., Sliusar, V., Sobczynska, D., Spolon, A., Stamerra, A., Strišković, J., Strom, D., Strzys, M., Suda, Y., Suutarinen, S., Tajima, H., Takahashi, M., Takeishi, R., Tavecchio, F., Temnikov, P., Terauchi, K., Terzić, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Acosta, M. Vazquez, Ventura, S., Verguilov, V., Viale, I., Vigorito, C. F., Vitale, V., Vovk, I., Walter, R., Will, M., and Yamamoto, T.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Phenomenology
Abstract

Axion-like particles (ALPs) are pseudo-Nambu-Goldstone bosons that emerge in various theories beyond the standard model. These particles can interact with high-energy photons in external magnetic fields, influencing the observed gamma-ray spectrum. This study analyzes 41.3 hrs of observational data from the Perseus Galaxy Cluster collected with the MAGIC telescopes. We focused on the spectra the radio galaxy in the center of the cluster: NGC 1275. By modeling the magnetic field surrounding this target, we searched for spectral indications of ALP presence. Despite finding no statistical evidence of ALP signatures, we were able to exclude ALP models in the sub-micro electronvolt range. Our analysis improved upon previous work by calculating the full likelihood and statistical coverage for all considered models across the parameter space. Consequently, we achieved the most stringent limits to date for ALP masses around 50 neV, with cross sections down to $g_{a\gamma} = 3 \times 10^{-12}$ GeV$^{-1}$., Comment: 25 pages, 10 figures, accepted for publication in Physics of the Dark Universe

Published
2024
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35. Detection of X-ray Polarization from the Blazar 1ES 1959+650 with the Imaging X-ray Polarimetry Explorer

Author

Errando, Manel, Liodakis, Ioannis, Marscher, Alan P., Marshall, Herman L., Middei, Riccardo, Negro, Michela, Peirson, Abel Lawrence, Perri, Matteo, Puccetti, Simonetta, Rabinowitz, Pazit L., Agudo, Iván, Jorstad, Svetlana G., Savchenko, Sergey S., Blinov, Dmitry, Bourbah, Ioakeim G., Kiehlmann, Sebastian, Kontopodis, Evangelos, Mandarakas, Nikos, Romanopoulos, Stylianos, Skalidis, Raphael, Vervelaki, Anna, Aceituno, Francisco José, Bernardos, Maria I., Bonnoli, Giacomo, Casanova, Víctor, Agís-González, Beatriz, Husillos, César, Marchini, Alessandro, Sota, Alfredo, Kouch, Pouya M., Lindfors, Elina, Casadio, Carolina, Escudero, Juan, Myserlis, Ioannis, Imazawa, Ryo, Sasada, Mahito, Fukazawa, Yasushi, Kawabata, Koji S., Uemura, Makoto, Mizuno, Tsunefumi, Nakaoka, Tatsuya, Akitaya, Hiroshi, Gurwell, Mark, Keating, Garrett K., Rao, Ramprasad, Ingram, Adam, Massaro, Francesco, Antonelli, Lucio Angelo, Bonino, Raffaella, Cavazzuti, Elisabetta, Chen, Chien-Ting, Cibrario, Nicolò, Ciprini, Stefano, De Rosa, Alessandra, Di Gesu, Laura, Di Pierro, Federico, Donnarumma, Immacolata, Ehlert, Steven R., Fenu, Francesco, Gau, Ephraim, Karas, Vladimir, Kim, Dawoon E., Krawczynski, Henric, Laurenti, Marco, Lisalda, Lindsey, López-Coto, Rubén, Madejski, Grzegorz, Marin, Frédéric, Marinucci, Andrea, Mitsuishi, Ikuyuki, Muleri, Fabio, Pacciani, Luigi, Paggi, Alessandro, Petrucci, Pierre-Olivier, Cavero, Nicole Rodriguez, Romani, Roger W., Tavecchio, Fabrizio, Tugliani, Stefano, Wu, Kinwah, Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Costa, Enrico, Del Monte, Ettore, Di Lalla, Niccolò, Di Marco, Alessandro, Doroshenko, Victor, Dovčiak, Michal, Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Kaaret, Philip, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Matt, Giorgio, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Xie, Fei, and Zane, Silvia

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Observations of linear polarization in the 2-8 keV energy range with the Imaging X-ray Polarimetry Explorer (IXPE) explore the magnetic field geometry and dynamics of the regions generating non-thermal radiation in relativistic jets of blazars. These jets, particularly in blazars whose spectral energy distribution peaks at X-ray energies, emit X-rays via synchrotron radiation from high-energy particles within the jet. IXPE observations of the X-ray selected BL Lac-type blazar 1ES 1959+650 in 2022 May 3-4 showed a significant linear polarization degree of $\Pi_\mathrm{x} = 8.0\% \pm 2.3\%$ at an electric-vector position angle $\psi_\mathrm{x} = 123^\circ \pm 8^\circ$. However, in 2022 June 9-12, only an upper limit of $\Pi_\mathrm{x} \leq 5.1\%$ could be derived (at the 99% confidence level). The degree of optical polarization at that time $\Pi_\mathrm{O} \sim 5\%$ is comparable to the X-ray measurement. We investigate possible scenarios for these findings, including temporal and geometrical depolarization effects. Unlike some other X-ray selected BL Lac objects, there is no significant chromatic dependence of the measured polarization in 1ES 1959+650, and its low X-ray polarization may be attributed to turbulence in the jet flow with dynamical timescales shorter than 1 day., Comment: 16 pages, 4 figures, accepted for publication in The Astrophysical Journal

Published
2024
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38. Complex rotational dynamics of the neutron star in Hercules X-1 revealed by X-ray polarization

Author

Heyl, Jeremy, Doroshenko, Victor, González-Caniulef, Denis, Caiazzo, Ilaria, Poutanen, Juri, Mushtukov, Alexander, Tsygankov, Sergey S., Kirmizibayrak, Demet, Bachetti, Matteo, Pavlov, George G., Forsblom, Sofia V., Malacaria, Christian, Suleimanov, Valery F., Agudo, Iván, Antonelli, Lucio Angelo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Di Marco, Alessandro, Donnarumma, Immacolata, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, C.-Y., O’Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Peirson, Abel Lawrence, Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia

Published
2024
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39. Cygnus X-3 revealed as a Galactic ultraluminous X-ray source by IXPE

Author

Veledina, Alexandra, Muleri, Fabio, Poutanen, Juri, Podgorný, Jakub, Dovčiak, Michal, Capitanio, Fiamma, Churazov, Eugene, De Rosa, Alessandra, Di Marco, Alessandro, Forsblom, Sofia V., Kaaret, Philip, Krawczynski, Henric, La Monaca, Fabio, Loktev, Vladislav, Lutovinov, Alexander A., Molkov, Sergey V., Mushtukov, Alexander A., Ratheesh, Ajay, Rodriguez Cavero, Nicole, Steiner, James F., Sunyaev, Rashid A., Tsygankov, Sergey S., Weisskopf, Martin C., Zdziarski, Andrzej A., Bianchi, Stefano, Bright, Joe S., Bursov, Nikolaj, Costa, Enrico, Egron, Elise, Garcia, Javier A., Green, David A., Gurwell, Mark, Ingram, Adam, Kajava, Jari J. E., Kale, Ruta, Kraus, Alex, Malyshev, Denys, Marin, Frédéric, Matt, Giorgio, McCollough, Michael, Mereminskiy, Ilya A., Nizhelsky, Nikolaj, Piano, Giovanni, Pilia, Maura, Pittori, Carlotta, Rao, Ramprasad, Righini, Simona, Soffitta, Paolo, Shevchenko, Anton, Svoboda, Jiri, Tombesi, Francesco, Trushkin, Sergei A., Tsybulev, Peter, Ursini, Francesco, Wu, Kinwah, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, Ng, Chi-Yung, O’Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Roberts, Oliver, Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Doug, Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Trois, Alessio, Turolla, Roberto, Vink, Jacco, Xie, Fei, and Zane, Silvia

Published
2024
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40. Randomised, double-blind, placebo-controlled, parallel-group, multicentric, phase IIA clinical trial for evaluating the safety, tolerability, and therapeutic efficacy of daily oral administration of NFX88 to treat neuropathic pain in individuals with spinal cord injury

Author

Escribá, Pablo V., Gil-Agudo, Ángel M., Vidal Samsó, Joan, Sánchez-Raya, Judith, Salvador-de la Barrera, Sebastián, Soto-León, Vanesa, León-Álvarez, Natacha, Méndez Ferrer, Bosco, Membrilla-Mesa, Miguel David, Redondo Galán, Carolina, Benito-Penalva, Jesús, Montoto-Marqués, Antonio, Medel Rebollo, Javier, Palazón García, Ramiro, Gutiérrez Henares, Francisco, Miralles, Marc, Torres, Manuel, Nieto-Librero, Ana B., García Marco, David, Gómez, Carmela, Jimeno, David, and Oliviero, Antonio

Published
2024
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41. Direct presentation of inflammation-associated self-antigens by thymic innate-like T cells induces elimination of autoreactive CD8+ thymocytes

Author

You, Yuanyuan, Dunst, Josefine, Ye, Kewei, Sandoz, Patrick A., Reinhardt, Annika, Sandrock, Inga, Comet, Natalia R., Sarkar, Rupak Dey, Yang, Emily, Duprez, Estelle, Agudo, Judith, Brown, Brian D., Utz, Paul J., Kastenmüller, Wolfgang, Gerlach, Carmen, Prinz, Immo, Önfelt, Björn, and Kreslavsky, Taras

Published
2024
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43. CLIL Realities through the Lens of English and Content Teachers

Author

Fielden Burns, Laura V. and Martínez Agudo, Juan de Dios

Abstract

This research investigated six established areas for quality (Ortega-Martín et al., 2018) in the implementation of CLIL programmes in a Spanish monolingual autonomous community from the perspective of its teachers, in particular focusing on possible differences of opinion between content and English language teachers, an understudied area. Both quantitative and qualitative data were collected from 36 teachers at four secondary schools in urban Extremadura so as to assess the perceptions of the execution and the effectiveness of current CLIL education programmes, identifying specifically their potential challenges. Significant differences between content teachers and English teachers' perceptions in six areas under study are examined, from programme management to academic results. Data results indicate that although programmes are viewed quite positively by both groups of teachers, some important areas of difference exist, including the amount of time the L2 is used in a content class and the language skills that are worked in a CLIL environment. To address this gap, suggestions are made to establish more widely accepted standards for CLIL programme objectives.

Published
2023

44. Lost in the curve: Investigating the disappearing knots in the blazar 3C 454.3

Author

Traianou, Efthalia, Krichbaum, Thomas P., Gómez, José L., Lico, Rocco, Paraschos, Georgios Filippos, Cho, Ilje, Ros, Eduardo, Zhao, Guang-Yao, Liodakis, Ioannis, Dahale, Rohan, Toscano, Teresa, Fuentes, Antonio, Foschi, Marianna, Casadio, Carolina, MacDonald, Nicholas, Kim, Jae-Young, Hervet, Olivier, Jorstad, Svetlana, Lobanov, Andrei P., Hodgson, Jeffrey, Myserlis, Ioannis, Agudo, Ivan, Zensus, Anton J., and Marscher, Alan P.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

One of the most well-known extragalactic sources in the sky, quasar 3C 454.3, shows a curved parsec-scale jet that has been exhaustively monitored with very-long-baseline interferometry (VLBI) over the recent years. In this work, we present a comprehensive analysis of four years of high-frequency VLBI observations at 43 GHz and 86 GHz, between 2013-2017, in total intensity and linear polarization. The images obtained from these observations enabled us to study the jet structure and the magnetic field topology of the source on spatial scales down to 4.6 parsec in projected distance. The kinematic analysis reveals the abrupt vanishing of at least four new superluminal jet features in a characteristic jet region (i.e., region C), which is located at an approximate distance of 0.6 milliarcseconds from the VLBI core. Our results support a model in which the jet bends, directing the relativistic plasma flow almost perfectly toward our line of sight, co-spatially with the region where components appear to stop., Comment: 15 pages, 7 figures

Published
2023

45. X-Ray Polarimetry of the Dipping Accreting Neutron Star 4U 1624-49

Author

Saade, M. Lynne, Kaaret, Philip, Gnarini, Andrea, Poutanen, Juri, Ursini, Francesco, Bianchi, Stefano, Bobrikova, Anna, La Monaca, Fabio, Di Marco, Alessandro, Capitanio, Fiamma, Veledina, Alexandra, Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesù, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Doroshenko, Victor, Dovciak, Michal, Ehlert, Steven R., Emote, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizudo, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Oliver, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Zwartz, Douglas Z., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tenant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present the first X-ray polarimetric study of the dipping accreting neutron star 4U 1624$-$49 with the Imaging X-ray Polarimetry Explorer (IXPE). We report a detection of polarization in the non-dip time intervals with a confidence level of 99.99%. We find an average polarization degree (PD) of $3.1\pm0.7$% and a polarization angle of $81\pm6$ degrees east of north in the 2-8 keV band. We report an upper limit on the PD of 22% during the X-ray dips with 95% confidence. The PD increases with energy, reaching from $3.0\pm0.9$% in the 4-6 keV band to $6\pm2$% in the 6-8 keV band. This indicates the polarization likely arises from Comptonization. The high PD observed is unlikely to be produced by Comptonization in the boundary layer or spreading layer alone. It can be produced by the addition of an extended geometrically thin slab corona covering part of the accretion disk, as assumed in previous models of dippers, and/or a reflection component from the accretion disk.

Published
2023

46. First characterization of the emission behavior of Mrk421 from radio to VHE gamma rays with simultaneous X-ray polarization measurements

Author

Abe, S., Abhir, J., Acciari, V. A., Agudo, I., Aniello, T., Ansoldi, S., Antonelli, L. A., Engels, A. Arbet, Arcaro, C., Artero, M., Asano, K., Babić, A., Baquero, A., de Almeida, U. Barres, Barrio, J. A., Batković, I., Baxter, J., González, J. Becerra, Bednarek, W., Bernardini, E., Bernete, J., Berti, A., Besenrieder, J., Bigongiari, C., Biland, A., Blanch, O., Bonnoli, G., Bošnjak, Ž., Burelli, I., Busetto, G., Campoy-Ordaz, A., Carosi, A., Carosi, R., Carretero-Castrillo, M., Castro-Tirado, A. J., Ceribella, G., Chai, Y., Cifuentes, A., Cikota, S., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., D'Ammando, F., D'Amico, G., D'Elia, V., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., de Menezes, R., Del Popolo, A., Delgado, J., Mendez, C. Delgado, Di Pierro, F., Di Venere, L., Prester, D. Dominis, Donini, A., Dorner, D., Doro, M., Elsaesser, D., Emery, G., Escudero, J., Fariña, L., Fattorini, A., Foffano, L., Font, L., Fröse, S., Fukami, S., Fukazawa, Y., López, R. J. García, Garczarczyk, M., Gasparyan, S., Gaug, M., Paiva, J. G. Giesbrecht, Giglietto, N., Giordano, F., Gliwny, P., Godinović, N., Gradetzke, T., Grau, R., Green, D., Green, J. G., Günther, P., Hadasch, D., Hahn, A., Hassan, T., Heckmann, L., Herrera, J., Hrupec, D., Hütten, M., Imazawa, R., Inada, T., Ishio, K., Martínez, I. Jiménez, Jormanainen, J., Kerszberg, D., Kluge, G. W., Kobayashi, Y., Kouch, P. M., Kubo, H., Kushida, J., Lezáun, M. Láinez, Lamastra, A., Leone, F., Lindfors, E., Linhoff, L., Lombardi, S., Longo, F., López-Coto, R., López-Moya, M., López-Oramas, A., Loporchio, S., Lorini, A., Fraga, B. Machado de Oliveira, Majumdar, P., Makariev, M., Maneva, G., Mang, N., Manganaro, M., Mangano, S., Mannheim, K., Mariotti, M., Martínez, M., Martínez-Chicharro, M., Mas-Aguilar, A., Mazin, D., Menchiari, S., Mender, S., Miceli, D., Miener, T., Miranda, J. M., Mirzoyan, R., González, M. Molero, Molina, E., Mondal, H. A., Moralejo, A., Morcuende, D., Nakamori, T., Nanci, C., Nava, L., Neustroev, V., Nickel, L., Rosillo, M. Nievas, Nigro, C., Nikolić, L., Nilsson, K., Nishijima, K., Ekoume, T. Njoh, Noda, K., Nozaki, S., Ohtani, Y., Okumura, A., Otero-Santos, J., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Pavlović, D., Peresano, M., Persic, M., Pihet, M., Pirola, G., Podobnik, F., Moroni, P. G. Prada, Prandini, E., Principe, G., Priyadarshi, C., Rhode, W., Ribó, M., Rico, J., Righi, C., Sahakyan, N., Saito, T., Satalecka, K., Saturni, F. G., Schleicher, B., Schmidt, K., Schmuckermaier, F., Schubert, J. L., Schweizer, T., Sciaccaluga, A., Sitarek, J., Sliusar, V., Sobczynska, D., Stamerra, A., Strišković, J., Strom, D., Strzys, M., Suda, Y., Suutarinen, S., Tajima, H., Takahashi, M., Takeishi, R., Tavecchio, F., Temnikov, P., Terauchi, K., Terzić, T., Teshima, M., Tosti, L., Truzzi, S., Tutone, A., Ubach, S., van Scherpenberg, J., Acosta, M. Vazquez, Ventura, S., Viale, I., Vigorito, C. F., Vitale, V., Vovk, I., Walter, R., Will, M., Wunderlich, C., Yamamoto, T., Liodakis, I., Jorstad, S. G., Gesu, L. D., Donnarumma, I., Kim, D. E., Marscher, A. P., Middei, R., Perri, M., Puccetti, S., Verrecchia, F., Leto, C., Pérez, I. De La Calle, Jiménez-Bailón, E., Blinov, D., Bourbah, I. G., Kiehlmann, S., Kontopodis, E., Mandarakas, N., Skalidis, R., Vervelaki, A., Aceituno, F. J., Agís-González, B., Sota, A., Sasada, M., Kawabata, K. S., Uemura, M., Mizuno, T., Akitaya, H., Casadio, C., Myserlis, I., Sievers, A., Lähteenmäki, A., Syrjärinne, I., Tornikoski, M., Salomé, Q., Gurwell, M., Keating, G. K., and Rao, R.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We perform the first broadband study of Mrk421 from radio to TeV gamma rays with simultaneous measurements of the X-ray polarization from IXPE. The data were collected within an extensive multiwavelength campaign organized between May and June 2022 using MAGIC, Fermi-LAT, NuSTAR, XMM-Newton, Swift, and several optical and radio telescopes to complement IXPE. During the IXPE exposures, the measured 0.2-1 TeV flux is close to the quiescent state and ranges from 25% to 50% of the Crab Nebula without intra-night variability. Throughout the campaign, the VHE and X-ray emission are positively correlated at a $4\sigma$ significance level. The IXPE measurements unveil a X-ray polarization degree that is a factor of 2-5 higher than in the optical/radio bands; that implies an energy-stratified jet in which the VHE photons are emitted co-spatially with the X-rays, in the vicinity of a shock front. The June 2022 observations exhibit a rotation of the X-ray polarization angle. Despite no simultaneous VHE coverage being available during a large fraction of the swing, the Swift-XRT monitoring unveils an X-ray flux increase with a clear spectral hardening. It suggests that flares in high synchrotron peaked blazars can be accompanied by a polarization angle rotation, as observed in some flat spectrum radio quasars. Finally, during the polarization angle rotation, NuSTAR data reveal two contiguous spectral hysteresis loops in opposite directions (clockwise and counter-clockwise), implying important changes in the particle acceleration efficiency on $\sim$hour timescales., Comment: Accepted for publication in Astronomy & Astrophysics. 29 pages, 22 figures. Corresponding authors: Axel Arbet Engels, Felix Schmuckermaier, David Paneque

Published
2023

47. VQ-HPS: Human Pose and Shape Estimation in a Vector-Quantized Latent Space

Author

Fiche, Guénolé, Leglaive, Simon, Alameda-Pineda, Xavier, Agudo, Antonio, and Moreno-Noguer, Francesc

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

Previous works on Human Pose and Shape Estimation (HPSE) from RGB images can be broadly categorized into two main groups: parametric and non-parametric approaches. Parametric techniques leverage a low-dimensional statistical body model for realistic results, whereas recent non-parametric methods achieve higher precision by directly regressing the 3D coordinates of the human body mesh. This work introduces a novel paradigm to address the HPSE problem, involving a low-dimensional discrete latent representation of the human mesh and framing HPSE as a classification task. Instead of predicting body model parameters or 3D vertex coordinates, we focus on predicting the proposed discrete latent representation, which can be decoded into a registered human mesh. This innovative paradigm offers two key advantages. Firstly, predicting a low-dimensional discrete representation confines our predictions to the space of anthropomorphic poses and shapes even when little training data is available. Secondly, by framing the problem as a classification task, we can harness the discriminative power inherent in neural networks. The proposed model, VQ-HPS, predicts the discrete latent representation of the mesh. The experimental results demonstrate that VQ-HPS outperforms the current state-of-the-art non-parametric approaches while yielding results as realistic as those produced by parametric methods when trained with little data. VQ-HPS also shows promising results when training on large-scale datasets, highlighting the significant potential of the classification approach for HPSE. See the project page at https://g-fiche.github.io/research-pages/vqhps/

Published
2023

48. Characterization of High-polarization Stars and Blazars with DIPOL-1 at Sierra Nevada Observatory

Author

Otero-Santos, J., Piirola, V., Pedrosa, J. Escudero, Agudo, I., Morcuende, D., Sota, A., Casanova, V., Aceituno, F. J., and Santos-Sanz, P.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report here the performance and first results of the new multiband optical polarimeter DIPOL-1, installed at the Sierra Nevada Observatory 90 cm T90 telescope (SNO, Granada, Spain). DIPOL-1 is equipped with a plane parallel calcite plate and $\lambda$/2 retarder for modulating the intensity of two perpendicularly polarized beams, and a high readout speed CMOS camera that allows for fast, time-dense coverage. We characterize the performance of this instrument through a series of tests on zero- and high-polarization standard stars. The instrumental polarization in the Nasmyth focus was well determined, with a very stable contribution of 4.0806% $\pm$ 0.0014% in the optical $R$ band. For bright high-polarization standards ($m_{R}<8$) we reach precisions $<$0.02% in polarization degree and 0.1$^{\circ}$ in polarization angle for exposures of 2$-$4 minutes. The polarization properties of these stars have been constrained, providing more recent results also about possible variability for future studies on some of the most used calibrators. Moreover, we have tested the capability of observing much fainter objects, in particular through blazar observations, where we reach a precision $<$0.5$-$0.6% and $<$0.5$^{\circ}$ for faint targets ($m_{R}\sim16.5$) with exposures of $\sim$1 hour. For brighter targets ($m_{R}\sim14.5-15$), we can aim for time-dense observations with errors $<$$0.2-0.4$% and $<$$1-1.5^{\circ}$ in 5-20 minutes. We have successfully performed a first campaign with DIPOL-1, detecting significant polarized emission of several blazars, with special attention to the highest ever polarization degree measured from blazar 3C~345 at $\sim$32%., Comment: Accepted in AJ

Published
2023
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49. Pulsar-wind-nebula-powered Galactic center X-ray filament G0.13-0.11: Proof of the synchrotron nature by IXPE

Author

Churazov, Eugene, Khabibullin, Ildar, Barnouin, Thibault, Bucciantini, Niccolò, Costa, Enrico, Di Gesu, Laura, Di Marco, Alessandro, Ferrazzoli, Riccardo, Forman, William, Kaaret, Philip, Kim, Dawoon E., Kolodziejczak, Jeffery J., Kraft, Ralph, Marin, Frédéric, Matt, Giorgio, Negro, Michela, Romani, Roger W., Silvestri, Stefano, Soffitta, Paolo, Sunyaev, Rashid, Svoboda, Jiri, Vikhlinin, Alexey, Weisskopf, Martin C., Xie, Fei, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Lalla, Niccolò, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, García, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Zane, Silvia

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the discovery of X-ray polarization from the X-ray-bright filament. G0.13-0.11 in the Galactic center (GC) region. This filament features a bright, hard X-ray source that is most plausibly a pulsar wind nebula (PWN) and an extended and structured diffuse component. Combining the polarization signal from IXPE with the imaging/spectroscopic data from Chandra, we find that X-ray emission of G0.13-0.11 is highly polarized PD=$57(\pm18)$% in the 3-6 keV band, while the polarization angle is PA=$21^\circ(\pm9^\circ)$. This high degree of polarization proves the synchrotron origin of the X-ray emission from G0.13-0.11. In turn, the measured polarization angle implies that the X-ray emission is polarized approximately perpendicular to a sequence of nonthermal radio filaments that may be part of the GC Radio Arc. The magnetic field on the order of $100\,{\rm\mu G}$ appears to be preferentially ordered along the filaments. The above field strength is the fiducial value that makes our model self-consistent, while the other conclusions are largely model independent., Comment: Accepted for publication in A&A

Published
2023
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50. Role of shape in particle-lipid membrane interactions: from surfing to full engulfment

Author

van der Ham, Stijn, Agudo-Canalejo, Jaime, and Vutukuri, Hanumantha Rao

Subjects
Condensed Matter - Soft Condensed Matter, Physics - Biological Physics
Abstract

Understanding and manipulating the interactions between foreign bodies and cell membranes during endo- and phagocytosis is of paramount importance, not only for the fate of living cells but also for numerous biomedical applications. This study aims to elucidate the role of variables such as anisotropic particle shape, curvature, orientation, membrane tension, and adhesive strength in this essential process, using a minimal experimental biomimetic system comprising giant unilamellar vesicles and rod-like particles with different curvatures and aspect ratios. We find that the particle wrapping process is dictated by the balance between the elastic energy penalty and adhesion energy gain, leading to two distinct engulfment pathways, tip-first and side-first, emphasizing the significance of the particle orientation in determining the pathway. Moreover, our experimental results are consistent with theoretical predictions in a state diagram, showcasing how to control the wrapping pathway from surfing to partial to complete wrapping by the interplay between membrane tension and adhesive strength. At moderate particle concentrations, we observed the formation of rod clusters, which exhibited cooperative and sequential wrapping. Our study not only contributes to a comprehensive understanding of the mechanistic intricacies of endocytosis by highlighting how the interplay between the anisotropic particle shape, curvature, orientation, membrane tension, and adhesive strength can influence the engulfment pathway but also provides a foundational base for future research in the field.

Published
2023

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