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1. A multi-frequency study of sub-parsec jets with the Event Horizon Telescope

Author

Röder, Jan, Wielgus, Maciek, Lobanov, Andrei P., Krichbaum, Thomas P., Nair, Dhanya G., Lee, Sang-Sung, Ros, Eduardo, Fish, Vincent L., Blackburn, Lindy, Chan, Chi-kwan, Issaoun, Sara, Janssen, Michael, Johnson, Michael D., Doeleman, Sheperd S., Bower, Geoffrey C., Crew, Geoffrey B., Tilanus, Remo P. J., Savolainen, Tuomas, Impellizzeri, C. M. Violette, Alberdi, Antxon, Baczko, Anne-Kathrin, Gómez, José L., Lu, Ru-Sen, Paraschos, Georgios F., Traianou, Efthalia, Goddi, Ciriaco, Kim, Daewon, Lisakov, Mikhail, Kovalev, Yuri Y., Voitsik, Petr A., Sokolovsky, Kirill V., Akiyama, Kazunori, Albentosa-Ruíz, Ezequiel, Alef, Walter, Algaba, Juan Carlos, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Bach, Uwe, Ball, David, Baloković, Mislav, Bandyopadhyay, Bidisha, Barrett, John, Bauböck, Michi, Benson, Bradford A., Bintley, Dan, Blundell, Raymond, Bouman, Katherine L., Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E., Broguiere, Dominique, Bronzwaer, Thomas, Bustamante, Sandra, Byun, Do-Young, Carlstrom, John E., Ceccobello, Chiara, Chael, Andrew, Chang, Dominic O., Chatterjee, Koushik, Chatterjee, Shami, Chen, Ming-Tang, Chen, Yongjun, Cheng, Xiaopeng, Cho, Ilje, Christian, Pierre, Conroy, Nicholas S., Conway, John E., Cordes, James M., Crawford, Thomas M., Cruz-Osorio, Alejandro, Cui, Yuzhu, Curd, Brandon, Dahale, Rohan, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dexter, Jason, Dhruv, Vedant, Dihingia, Indu K., Dougall, Sean Taylor, Dzib, Sergio A., Eatough, Ralph P., Emami, Razieh, Falcke, Heino, Farah, Joseph, Fomalont, Edward, Ford, H. Alyson, Foschi, Marianna, Fraga-Encinas, Raquel, Freeman, William T., Friberg, Per, Fromm, Christian M., Fuentes, Antonio, Galison, Peter, Gammie, Charles F., García, Roberto, Gentaz, Olivier, Georgiev, Boris, Gold, Roman, Gómez-Ruiz, Arturo I., Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Haggard, Daryl, Haworth, Kari, Hecht, Michael H., Hesper, Ronald, Heumann, Dirk, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Inoue, Makoto, James, David J., Jannuzi, Buell T., Jeter, Britton, Jiang, Wu, Jiménez-Rosales, Alejandra, Jorstad, Svetlana, Joshi, Abhishek V., Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kim, Junhan, Kino, Motoki, Koay, Jun Yi, Kocherlakota, Prashant, Kofuji, Yutaro, Koyama, Shoko, Kramer, Carsten, Kramer, Joana A., Kramer, Michael, Kuo, Cheng-Yu, La Bella, Noemi, Lauer, Tod R., Lee, Daeyoung, Leung, Po Kin, Levis, Aviad, Li, Zhiyuan, Lico, Rocco, Lindahl, Greg, Lindqvist, Michael, Liu, Jun, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Loinard, Laurent, Lonsdale, Colin J., Lowitz, Amy E., MacDonald, Nicholas R., Mao, Jirong, Marchili, Nicola, Markoff, Sera, Marrone, Daniel P., Marscher, Alan P., Martí-Vidal, Iván, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Michalik, Daniel, Mizuno, Izumi, Mizuno, Yosuke, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Mulaudzi, Wanga, Müller, Cornelia, Müller, Hendrik, Mus, Alejandro, Musoke, Gibwa, Myserlis, Ioannis, Nadolski, Andrew, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayanan, Gopal, Natarajan, Iniyan, Nathanail, Antonios, Fuentes, Santiago Navarro, Neilsen, Joey, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Nowak, Michael A., Oh, Junghwan, Okino, Hiroki, Sánchez, Héctor R. Olivares, Ortiz-León, Gisela N., Oyama, Tomoaki, özel, Feryal, Palumbo, Daniel C. M., Park, Jongho, Parsons, Harriet, Patel, Nimesh, Pen, Ue-Li, Pesce, Dominic W., Piétu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Pötzl, Felix M., Prather, Ben, Preciado-López, Jorge A., Principe, Giacomo, Psaltis, Dimitrios, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Ricarte, Angelo, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Romero-Cañizales, Cristina, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruiz, Ignacio, Ruszczyk, Chet, Rygl, Kazi L. J., Sánchez, Salvador, Sánchez-Argüelles, David, Sánchez-Portal, Miguel, Sasada, Mahito, Satapathy, Kaushik, Schloerb, F. Peter, Schonfeld, Jonathan, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Salas, León David Sosapanta, Souccar, Kamal, Stanway, Joshua S., Sun, He, Tazaki, Fumie, Tetarenko, Alexandra J., Tiede, Paul, Titus, Michael, Torne, Pablo, Toscano, Teresa, Trent, Tyler, Trippe, Sascha, Turk, Matthew, van Bemmel, Ilse, van Langevelde, Huib J., van Rossum, Daniel R., Vos, Jesse, Wagner, Jan, Ward-Thompson, Derek, Wardle, John, Washington, Jasmin E., Weintroub, Jonathan, Wharton, Robert, Wiik, Kaj, Witzel, Gunther, Wondrak, Michael F., Wong, George N., Wu, Qingwen, Yadlapalli, Nitika, Yamaguchi, Paul, Yfantis, Aristomenis, Yoon, Doosoo, Young, André, Young, Ken, Younsi, Ziri, Yu, Wei, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhang, Shuo, Zhao, Guang-Yao, and Zhao, Shan-Shan

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

The 2017 observing campaign of the Event Horizon Telescope (EHT) delivered the first very long baseline interferometry (VLBI) images at the observing frequency of 230 GHz, leading to a number of unique studies on black holes and relativistic jets from active galactic nuclei (AGN). In total, eighteen sources were observed: the main science targets, Sgr A* and M87 along with various calibrators. We investigated the morphology of the sixteen AGN in the EHT 2017 data set, focusing on the properties of the VLBI cores: size, flux density, and brightness temperature. We studied their dependence on the observing frequency in order to compare it with the Blandford-K\"onigl (BK) jet model. We modeled the source structure of seven AGN in the EHT 2017 data set using linearly polarized circular Gaussian components and collected results for the other nine AGN from dedicated EHT publications, complemented by lower frequency data in the 2-86 GHz range. Then, we studied the dependences of the VLBI core flux density, size, and brightness temperature on the frequency measured in the AGN host frame. We compared the observations with the BK jet model and estimated the magnetic field strength dependence on the distance from the central black hole. Our results indicate a deviation from the standard BK model, particularly in the decrease of the brightness temperature with the observing frequency. Either bulk acceleration of the jet material, energy transfer from the magnetic field to the particles, or both are required to explain the observations.

Published
2025

2. First Very Long Baseline Interferometry Detections at 870{\mu}m

Author

Raymond, Alexander W., Doeleman, Sheperd S., Asada, Keiichi, Blackburn, Lindy, Bower, Geoffrey C., Bremer, Michael, Broguiere, Dominique, Chen, Ming-Tang, Crew, Geoffrey B., Dornbusch, Sven, Fish, Vincent L., García, Roberto, Gentaz, Olivier, Goddi, Ciriaco, Han, Chih-Chiang, Hecht, Michael H., Huang, Yau-De, Janssen, Michael, Keating, Garrett K., Koay, Jun Yi, Krichbaum, Thomas P., Lo, Wen-Ping, Matsushita, Satoki, Matthews, Lynn D., Moran, James M., Norton, Timothy J., Patel, Nimesh, Pesce, Dominic W., Ramakrishnan, Venkatessh, Rottmann, Helge, Roy, Alan L., Sánchez, Salvador, Tilanus, Remo P. J., Titus, Michael, Torne, Pablo, Wagner, Jan, Weintroub, Jonathan, Wielgus, Maciek, Young, André, Akiyama, Kazunori, Albentosa-Ruíz, Ezequiel, Alberdi, Antxon, Alef, Walter, Algaba, Juan Carlos, Anantua, Richard, Azulay, Rebecca, Bach, Uwe, Baczko, Anne-Kathrin, Ball, David, Baloković, Mislav, Bandyopadhyay, Bidisha, Barrett, John, Bauböck, Michi, Benson, Bradford A., Bintley, Dan, Blundell, Raymond, Bouman, Katherine L., Boyce, Hope, Brissenden, Roger, Britzen, Silke, Broderick, Avery E., Bronzwaer, Thomas, Bustamante, Sandra, Carlstrom, John E., Chael, Andrew, Chan, Chi-kwan, Chang, Dominic O., Chatterjee, Koushik, Chatterjee, Shami, Chen, Yongjun, Cheng, Xiaopeng, Cho, Ilje, Christian, Pierre, Conroy, Nicholas S., Conway, John E., Crawford, Thomas M., Cruz-Osorio, Alejandro, Cui, Yuzhu, Dahale, Rohan, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dexter, Jason, Dhruv, Vedant, Dihingia, Indu K., Dzib, Sergio A., Eatough, Ralph P., Emami, Razieh, Falcke, Heino, Farah, Joseph, Fomalont, Edward, Fontana, Anne-Laure, Ford, H. Alyson, Foschi, Marianna, Fraga-Encinas, Raquel, Freeman, William T., Friberg, Per, Fromm, Christian M., Fuentes, Antonio, Galison, Peter, Gammie, Charles F., Georgiev, Boris, Gold, Roman, Gómez-Ruiz, Arturo I., Gómez, José L., Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Haggard, Daryl, Hesper, Ronald, Heumann, Dirk, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Impellizzeri, C. M. Violette, Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Jeter, Britton, Jiang, Wu, Jiménez-Rosales, Alejandra, Johnson, Michael D., Jorstad, Svetlana, Jones, Adam C., Joshi, Abhishek V., Jung, Taehyun, Karuppusamy, Ramesh, Kawashima, Tomohisa, Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kim, Junhan, Kino, Motoki, Kocherlakota, Prashant, Kofuji, Yutaro, Koch, Patrick M., Koyama, Shoko, Kramer, Carsten, Kramer, Joana A., Kramer, Michael, Kubo, Derek, Kuo, Cheng-Yu, La Bella, Noemi, Lee, Sang-Sung, Levis, Aviad, Li, Zhiyuan, Lico, Rocco, Lindahl, Greg, Lindqvist, Michael, Lisakov, Mikhail, Liu, Jun, Liu, Kuo, Liuzzo, Elisabetta, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin J., Lowitz, Amy E., Lu, Ru-Sen, MacDonald, Nicholas R., Mahieu, Sylvain, Maier, Doris, Mao, Jirong, Marchili, Nicola, Markoff, Sera, Marrone, Daniel P., Marscher, Alan P., Martí-Vidal, Iván, Medeiros, Lia, Menten, Karl M., Mizuno, Izumi, Mizuno, Yosuke, Montgomery, Joshua, Moriyama, Kotaro, Moscibrodzka, Monika, Mulaudzi, Wanga, Müller, Cornelia, Müller, Hendrik, Mus, Alejandro, Musoke, Gibwa, Myserlis, Ioannis, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayanan, Gopal, Natarajan, Iniyan, Nathanail, Antonios, Fuentes, Santiago Navarro, Neilsen, Joey, Ni, Chunchong, Nowak, Michael A., Oh, Junghwan, Okino, Hiroki, Sánchez, Héctor Raúl Olivares, Oyama, Tomoaki, Özel, Feryal, Palumbo, Daniel C. M., Paraschos, Georgios Filippos, Park, Jongho, Parsons, Harriet, Pen, Ue-Li, Piétu, Vincent, PopStefanija, Aleksandar, Porth, Oliver, Prather, Ben, Principe, Giacomo, Psaltis, Dimitrios, Pu, Hung-Yi, Raffin, Philippe A., Rao, Ramprasad, Rawlings, Mark G., Ricarte, Angelo, Ripperda, Bart, Roelofs, Freek, Romero-Cañizales, Cristina, Ros, Eduardo, Roshanineshat, Arash, Ruiz, Ignacio, Ruszczyk, Chet, Rygl, Kazi L. J., Sánchez-Argüelles, David, Sánchez-Portal, Miguel, Sasada, Mahito, Satapathy, Kaushik, Savolainen, Tuomas, Schloerb, F. Peter, Schonfeld, Jonathan, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Salas, León David Sosapanta, Souccar, Kamal, Srinivasan, Ranjani, Stanway, Joshua S., Sun, He, Tazaki, Fumie, Tetarenko, Alexandra J., Tiede, Paul, Toma, Kenji, Toscano, Teresa, Traianou, Efthalia, Trent, Tyler, Trippe, Sascha, Turk, Matthew, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Vos, Jesse, Ward-Thompson, Derek, Wardle, John, Washington, Jasmin E., Wharton, Robert, Wiik, Kaj, Witzel, Gunther, Wondrak, Michael F., Wong, George N., Wu, Qingwen, Yadlapalli, Nitika, Yamaguchi, Paul, Yfantis, Aristomenis, Yoon, Doosoo, Younsi, Ziri, Yu, Wei, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhang, Shuo, Zhao, Guang-Yao, and Zhao, Shan-Shan

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

The first very long baseline interferometry (VLBI) detections at 870$\mu$m wavelength (345$\,$GHz frequency) are reported, achieving the highest diffraction-limited angular resolution yet obtained from the surface of the Earth, and the highest-frequency example of the VLBI technique to date. These include strong detections for multiple sources observed on inter-continental baselines between telescopes in Chile, Hawaii, and Spain, obtained during observations in October 2018. The longest-baseline detections approach 11$\,$G$\lambda$ corresponding to an angular resolution, or fringe spacing, of 19$\mu$as. The Allan deviation of the visibility phase at 870$\mu$m is comparable to that at 1.3$\,$mm on the relevant integration time scales between 2 and 100$\,$s. The detections confirm that the sensitivity and signal chain stability of stations in the Event Horizon Telescope (EHT) array are suitable for VLBI observations at 870$\mu$m. Operation at this short wavelength, combined with anticipated enhancements of the EHT, will lead to a unique high angular resolution instrument for black hole studies, capable of resolving the event horizons of supermassive black holes in both space and time., Comment: Corresponding author: S. Doeleman

Published
2024
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3. 3D hybrid fluid-particle jet simulations and the importance of synchrotron radiative losses

Author

Kramer, Joana A., MacDonald, Nicholas R., Paraschos, Georgios F., and Ricci, L.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Context. Relativistic jets in active galactic nuclei are known for their exceptional energy output, and imaging the synthetic synchrotron emission of numerical jet simulations is essential for a comparison with observed jet polarization emission. Aims. Through the use of 3D hybrid fluid-particle jet simulations (with the PLUTO code), we overcome some of the commonly made assumptions in relativistic magnetohydrodynamic (RMHD) simulations by using non-thermal particle attributes to account for the resulting synchrotron radiation. Polarized radiative transfer and ray-tracing (via the RADMC-3D code) highlight the differences in total intensity maps when (i) the jet is simulated purely with the RMHD approach, (ii) a jet tracer is considered in the RMHD approach, and (iii) a hybrid fluid-particle approach is used. The resulting emission maps were compared to the example of the radio galaxy Centaurus A. Methods. We applied the Lagrangian particle module implemented in the latest version of the PLUTO code. This new module contains a state-of-the-art algorithm for modeling diffusive shock acceleration and for accounting for radiative losses in RMHD jet simulations. The module implements the physical postulates missing in RMHD jet simulations by accounting for a cooled ambient medium and strengthening the central jet emission. Results. We find a distinction between the innermost structure of the jet and the back-flowing material by mimicking the radio emission of the Seyfert II radio galaxy Centaurus A when considering an edge-brightened jet with an underlying purely toroidal magnetic field. We demonstrate the necessity of synchrotron cooling as well as the improvements gained when directly accounting for non-thermal synchrotron radiation via non-thermal particles.

Published
2024

4. Analytic approximations for massive close post-mass transfer binary systems

Author

Schürmann, Christoph, Langer, Norbert, Kramer, Joana A., Marchant, Pablo, Wang, Chen, and Sen, Koushik

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

Massive binary evolution models are needed to predict massive star populations in star forming galaxies, the supernova diversity, and the number and properties of gravitational wave sources. Such models are often computed using so called rapid binary evolution codes, which approximate the evolution of the binary components based on detailed single star models. However, about one third of the interacting massive binary stars undergo mass transfer during core hydrogen burning (Case A mass transfer), whose outcome is difficult to derive from single star models. Here, we use a large grid of detailed binary evolution models for primaries in the initial mass range 10 to 40 Solar masses of LMC and SMC composition, to derive analytic fits for the key quantities needed in rapid binary evolution codes, i.e., the duration of core hydrogen burning, and the resulting donor star mass. Systems with shorter orbital periods produce up to 50% lighter stripped donors and have a up to 30% larger lifetime than wider systems. We find that both quantities depend strongly on the initial binary orbital period, but that the initial mass ratio and the mass transfer efficiency of the binary have little impact on the outcome. Our results are easily parameterisable and can be used to capture the effects of Case A mass transfer more accurately in rapid binary evolution codes., Comment: 10 pages

Published
2024
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5. The Repeating Flaring Activity of Blazar AO 0235+164

Author

Pedrosa, Juan Escudero, Agudo, Iván, Tramacere, Andrea, Marscher, Alan P., Jorstad, Svetlana, Weaver, Z. R., Casadio, Carolina, Thum, Clemens, Myserlis, Ioannis, Fuentes, Antonio, Traianou, Efthalia, Kim, Jae-Young, Kramer, Joana, López-Coto, Rubén, D'Ammando, Filippo, Bernardos, M., Bonnoli, Giacomo, Blinov, Dmitriy A., Borman, G. A., Grishina, T. S., Hagen-Thorn, V. A., Kopatskaya, E. N., Larionova, E. G., Larionov, V. M., Larionova, L. V., Morozova, D. A., Savchenko, S. S., Troitskiy, I. S., Troitskaya, Y. V., and Vasilyev, A. A.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Context. Blazar AO 0235+164, located at redshift z = 0.94, has undergone several sharp multi-spectral-range flaring episodes during the last decades. In particular, the episodes peaking in 2008 and 2015, that received extensive multi-wavelength coverage, exhibited interesting behavior. Aims. We study the actual origin of these two observed flares by constraining the properties of the observed photo-polarimetric variability, those of the broad-band spectral energy-distribution and the observed time-evolution behavior of the source as seen by ultra-high resolution total-flux and polarimetric Very-long-baseline interferometry (VLBI) imaging. Methods. The analysis of VLBI images allows us to constrain kinematic and geometrical parameters of the 7 mm jet. We use the Discrete Correlation Function to compute the statistical correlation and the delays between emission at different spectral ranges. Multi-epoch modeling of the spectral energy distributions allows us to propose specific models of emission; in particular for the unusual spectral features observed in this source in the X-ray region of the spectrum during strong multi spectral-range flares. Results. We find that these X-ray spectral features can be explained by an emission component originating in a separate particle distribution than the one responsible for the two standard blazar bumps. This is in agreement with the results of our correlation analysis that do not find a strong correlation between the X-rays and the remaining spectral ranges. We find that both external Compton dominated and synchrotron self-Compton dominated models can explain the observed spectral energy distributions. However, synchrotron self-Compton models are strongly favored by the delays and geometrical parameters inferred from the observations.

Published
2023
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6. Observations of Low and Intermediate Spectral Peak Blazars with the Imaging X-ray Polarimetry Explorer

Author

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

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We 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$\sigma$ level. However, we placed upper limits on the polarization degree at $\sim$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., Comment: 19 pages, 10 figures, 6 tables; submitted to the Astrophysical Journal

Published
2023

7. Probing plasma composition with the next generation Event Horizon Telescope (ngEHT)

Author

Emami, Razieh, Anantua, Richard, Ricarte, Angelo, Doeleman, Sheperd S., Broderick, Avery, Wong, George, Blackburn, Lindy, Wielgus, Maciek, Narayan, Ramesh, Tremblay, Grant, Alcock, Charles, Hernquist, Lars, Smith, Randall, Liska, Matthew, Natarajan, Priyamvada, Vogelsberger, Mark, Curd, Brandon, and Kramer, Joana A.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, High Energy Physics - Phenomenology
Abstract

We explore the plasma matter content in the innermost accretion disk/jet in M87* as relevant for an enthusiastic search for the signatures of anti-matter in the next generation of the Event Horizon Telescope (ngEHT). We model the impact of non-zero positron-to-electron ratio using different emission models including a constant electron to magnetic pressure (constant $\beta_e$ model) with a population of non-thermal electrons as well as a R-beta model populated with thermal electrons. In the former case, we pick a semi-analytic fit to the force-free region of a general relativistic magnetohydrodynamic (GRMHD) simulation, while in the latter case, we analyze the GRMHD simulations directly. In both cases, positrons are being added at the post-processing level. We generate polarized images and spectra for some of these models and find out that at the radio frequencies, both of the linear and the circular polarizations get enhanced per adding pairs. On the contrary, we show that at higher frequencies a substantial positron fraction washes out the circular polarization. We report strong degeneracies between different emission models and the positron fraction, though our non-thermal models show more sensitivities to the pair fraction than the thermal models. We conclude that a large theoretical image library is indeed required to fully understand the trends probed in this study, and to place them in the context of large set of parameters which also affect polarimetric images, such as magnetic field strength, black hole spin, and detailed aspects of the electron temperature and the distribution function., Comment: 14 pages, 9 figures

Published
2022

8. Ray-Tracing in Relativistic Jet Simulations: A Polarimetric Study of Magnetic Field Morphology and Electron Scaling Relations

Author

Kramer, Joana A. and MacDonald, Nicholas R.

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

The jets emanating from the centers of active galactic nuclei (AGN) are among the most energetic objects in the universe. Investigating how the morphology of the jet's synchrotron emission depends on the magnetic nature of the jet's relativistic plasma is fundamental to the comparison between numerical simulations and the observed polarization of relativistic jets. Through the use of 3D relativistic magnetohydrodynamic (RMHD) jet simulations (computed using the PLUTO code) we study how the jet's synchrotron emission depends upon the morphology of the jet's magnetic field structure. Through the application of polarized radiative transfer and ray-tracing (via the RADMC-3D code) we create synthetic radio maps of the jet's total intensity as well as the linearly and circularly polarized intensity for each jet simulation. In particular, we create synthetic ray-traced images of the jet's polarized synchrotron emission when the jet carries a predominantly poloidal, helical, and toroidal magnetic field. We also explore several scaling relations in which the underlying electron power-law distribution is set proportional to: (i) the jet's thermal plasma density, (ii) the jet's internal energy density, and (iii) the jet's magnetic energy density. We find that: (i) the jet emission is edge brightened when the magnetic field is toroidal in nature and spine brightened when the magnetic field is poloidal in nature, (ii) the circularly polarized emission exhibits both negative and positive signs for the toroidal magnetic field morphology at an inclination of 45{\deg} as well as 5{\deg}, and (iii) the relativistic jet's emission is largely independent of different emission scaling relations when the ambient medium is excluded., Comment: 17 pages, 92 figures, Accepted for publication in A&A

Published
2021
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9. Repeating flaring activity of the blazar AO 0235+164

Author

Escudero Pedrosa, Juan, primary, Agudo, Iván, additional, Tramacere, Andrea, additional, Alan Marscher, P., additional, Jorstad, Svetlana, additional, Weaver, Z.R., additional, Casadio, Carolina, additional, Thum, Clemens, additional, Myserlis, Ioannis, additional, Fuentes, Antonio, additional, Traianou, Efthalia, additional, Kim, Jae-Young, additional, Kramer, Joana, additional, López-Coto, Rubén, additional, D'Ammando, Filippo, additional, Bernardos, M., additional, Bonnoli, Giacomo, additional, Dmitriy Blinov, A., additional, Borman, G.A., additional, Grishina, T.S., additional, Hagen-Thorn, V.A., additional, Kopatskaya, E.N., additional, Larionova, E.G., additional, Larionov, V.M., additional, Larionova, L.V., additional, Morozova, D.A., additional, Savchenko, S.S., additional, Troitskiy, I.S., additional, Troitskaya, Y.V., additional, and Vasilyev, A.A., additional

Published
2023
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10. Polarimetric Geometric Modeling for mm-VLBI Observations of Black Holes

Author

Roelofs, Freek, primary, Johnson, Michael D., additional, Chael, Andrew, additional, Janssen, Michael, additional, Wielgus, Maciek, additional, Broderick, Avery E., additional, Akiyama, Kazunori, additional, Alberdi, Antxon, additional, Alef, Walter, additional, Algaba, Juan Carlos, additional, Anantua, Richard, additional, Asada, Keiichi, additional, Azulay, Rebecca, additional, Bach, Uwe, additional, Baczko, Anne-Kathrin, additional, Ball, David, additional, Baloković, Mislav, additional, Barrett, John, additional, Bauböck, Michi, additional, Benson, Bradford A., additional, Bintley, Dan, additional, Blackburn, Lindy, additional, Blundell, Raymond, additional, Bouman, Katherine L., additional, Bower, Geoffrey C., additional, Boyce, Hope, additional, Bremer, Michael, additional, Brinkerink, Christiaan D., additional, Brissenden, Roger, additional, Britzen, Silke, additional, Broguiere, Dominique, additional, Bronzwaer, Thomas, additional, Bustamante, Sandra, additional, Byun, Do-Young, additional, Carlstrom, John E., additional, Ceccobello, Chiara, additional, Chan, Chi-kwan, additional, Chang, Dominic O., additional, Chatterjee, Koushik, additional, Chatterjee, Shami, additional, Chen, Ming-Tang, additional, Chen 陈, Yongjun 永军, additional, Cheng, Xiaopeng, additional, Cho, Ilje, additional, Christian, Pierre, additional, Conroy, Nicholas S., additional, Conway, John E., additional, Cordes, James M., additional, Crawford, Thomas M., additional, Crew, Geoffrey B., additional, Cruz-Osorio, Alejandro, additional, Cui 崔, Yuzhu 玉竹, additional, Dahale, Rohan, additional, Davelaar, Jordy, additional, De Laurentis, Mariafelicia, additional, Deane, Roger, additional, Dempsey, Jessica, additional, Desvignes, Gregory, additional, Dexter, Jason, additional, Dhruv, Vedant, additional, Doeleman, Sheperd S., additional, Dougal, Sean, additional, Dzib, Sergio A., additional, Eatough, Ralph P., additional, Emami, Razieh, additional, Falcke, Heino, additional, Farah, Joseph, additional, Fish, Vincent L., additional, Fomalont, Ed, additional, Ford, H. Alyson, additional, Foschi, Marianna, additional, Fraga-Encinas, Raquel, additional, Freeman, William T., additional, Friberg, Per, additional, Fromm, Christian M., additional, Fuentes, Antonio, additional, Galison, Peter, additional, Gammie, Charles F., additional, García, Roberto, additional, Gentaz, Olivier, additional, Georgiev, Boris, additional, Goddi, Ciriaco, additional, Gold, Roman, additional, Gómez-Ruiz, Arturo I., additional, Gómez, José L., additional, Gu 顾, Minfeng 敏峰, additional, Gurwell, Mark, additional, Hada, Kazuhiro, additional, Haggard, Daryl, additional, Haworth, Kari, additional, Hecht, Michael H., additional, Hesper, Ronald, additional, Heumann, Dirk, additional, Ho 何, Luis C. 子山, additional, Ho, Paul, additional, Honma, Mareki, additional, Huang, Chih-Wei L., additional, Huang 黄, Lei 磊, additional, Hughes, David H., additional, Ikeda, Shiro, additional, Impellizzeri, C. M. Violette, additional, Inoue, Makoto, additional, Issaoun, Sara, additional, James, David J., additional, Jannuzi, Buell T., additional, Jeter, Britton, additional, Jiang 江, Wu 悟, additional, Jiménez-Rosales, Alejandra, additional, Jorstad, Svetlana, additional, Joshi, Abhishek V., additional, Jung, Taehyun, additional, Karami, Mansour, additional, Karuppusamy, Ramesh, additional, Kawashima, Tomohisa, additional, Keating, Garrett K., additional, Kettenis, Mark, additional, Kim, Dong-Jin, additional, Kim, Jae-Young, additional, Kim, Jongsoo, additional, Kim, Junhan, additional, Kino, Motoki, additional, Koay, Jun Yi, additional, Kocherlakota, Prashant, additional, Kofuji, Yutaro, additional, Koch, Patrick M., additional, Koyama, Shoko, additional, Kramer, Carsten, additional, Kramer, Joana A., additional, Kramer, Michael, additional, Krichbaum, Thomas P., additional, Kuo, Cheng-Yu, additional, La Bella, Noemi, additional, Lauer, Tod R., additional, Lee, Daeyoung, additional, Lee, Sang-Sung, additional, Leung, Po Kin, additional, Levis, Aviad, additional, Li 李, Zhiyuan 志远, additional, Lico, Rocco, additional, Lindahl, Greg, additional, Lindqvist, Michael, additional, Lisakov, Mikhail, additional, Liu 刘, Jun 俊, additional, Liu, Kuo, additional, Liuzzo, Elisabetta, additional, Lo, Wen-Ping, additional, Lobanov, Andrei P., additional, Loinard, Laurent, additional, Lonsdale, Colin J., additional, Lowitz, Amy E., additional, Lu 路, Ru-Sen 如森, additional, MacDonald, Nicholas R., additional, Mao 毛, Jirong 基荣, additional, Marchili, Nicola, additional, Markoff, Sera, additional, Marrone, Daniel P., additional, Marscher, Alan P., additional, Martí-Vidal, Iván, additional, Matsushita, Satoki, additional, Matthews, Lynn D., additional, Medeiros, Lia, additional, Menten, Karl M., additional, Michalik, Daniel, additional, Mizuno, Izumi, additional, Mizuno, Yosuke, additional, Moran, James M., additional, Moriyama, Kotaro, additional, Moscibrodzka, Monika, additional, Mulaudzi, Wanga, additional, Müller, Cornelia, additional, Müller, Hendrik, additional, Mus, Alejandro, additional, Musoke, Gibwa, additional, Myserlis, Ioannis, additional, Nadolski, Andrew, additional, Nagai, Hiroshi, additional, Nagar, Neil M., additional, Nakamura, Masanori, additional, Narayan, Ramesh, additional, Narayanan, Gopal, additional, Natarajan, Iniyan, additional, Nathanail, Antonios, additional, Fuentes, Santiago Navarro, additional, Neilsen, Joey, additional, Neri, Roberto, additional, Ni, Chunchong, additional, Noutsos, Aristeidis, additional, Nowak, Michael A., additional, Oh, Junghwan, additional, Okino, Hiroki, additional, Olivares, Héctor, additional, Ortiz-León, Gisela N., additional, Oyama, Tomoaki, additional, Özel, Feryal, additional, Palumbo, Daniel C. M., additional, Paraschos, Georgios Filippos, additional, Park, Jongho, additional, Parsons, Harriet, additional, Patel, Nimesh, additional, Pen, Ue-Li, additional, Pesce, Dominic W., additional, Piétu, Vincent, additional, Plambeck, Richard, additional, PopStefanija, Aleksandar, additional, Porth, Oliver, additional, Pötzl, Felix M., additional, Prather, Ben, additional, Preciado-López, Jorge A., additional, Psaltis, Dimitrios, additional, Pu, Hung-Yi, additional, Ramakrishnan, Venkatessh, additional, Rao, Ramprasad, additional, Rawlings, Mark G., additional, Raymond, Alexander W., additional, Rezzolla, Luciano, additional, Ricarte, Angelo, additional, Ripperda, Bart, additional, Rogers, Alan, additional, Romero-Cañizales, Cristina, additional, Ros, Eduardo, additional, Roshanineshat, Arash, additional, Rottmann, Helge, additional, Roy, Alan L., additional, Ruiz, Ignacio, additional, Ruszczyk, Chet, additional, Rygl, Kazi L. J., additional, Sánchez, Salvador, additional, Sánchez-Argüelles, David, additional, Sánchez-Portal, Miguel, additional, Sasada, Mahito, additional, Satapathy, Kaushik, additional, Savolainen, Tuomas, additional, Schloerb, F. Peter, additional, Schonfeld, Jonathan, additional, Schuster, Karl-Friedrich, additional, Shao, Lijing, additional, Shen 沈, Zhiqiang 志强, additional, Small, Des, additional, Sohn, Bong Won, additional, SooHoo, Jason, additional, Sosapanta Salas, León David, additional, Souccar, Kamal, additional, Sun 孙, He 赫, additional, Tazaki, Fumie, additional, Tetarenko, Alexandra J., additional, Tiede, Paul, additional, Tilanus, Remo P. J., additional, Titus, Michael, additional, Torne, Pablo, additional, Toscano, Teresa, additional, Traianou, Efthalia, additional, Trent, Tyler, additional, Trippe, Sascha, additional, Turk, Matthew, additional, van Bemmel, Ilse, additional, van Langevelde, Huib Jan, additional, van Rossum, Daniel R., additional, Vos, Jesse, additional, Wagner, Jan, additional, Ward-Thompson, Derek, additional, Wardle, John, additional, Washington, Jasmin E., additional, Weintroub, Jonathan, additional, Wharton, Robert, additional, Wiik, Kaj, additional, Witzel, Gunther, additional, Wondrak, Michael F., additional, Wong, George N., additional, Wu 吴, Qingwen 庆文, additional, Yadlapalli, Nitika, additional, Yamaguchi, Paul, additional, Yfantis, Aristomenis, additional, Yoon, Doosoo, additional, Young, André, additional, Young, Ken, additional, Younsi, Ziri, additional, Yu 于, Wei 威, additional, Yuan 袁, Feng 峰, additional, Yuan 袁, Ye-Fei 业飞, additional, Zensus, J. Anton, additional, Zhang, Shuo, additional, Zhao, Guang-Yao, additional, and Zhao 赵, Shan-Shan 杉杉, additional

Published
2023
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11. Polarimetric Geometric Modeling for mm-VLBI Observations of Black Holes

Author

Roelofs, Freek, Johnson, Michael D., Chael, Andrew, Janssen, Michael, Wielgus, Maciek, Broderick, Avery E., Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Algaba, Juan Carlos, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Bach, Uwe, Baczko, Anne-Kathrin, Ball, David, Baloković, Mislav, Barrett, John, Bauböck, Michi, Benson, Bradford A., Bintley, Dan, Blackburn, Lindy, Blundell, Raymond, Bouman, Katherine L., Bower, Geoffrey C., Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broguiere, Dominique, Bronzwaer, Thomas, Bustamante, Sandra, Byun, Do-Young, Carlstrom, John E., Ceccobello, Chiara, Chan, Chi-kwan, Chang, Dominic O., Chatterjee, Koushik, Chatterjee, Shami, Chen, Ming-Tang, Chen, Yongjun, Cheng, Xiaopeng, Cho, Ilje, Christian, Pierre, Conroy, Nicholas S., Conway, John E., Cordes, James M., Crawford, Thomas M., Crew, Geoffrey B., Cruz-Osorio, Alejandro, Cui, Yuzhu, Dahale, Rohan, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dexter, Jason, Dhruv, Vedant, Doeleman, Sheperd S., Dougal, Sean, Dzib, Sergio A., Eatough, Ralph P., Emami, Razieh, Falcke, Heino, Farah, Joseph, Fish, Vincent L., Fomalont, Ed, Ford, H. Alyson, Foschi, Marianna, Fraga-Encinas, Raquel, Freeman, William T., Friberg, Per, Fromm, Christian M., Fuentes, Antonio, Galison, Peter, Gammie, Charles F., García, Roberto, Gentaz, Olivier, Georgiev, Boris, Goddi, Ciriaco, Gold, Roman, Gómez-Ruiz, Arturo I., Gómez, José L., Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Haggard, Daryl, Haworth, Kari, Hecht, Michael H., Hesper, Ronald, Heumann, Dirk, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Impellizzeri, C. M. Violette, Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Jeter, Britton, Jiang, Wu, Jiménez-Rosales, Alejandra, Jorstad, Svetlana, Joshi, Abhishek V., Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kim, Junhan, Kino, Motoki, Koay, Jun Yi, Kocherlakota, Prashant, Kofuji, Yutaro, Koch, Patrick M., Koyama, Shoko, Kramer, Carsten, Kramer, Joana A., Kramer, Michael, Krichbaum, Thomas P., Kuo, Cheng-Yu, La Bella, Noemi, Lauer, Tod R., Lee, Daeyoung, Lee, Sang-Sung, Leung, Po Kin, Levis, Aviad, Li, Zhiyuan, Lico, Rocco, Lindahl, Greg, Lindqvist, Michael, Lisakov, Mikhail, Liu, Jun, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin J., Lowitz, Amy E., Lu, Ru-Sen, MacDonald, Nicholas R., Mao, Jirong, Marchili, Nicola, Markoff, Sera, Marrone, Daniel P., Marscher, Alan P., Martí-Vidal, Iván, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Michalik, Daniel, Mizuno, Izumi, Mizuno, Yosuke, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Mulaudzi, Wanga, Müller, Cornelia, Müller, Hendrik, Mus, Alejandro, Musoke, Gibwa, Myserlis, Ioannis, Nadolski, Andrew, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayanan, Gopal, Natarajan, Iniyan, Nathanail, Antonios, Fuentes, Santiago Navarro, Neilsen, Joey, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Nowak, Michael A., Oh, Junghwan, Okino, Hiroki, Olivares, Héctor, Ortiz-León, Gisela N., Oyama, Tomoaki, Özel, Feryal, Palumbo, Daniel C. M., Paraschos, Georgios Filippos, Park, Jongho, Parsons, Harriet, Patel, Nimesh, Pen, Ue-Li, Pesce, Dominic W., Piétu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Pötzl, Felix M., Prather, Ben, Preciado-López, Jorge A., Psaltis, Dimitrios, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Rezzolla, Luciano, Ricarte, Angelo, Ripperda, Bart, Rogers, Alan, Romero-Cañizales, Cristina, Ros, Eduardo, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruiz, Ignacio, Ruszczyk, Chet, Rygl, Kazi L. J., Sánchez, Salvador, Sánchez-Argüelles, David, Sánchez-Portal, Miguel, Sasada, Mahito, Satapathy, Kaushik, Savolainen, Tuomas, Schloerb, F. Peter, Schonfeld, Jonathan, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Sosapanta Salas, León David, Souccar, Kamal, Sun, He, Tazaki, Fumie, Tetarenko, Alexandra J., Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Torne, Pablo, Toscano, Teresa, Traianou, Efthalia, Trent, Tyler, Trippe, Sascha, Turk, Matthew, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Vos, Jesse, Wagner, Jan, Ward-Thompson, Derek, Wardle, John, Washington, Jasmin E., Weintroub, Jonathan, Wharton, Robert, Wiik, Kaj, Witzel, Gunther, Wondrak, Michael F., Wong, George N., Wu, Qingwen, Yadlapalli, Nitika, Yamaguchi, Paul, Yfantis, Aristomenis, Yoon, Doosoo, Young, André, Young, Ken, Younsi, Ziri, Yu, Wei, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhang, Shuo, Zhao, Guang-Yao, Zhao, Shan-Shan, Roelofs, Freek, Johnson, Michael D., Chael, Andrew, Janssen, Michael, Wielgus, Maciek, Broderick, Avery E., Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Algaba, Juan Carlos, Anantua, Richard, Asada, Keiichi, Azulay, Rebecca, Bach, Uwe, Baczko, Anne-Kathrin, Ball, David, Baloković, Mislav, Barrett, John, Bauböck, Michi, Benson, Bradford A., Bintley, Dan, Blackburn, Lindy, Blundell, Raymond, Bouman, Katherine L., Bower, Geoffrey C., Boyce, Hope, Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broguiere, Dominique, Bronzwaer, Thomas, Bustamante, Sandra, Byun, Do-Young, Carlstrom, John E., Ceccobello, Chiara, Chan, Chi-kwan, Chang, Dominic O., Chatterjee, Koushik, Chatterjee, Shami, Chen, Ming-Tang, Chen, Yongjun, Cheng, Xiaopeng, Cho, Ilje, Christian, Pierre, Conroy, Nicholas S., Conway, John E., Cordes, James M., Crawford, Thomas M., Crew, Geoffrey B., Cruz-Osorio, Alejandro, Cui, Yuzhu, Dahale, Rohan, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dexter, Jason, Dhruv, Vedant, Doeleman, Sheperd S., Dougal, Sean, Dzib, Sergio A., Eatough, Ralph P., Emami, Razieh, Falcke, Heino, Farah, Joseph, Fish, Vincent L., Fomalont, Ed, Ford, H. Alyson, Foschi, Marianna, Fraga-Encinas, Raquel, Freeman, William T., Friberg, Per, Fromm, Christian M., Fuentes, Antonio, Galison, Peter, Gammie, Charles F., García, Roberto, Gentaz, Olivier, Georgiev, Boris, Goddi, Ciriaco, Gold, Roman, Gómez-Ruiz, Arturo I., Gómez, José L., Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Haggard, Daryl, Haworth, Kari, Hecht, Michael H., Hesper, Ronald, Heumann, Dirk, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Impellizzeri, C. M. Violette, Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Jeter, Britton, Jiang, Wu, Jiménez-Rosales, Alejandra, Jorstad, Svetlana, Joshi, Abhishek V., Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Dong-Jin, Kim, Jae-Young, Kim, Jongsoo, Kim, Junhan, Kino, Motoki, Koay, Jun Yi, Kocherlakota, Prashant, Kofuji, Yutaro, Koch, Patrick M., Koyama, Shoko, Kramer, Carsten, Kramer, Joana A., Kramer, Michael, Krichbaum, Thomas P., Kuo, Cheng-Yu, La Bella, Noemi, Lauer, Tod R., Lee, Daeyoung, Lee, Sang-Sung, Leung, Po Kin, Levis, Aviad, Li, Zhiyuan, Lico, Rocco, Lindahl, Greg, Lindqvist, Michael, Lisakov, Mikhail, Liu, Jun, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin J., Lowitz, Amy E., Lu, Ru-Sen, MacDonald, Nicholas R., Mao, Jirong, Marchili, Nicola, Markoff, Sera, Marrone, Daniel P., Marscher, Alan P., Martí-Vidal, Iván, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Michalik, Daniel, Mizuno, Izumi, Mizuno, Yosuke, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Mulaudzi, Wanga, Müller, Cornelia, Müller, Hendrik, Mus, Alejandro, Musoke, Gibwa, Myserlis, Ioannis, Nadolski, Andrew, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayanan, Gopal, Natarajan, Iniyan, Nathanail, Antonios, Fuentes, Santiago Navarro, Neilsen, Joey, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Nowak, Michael A., Oh, Junghwan, Okino, Hiroki, Olivares, Héctor, Ortiz-León, Gisela N., Oyama, Tomoaki, Özel, Feryal, Palumbo, Daniel C. M., Paraschos, Georgios Filippos, Park, Jongho, Parsons, Harriet, Patel, Nimesh, Pen, Ue-Li, Pesce, Dominic W., Piétu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Pötzl, Felix M., Prather, Ben, Preciado-López, Jorge A., Psaltis, Dimitrios, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Rezzolla, Luciano, Ricarte, Angelo, Ripperda, Bart, Rogers, Alan, Romero-Cañizales, Cristina, Ros, Eduardo, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruiz, Ignacio, Ruszczyk, Chet, Rygl, Kazi L. J., Sánchez, Salvador, Sánchez-Argüelles, David, Sánchez-Portal, Miguel, Sasada, Mahito, Satapathy, Kaushik, Savolainen, Tuomas, Schloerb, F. Peter, Schonfeld, Jonathan, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Sosapanta Salas, León David, Souccar, Kamal, Sun, He, Tazaki, Fumie, Tetarenko, Alexandra J., Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Torne, Pablo, Toscano, Teresa, Traianou, Efthalia, Trent, Tyler, Trippe, Sascha, Turk, Matthew, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Vos, Jesse, Wagner, Jan, Ward-Thompson, Derek, Wardle, John, Washington, Jasmin E., Weintroub, Jonathan, Wharton, Robert, Wiik, Kaj, Witzel, Gunther, Wondrak, Michael F., Wong, George N., Wu, Qingwen, Yadlapalli, Nitika, Yamaguchi, Paul, Yfantis, Aristomenis, Yoon, Doosoo, Young, André, Young, Ken, Younsi, Ziri, Yu, Wei, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhang, Shuo, Zhao, Guang-Yao, and Zhao, Shan-Shan

Abstract

The Event Horizon Telescope (EHT) is a millimeter very long baseline interferometry (VLBI) array that has imaged the apparent shadows of the supermassive black holes M87* and Sagittarius A*. Polarimetric data from these observations contain a wealth of information on the black hole and accretion flow properties. In this work, we develop polarimetric geometric modeling methods for mm-VLBI data, focusing on approaches that fit data products with differing degrees of invariance to broad classes of calibration errors. We establish a fitting procedure using a polarimetric “m-ring” model to approximate the image structure near a black hole. By fitting this model to synthetic EHT data from general relativistic magnetohydrodynamic models, we show that the linear and circular polarization structure can be successfully approximated with relatively few model parameters. We then fit this model to EHT observations of M87* taken in 2017. In total intensity and linear polarization, the m-ring fits are consistent with previous results from imaging methods. In circular polarization, the m-ring fits indicate the presence of event-horizon-scale circular polarization structure, with a persistent dipolar asymmetry and orientation across several days. The same structure was recovered independently of observing band, used data products, and model assumptions. Despite this broad agreement, imaging methods do not produce similarly consistent results. Our circular polarization results, which imposed additional assumptions on the source structure, should thus be interpreted with some caution. Polarimetric geometric modeling provides a useful and powerful method to constrain the properties of horizon-scale polarized emission, particularly for sparse arrays like the EHT.

Published
2023

12. Magnetohydrodynamic Processes and Polarized Emission in AGN Jets

Author

Hoellmer (neé Kramer), Joana Anna and Hoellmer (neé Kramer), Joana Anna

Abstract

Active galactic nuclei (AGN) stand out as some of the most powerful entities in the universe. At their core lies a supermassive black hole (SMBH) with a mass ranging up to several billion times the mass of the Sun, surrounded by an accretion disk that feeds the system. As matter falls toward the black hole, a portion of it is expelled perpendicularly to the accretion disk, forming what we call jets. These relativistic flows are highly collimated and can travel enormous distances up to kiloparsecs away from the central engine. The radiation emitted by AGN jets display significant features in structure across the electromagnetic spectrum and in polarized emission, reflecting changes in intrinsic parameters, such as the magnetic field and the rest-mass density. It is essential to understand how magnetic properties of the relativistic plasma impact the morphology of polarized synchrotron emission in jets. In order to study this, it is necessary to compare numerical simulations to the observed structure of the polarized radio signal in relativistic jets and to uncover the nature of the underlying physics. To investigate the structural behaviour of polarized AGN jets, I employ a numer- ical laboratory using a three-dimensional relativistic magnetohydrodynamic (RMHD) module within the PLUTO code. I study how non-thermal synchrotron radiation, re- sulting from relativistic electrons spiraling around magnetic field lines, is affected by three primary factors: first, the implementation of various magnetic field morphologies, such as purely poloidal, helical, and purely toroidal; second, the application of differ- ent electron scaling relations to map non-thermal physics from the thermal parameters calculated in each simulation; and third, the requirement for a jet tracer to exclude the non-cooled ambient medium in RMHD codes. This study analyzes for the first time the polarized synthetic synchrotron emission in full Stokes. This results in major find- ings: The synthetic maps

Published
2023

13. Probing Plasma Composition with the Next Generation Event Horizon Telescope (ngEHT)

Author

Massachusetts Institute of Technology. Department of Physics, MIT Kavli Institute for Astrophysics and Space Research, Emami, Razieh, Anantua, Richard, Ricarte, Angelo, Doeleman, Sheperd S., Broderick, Avery, Wong, George, Blackburn, Lindy, Wielgus, Maciek, Narayan, Ramesh, Tremblay, Grant, Alcock, Charles, Hernquist, Lars, Smith, Randall, Liska , Matthew, Natarajan, Priyamvada, Vogelsberger, Mark, Curd, Brandon, Kramer , Joana A., Massachusetts Institute of Technology. Department of Physics, MIT Kavli Institute for Astrophysics and Space Research, Emami, Razieh, Anantua, Richard, Ricarte, Angelo, Doeleman, Sheperd S., Broderick, Avery, Wong, George, Blackburn, Lindy, Wielgus, Maciek, Narayan, Ramesh, Tremblay, Grant, Alcock, Charles, Hernquist, Lars, Smith, Randall, Liska , Matthew, Natarajan, Priyamvada, Vogelsberger, Mark, Curd, Brandon, and Kramer , Joana A.

Abstract

We explore the plasma matter content in the innermost accretion disk/jet in M87* as relevant for an enthusiastic search for the signatures of anti-matter in the next generation of the Event Horizon Telescope (ngEHT). We model the impact of non-zero positron-to-electron ratio using different emission models, including a constant electron to magnetic pressure (constant βeemantics> model) with a population of non-thermal electrons as well as an R-beta model populated with thermal electrons. In the former case, we pick a semi-analytic fit to the force-free region of a general relativistic magnetohydrodynamic (GRMHD) simulation, while in the latter case, we analyze the GRMHD simulations directly. In both cases, positrons are being added at the post-processing level. We generate polarized images and spectra for some of these models and find out that at the radio frequencies, both of the linear and the circular polarizations are enhanced with every pair added. On the contrary, we show that, at higher frequencies, a substantial positron fraction washes out the circular polarization. We report strong degeneracies between different emission models and the positron fraction, though our non-thermal models show more sensitivities to the pair fraction than the thermal models. We conclude that a large theoretical image library is indeed required to fully understand the trends probed in this study, and to place them in the context of a large set of parameters which also affect polarimetric images, such as magnetic field strength, black hole spin, and detailed aspects of the electron temperature and the distribution function.

Published
2023

14. Probing Plasma Composition with the Next Generation Event Horizon Telescope (ngEHT)

Author

Emami, Razieh, primary, Anantua, Richard, additional, Ricarte, Angelo, additional, Doeleman, Sheperd S., additional, Broderick, Avery, additional, Wong, George, additional, Blackburn, Lindy, additional, Wielgus, Maciek, additional, Narayan, Ramesh, additional, Tremblay, Grant, additional, Alcock, Charles, additional, Hernquist, Lars, additional, Smith, Randall, additional, Liska , Matthew, additional, Natarajan, Priyamvada, additional, Vogelsberger, Mark, additional, Curd, Brandon, additional, and Kramer , Joana A., additional

Published
2023
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