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1. Sizing Procedure of Reactive Electric Spring

Author

Giuseppe Buja, Simone Castellan, and Qingsong Wang

Subjects
User voltage stabilization, Reactive Electric Spring (RES), RES sizing, HIL experimentation, Electronics, TK7800-8360, Industrial engineering. Management engineering, T55.4-60.8
Abstract

Reactive electric spring (RES) is a technique aimed at stabilizing the user voltage in presence of grid voltage variations by means of a user-encapsulated circuit. In spite of the numerous papers on the matter, no expressions are still available to size the RES elements. This paper fills this lack, by drawing up a sizing procedure of them. The procedure starts with a targeted investigation of the RES operation and exploits the outcomes to provide expressions for the values of the passive elements as well as for the voltage-current ratings of the voltage source inverter (VSI). The sizing expressions are formulated in normalized form to emphasize their dependence on the parameters of the user non-critical load. Focus of the sizing procedure is on the two RES key-elements, namely the AC-side capacitor and VSI but the AC filter inductor and the DC-side capacitor are also sized. Two options for sizing the AC-side capacitor are also discussed. At last, the study case of a user supplied by a low-voltage distribution line is considered and the sizing expressions are utilized to calculate the RES data. Experimental results, obtained by an on-purpose arranged hardware-in-the-loop (HIL) rig, validate the sizing procedure.

Published
2022
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2. Design, Prototyping and Testing of a Rotating Electrical Machine With Linear Geometry for Shipboard Applications

Author

Mario Mezzarobba, Alberto Tessarolo, Nicola Barbini, Simone Castellan, Barbara Codan, Martina Terconi, Claudio Bruzzese, and Augusto Fusari

Subjects
Direct-drive actuators, electromagnetic design, finite element analysis, linear electric machines, permanent-magnet machines, ship propulsion, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

Conventional rotating electrical machines are characterized by stator and rotor structures featuring a cylindrical geometry around the shaft rotational axis. Although advantageous for mechanical reasons, the cylindrical geometry results in overall machine shapes and dimensions that may be unsuitable for installation. This particularly occurs in shipboard applications, where electric motors and generators are subject to stringent room constraints and need to be fit in unusually shaped compartments. This paper presents the development and test of a dual-shaft rotating permanent-magnet electric machine prototype having a linear structure that facilitates its onboard use for such applications as electric propulsion and rudder actuation. In fact, the proposed machine topology has overall dimensions which can be adjusted to fit the space available for installation. The operating concept and the detailed electromechanical design of the machine are first described. Then the manufacturing and factory test of the prototype under inverter supply are illustrated. Finally, the validation of the prototype as a boat propulsion variable-speed inverter-fed motor is presented. It is proved that, despite of its highly non-conventional electromechanical design, the machine can be effectively fed from a general-purpose inverter for permanent magnet motors.

Published
2020
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4. Possible Tests of Fundamental Physics with GINGER

Author

Giuseppe Di Somma, Carlo Altucci, Francesco Bajardi, Andrea Basti, Nicolò Beverini, Salvatore Capozziello, Giorgio Carelli, Simone Castellano, Donatella Ciampini, Gaetano De Luca, Angela D. V. Di Virgilio, Francesco Fuso, Francesco Giovinetti, Enrico Maccioni, Paolo Marsili, Antonello Ortolan, Alberto Porzio, Matteo Luca Ruggiero, and Raffaele Velotta

Subjects
ring laser gyroscope, Sagnac effect, modified theories of gravity, weak field limit, experimental gravity, Astronomy, QB1-991
Abstract

The GINGER (gyroscopes in general relativity) project foresees the construction of an array of large frame ring laser gyroscopes, rigidly connected to the Earth. Large frame ring laser gyroscopes are high-sensitivity instruments used to measure angular velocity with respect to the local inertial frame. In particular, they can provide sub-daily variations in the Earth rotation rate, a measurement relevant for geodesy and for fundamental physics at the same time. Sensitivity is the key point in determining the relevance of this instrument for fundamental science. The most recent progress in sensitivity evaluation, obtained on a ring laser prototype, indicates that GINGER should reach the level of 1 part in 1011 of the Earth’s rotation rate. The impact on fundamental physics of this kind of apparatus is reviewed.

Published
2024
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6. Design, prototyping and testing of a rotating electrical machine with linear geometry for shipboard applications

Author

Alberto Tessarolo, Barbara Codan, Claudio Bruzzese, Nicola Barbini, Simone Castellan, Augusto Fusari, Mario Mezzarobba, Martina Terconi, Mezzarobba, M., Tessarolo, A., Barbini, N., Castellan, S., Codan, B., Terconi, M., Bruzzese, C., and Fusari, A.

Subjects
Electric motor, variable-speed drives, 0209 industrial biotechnology, business.product_category, direct-drive actuators, General Computer Science, Stator, Computer science, electromagnetic design, finite element analysis, linear electric machines, permanent-magnet machines, ship propulsion, shipboard applications, Mechanical engineering, 02 engineering and technology, Propulsion, Direct-drive actuator, permanent-magnet machine, law.invention, 020901 industrial engineering & automation, law, 0202 electrical engineering, electronic engineering, information engineering, General Materials Science, Electric machine, Rotor (electric), 020208 electrical & electronic engineering, General Engineering, Rudder, finite element analysi, Electrically powered spacecraft propulsion, Magnet, shipboard application, Inverter, lcsh:Electrical engineering. Electronics. Nuclear engineering, linear electric machine, business, lcsh:TK1-9971
Abstract

Conventional rotating electrical machines are characterized by stator and rotor structures featuring a cylindrical geometry around the shaft rotational axis. Although advantageous for mechanical reasons, the cylindrical geometry results in overall machine shapes and dimensions that may be unsuitable for installation. This particularly occurs in shipboard applications, where electric motors and generators are subject to stringent room constraints and need to be fit in unusually shaped compartments. This paper presents the development and test of a dual-shaft rotating permanent-magnet electric machine prototype having a linear structure that facilitates its onboard use for such applications as electric propulsion and rudder actuation. In fact, the proposed machine topology has overall dimensions which can be adjusted to fit the space available for installation. The operating concept and the detailed electromechanical design of the machine are first described. Then the manufacturing and factory test of the prototype under inverter supply are illustrated. Finally, the validation of the prototype as a boat propulsion variable-speed inverter-fed motor is presented. It is proved that, despite of its highly non-conventional electromechanical design, the machine can be effectively fed from a general-purpose inverter for permanent magnet motors.

Published
2020

7. Design and simulation of a vehicle-To-grid system

Author

Giuseppe Buja, Mario Mezzarobba, Alessandro Massi Pavan, Nicola Blasuttigh, Simone Castellan, Roberto Menis, S. Castellan, N. Blasuttigh, R. Menis, A. M. Pavan, M. Mezzarobba, G. Buja, Castellan, S., Blasuttigh, N., Menis, R., Massi, Pavan, Mezzarobba, M., and Buja, G.

Subjects
vehicle-To-grid, ancillary service, three phase dual active bridge, business.industry, Computer science, 020209 energy, Voltage control, 020208 electrical & electronic engineering, Electrical engineering, Vehicle-to-grid, 02 engineering and technology, batteries of electric vehicles, Converters, Grid, ancillary services, Power (physics), Control system, 0202 electrical engineering, electronic engineering, information engineering, Bandwidth (computing), smart grids, business, smart grid, batteries of electric vehicle
Abstract

Batteries of electric vehicles have to be charged by power electronic converters connected to the electric grid. If these power converters are bidirectional they can be exploited to act in support to the grid operation, thus realizing the so called vehicle-to-grid (V2G) systems. At the University of Trieste an experimental V2G apparatus is under construction. Its control system has been developed and the first simulation tests has been performed. The paper describes the V2G experimental apparatus with its control system and reports the results of the preliminary simulation tests.

Published
2020

8. GINGERINO: a high sensitivity ring laser gyroscope for fundamental and quantum physics investigation

Author

Francesco Giovinetti, Carlo Altucci, Francesco Bajardi, Andrea Basti, Nicolò Beverini, Salvatore Capozziello, Giorgio Carelli, Simone Castellano, Donatella Ciampini, Giuseppe Di Somma, Angela D. V. Di Virgilio, Francesco Fuso, Gaetano Lambiase, Enrico Maccioni, Paolo Marsili, Antonello Ortolan, Alberto Porzio, and Raffaele Velotta

Subjects
quantum optic, general relativity (GR), sagnac beat frequency, sagnac and fabry-pérot interferometers, quantum noise (QN), Technology
Abstract

Ring Laser Gyroscopes, based on the Sagnac effect, are currently the most sensitive rotation sensors. GINGERINO, a RLG installed underground, shows a proved sensitivity that enters the few frad/s regime in about 2.5 days of integration time. On one hand, this sensitivity is well below the shot–noise–level as predicted applying to GINGERINO the so called independent beam model. On the other hand, it paves the way to the use of RLG in fundamental and quantum physics research. Indeed, high sensitivity rotation measurement opens to test general relativity and alternative theory of gravity. Moreover, it make possible to study the interplay between quantum effects in the optical domain and non-inertial reference frames.

Published
2024
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9. An IXPE-led X-Ray Spectropolarimetric Campaign on the Soft State of Cygnus X-1: X-Ray Polarimetric Evidence for Strong Gravitational Lensing

Author

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

Subjects
Accretion, Polarimetry, X-ray astronomy, Stellar mass black holes, Astrophysics, QB460-466
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 the Imaging X-ray Polarimetry Explorer’s (IXPE) 2–8 keV bandpass. The polarized X-rays exhibit an energy-independent polarization angle of PA = −25.°7 ± 1.°8 east of north (68% confidence). This is consistent with being aligned to Cyg X-1’s au-scale compact radio jet and its parsec-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 trend line in the polarization degree between the soft and hard states. Our favored polarimetric model indicates that Cyg X-1’s spin is likely high ( a _* ≳ 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.

Published
2024
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10. Highly Significant Detection of X-Ray Polarization from the Brightest Accreting Neutron Star Sco X-1

Author

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

Subjects
Polarimetry, Spectropolarimetry, Neutron stars, Accretion, Stellar accretion disks, Low-mass x-ray binary stars, Astrophysics, QB460-466
Abstract

The Imaging X-ray Polarimetry Explorer measured with high significance the X-ray polarization of the brightest Z-source, Sco X-1, resulting in the nominal 2–8 keV energy band in a polarization degree of 1.0% ± 0.2% and a polarization angle of 8° ± 6° at a 90% confidence level. This observation was strictly simultaneous with observations performed by NICER, NuSTAR, and Insight-HXMT, which allowed for a precise characterization of its broadband spectrum from soft to hard X-rays. The source has been observed mainly in its soft state, with short periods of flaring. We also observed low-frequency quasiperiodic oscillations. From a spectropolarimetric analysis, we associate a polarization to the accretion disk at

Published
2024
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11. Discovery of a Shock-compressed Magnetic Field in the Northwestern Rim of the Young Supernova Remnant RX J1713.7–3946 with X-Ray Polarimetry

Author

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

Subjects
X-ray astronomy, Polarimetry, Supernova remnants, Astrophysics, QB460-466
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 the 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 synchrotron emission is 12.5% ± 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 subparsec scales, localized patches within RX J1713.7–3946 display a PD of up to 41.5% ± 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 magnetohydrodynamical instabilities can be invoked. From comparison of PD and magnetic field distribution with γ -rays and ^12 CO data, our results provide new inputs in favor of a leptonic origin of the γ -ray emission.

Published
2024
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12. X-Ray Polarization of the Eastern Lobe of SS 433

Author

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

Subjects
High mass x-ray binary stars, Jets, High energy astrophysics, Supernova remnants, Astrophysical black holes, Astrophysics, QB460-466
Abstract

How astrophysical systems translate the kinetic energy of bulk motion into the acceleration of particles to very high energies is a pressing question. SS 433 is a microquasar that emits TeV γ -rays indicating the presence of high-energy particles. A region of hard X-ray emission in the eastern lobe of SS 433 was recently identified as an acceleration site. We observed this region with the Imaging X-ray Polarimetry Explorer and measured a polarization degree in the range 38%–77%. The high polarization degree indicates the magnetic field has a well-ordered component if the X-rays are due to synchrotron emission. The polarization angle is in the range −12° to +10° (east of north), which indicates that the magnetic field is parallel to the jet. Magnetic fields parallel to the bulk flow have also been found in supernova remnants and the jets of powerful radio galaxies. This may be caused by interaction of the flow with the ambient medium.

Published
2024
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13. X-Ray Polarized View of the Accretion Geometry in the X-Ray Binary Circinus X-1

Author

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

Subjects
X-ray binary stars, Polarimetry, X-ray astronomy, X-ray sources, Astrophysics, QB460-466
Abstract

Cir X-1 is a neutron star X-ray binary characterized by strong variations in flux during its eccentric ∼16.6 day orbit. There are also strong variations in the spectral state, and it has historically shown both atoll and Z state properties. We observed the source with the Imaging X-ray Polarimetry Explorer during two orbital segments, 6 days apart, for a total of 263 ks. We find an X-ray polarization degree in these segments of 1.6% ± 0.3% and 1.4% ± 0.3% at polarization angles of 37° ± 5° and −12° ± 7°, respectively. Thus, we observed a rotation of the polarization angle by 49° ± 8° along the orbit. Because variations of accretion flow, and then of the hardness ratio, are expected during the orbit, we also studied the polarization binned in hardness ratio and found the polarization angle differing by 67° ± 11° between the lowest and highest values of the hardness ratio. We discuss possible interpretations of this result that could indicate a possible misalignment between the symmetry axes of the accretion disk and the Comptonizing region caused by the misalignment of the neutron star’s angular momentum with respect to the orbital one.

Published
2024
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14. Single-phase power line conditioning with unity power factor under distorted utility voltage

Author

Roberto Menis, Simone Castellan, Giuseppe Buja, Castellan, S., Buja, G., and Menis, R.

Subjects
Voltage distortion, Single-phase grid, Computer science, Active power line conditioner, 020209 energy, 020208 electrical & electronic engineering, Energy Engineering and Power Technology, 02 engineering and technology, Power factor, Single-phase electric power, Active power line conditioners, Unity power factor, Signal, Line (electrical engineering), Reduction (complexity), Control theory, Integrator, Distortion, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Voltage
Abstract

The paper proposes a control method of a single-phase active power line conditioner (APLC) aimed at correcting the power factor of linear and non-linear loads supplied by distorted voltage utility. The method, that is based on the single-phase p-q theory and utilizes a third-order sinusoidal signal integrator, gets utility unity power factor and, at the same time, overcomes the shortcomings of the solutions pursuing utility sinusoidal current, namely the possible onset of un-damped resonance phenomena and the reduction in the energy delivery capabilities; moreover, the method makes the power factor correction robust against the supply distortion. The excellent performance of the method is substantiated by testing it by means of a hardware-in-the-loop setup.

Published
2020

15. A Novel Thyristor-Based CSI Topology With Multilevel Current Waveform for Improved Drive Performance

Author

Abbas Shoulaie, Alberto Tessarolo, M. H. Khanzade, Sobhan Mohamadian, Simone Castellan, Mohamadian, S., Castellan, S., Tessarolo, A., Khanzade, M. H., and Shoulaie, A.

Subjects
Engineering, Current harmonics, five-level current source, forced commutation, load-commutated inverter (LCI)-fed drive, power factor improvement, start up, torque pulsations, Electrical and Electronic Engineering, 020209 energy, Topology (electrical circuits), 02 engineering and technology, Power factor, torque pulsation, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Current harmonic, Torque, Waveform, business.industry, 020208 electrical & electronic engineering, Thyristor, Power (physics), Direct torque control, Harmonics, business
Abstract

Load-commutated inverters (LCIs), combined with wound-field synchronous machines (WFSMs), can be an excellent solution for high power drives, but their present technology suffers from important drawbacks related to low power factor, large torque pulsations, and poor starting performance. This paper presents a new LCI design intended to overcome the mentioned limitations. An SCR-based forced-commutation circuit is added to the common inverter topology to obtain a five-level waveform for the stator current. This leads to significantly reduced current harmonics and torque pulsations, in addition to bringing benefits in terms of lower additional losses. As a further advantage, the proposed design allows for a significant power factor enhancement. Finally, it enables the WFSM to be started with a much smoother torque compared to the traditional pulsed operating mode of conventional LCI drives. Simulation studies are conducted on a high-power drive scheme to show the aforementioned improvements. Also, a reduced-scale laboratory prototype of a WFSM drive system is tested to verify the feasibility of the proposed converter.

Published
2018

16. A review of power electronics equipment for all-electric ship MVDC power systems

Author

Simone Castellan, Alberto Tessarolo, F. Luise, Roberto Menis, Teresa Mazzuca, Castellan, S., Menis, R., Tessarolo, A., Luise, F., and Mazzuca, T.

Subjects
Engineering, 020209 energy, Electric generator, Energy Engineering and Power Technology, 02 engineering and technology, Energy storage, Medium Voltage DC (MVDC), law.invention, Solid State Transformer (SST), Electric power system, law, Power electronics, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Transformer, DC generator system, DC circuit breaker, DC distribution, business.industry, 020208 electrical & electronic engineering, Electrical engineering, Converters, Power engineering, business, Voltage
Abstract

Medium Voltage DC (MVDC) distribution Power Systems for all-electric ships (AES) can be regarded as functionally composed of three subsystems, namely the power sources, the load centers and the distribution network. Extensive use of power electronics is required for connecting power sources and load centers to the MVDC bus and for protecting the MVDC power system through properly placed DC circuit breakers. In this paper, an overview is given of the power electronics equipment found in the literature and on the market that could be suitable for use in future AES MVDC power systems. Some industrial experiences regarding DC generator systems, energy storage apparatus and solid-state DC circuit breaker prototypes are reported in the paper as examples of state-of-the-art realizations. Different DC/DC converters, which can be employed as solid-state transformers, are also discussed and a structure obtained by combining them is proposed.

Published
2018

17. Observations of Low and Intermediate Spectral Peak Blazars with the Imaging X-Ray Polarimetry Explorer

Author

Herman L. Marshall, Ioannis Liodakis, Alan P. Marscher, Niccolò Di Lalla, Svetlana G. Jorstad, Dawoon E. Kim, Riccardo Middei, Michela Negro, Nicola Omodei, Abel L. Peirson, Matteo Perri, Simonetta Puccetti, Marco Laurenti, Iván Agudo, Giacomo Bonnoli, Andrei V. Berdyugin, Elisabetta Cavazzuti, Nicole Rodriguez Cavero, Immacolata Donnarumma, Laura Di Gesu, Jenni Jormanainen, Henric Krawczynski, Elina Lindfors, Greg Madjeski, Frédéric Marin, Francesco Massaro, Luigi Pacciani, Juri Poutanen, Fabrizio Tavecchio, Pouya M. Kouch, Francisco José Aceituno, Maria I. Bernardos, Víctor Casanova, Maya García-Comas, Beatriz Agís-González, César Husillos, Alessandro Marchini, Alfredo Sota, Dmitry Blinov, Ioakeim G. Bourbah, Sebastian Kielhmann, Evangelos Kontopodis, Nikos Mandarakas, Stylianos Romanopoulos, Raphael Skalidis, Anna Vervelaki, George A. Borman, Evgenia N. Kopatskaya, Elena G. Larionova, Daria A. Morozova, Sergey S. Savchenko, Andrey A. Vasilyev, Alexey V. Zhovtan, Carolina Casadio, Juan Escudero, Joana Kramer, Ioannis Myserlis, Efthalia Trainou, Ryo Imazawa, Mahito Sasada, Yasushi Fukazawa, Koji S. Kawabata, Makoto Uemura, Tsunefumi Mizuno, Tatsuya Nakaoka, Hiroshi Akitaya, Joseph R. Masiero, Dimitri Mawet, Georgia V. Panopoulou, Samaporn Tinyanont, Masato Kagitani, Vadim Kravtsov, Takeshi Sakanoi, Matthew Dattolo, Mark Gurwell, Garrett Keating, Ramprasad Rao, Whee Yeon Cheong, Hyeon-Woo Jeong, Sincheol Kang, Sang-Hyun Kim, Sang-Sung Lee, Emmanouil Angelakis, Alexander Kraus, Antonio Hales, Seiji Kameno, Ruediger Kneissl, Hugo Messias, Hiroshi Nagai, Lucio A. Antonelli, Matteo Bachetti, Luca Baldini, Wayne H. Baumgartner, Ronaldo Bellazzini, Stefano Bianchi, Stephen D. Bongiorno, Raffaella Bonino, Alessandro Brez, Niccolò Bucciantini, Fiamma Capitanio, Simone Castellano, Chen-Ting Chen, Stefano Ciprini, Enrico Costa, Alessandra De Rosa, Ettore Del Monte, Alessandro Di Marco, Victor Doroshenko, Michal Dovčiak, Steven R. Ehlert, Teruaki Enoto, Yuri Evangelista, Sergio Fabiani, Riccardo Ferrazzoli, Javier A. Garcia, Shuichi Gunji, Kiyoshi Hayashida, Jeremy Heyl, Wataru Iwakiri, Philip Kaaret, Vladimir Karas, Fabian Kislat, Takao Kitaguchi, Jeffery J. Kolodziejczak, Fabio La Monaca, Luca Latronico, Simone Maldera, Alberto Manfreda, Andrea Marinucci, Giorgio Matt, Ikuyuki Mitsuishi, Fabio Muleri, C.-Y. Ng, Stephen L. O’Dell, Chiara Oppedisano, Alessandro Papitto, George G. Pavlov, Melissa Pesce-Rollins, Pierre-Olivier Petrucci, Maura Pilia, Andrea Possenti, Brian D. Ramsey, John Rankin, Ajay Ratheesh, Oliver J. Roberts, Roger W. Romani, Carmelo Sgrò, Patrick Slane, Paolo Soffitta, Gloria Spandre, Douglas A. Swartz, Toru Tamagawa, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicholas E. Thomas, Francesco Tombesi, Alessio Trois, Sergey S. Tsygankov, Roberto Turolla, Jacco Vink, Martin C. Weisskopf, Kinwah Wu, Fei Xie, and Silvia Zane

Subjects
X-ray astronomy, Polarimetry, Spectropolarimetry, Radio loud quasars, X-ray quasars, Blazars, Astrophysics, QB460-466
Abstract

We present X-ray polarimetry observations from the Imaging X-ray Polarimetry Explorer (IXPE) of three low spectral peak and one intermediate spectral peak blazars, namely 3C 273, 3C 279, 3C 454.3, and S5 0716+714. For none of these objects was IXPE able to detect X-ray polarization at the 3 σ level. However, we placed upper limits on the polarization degree at ∼10%–30%. The undetected polarizations favor models where the X-ray band is dominated by unpolarized photons upscattered by relativistic electrons in the jets of blazars, although hadronic models are not completely eliminated. We discuss the X-ray polarization upper limits in the context of our contemporaneous multiwavelength polarization campaigns.

Published
2024
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18. Tracking the X-Ray Polarization of the Black Hole Transient Swift J1727.8–1613 during a State Transition

Author

Adam Ingram, Niek Bollemeijer, Alexandra Veledina, Michal Dovčiak, Juri Poutanen, Elise Egron, Thomas D. Russell, Sergei A. Trushkin, Michela Negro, Ajay Ratheesh, Fiamma Capitanio, Riley Connors, Joseph Neilsen, Alexander Kraus, Maria Noemi Iacolina, Alberto Pellizzoni, Maura Pilia, Francesco Carotenuto, Giorgio Matt, Guglielmo Mastroserio, Philip Kaaret, Stefano Bianchi, Javier A. García, Matteo Bachetti, Kinwah Wu, Enrico Costa, Melissa Ewing, Vadim Kravtsov, Henric Krawczynski, Vladislav Loktev, Andrea Marinucci, Lorenzo Marra, Romana Mikušincová, Edward Nathan, Maxime Parra, Pierre-Olivier Petrucci, Simona Righini, Paolo Soffitta, James F. Steiner, Jiří Svoboda, Francesco Tombesi, Stefano Tugliani, Francesco Ursini, Yi-Jung Yang, Silvia Zane, Wenda Zhang, Iván Agudo, Lucio A. Antonelli, Luca Baldini, Wayne H. Baumgartner, Ronaldo Bellazzini, Stephen D. Bongiorno, Raffaella Bonino, Alessandro Brez, Niccolò Bucciantini, Simone Castellano, Elisabetta Cavazzuti, Chien-Ting Chen, Stefano Ciprini, Alessandra De Rosa, Ettore Del Monte, Laura Di Gesu, Niccolò Di Lalla, Alessandro Di Marco, Immacolata Donnarumma, Victor Doroshenko, Steven R. Ehlert, Teruaki Enoto, Yuri Evangelista, Sergio Fabiani, Riccardo Ferrazzoli, Shuichi Gunji, Kiyoshi Hayashida, Jeremy Heyl, Wataru Iwakiri, Svetlana G. Jorstad, Vladimir Karas, Fabian Kislat, Takao Kitaguchi, Jeffery J. Kolodziejczak, Fabio La Monaca, Luca Latronico, Ioannis Liodakis, Simone Maldera, Alberto Manfreda, Frédéric Marin, Alan P. Marscher, Herman L. Marshall, Francesco Massaro, Ikuyuki Mitsuishi, Tsunefumi Mizuno, Fabio Muleri, Chi-Yung Ng, Stephen L. O’Dell, Nicola Omodei, Chiara Oppedisano, Alessandro Papitto, George G. Pavlov, Abel L. Peirson, Matteo Perri, Melissa Pesce-Rollins, Andrea Possenti, Simonetta Puccetti, Brian D. Ramsey, John Rankin, Oliver J. Roberts, Roger W. Romani, Carmelo Sgrò, Patrick Slane, Gloria Spandre, Douglas A. Swartz, Toru Tamagawa, Fabrizio Tavecchio, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicholas E. Thomas, Alessio Trois, Sergey S. Tsygankov, Roberto Turolla, Jacco Vink, Martin C. Weisskopf, Fei Xie, and IXPE Collaboration

Subjects
Accretion, X-ray astronomy, Low-mass x-ray binary stars, Polarimetry, Astrophysical black holes, Astrophysics, QB460-466
Abstract

We report on an observational campaign on the bright black hole (BH) X-ray binary Swift J1727.8–1613 centered around five observations by the Imaging X-ray Polarimetry Explorer. These observations track for the first time the evolution of the X-ray polarization of a BH X-ray binary across a hard to soft state transition. The 2–8 keV polarization degree decreased from ∼4% to ∼3% across the five observations, but the polarization angle remained oriented in the north–south direction throughout. Based on observations with the Australia Telescope Compact Array, we find that the intrinsic 7.25 GHz radio polarization aligns with the X-ray polarization. Assuming the radio polarization aligns with the jet direction (which can be tested in the future with higher-spatial-resolution images of the jet), our results imply that the X-ray corona is extended in the disk plane, rather than along the jet axis, for the entire hard intermediate state. This in turn implies that the long (≳10 ms) soft lags that we measure with the Neutron star Interior Composition ExploreR are dominated by processes other than pure light-crossing delays. Moreover, we find that the evolution of the soft lag amplitude with spectral state does not follow the trend seen for other sources, implying that Swift J1727.8–1613 is a member of a hitherto undersampled subpopulation.

Published
2024
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19. X-Ray Polarization of the Black Hole X-Ray Binary 4U 1630–47 Challenges the Standard Thin Accretion Disk Scenario

Author

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

Subjects
Polarimetry, X-ray astronomy, Stellar mass black holes, Accretion, Astrophysics, QB460-466
Abstract

A large energy-dependent X-ray polarization degree is detected by the Imaging X-ray Polarimetry Explorer (IXPE) in the high-soft emission state of the black hole X-ray binary 4U 1630–47. The highly significant detection (at ≈50 σ confidence level) of an unexpectedly high polarization, rising from ∼6% at 2 keV to ∼10% at 8 keV, cannot be easily reconciled with standard models of thin accretion disks. In this work, we compare the predictions of different theoretical models with the IXPE data and conclude that the observed polarization properties are compatible with a scenario in which matter accretes onto the black hole through a thin disk covered by a partially ionized atmosphere flowing away at mildly relativistic velocities.

Published
2024
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20. X-Ray Polarimetry of the Dipping Accreting Neutron Star 4U 1624–49

Author

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

Subjects
X-ray binary stars, Neutron stars, X-ray astronomy, Polarimetry, Astrophysics, QB460-466
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. We report a detection of polarization in the nondip time intervals with a confidence level of 99.99%. We find an average polarization degree (PD) of 3.1% ± 0.7% and a polarization angle of 81° ± 6° 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% ± 0.9% in the 4–6 keV band to 6% ± 2% 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
2024
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21. Detection of X-Ray Polarization from the Blazar 1ES 1959+650 with the Imaging X-Ray Polarimetry Explorer

Author

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

Subjects
Relativistic jets, X-ray active galactic nuclei, Active galactic nuclei, Blazars, Polarimetry, Spectropolarimetry, Astrophysics, QB460-466
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 nonthermal 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 on 2022 May 3–4 showed a significant linear polarization degree of Π _x = 8.0% ± 2.3% at an electric-vector position angle ψ _x = 123° ± 8°. However, on 2022 June 9–12, only an upper limit of Π _x ≤ 5.1% could be derived (at the 99% confidence level). The degree of optical polarization at that time, Π _O ∼ 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.

Published
2024
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22. First Detection of Polarization in X-Rays for PSR B0540-69 and Its Nebula

Author

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

Subjects
Pulsars, Pulsar wind nebulae, Polarimetry, Astrophysics, QB460-466
Abstract

We report on X-ray polarization measurements of the extragalactic Crab-like PSR B0540-69 and its Pulsar Wind Nebula (PWN) in the Large Magellanic Cloud, 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 (MDP _99 ) of 5.3% in the 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 ± 5.3)% and polarization angle (PA) of (78.1 ± 6.2)° is detected at 4.6 σ 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 σ with PD of (50.0 ± 13.1)% and PA of (6.2 ± 7.4)°. A “simultaneous” PSR/PWN analysis finds two bins at the edges of the pulse exceeding 3 σ PD significance, with PD of (68 ± 20)% and (62 ± 20)%; intervening bins at 2–3 σ significance have lower PD, hinting at additional polarization structure.

Published
2024
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23. Steady-State Simulation of LCI-Fed Synchronous Motor Drives Through a Computationally Efficient Algebraic Method

Author

Alberto Tessarolo, Sobhan Mohamadian, Simone Castellan, Abbas Shoulaie, Mohamadian, S., Tessarolo, A., Castellan, S., and Shoulaie, A.

Subjects
Engineering, Steady state (electronics), Differential equation, Algebraic model, load-commutated inverter, switching function, torque pulsations, wound-field synchronous motors, 02 engineering and technology, Propulsion, 01 natural sciences, Harmonic analysis, Control theory, Wound-Field synchronous motor, 0103 physical sciences, torque pulsation, 0202 electrical engineering, electronic engineering, information engineering, Torque, Wound-Field synchronous motors, Electrical and Electronic Engineering, MATLAB, computer.programming_language, 010302 applied physics, business.industry, 020208 electrical & electronic engineering, Control engineering, Dynamic simulation, business, Synchronous motor, computer
Abstract

Wound-field synchronous motors (WFSMs) fed by load-commutated inverters (LCIs) are widely used for high-power applications in many fields like ship propulsion, oil and gas industry, and pumped-storage hydropower generation. Several design architectures exist for LCI drives, depending on the number of LCIs and their dc-link connection as well as on the number of WFSM phase count. The prediction of LCI drive performance at steady state is important in the design stage, especially in regard to the prediction of the torque pulsations, which can give rise to serious mechanical resonance issues. This paper proposes an algebraic method to simulate the steady-state behavior of LCI drives in all their configurations of practical interest. Compared to conventional dynamic simulation approaches based on differential equation solution, the method is much more computationally efficient and requires a very limited knowledge of system parameters. Its accuracy is experimentally assessed by comparison against measurements taken on a real LCI drive arranged according to various possible schemes. Furthermore, the advantages of the proposed algebraic method over the dynamic simulations are highlighted by comparison against the simulation results on a high-power LCI-fed WFSM drive in MATLAB/Simulink environment.

Published
2017

24. Effective reactive power compensation in single-phase systems under distorted utility voltage

Author

Roberto Menis, Simone Castellan, Giuseppe Buja, Luca Zarri, Castellan, Simone, Buja, Giuseppe, and Menis, Roberto

Subjects
Engineering, business.industry, Integrated circuit, Power factor, Unity Power Factor, AC power, Active Power Line Conditioner, Single-phase System, Utility Voltage Distortion, Compensation (engineering), Power (physics), law.invention, Harmonic analysis, law, Line (geometry), Electronic engineering, business, Voltage
Abstract

The paper deals with the reactive power compensation in single-phase systems by active power line conditioners (APLCs), focusing on the effectiveness of the compensating action when the utility voltage is distorted. The existing compensation approach, based on the achievement of a sinusoidal load current, is first presented, showing that it suffers from some shortcomings. A novel compensation approach, based on the achievement of a unity power factor, is then proposed that has the merit of overcoming the shortcomings of the existing one and, in addition, of outperforming it in terms of power delivery capabilities of the utility. Effectiveness of the proposed compensation approach is corroborated by simulation results.

Published
2017

25. An Algebraic Algorithm for Motor Voltage Waveform Prediction in Dual-LCI Drives With Interconnected DC-Links

Author

Abbas Shoulaie, Sobhan Mohamadian, Simone Castellan, Alberto Tessarolo, Giancarlo Ferrari, Mohamadian, S., Castellan, S., Tessarolo, A., Ferrari, G., and Shoulaie, A.

Subjects
Integrated circuit interconnections, Engineering, motor winding insulation, Stre, 020209 energy, Reliability (computer networking), load-commutated inverter, Commutation, Energy Engineering and Power Technology, load-commutated inverters, Synchronous motors, 02 engineering and technology, Integrated circuit interconnection, Prediction algorithm, Electrical and Electronic Engineering, Insulation, Prediction algorithms, Stress, Windings, DC-link interconnection, split-phase motors, Control theory, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Waveform, Interconnection, business.industry, 020208 electrical & electronic engineering, Winding, Sizing, Electromagnetic coil, Synchronous motor, business, Voltage
Abstract

Load-commutated inverters (LCI's) are often used to supply dual-three-phase synchronous motors in high-power variable-speed applications. A pair of LCIs is used in this arrangement to feed the two motor three-phase winding sets. In order to cope with inter-harmonic issues, a drive configuration with an interconnection of the two LCI dc-links has been proposed. In this paper, such a drive design is shown to produce an increased voltage stress on motor windings compared with traditional configurations. The problem is investigated in the paper by proposing an algebraic algorithm capable of predicting the steady-state voltage waveform applied to the motor terminals and arising between the star points of the two winding sets. Unlike conventional dynamic simulations, the proposed approach gives practically instantaneous results, making it possible to quickly investigate a wide number of possible operating conditions. Furthermore, it requires a limited knowledge of system parameters, which are often hardly available. Its reliability and accuracy are assessed by comparison with measurements on a test drive system and examples are given of the method application to the sizing of motor insulation system.

Published
2016

26. On the Modeling of Commutation Transients in Split-Phase Synchronous Motors Supplied by Multiple Load-Commutated Inverters

Author

Roberto Menis, Alberto Tessarolo, Simone Castellan, G. Ferrari, Tessarolo, Alberto, Castellan, Simone, Menis, Roberto, and Ferrari, G.

Subjects
thyristor motor drives, Rotor (electric), Computer science, Split-phase electric power, AC motor, Inductive coupling, law.invention, Quantitative Biology::Subcellular Processes, Inductance, Control and Systems Engineering, Control theory, law, Electromagnetic coil, Inverter, Transient (oscillation), Commutation, Electrical and Electronic Engineering, Synchronous motor, Electronic circuit, Voltage
Abstract

Split-phase synchronous motors equipped with multiple-stator three-phase windings, each supplied by a load-commutated inverter, play an important role in today's very high power electrical-drive applications. A criticality of these systems is the possibility that commutations occur in different motor windings simultaneously. The resulting electromagnetic transient depends on the magnetic coupling of motor phases among them and with rotor circuits. In this paper, a model to describe this phenomenon is presented along with some dedicated tests, conducted on various split-phase configurations, to assess the model validity.

Published
2010

27. A Flicker Compensation Strategy

Author

Giuseppe Buja, Simone Castellan, Buja, G, and Castellan, Simone

Subjects
Engineering, business.industry, Flicker, Active compensator, DC-BUS, law.invention, Power (physics), Electric power system, Capacitor, Power system simulation, law, Control theory, Electrical network, Electronic engineering, Electrical and Electronic Engineering, business, Voltage
Abstract

This letter is concerned with the strategy adopted by an active compensator to mitigate the flicker phenomenon in a power system. After illustrating two conventional strategies, a novel strategy that forces the compensator to deliver a particular value of the instantaneous imaginary power absorbed by the time-variant load is proposed. The strategy is compared with the two conventional ones in terms of magnitude of the voltage fluctuations at the point of common coupling (PCC) and size of the capacitor in the dc bus of the active compensator. Suitable equations and vector diagrams are derived. They show that the novel strategy outweighs the other two by eliminating most of the PCC voltage fluctuations without the need for a large capacitor. The theoretical findings are substantiated by simulation results.

Published
2009

28. Discovery of X-Ray Polarization from the Black Hole Transient Swift J1727.8−1613

Author

Alexandra Veledina, Fabio Muleri, Michal Dovčiak, Juri Poutanen, Ajay Ratheesh, Fiamma Capitanio, Giorgio Matt, Paolo Soffitta, Allyn F. Tennant, Michela Negro, Philip Kaaret, Enrico Costa, Adam Ingram, Jiří Svoboda, Henric Krawczynski, Stefano Bianchi, James F. Steiner, Javier A. García, Vadim Kravtsov, Anagha P. Nitindala, Melissa Ewing, Guglielmo Mastroserio, Andrea Marinucci, Francesco Ursini, Francesco Tombesi, Sergey S. Tsygankov, Yi-Jung Yang, Martin C. Weisskopf, Sergei A. Trushkin, Elise Egron, Maria Noemi Iacolina, Maura Pilia, Lorenzo Marra, Romana Mikušincová, Edward Nathan, Maxime Parra, Pierre-Olivier Petrucci, Jakub Podgorný, Stefano Tugliani, Silvia Zane, Wenda Zhang, Iván Agudo, Lucio A. Antonelli, Matteo Bachetti, Luca Baldini, Wayne H. Baumgartner, Ronaldo Bellazzini, Stephen D. Bongiorno, Raffaella Bonino, Alessandro Brez, Niccolò Bucciantini, Simone Castellano, Elisabetta Cavazzuti, Chien-Ting Chen, Stefano Ciprini, Alessandra De Rosa, Ettore Del Monte, Laura Di Gesu, Niccolò Di Lalla, Alessandro Di Marco, Immacolata Donnarumma, Victor Doroshenko, Steven R. Ehlert, Teruaki Enoto, Yuri Evangelista, Sergio Fabiani, Riccardo Ferrazzoli, Shuichi Gunji, Kiyoshi Hayashida, Jeremy Heyl, Wataru Iwakiri, Svetlana G. Jorstad, Vladimir Karas, Fabian Kislat, Takao Kitaguchi, Jeffery J. Kolodziejczak, Fabio La Monaca, Luca Latronico, Ioannis Liodakis, Simone Maldera, Alberto Manfreda, Frédéric Marin, Alan P. Marscher, Herman L. Marshall, Francesco Massaro, Ikuyuki Mitsuishi, Tsunefumi Mizuno, Chi-Yung Ng, Stephen L. O’Dell, Nicola Omodei, Chiara Oppedisano, Alessandro Papitto, George G. Pavlov, Abel L. Peirson, Matteo Perri, Melissa Pesce-Rollins, Andrea Possenti, Simonetta Puccetti, Brian D. Ramsey, John Rankin, Oliver J. Roberts, Roger W. Romani, Carmelo Sgrò, Patrick Slane, Gloria Spandre, Douglas A. Swartz, Toru Tamagawa, Fabrizio Tavecchio, Roberto Taverna, Yuzuru Tawara, Nicholas E. Thomas, Alessio Trois, Roberto Turolla, Jacco Vink, Kinwah Wu, and Fei Xie

Subjects
Accretion, X-ray astronomy, Low-mass x-ray binary stars, Polarimetry, Astrophysical black holes, Astrophysics, QB460-466
Abstract

We report the first detection of the X-ray polarization of the bright transient Swift J1727.8−1613 with the Imaging X-ray Polarimetry Explorer. The observation was performed at the beginning of the 2023 discovery outburst, when the source resided in the bright hard state. We find a time- and energy-averaged polarization degree of 4.1% ± 0.2% and a polarization angle of 2.°2 ± 1.°3 (errors at 68% confidence level; this translates to ∼20 σ significance of the polarization detection). This finding suggests that the hot corona emitting the bulk of the detected X-rays is elongated, rather than spherical. The X-ray polarization angle is consistent with that found in submillimeter wavelengths. Since the submillimeter polarization was found to be aligned with the jet direction in other X-ray binaries, this indicates that the corona is elongated orthogonal to the jet.

Published
2023
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29. The First X-Ray Polarization Observation of the Black Hole X-Ray Binary 4U 1630–47 in the Steep Power-law State

Author

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

Subjects
X-ray astronomy, Polarimetry, Stellar mass black holes, High energy astrophysics, Astrophysics, QB460-466
Abstract

The Imaging X-ray Polarimetry Explorer (IXPE) observed the black hole X-ray binary 4U 1630–47 in the steep power-law (or very high) state. The observations reveal a linear polarization degree of the 2–8 keV X-rays of 6.8% ± 0.2% at a position angle of 21.°3 ± 0.°9 east of north (all errors at 1 σ confidence level). Whereas the polarization degree increases with energy, the polarization angle stays constant within the accuracy of our measurements. We compare the polarization of the source in the steep power-law state with the previous IXPE measurement of the source in the high soft state. We find that, even though the source flux and spectral shape are significantly different between the high soft state and the steep power-law state, their polarization signatures are similar. Assuming that the polarization of both the thermal and power-law emission components are constant over time, we estimate the power-law component polarization to be 6.8%–7.0% and note that the polarization angle of the thermal and power-law components must be approximately aligned. We discuss the implications for the origin of the power-law component and the properties of the emitting plasma.

Published
2023
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30. IXPE and Multiwavelength Observations of Blazar PG 1553+113 Reveal an Orphan Optical Polarization Swing

Author

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

Subjects
BL Lacertae objects, Spectropolarimetry, Polarimetry, Active galactic nuclei, Jets, X-ray active galactic nuclei, Astrophysics, QB460-466
Abstract

The lower-energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consensus regarding jet emission processes, the particle acceleration mechanism is still debated. Here, we present the first X-ray polarization observations of PG 1553+113, a high-synchrotron-peak blazar observed by the Imaging X-ray Polarimetry Explorer (IXPE). We detect an X-ray polarization degree of (10 ± 2)% along an electric-vector position angle of ψ _X = 86° ± 8°. At the same time, the radio and optical polarization degrees are lower by a factor of ∼3. During our IXPE pointing, we observed the first orphan optical polarization swing of the IXPE era, as the optical angle of PG 1553+113 underwent a smooth monotonic rotation by about 125°, with a rate of ∼17° day ^–1 . We do not find evidence of a similar rotation in either radio or X-rays, which suggests that the X-ray and optically emitting regions are separate or, at most, partially cospatial. Our spectropolarimetric results provide further evidence that the steady-state X-ray emission in blazars originates in a shock-accelerated and energy-stratified electron population.

Published
2023
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31. First Detection of X-Ray Polarization from the Accreting Neutron Star 4U 1820−303

Author

Alessandro Di Marco, Fabio La Monaca, Juri Poutanen, Thomas D. Russell, Alessio Anitra, Ruben Farinelli, Guglielmo Mastroserio, Fabio Muleri, Fei Xie, Matteo Bachetti, Luciano Burderi, Francesco Carotenuto, Melania Del Santo, Tiziana Di Salvo, Michal Dovčiak, Andrea Gnarini, Rosario Iaria, Jari J. E. Kajava, Kuan Liu, Riccardo Middei, Stephen L. O’Dell, Maura Pilia, John Rankin, Andrea Sanna, Jakob van den Eijnden, Martin C. Weisskopf, Anna Bobrikova, Fiamma Capitanio, Enrico Costa, Philip Kaaret, Alessio Marino, Paolo Soffitta, Francesco Ursini, Filippo Ambrosino, Massimo Cocchi, Sergio Fabiani, Herman L. Marshall, Giorgio Matt, Sara Elisa Motta, Alessandro Papitto, Luigi Stella, Antonella Tarana, Silvia Zane, Iván Agudo, Lucio A. Antonelli, Luca Baldini, Wayne H. Baumgartner, Ronaldo Bellazzini, Stefano Bianchi, Stephen D. Bongiorno, Raffaella Bonino, Alessandro Brez, Niccolò Bucciantini, Simone Castellano, Elisabetta Cavazzuti, Chien-Ting Chen, Stefano Ciprini, Alessandra De Rosa, Ettore Del Monte, Laura Di Gesu, Niccolò Di Lalla, Immacolata Donnarumma, Victor Doroshenko, Steven R. Ehlert, Teruaki Enoto, Yuri Evangelista, Riccardo Ferrazzoli, Javier A. Garcia, Shuichi Gunji, Kiyoshi Hayashida, Jeremy Heyl, Wataru Iwakiri, Svetlana G. Jorstad, Vladimir Karas, Fabian Kislat, Takao Kitaguchi, Jeffery J. Kolodziejczak, Henric Krawczynski, Luca Latronico, Ioannis Liodakis, Simone Maldera, Alberto Manfreda, Frédéric Marin, Andrea Marinucci, Alan P. Marscher, Francesco Massaro, Ikuyuki Mitsuishi, Tsunefumi Mizuno, Michela Negro, Chi-Yung Ng, Nicola Omodei, Chiara Oppedisano, George G. Pavlov, Abel L. Peirson, Matteo Perri, Melissa Pesce-Rollins, Pierre-Olivier Petrucci, Andrea Possenti, Simonetta Puccetti, Brian D. Ramsey, Ajay Ratheesh, Oliver J. Roberts, Roger W. Romani, Carmelo Sgrò, Patrick Slane, Gloria Spandre, Douglas A. Swartz, Toru Tamagawa, Fabrizio Tavecchio, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicholas E. Thomas, Francesco Tombesi, Alessio Trois, Sergey S. Tsygankov, Roberto Turolla, Jacco Vink, Kinwah Wu, and IXPE Collaboration

Subjects
Low-mass x-ray binary stars, Neutron stars, Polarimetry, Spectropolarimetry, Stellar accretion disks, Astrophysics, QB460-466
Abstract

This paper reports the first detection of polarization in the X-rays for atoll-source 4U 1820−303, obtained with the Imaging X-ray Polarimetry Explorer (IXPE) at 99.999% confidence level (CL). Simultaneous polarimetric measurements were also performed in the radio with the Australia Telescope Compact Array. The IXPE observations of 4U 1820−303 were coordinated with Swift X-ray Telescope, Neutron Star Interior Composition Explorer, and Nuclear Spectroscopic Telescope Array aiming to obtain an accurate X-ray spectral model covering a broad energy interval. The source shows a significant polarization above 4 keV, with a polarization degree of 2.0% ± 0.5% and a polarization angle of −55° ± 7° in the 4–7 keV energy range, and a polarization degree of 10% ± 2% and a polarization angle of −67° ± 7° in the 7–8 keV energy bin. This polarization also shows a clear energy trend with polarization degree increasing with energy and a hint for a position-angle change of ≃90° at 96% CL around 4 keV. The spectro-polarimetric fit indicates that the accretion disk is polarized orthogonally to the hard spectral component, which is presumably produced in the boundary/spreading layer. We do not detect linear polarization from the radio counterpart, with a 3 σ upper limit of 50% at 7.25 GHz.

Published
2023
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32. X-Ray Polarization of BL Lacertae in Outburst

Author

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

Subjects
Astrophysical black holes, Black hole physics, Supermassive black holes, Active galactic nuclei, Active galaxies, Jets, Astrophysics, QB460-466
Abstract

We report the first >99% confidence detection of X-ray polarization in BL Lacertae. During a recent X-ray/ γ -ray outburst, a 287 ks observation (2022 November 27–30) was taken using the Imaging X-ray Polarimetry Explorer (IXPE), together with contemporaneous multiwavelength observations from the Neil Gehrels Swift observatory and XMM-Newton in soft X-rays (0.3–10 keV), NuSTAR in hard X-rays (3–70 keV), and optical polarization from the Calar Alto and Perkins Telescope observatories. Our contemporaneous X-ray data suggest that the IXPE energy band is at the crossover between the low- and high-frequency blazar emission humps. The source displays significant variability during the observation, and we measure polarization in three separate time bins. Contemporaneous X-ray spectra allow us to determine the relative contribution from each emission hump. We find >99% confidence X-ray polarization ${{\rm{\Pi }}}_{2\mbox{--}4\mathrm{keV}}={21.7}_{-7.9}^{+5.6} \% $ and electric vector polarization angle ψ _2–4keV = −28.°7 ± 8.°7 in the time bin with highest estimated synchrotron flux contribution. We discuss possible implications of our observations, including previous IXPE BL Lacertae pointings, tentatively concluding that synchrotron self-Compton emission dominates over hadronic emission processes during the observed epochs.

Published
2023
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33. IXPE Observations of the Quintessential Wind-accreting X-Ray Pulsar Vela X-1

Author

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

Subjects
Pulsars, Starlight polarization, Neutron stars, High mass x-ray binary stars, Magnetic fields, Accretion, Astrophysics, QB460-466
Abstract

The radiation from accreting X-ray pulsars was expected to be highly polarized, with some estimates for the polarization degree of up to 80%. However, phase-resolved and energy-resolved polarimetry of X-ray pulsars is required in order to test different models and to shed light on the emission processes and the geometry of the emission region. Here we present the first results of the observations of the accreting X-ray pulsar Vela X-1 performed with the Imaging X-ray Polarimetry Explorer. Vela X-1 is considered to be the archetypal example of a wind-accreting, high-mass X-ray binary system, consisting of a highly magnetized neutron star accreting matter from its supergiant stellar companion. The spectropolarimetric analysis of the phase-averaged data for Vela X-1 reveals a polarization degree (PD) of 2.3% ± 0.4% at the polarization angle (PA) of −47.°3 ± 5.°4. A low PD is consistent with the results obtained for other X-ray pulsars and is likely related to the inverse temperature structure of the neutron star atmosphere. The energy-resolved analysis shows the PD above 5 keV reaching 6%–10% and a ∼90° difference in the PA compared to the data in the 2–3 keV range. The phase-resolved spectropolarimetric analysis finds a PD in the range 0%–9% with the PA varying between −80° and 40°.

Published
2023
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34. The IXPE View of GRB 221009A

Author

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

Subjects
Gamma-ray bursts, Polarimetry, X-ray astronomy, Astrophysics, QB460-466
Abstract

We present the IXPE observation of GRB 221009A, which includes upper limits on the linear polarization degree of both prompt and afterglow emission in the soft X-ray energy band. GRB 221009A is an exceptionally bright gamma-ray burst (GRB) that reached Earth on 2022 October 9 after traveling through the dust of the Milky Way. The Imaging X-ray Polarimetry Explorer (IXPE) pointed at GRB 221009A on October 11 to observe, for the first time, the 2–8 keV X-ray polarization of a GRB afterglow. We set an upper limit to the polarization degree of the afterglow emission of 13.8% at a 99% confidence level. This result provides constraints on the jet opening angle and the viewing angle of the GRB, or alternatively, other properties of the emission region. Additionally, IXPE captured halo-rings of dust-scattered photons that are echoes of the GRB prompt emission. The 99% confidence level upper limit to the prompt polarization degree depends on the background model assumption, and it ranges between ∼55% and ∼82%. This single IXPE pointing provides both the first assessment of X-ray polarization of a GRB afterglow and the first GRB study with polarization observations of both the prompt and afterglow phases.

Published
2023
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35. A Strong X-Ray Polarization Signal from the Magnetar 1RXS J170849.0-400910

Author

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

Subjects
Polarimetry, Magnetars, Astrophysics, QB460-466
Abstract

Magnetars are the most strongly magnetized neutron stars, and one of the most promising targets for X-ray polarimetric measurements. We present here the first Imaging X-ray Polarimetry Explorer observation of the magnetar 1RXS J170849.0-400910, jointly analyzed with a new Swift observation and archival NICER data. The total (energy- and phase-integrated) emission in the 2–8 keV energy range is linerarly polarized, at a ∼35% level. The phase-averaged polarization signal shows a marked increase with energy, ranging from ∼20% at 2–3 keV up to ∼80% at 6–8 keV, while the polarization angle remains constant. This indicates that radiation is mostly polarized in a single direction. The spectrum is well reproduced by a combination of either two thermal (blackbody) components or a blackbody and a power law. Both the polarization degree and angle also show a variation with the spin phase, and the former is almost anticorrelated with the source counts in the 2–8 and 2–4 keV bands. We discuss the possible implications and interpretations, based on a joint analysis of the spectral, polarization, and pulsation properties of the source. A scenario in which the surface temperature is not homogeneous, with a hotter cap covered by a gaseous atmosphere and a warmer region in a condensed state, provides a satisfactory description of both the phase- and energy-dependent spectro-polarimetric data. The (comparatively) small size of the two emitting regions, required to explain the observed pulsations, does not allow to reach a robust conclusion about the presence of vacuum birefringence effects.

Published
2023
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36. Fault tolerant electric generation systems for DC distribution network supply

Author

Giorgio Sulligoi, Alberto Tessarolo, Simone Castellan, Roberto Menis, IEEE, Tessarolo, Alberto, Castellan, Simone, Menis, Roberto, and Sulligoi, Giorgio

Subjects
Engineering, business.industry, modular design, power electronics rectifiers, Fault tolerance, Control engineering, Single-phase electric power, AC power, DC distribution network, Electric power system, Electricity generation, Power electronics, Power module, fault tolerance, Power engineering, DC distribution network, electric power generation, fault tolerance, modular design, power electronics rectifiers, business, electric power generation
Abstract

DC distribution is being considered as an attractive alternative to its traditional AC counterpart in many fields of applications and, in particular, for shipboard power systems. The adoption of a DC distribution network makes it possible and sometimes necessary to radically revise the technology of the generation systems in many regards. Not only frequency-related constraints are removed, allowing for high-speed smaller generators to be used, but new fault-tolerant configurations, involving power electronics, generation control and management too, become feasible as a natural alternative to the traditional arrangement of AC power plants. In this paper some of these new technological scenarios are outlined, referring to state-of-the-art realizations as well as to novel concept designs presently under development and investigation.

Published
2014

37. Analysis of asymmetrical short circuits downstream of 12 pulse diode rectifier fed by double three phase synchronous machines

Author

Alberto Tessarolo, Mario Mezzarobba, Simone Castellan, Mauro Bortolozzi, IET, Castellan, Simone, Mezzarobba, Mario, Tessarolo, Alberto, and Bortolozzi, Mauro

Subjects
DC generators, model validation, Engineering, 12-pulse DC generator system, MVDC grid, Electric generator, Hardware_PERFORMANCEANDRELIABILITY, Permanent magnet synchronous generator, Fault (power engineering), Precision rectifier, law.invention, law, Electronic engineering, asymmetrical short circuit downstream analysis, DC power generation, Diode, business.industry, rectifiers,smart power grids,synchronous generators,12 pulse diode rectifier,12-pulse DC generator system,DC power generation,MVDC grid,asymmetrical short circuit downstream analysis,double three phase synchronous machine,software simulation,synchronous generator,transient short circuit current,DC generators,asymmetrical short circuit,diode rectifiers,model validation,transient short circuit current, Electrical engineering, transient short circuit current, smart power grids, double three phase synchronous machine, 12 pulse diode rectifier, Three-phase, synchronous generator, rectifiers, software simulation, diode rectifiers, synchronous generators, Transient (oscillation), asymmetrical short circuit, business, Short circuit
Abstract

DC power generation for MVDC grids is in the easiest way realized by a cascade connection of a synchronous generator and a diode rectifier. Due to large peak fault currents, including oscillating transient components, it is important to know in depth the short circuit behaviour of diode rectifiers, mainly during the first moments after the fault. This is helpful to be able to perform a suitable sizing of the system and its protections. In order to obtain an accurate estimation of the transient short circuit current, models for software simulation of 6-pulse and 12-pulse DC generator systems have been implemented. This paper shows the validation of such models by the comparison of simulation results with experimental tests.

Published
2014

38. LCI-fed wound-field synchronous motors: A technology status review and new development trends

Author

Sobhan Mohamadian, Simone Castellan, Alberto Tessarolo, M. H. Khanzade, IEEE, Mohamadian, Sobhan, Khanzade, Mohammad Hosein, Castellan, Simone, and Tessarolo, Alberto

Subjects
LCI-fed WFSM drive, Engineering, Field oriented control (FOC), business.industry, Field oriented control (FOC), high-power medium voltage applications, LCI-fed WFSM drive, stator flux reference frame, start up, stator flux reference frame, Field oriented control (FOC), LCI-fed WFSM drive, high-power mediumvoltage applications, start up, stator flux reference frame, Insulated-gate bipolar transistor, Network topology, high-power mediumvoltage applications, Automotive engineering, start up, Power (physics), Integrated gate-commutated thyristor, High-definition video, Electronic engineering, business, Synchronous motor, high-power medium voltage applications, Pulse-width modulation, Strengths and weaknesses
Abstract

Load-Commutated Inverters (LCIs) are today one of the main converter topologies used for very-high-power drive applications, although new topologies, based on PWM technology and employing IGBT or IGCT as power switches instead of SCR's, have been recently gaining attractiveness also for increasing power ratings. The paper presents an overview of today's LCI technology and its applications, highlighting its strengths and weaknesses. Furthermore, the most promising lines of development are drawn along which LCI drive technology is being improved to overcome its major drawbacks and maintain competitiveness with Voltage-Source-Inverter (VSI) based counterparts.

Published
2014

39. Power electronics for all-electric ships with MVDC power distribution system: An overview

Author

Alberto Tessarolo, Roberto Menis, Giorgio Sulligoi, Simone Castellan, IEEE, Castellan, Simone, Menis, Roberto, Tessarolo, Alberto, and Sulligoi, Giorgio

Subjects
Employment, Engineering, Switched-mode power supply, voltage levels, DC/DC power converters, medium voltage high power users, air conditioning, Power transformers, Power factor, AC distribution systems, DC distribution systems, Medium Voltage DC (MVDC), bow thrusters, Solid State Transformer (SST), Electric power system, marine power systems, integrated power systems, Power electronics, AC adapter, three-wire MVDC power systems, Prototypes, output voltage rectification, electric vehicles, Electric power distribution, solid-state transformers, Rectifiers, energy storage, business.industry, Electrical engineering, DC-DC power convertors, MVDC power distribution system, Integrated Power System (IPS), Voltage optimisation, Generators, propulsion drives, DC distribution, all-electric ships, compressors, Power module, energy storage systems, Power engineering, business, ships, DC-DC power convertors,electric vehicles,energy storage,marine power systems,power transformers,ships,AC distribution systems,DC distribution systems,DC/DC power converters,MVDC power distribution system,air conditioning,all-electric ships,bow thrusters,compressors,energy storage systems,integrated power systems,medium voltage high power users,output voltage rectification,power electronics,power transformers,propulsion drives,solid-state transformers,three-wire MVDC power systems,voltage levels,Employment,Generators,Power electronics,Power transformers,Prototypes,Rectifiers,DC distribution,Integrated Power System (IPS),Medium Voltage DC (MVDC),Solid State Transformer (SST)
Abstract

Integrated Power Systems (IPS) with DC distribution require the massive use of power electronics for many tasks: 1) the output voltage rectification of generators and the connection of energy storage systems to the IPS, 2) the supply of medium voltage high power users (propulsion drives, bow thrusters, compressors for air conditioning), 3) the adjustment of voltage levels, which is performed by power transformers in AC distribution systems and by DC/DC power converters called Solid-State Transformers (SST) in DC distribution systems. In this paper, an overview is given of the power converters found in the literature and on the market that could be suitable for employment in the mentioned subsystems as parts of a future MVDC IPS. Finally authors propose a structure for an SST to be employed in three-wire MVDC power systems.

Published
2014

40. Rapidly Design, Prototype, and Test your DSP Controller with PSIM and Typhoon HIL

Author

Ivan Celanovic, Nikola Celanovic, Hua Jin, Simone Castellan, Celanovic, Ivan, Celanovic, Nikola, Jin, Hua, and Castellan, Simone

Subjects
hardware-in-the-loop
Abstract

The growing complexity of power electronics (PE) systems, intensifying competition, rapidly shrinking product development cycles, and exploding test and quality assurance costs are forcing power electronics industry to accelerate the adoption of advanced tools for design, test, and verification. This trend is particularly evident in power electronics embedded control software whose size, complexity and importance is rapidly increasing. This is only to be expected because power electronics control software: • Provides large value added to the product via increased functionality and new features; • Provides an opportunity to quickly develop new products based on existing hardware platforms; (i.e. using solar inverter power hardware for grid storage power hardware); • Provides the opportunity for newcomers to offer competitive solutions in different verticals thanks to the availability of modularized hardware. If automotive industry can be taken as an indication of how the power electronics is going to develop, we should brace ourselves for a software dominated power electronics. For example, today’s car has between 20 and 70 processors with 100 million lines of embedded code amounting to approximately 1GByte of embedded code. Less than 20 years ago cars had one or no processors. Testing automotive embedded software then was much simpler. Manual testing was acceptable, as it is still the standard practice in most of the power electronics industry today. But times are rapidly changing. In addition, power electronics industry is currently undergoing a power semiconductor revolution with the development of new wide-bandgap semiconductor devices, i.e. SiC, GaN, which are imposing more demanding design requirement specifications for controllers which in turn require a new set of tools for automated design, test, and verification.

Published
2014

41. Electric generation technologies for all-electric ships with Medium-Voltage DC power distribution systems

Author

Giorgio Sulligoi, Alberto Tessarolo, Simone Castellan, Roberto Menis, Electric Ship Technologies Symposium (ESTS), 2013 IEEE, Tessarolo, Alberto, Castellan, Simone, Menis, Roberto, and Sulligoi, Giorgio

Subjects
Electric machine, Engineering, shipboard power generation, business.product_category, business.industry, Electrical engineering, Electric generator, ComputerApplications_COMPUTERSINOTHERSYSTEMS, Grid, All Electric Ship, law.invention, Electric power system, Electricity generation, law, integrated power system, ultra-high speed generators, fault tolerance, Power engineering, Electric power, business, Voltage
Abstract

A promising solution to improve tomorrow's all-electric ship onboard power system design and performance relies on moving from 50-Hz or 60-Hz AC distribution to a Medium-Voltage DC (MVDC) grid. This paper provides a review of presently-available and under-development technologies for electric generators to be used in perspective MVDC shipboard systems. The inspiring reason for the survey lies in the fact that an MVDC grid design removes the constraints usually imposed on shipboard generation group design and opens the way for a wide variety of non-conventional machine alternatives. In combination of high-speed gas turbines, that can be employed as prime movers, several electric machine topologies, not yet used for ship applications, can be selected to feed MVDC onboard systems. Along with a review of possible generator types suitable for such use, the paper critically reviews some emerging technologies for their fault-tolerance enhancement through conventional and innovative split-phase architectures.

Published
2013

42. A distributed driving and steering system for electric vehicles using rotary-linear motors

Author

Roberto Menis, Ottorino Bruno, Simone Castellan, Santolo Meo, Giuseppe Buja, V. Isastia, Paolo Bolognesi, Manuele Bertoluzzo, IEEE, M., Bertoluzzo, P., Bolognesi, O., Bruno, G., Buja, S., Castellan, ISASTIA CIMINO, Vittorio, R., Meni, Meo, Santolo, Bertoluzzo, M., Bolognesi, P., Bruno, O., Buja, Giuseppe, Castellan, Simone, Isastia, V, Menis, Roberto, and Meo, S.

Subjects
Electronic control unit, Engineering, Distributed driving and steering system, business.product_category, business.industry, Motor control, Distributed Driving and Steering system, Electric Vehicle, Rotary-linear motor, Control engineering, Linear motor, Electric vehicle, Automation, Automotive engineering, Power (physics), Power electronics, Rotary-linear motor, business, Fieldbus
Abstract

The paper presents the activities ongoing in the framework of a two-year Italian National Research Project aimed at developing a distributed Driving and Steering (DaS) system for Electric Vehicles (EVs). The system is built up around an actuation module embedding a rotary-linear motor and including a power converter and a local Electronic Control Unit (ECU) to supply and control the motor. The actuation module is intended to make a wheel active so as to give it propelling and steering capabilities. The DaS system, in turn, includes a central ECU and a fieldbus to govern and network the system, and a power supply stage. The Project under consideration is focused on a DaS system with two active wheels for a light-duty EV.

Published
2010

43. An innovative photovoltaic field simulator for hardware-in-the-loop test of power conditioning units

Author

A. Massi Pavan, Simone Castellan, Giorgio Sulligoi, International Conference on Clean Electrical Power, MASSI PAVAN, Alessandro, Castellan, Simone, and Sulligoi, Giorgio

Subjects
Engineering, simulator, business.industry, PV inverter, Photovoltaic system, real time control systems, Hardware-in-the-loop simulation, Electrical engineering, photovoltaic, Field (computer science), Power (physics), Work (electrical), Control system, real time control system, business, Simulation, Voltage
Abstract

In this work a review of photovoltaic (PV) field simulators and a project for the development of an innovative Hardware-In-the-Loop (HIL) PV field simulator are presented. The simulator is conceptually designed to be part of a future PV field demonstrator to be realized in the area of Trieste (Italy), which will include measurement facilities, networked PV fields, laboratories in universities and other research centers.

Published
2009

44. Feasibility and performance analysis of a high power drive based on four synchro-converters supplying a twelve-phase synchronous motor

Author

Roberto Menis, Simone Castellan, Alberto Tessarolo, IEEE, Tessarolo, Alberto, Castellan, Simone, and Menis, Roberto

Subjects
Synchro, Electromagnetic coil, Computer science, high power drive, twelve-phase synchronous motor, Torque, Control engineering, Converters, Synchronous motor, DC motor, Power (physics), Voltage
Abstract

In this paper a high-power electric drive based on a quadruple-three-phase synchronous motor and four load commutated inverters (LCI) is investigated to evaluate its feasibility and performance. Based on accurate simulation analyses, the advantages of the proposed solution compared to the technologically-proven dual three-phase scheme are highlighted in terms of torque quality and motor efficiency improvement.

Published
2008

45. A simple fault-tolerant induction motor drive for dependable electrical auxiliary equipment of railway locomotives

Author

Roberto Menis, Simone Castellan, M. Favot, Alberto Tessarolo, IEEE, Castellan, Simone, Favot, M., Menis, Roberto, and Tessarolo, Alberto

Subjects
Electronic speed control, Engineering, business.industry, Stator, Fault tolerance, Fault (power engineering), Automotive engineering, law.invention, Motor drive, law, Torque, Dependability, business, Induction motor
Abstract

A simple fault-tolerant induction motor drive with v/f speed control included in the electrical auxiliary equipment of railway locomotives is presented in the paper. The employment of fault tolerant on-board electrical auxiliary equipment increases the dependability and then the quality of the railway service. The fault tolerance technique consists of some emergency countermeasures applied in case of fault. It includes a fault diagnosis procedure based on the analysis of the current vector, the connection of the stator winding neutral point to the dc-link middle point and the variation of the v/f law, taking into account the contribution of the zero-sequence impedance and the need for a flux weakening in order to avoid saturation. Some experimental results are reported showing the improved performance of the motor drive under fault conditions by means of the proposed remedial strategy.

Published
2008

46. First X-Ray Polarization Measurement Confirms the Low Black Hole Spin in LMC X-3

Author

Jiří Svoboda, Michal Dovčiak, James F. Steiner, Fabio Muleri, Adam Ingram, Anastasiya Yilmaz, Nicole Rodriguez Cavero, Lorenzo Marra, Juri Poutanen, Alexandra Veledina, Mehrnoosh Rahbardar Mojaver, Stefano Bianchi, Javier A. García, Philip Kaaret, Henric Krawczynski, Giorgio Matt, Jakub Podgorný, Martin C. Weisskopf, Fabian Kislat, Pierre-Olivier Petrucci, Maimouna Brigitte, Michal Bursa, Sergio Fabiani, Kun Hu, Sohee Chun, Guglielmo Mastroserio, Romana Mikus̆incová, Ajay Ratheesh, Roger W. Romani, Paolo Soffitta, Francesco Ursini, Silvia Zane, Iván Agudo, Lucio A. Antonelli, Matteo Bachetti, Luca Baldini, Wayne H. Baumgartner, Ronaldo Bellazzini, Stephen D. Bongiorno, Raffaella Bonino, Alessandro Brez, Niccolò Bucciantini, Fiamma Capitanio, Simone Castellano, Elisabetta Cavazzuti, Chien-Ting Chen, Stefano Ciprini, Enrico Costa, Alessandra De Rosa, Ettore Del Monte, Laura Di Gesu, Niccolò Di Lalla, Alessandro Di Marco, Immacolata Donnarumma, Victor Doroshenko, Steven R. Ehlert, Teruaki Enoto, Yuri Evangelista, Riccardo Ferrazzoli, Shuichi Gunji, Kiyoshi Hayashida, Jeremy Heyl, Wataru Iwakiri, Svetlana G. Jorstad, Vladimír Karas, Takao Kitaguchi, Jeffery J. Kolodziejczak, Fabio La Monaca, Luca Latronico, Ioannis Liodakis, Simone Maldera, Alberto Manfreda, Frédéric Marin, Andrea Marinucci, Alan P. Marscher, Herman L. Marshall, Francesco Massaro, Ikuyuki Mitsuishi, Tsunefumi Mizuno, Michela Negro, Chi-Yung Ng, Stephen L. O’Dell, Nicola Omodei, Chiara Oppedisano, Alessandro Papitto, George G. Pavlov, Abel L. Peirson, Matteo Perri, Melissa Pesce-Rollins, Maura Pilia, Andrea Possenti, Simonetta Puccetti, Brian D. Ramsey, John Rankin, Oliver J. Roberts, Carmelo Sgrò, Patrick Slane, Gloria Spandre, Douglas A. Swartz, Toru Tamagawa, Fabrizio Tavecchio, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicholas E. Thomas, Francesco Tombesi, Alessio Trois, Sergey S. Tsygankov, Roberto Turolla, Jacco Vink, Kinwah Wu, and Fei Xie

Subjects
X-ray binary stars, X-ray observatories, Accretion, Astrophysical black holes, Black hole physics, Spectropolarimetry, Astrophysics, QB460-466
Abstract

X-ray polarization is a powerful tool to investigate the geometry of accreting material around black holes, allowing independent measurements of the black hole spin and orientation of the innermost parts of the accretion disk. We perform X-ray spectropolarimetric analysis of an X-ray binary system in the Large Magellanic Cloud, LMC X-3, that hosts a stellar-mass black hole, known to be persistently accreting since its discovery. We report the first detection of the X-ray polarization in LMC X-3 with the Imaging X-ray Polarimetry Explorer, and find the average polarization degree (PD) of 3.2% ± 0.6% and a constant polarization angle of −42° ± 6° over the 2–8 keV range. Using accompanying spectroscopic observations by NICER, NuSTAR, and the Neil Gehrels Swift observatories, we confirm previous measurements of the black hole spin via the X-ray continuum method, a ≈ 0.2. From polarization analysis only, we found consistent results with low black hole spin, with an upper limit of a < 0.7 at a 90% confidence level. A slight increase in the PD with energy, similar to other black hole X-ray binaries in the soft state, is suggested from the data but with a low statistical significance.

Published
2023
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47. X-Ray Polarization of the BL Lacertae Type Blazar 1ES 0229+200

Author

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

Subjects
Polarimetry, X-ray quasars, Radio galaxies, Astrophysics, QB460-466
Abstract

We present polarization measurements in the 2–8 keV band from blazar 1ES 0229+200, the first extreme high synchrotron peaked source to be observed by the Imaging X-ray Polarimetry Explorer (IXPE). Combining two exposures separated by about two weeks, we find the degree of polarization to be Π _X = 17.9% ± 2.8% at an electric-vector position angle ψ _X = 25.°0 ± 4.°6 using a spectro-polarimetric fit from joint IXPE and XMM-Newton observations. There is no evidence for the polarization degree or angle varying significantly with energy or time on both short timescales (hours) or longer timescales (days). The contemporaneous polarization degree at optical wavelengths was >7× lower, making 1ES 0229+200 the most strongly chromatic blazar yet observed. This high X-ray polarization compared to the optical provides further support that X-ray emission in high-peaked blazars originates in shock-accelerated, energy-stratified electron populations, but is in tension with many recent modeling efforts attempting to reproduce the spectral energy distribution of 1ES 0229+200, which attribute the extremely high energy synchrotron and Compton peaks to Fermi acceleration in the vicinity of strongly turbulent magnetic fields.

Published
2023
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48. Magnetic Structures and Turbulence in SN 1006 Revealed with Imaging X-Ray Polarimetry

Author

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

Subjects
Supernova remnants, Polarimetry, X-ray astronomy, Shocks, Cosmic rays, Astrophysics, QB460-466
Abstract

Young supernova remnants strongly modify the surrounding magnetic fields, which in turn play an essential role in accelerating cosmic rays (CRs). The X-ray polarization measurements probe magnetic field morphology and turbulence at the immediate acceleration site. We report the X-ray polarization distribution in the northeastern shell of SN 1006 from a 1 Ms observation with the Imaging X-ray Polarimetry Explorer. We found an average polarization degree of 22.4% ± 3.5% and an average polarization angle of −45.°4 ± 4.°5 (measured on the plane of the sky from north to east). The X-ray polarization angle distribution reveals that the magnetic fields immediately behind the shock in the northeastern shell of SN 1006 are nearly parallel to the shock normal or radially distributed, similar to that in the radio observations, and consistent with the quasi-parallel CR acceleration scenario. The X-ray emission is marginally more polarized than that in the radio band. The X-ray polarization degree of SN 1006 is much larger than that in Cas A and Tycho, together with the relatively tenuous and smooth ambient medium of the remnant, favoring that CR-induced instabilities set the magnetic turbulence in SN 1006, and CR acceleration is environment-dependent.

Published
2023
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49. The Polarized Cosmic Hand: IXPE Observations of PSR B1509−58/MSH 15−52

Author

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

Subjects
Pulsar wind nebulae, Rotation powered pulsars, Polarimetry, Astrophysics, QB460-466
Abstract

We describe IXPE polarization observations of the pulsar wind nebula (PWN) MSH 15−5 ^2 , the “Cosmic Hand.” We find X-ray polarization across the PWN, with B -field vectors generally aligned with filamentary X-ray structures. High-significance polarization is seen in arcs surrounding the pulsar and toward the end of the “jet,” with polarization degree PD > 70%, thus approaching the maximum allowed synchrotron value. In contrast, the base of the jet has lower polarization, indicating a complex magnetic field at significant angle to the jet axis. We also detect significant polarization from PSR B1509−58 itself. Although only the central pulse phase bin of the pulse has high individual significance, flanking bins provide lower-significance detections and, in conjunction with the X-ray image and radio polarization, can be used to constrain rotating vector model solutions for the pulsar geometry.

Published
2023
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50. IXPE and XMM-Newton Observations of the Soft Gamma Repeater SGR 1806–20

Author

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

Subjects
Neutron stars, Magnetars, Polarimetry, X-ray sources, Astrophysics, QB460-466
Abstract

Recent observations with the Imaging X-ray Polarimetry Explorer (IXPE) of two anomalous X-ray pulsars provided evidence that X-ray emission from magnetar sources is strongly polarized. Here we report on the joint IXPE and XMM-Newton observations of the soft γ -repeater SGR 1806–20. The spectral and timing properties of SGR 1806–20 derived from XMM-Newton data are in broad agreement with previous measurements; however, we found the source at an all-time low persistent flux level. No significant polarization was measured apart from the 4–5 keV energy range, where a probable detection with PD = 31.6% ± 10.5% and $\mathrm{PA}=-17\buildrel{\circ}\over{.} {6}_{-15\buildrel{\circ}\over{.} 0}^{+15\buildrel{\circ}\over{.} 5}$ was obtained. The resulting polarization signal, together with the upper limits we derive at lower and higher energies (2–4 and 5–8 keV, respectively), is compatible with a picture in which thermal radiation from the condensed star surface is reprocessed by resonant Compton scattering in the magnetosphere, similar to what was proposed for the bright magnetar 4U 0142+61.

Published
2023
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