Author: "Marin, Frederic" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Marin, Frederic"' showing total 235 results

Start Over Author "Marin, Frederic"

235 results on '"Marin, Frederic"'

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

Author: Wong, Josephine, Mizuno, Tsunefumi, Bucciantini, Niccoló, Romani, Roger W., Yang, Yi-Jung, Liu, Kuan, Deng, Wei, Goya, Kazuho, Xie, Fei, Pilia, Maura, Kaaret, Philip, Weisskopf, Martin C., Silvestri, Stefano, Ng, C. -Y., Chen, Chien-Ting, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccoló, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Negro, Michela, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel Lawrence, Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Sgró, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey, Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present Crab X-ray polarization measurements using IXPE data with a total exposure of 300ks, three times more than the initial 2022 discovery paper. Polarization is detected in three times more pulsar phase bins, revealing an S-shaped $+40^\circ$ polarization angle sweep in the main pulse and ${>}1\sigma$ departures from the OPTIMA optical polarization in both pulses, suggesting different radiation mechanisms or sites for the polarized emission at the two wavebands. Our polarization map of the inner nebula reveals a toroidal magnetic field, as seen in prior IXPE analyses. Along the southern jet, the magnetic field orientation relative to the jet axis changes from perpendicular to parallel and the polarization degree decreases by ${\sim}6\%$. These observations may be explained by kink instabilities along the jet or a collision with a dense, jet-deflecting medium at the tip. Using spectropolarimetric analysis, we find asymmetric polarization in the four quadrants of the inner nebula, as expected for a toroidal field geometry, and a spatial correlation between polarization degree and photon index., Comment: 14 pages, 7 figures, 3 tables. Accepted by The Astrophysical Journal
Published: 2024

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

Author: Chen, Chien-Ting J., Liodakis, Ioannis, Middei, Riccardo, Kim, Dawoon E., Di Gesu, Laura, Di Marco, Alessandro, Ehlert, Steven R., Errando, Manel, Negro, Michela, Jorstad, Svetlana G., Marscher, Alan P., Wu, Kinwah, Agudo, Iván, Poutanen, Juri, Mizuno, Tsunefumi, Kouch, Pouya M., Lindfors, Elina, Borman, George A., Grishina, Tatiana S., Kopatskaya, Evgenia N., Larionova, Elena G., Morozova, Daria A., Savchenko, Sergey S., Troitsky, Ivan S., Troitskaya, Yulia V., Vasilyev, Andrey A., Zhovtan, Alexey V., Aceituno, Francisco José, Bonnoli, Giacomo, Casanova, Víctor, Escudero, Juan, Agís-González, Beatriz, Husillos, César, Santos, Jorge Otero, Sota, Alfredo, Piirola, Vilppu, Myserlis, Ioannis, Angelakis, Emmanouil, Kraus, Alexander, Gurwell, Mark, Keating, Garrett, Rao, Ramprasad, Kang, Sincheol, Lee, Sang-Sung, Kim, Sang-Hyun, Cheong, Whee Yeon, Jeong, Hyeon-Woo, Song, Chanwoo, Berdyugin, Andrei V., Kagitani, Masato, Kravtsov, Vadim, Nitindala, Anagha P., Sakanoi, Takeshi, Imazawa, Ryo, Sasada, Mahito, Fukazawa, Yasushi, Kawabata, Koji S., Uemura, Makoto, Nakaoka, Tatsuya, Akitaya, Hiroshi, Casadio, Carolina, Sievers, Albrecht, Antonelli, Lucio Angelo, Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccoló, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Lalla, Niccoló, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel Lawrence, Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgró, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract: We present multiwavelength polarization measurements of the luminous blazar Mrk~501 over a 14-month period. The 2--8 keV X-ray polarization was measured with the Imaging X-ray Polarimetry Explorer (IXPE) with six 100-ks observations spanning from 2022 March to 2023 April. Each IXPE observation was accompanied by simultaneous X-ray data from NuSTAR, Swift/XRT, and/or XMM-Newton. Complementary optical-infrared polarization measurements were also available in the B, V, R, I, and J bands, as were radio polarization measurements from 4.85 GHz to 225.5 GHz. Among the first five IXPE observations, we did not find significant variability in the X-ray polarization degree and angle with IXPE. However, the most recent sixth observation found an elevated polarization degree at $>3\sigma$ above the average of the other five observations. The optical and radio measurements show no apparent correlations with the X-ray polarization properties. Throughout the six IXPE observations, the X-ray polarization degree remained higher than, or similar to, the R-band optical polarization degree, which remained higher than the radio value. This is consistent with the energy-stratified shock scenario proposed to explain the first two IXPE observations, in which the polarized X-ray, optical, and radio emission arises from different regions., Comment: Accepted for publication in ApJ
Published: 2024

3. Revealing the burning and soft heart of the bright bare AGN ESO 141-G55: X-ray broadband and SED analysis

Author: Porquet, Delphine, Reeves, James N., Hagen, Scott, Lobban, Andrew, Braito, Valentina, Grosso, Nicolas, and Marin, Frédéric
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract: [Abridged] ESO 141-G55 is a nearby X-ray bright BLS1, which has been classified as a bare AGN due to the lack of warm absorption along its line-of-sight, providing an unhampered view into its disc-corona system. We aim to probe its disc-corona system thanks to the first simultaneous XMM-Newton and NuSTAR observation obtained on October 1-2, 2022. We carry out the X-ray broadband spectral analysis to determine the dominant process(es) at work, as well as the SED analysis to determine the disc-corona properties. The simultaneous broadband X-ray spectrum of ESO 141-G55 is characterised by the presence of a prominent smooth soft X-ray excess, a broad Fe K emission line and a significant Compton hump. The RGS spectra confirmed the lack of intrinsic warm-absorbing gas along our line of sight in the AGN rest frame, confirming that it is still in a bare state. However, soft X-ray emission lines are observed indicating substantial warm gas out of our line of sight. The intermediate inclination of the disc-corona system, ~43{\deg}, may offer us a favourable configuration to observe UFOs from the disc, but none is found in this 2022 observation, contrary to a previous 2007 XMM-Newton one. Relativistic reflection alone on a standard disc is ruled out from the X-ray broadband analysis, while a combination of soft and hard Comptonisation by a warm and hot corona (relagn), plus relativistic reflection (reflkerrd) reproduces its SED quite well. The hot corona temperature is very hot, ~140 keV, much higher than about 80% of the AGNs, whereas the warm corona temperature, ~0.3 keV, is similar to the values found in other sub-Eddington AGNs. ESO 141-G55 is accreting at a moderate Eddington accretion rate (~10--20%). Our analysis points to a significant contribution of an optically-thick warm corona to both the soft X-ray and UV emission in ESO 141-G55., Comment: 16 pages, 14 figures, 3 appendices; accepted for publication in Astronomy & Astrophysics
Published: 2024

4. Forgotten treasures in the HST/FOC UV imaging polarimetric archives of active galactic nuclei. II. Mrk 463E

Author: Barnouin, Thibault, Marin, Frédéric, and Lopez-Rodriguez, Enrique
Subjects: Astrophysics - Astrophysics of Galaxies, 85-04 (Primary), 85-08, 85A25 (Secondary), J.2, I.4.1, I.4.7, I.6.4
Abstract: The Mrk 463 system is known to host two powerful sources separated by about 4 kpc, both identified as active galactic nuclei (AGN). This makes the Mrk 463 system a unique laboratory to study the geometry and dynamics of galaxy merging and its relation to AGN duty cycles. The eastern nuclei, Mrk 463E, is the brightest of the two and thus a prime target for a polarimetric study. It is classified as a Seyfert 2 galaxy, meaning that one could expect large polarization degrees from scattering off electrons and dust in the polar winds. In the continuity of our series of papers, we reduced archived and previously unpublished polarization observations obtained with the Faint Object Camera (FOC) onboard the Hubble Space Telescope (HST), to obtain a high resolution near ultraviolet (near-UV) polarization map of the Mrk 463E nuclei. We coupled this map to near infrared (NIR) and X-ray observations to get a clear picture of the geometric arrangement of matter around the core of Mrk 463E. We found that the nucleus location is further South from the optical peak flux than previously estimated. The strongly polarized conical wind has a half-opening angle of ~15{\deg} and display three main periods of mass ejection. Its polarization allowed us to estimate the AGN inclination towards the observer (~55{\deg}) Finally, our maps revealed a gas streamer connecting Mrk 463E and Mrk 463W, with a tentative detection of a large kpc-scale ordered magnetic field connecting both galaxies. This unpublished observation turned out to offer more than the original proposal asked for and allowed to derive tight geometric and dynamical constraints for Mrk 463E. High resolution radio maps and IR polarimetry are now necessary to further study the jet and the newly discovered gas streamer., Comment: 9 pages, 7 figures, submitted Astronomy & Astrophysics, comments are welcome
Published: 2024

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

Author: Steiner, James F., Nathan, Edward, Hu, Kun, Krawczynski, Henric, Dovciak, Michal, Veledina, Alexandra, Muleri, Fabio, Svoboda, Jiri, Alabarta, Kevin, Parra, Maxime, Bhargava, Yash, Matt, Giorgio, Poutanen, Juri, Petrucci, Pierre-Olivier, Tennant, Allyn F., Baglio, M. Cristina, Baldini, Luca, Barnier, Samuel, Bhattacharyya, Sudip, Bianchi, Stefano, Brigitte, Maimouna, Cabezas, Mauricio, Cangemi, Floriane, Capitanio, Fiamma, Casey, Jacob, Cavero, Nicole Rodriguez, Castellano, Simone, Cavazzuti, Elisabetta, Chun, Sohee, Churazov, Eugene, Costa, Enrico, Di Lalla, Niccolo, Di Marco, Alessandro, Egron, Elise, Ewing, Melissa, Fabiani, Sergio, Garcia, Javier A., Green, David A., Grinberg, Victoria, Hadrava, Petr, Ingram, Adam, Kaaret, Philip, Kislat, Fabian, Kitaguchi, Takao, Kravtsov, Vadim, Kubatova, Brankica, La Monaca, Fabio, Latronico, Luca, Loktev, Vladislav, Malacaria, Christian, Marin, Frederic, Marinucci, Andrea, Maryeva, Olga, Mastroserio, Guglielmo, Mizuno, Tsunefumi, Negro, Michela, Omodei, Nicola, Podgorny, Jakub, Rankin, John, Ratheesh, Ajay, Rhodes, Lauren, Russell, David M., Slechta, Miroslav, Soffitta, Paolo, Spooner, Sean, Suleimanov, Valery, Tombesi, Francesco, Trushkin, Sergei A., Weisskopf, Martin C., Zane, Silvia, Zdziarski, Andrzej A., Zhang, Sixuan, Zhang, Wenda, Zhou, Menglei, Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kolodziejczak, Jeffery J., Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Ng, Chi-Yung, O'Dell, Stephen L., Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Thomas, Nicholas E., Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the first X-ray spectropolarimetric results for Cygnus X-1 in its soft state from a campaign of five IXPE observations conducted during 2023 May-June. Companion multiwavelength data during the campaign are likewise shown. The 2-8 keV X-rays exhibit a net polarization degree PD=1.99%+/-0.13% (68% confidence). The polarization signal is found to increase with energy across IXPE's 2-8 keV bandpass. The polarized X-rays exhibit an energy-independent polarization angle of PA=-25.7+/-1.8 deg. East of North (68% confidence). This is consistent with being aligned to Cyg X-1's AU-scale compact radio jet and its pc-scale radio lobes. In comparison to earlier hard-state observations, the soft state exhibits a factor of 2 lower polarization degree, but a similar trend with energy and a similar (also energy-independent) position angle. When scaling by the natural unit of the disk temperature, we find the appearance of a consistent trendline in the polarization degree between soft and hard states. Our favored polarimetric model indicates Cyg X-1's spin is likely high (a* above ~0.96). The substantial X-ray polarization in Cyg X-1's soft state is most readily explained as resulting from a large portion of X-rays emitted from the disk returning and reflecting off the disk surface, generating a high polarization degree and a polarization direction parallel to the black hole spin axis and radio jet. In IXPE's bandpass, the polarization signal is dominated by the returning reflection emission. This constitutes polarimetric evidence for strong gravitational lensing of X-rays close to the black hole., Comment: 20 pages, accepted for publication in ApJL
Published: 2024

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

Author: Forsblom, Sofia V., Tsygankov, Sergey S., Poutanen, Juri, Doroshenko, Victor, Mushtukov, Alexander A., Ng, Mason, Ravi, Swati, Marshall, Herman L., Di Marco, Alessandro, La Monaca, Fabio, Malacaria, Christian, Mastroserio, Guglielmo, Loktev, Vladislav, Possenti, Andrea, Suleimanov, Valery F., Taverna, Roberto, Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Dovciak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Recent observations of X-ray pulsars (XRPs) performed by the Imaging X-ray Polarimetry Explorer (IXPE) have made it possible to investigate the intricate details of these objects in a new way, thanks to the added value of X-ray polarimetry. Here we present the results of the IXPE observations of SMC X-1, a member of the small group of XRPs displaying super-orbital variability. SMC X-1 was observed by IXPE three separate times during the high state of its super-orbital period. The observed luminosity in the 2-8 keV energy band of $L=2\times10^{38}$ erg/s makes SMC X-1 the brightest XRP ever observed by IXPE. We detect significant polarization in all three observations, with values of the phase-averaged polarization degree (PD) and polarization angle (PA) of $3.2\pm0.8$% and $97\deg\pm8\deg$ for Observation 1, $3.0\pm0.9$% and $90\deg\pm8\deg$ for Observation 2, and $5.5\pm1.1$% and $80\deg\pm6\deg$ for Observation 3, for the spectro-polarimetric analysis. The observed PD shows an increase over time with decreasing luminosity, while the PA decreases in decrements of 10\deg. The phase-resolved spectro-polarimetric analysis reveals significant detection of polarization in three out of seven phase bins, with the PD ranging between 2% and 10%, and a corresponding range in the PA from $\sim$70\deg\ to $\sim$100\deg. The pulse-phase resolved PD displays an apparent anti-correlation with the flux. Using the rotating vector model, we obtain constraints on the pulsar's geometrical properties for the individual observations. The position angle of the pulsar displays an evolution over time supporting the idea that we observe changes related to different super-orbital phases. Scattering in the wind of the precessing accretion disk may be responsible for the behavior of the polarimetric properties observed during the high-state of SMC X-1's super-orbital period., Comment: 11 pages, 11 figures, submitted to A&A
Published: 2024

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

Author: Kouch, Pouya M., Liodakis, Ioannis, Middei, Riccardo, Kim, Dawoon E., Tavecchio, Fabrizio, Marscher, Alan P., Marshall, Herman L., Ehlert, Steven R., Di Gesu, Laura, Jorstad, Svetlana G., Agudo, Iván, Madejski, Grzegorz M., Romani, Roger W., Errando, Manel, Lindfors, Elina, Nilsson, Kari, Toppari, Ella, Potter, Stephen B., Imazawa, Ryo, Sasada, Mahito, Fukazawa, Yasushi, Kawabata, Koji S., Uemura, Makoto, Mizuno, Tsunefumi, Nakaoka, Tatsuya, Akitaya, Hiroshi, McCall, Callum, Jermak, Helen E., Steele, Iain A., Myserlis, Ioannis, Gurwell, Mark, Keating, Garrett K., Rao, Ramprasad, Kang, Sincheol, Lee, Sang-Sung, Kim, Sang-Hyun, Cheong, Whee Yeon, Jeong, Hyeon-Woo, Angelakis, Emmanouil, Kraus, Alexander, Aceituno, Francisco José, Bonnoli, Giacomo, Casanova, Víctor, Escudero, Juan, Agís-González, Beatriz, Husillos, César, Morcuende, Daniel, Otero-Santos, Jorge, Sota, Alfredo, Bachev, Rumen, Antonelli, Lucio Angelo, Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Lalla, Niccolò, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Negro, Michela, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel Lawrence, Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report the X-ray polarization properties of the high-synchrotron-peaked (HSP) blazar PKS 2155$-$304 based on observations with the Imaging X-ray Polarimetry Explorer (IXPE). We observed the source between Oct 27 and Nov 7, 2023. We also conducted an extensive contemporaneous multiwavelength (MW) campaign. We find that during the first half ($T_1$) of the IXPE pointing, the source exhibited the highest X-ray polarization degree detected for an HSP blazar thus far, (30.7$\pm$2.0)%, which dropped to (15.3$\pm$2.1)% during the second half ($T_2$). The X-ray polarization angle remained stable during the IXPE pointing at 129.4$^\circ$$\pm$1.8$^\circ$ and 125.4$^\circ$$\pm$3.9$^\circ$ during $T_1$ and $T_2$, respectively. Meanwhile, the optical polarization degree remained stable during the IXPE pointing, with average host-galaxy-corrected values of (4.3$\pm$0.7)% and (3.8$\pm$0.9)% during the $T_1$ and $T_2$, respectively. During the IXPE pointing, the optical polarization angle changed achromatically from $\sim$140$^\circ$ to $\sim$90$^\circ$ and back to $\sim$130$^\circ$. Despite several attempts, we only detected (99.7% conf.) the radio polarization once (during $T_2$, at 225.5 GHz): with degree (1.7$\pm$0.4)% and angle 112.5$^\circ$$\pm$5.5$^\circ$. The direction of the broad pc-scale jet is rather ambiguous and has been found to point to the east and south at different epochs; however, on larger scales (> 1.5 pc) the jet points toward the southeast ($\sim$135$^\circ$), similar to all of the MW polarization angles. Moreover, the X-ray to optical polarization degree ratios of $\sim$7 and $\sim$4 during $T_1$ and $T_2$, respectively, are similar to previous IXPE results for several HSP blazars. These findings, combined with the lack of correlation of temporal variability between the MW polarization properties, agree with an energy-stratified shock-acceleration scenario in HSP blazars., Comment: 17 pages, 10 figures, 4 tables, Accepted for publication in A&A
Published: 2024
Full Text: View/download PDF

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

Author: Poutanen, Juri, Tsygankov, Sergey S., Doroshenko, Victor, Forsblom, Sofia V., Jenke, Peter, Kaaret, Philip, Berdyugin, Andrei V., Blinov, Dmitry, Kravtsov, Vadim, Liodakis, Ioannis, Tzouvanou, Anastasia, Di Marco, Alessandro, Heyl, Jeremy, La Monaca, Fabio, Mushtukov, Alexander A., Pavlov, George G., Salganik, Alexander, Veledina, Alexandra, Weisskopf, Martin C., Zane, Silvia, Loktev, Vladislav, Suleimanov, Valery F., Wilson-Hodge, Colleen, Berdyugina, Svetlana V., Kagitani, Masato, Piirola, Vilppu, Sakanoi, Takeshi, Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Dovciak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract: Discovery of pulsations from a number of ultra-luminous X-ray (ULX) sources proved that accretion onto neutron stars can produce luminosities exceeding the Eddington limit by a couple of orders of magnitude. The conditions necessary to achieve such high luminosities as well as the exact geometry of the accretion flow in the neutron star vicinity are, however, a matter of debate. The pulse phase-resolved polarization measurements that became possible with the launch of the IXPE can be used to determine the pulsar geometry and its orientation relative to the orbital plane. They provide an avenue to test different theoretical models of ULX pulsars. In this paper we present the results of three IXPE observations of the first Galactic ULX pulsar Swift J0243.6+6124 during its 2023 outburst. We find strong variations of the polarization characteristics with the pulsar phase. The average polarization degree increases from about 5% to 15% as the flux dropped by a factor of three in the course of the outburst. The polarization angle (PA) as function of the pulsar phase shows two peaks in the first two observations, but changes to a characteristic sawtooth pattern in the remaining data set. This is not consistent with a simple rotating vector model. Assuming the existence of an additional constant polarized component, we were able to fit the three observations with a common rotating vector model and obtain constraints on the pulsar geometry. In particular, we find the pulsar angular momentum inclination with respect to the line-of-sight of 15-40 deg, the magnetic obliquity of 60-80 deg, and the pulsar spin position angle of -50 deg, which differs from the constant component PA of about 10 deg. Combining these X-ray measurements with the optical PA, we find evidence for a 30 deg misalignment between the pulsar spin and the binary orbital axis., Comment: 13 pages, 10 figures, submitted to A&A
Published: 2024

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

Author: Ferrazzoli, Riccardo, Prokhorov, Dmitry, Bucciantini, Niccolò, Slane, Patrick, Vink, Jacco, Cardillo, Martina, Yang, Yi-Jung, Silvestri, Stefano, Zhou, Ping, Costa, Enrico, Omodei, Nicola, Ng, C. -Y., Soffitta, Paolo, Weisskopf, Martin C., Baldini, Luca, Di Marco, Alessandro, Doroshenko, Victor, Heyl, Jeremy, Kaaret, Philip, Kim, Dawoon E., Marin, Frédéric, Mizuno, Tsunefumi, Pesce-Rollins, Melissa, Sgrò, Carmelo, Swartz, Douglas A., Tamagawa, Toru, Xie, Fei, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Donnarumma, Immacolata, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Negro, Michela, O'Dell, Stephen L., Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Spandre, Gloria, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Wu, Kinwah, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract: Supernova remnants (SNRs) provide insights into cosmic-ray acceleration and magnetic field dynamics at shock fronts. Recent X-ray polarimetric measurements by the Imaging X-ray Polarimetry Explorer (IXPE) have revealed radial magnetic fields near particle acceleration sites in young SNRs, including Cassiopeia A, Tycho, and SN 1006. We present here the spatially-resolved IXPE X-ray polarimetric observation of the northwestern rim of SNR RX J1713.7-3946. For the first time, our analysis shows that the magnetic field in particle acceleration sites of this SNR is oriented tangentially with respect to the shock front. Because of the lack of precise Faraday-rotation measurements in the radio band, this was not possible before. The average measured polarization degree (PD) of the synchtrotron emission is 12.5 {\pm} 3.3%, lower than the one measured by IXPE in SN 1006, comparable to the Tycho one, but notably higher than the one in Cassiopeia A. On sub-parsec scales, localized patches within RX J1713.7-3946 display PD up to 41.5 {\pm} 9.5%. These results are compatible with a shock-compressed magnetic field. However, in order to explain the observed PD, either the presence of a radial net magnetic field upstream of the shock, or partial reisotropization of the turbulence downstream by radial magneto-hydrodynamical instabilities, can be invoked. From comparison of PD and magnetic field distribution with {\gamma}-rays and 12 CO data, our results provide new inputs in favor of a leptonic origin of the {\gamma}-ray emission., Comment: 18 pages, 6 figures, 2 tables, published in ApJ Letters
Published: 2024
Full Text: View/download PDF

10. Investigating the Properties of the Relativistic Jet and Hot Corona in AGN with X-ray Polarimetry

Author: Kim, Dawoon E., Di Gesu, Laura, Marin, Frédéric, Marscher, Alan P., Matt, Giorgio, Soffitta, Paolo, Tombesi, Francesco, Costa, Enrico, and Donnarumma, Immacolata
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: X-ray polarimetry has been suggested as a prominent tool for investigating the geometrical and physical properties of the emissions from active galactic nuclei (AGN). The successful launch of the Imaging X-ray Polarimetry Explorer (IXPE) on 9 December 2021 has expanded the previously restricted scope of polarimetry into the X-ray domain, enabling X-ray polarimetric studies of AGN. Over a span of two years, IXPE has observed various AGN populations, including blazars and radio-quiet AGN. In this paper, we summarize the remarkable discoveries achieved thanks to the opening of the new window of X-ray polarimetry of AGN through IXPE observations. We will delve into two primary areas of interest: first, the magnetic field geometry and particle acceleration mechanisms in the jets of radio-loud AGN, such as blazars, where the relativistic acceleration process dominates the spectral energy distribution; and second, the geometry of the hot corona in radio-quiet AGN. Thus far, the IXPE results from blazars favor the energy-stratified shock acceleration model, and they provide evidence of helical magnetic fields inside the jet. Concerning the corona geometry, the IXPE results are consistent with a disk-originated slab-like or wedge-like shape, as could result from Comptonization around the accretion disk., Comment: 16 pages, 5 figures, 2 tables; Accepted for publication in Galaxies, Special Issue "Multi-Phase Fueling and Feedback Processes in Jetted AGN."
Published: 2024

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

Author: Xie, Fei, Wong, Josephine, La Monaca, Fabio, Romani, Roger W., Heyl, Jeremy, Kaaret, Philip, Di Marco, Alessandro, Bucciantini, Niccolò, Liu, Kuan, Ng, Chi-Yung, Di Lalla, Niccolò, Weisskopf, Martin C., Costa, Enrico, Soffitta, Paolo, Muleri, Fabio, Bachetti, Matteo, Pilia, Maura, Rankin, John, Fabiani, Sergio, Agudo, Iván, Antonelli, Lucio A., Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Ratheesh, Ajay, Roberts, Oliver J., Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, Zane, Silvia, Wadiasingh, Zorawar, Ho, Wynn C. G., Harding, Alice K., Gendreau, Keith C., and Arzoumanian, Zaven
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on X-ray polarization measurements of the extra-galactic Crab-like PSR B0540-69 and its Pulsar Wind Nebula (PWN) in the Large Magellanic Cloud (LMC), using a ~850 ks Imaging X-ray Polarimetry Explorer (IXPE) exposure. The PWN is unresolved by IXPE. No statistically significant polarization is detected for the image-averaged data, giving a 99% confidence polarization upper limit (MDP99) of 5.3% in 2-8 keV energy range. However, a phase-resolved analysis detects polarization for both the nebula and pulsar in the 4-6 keV energy range. For the PWN defined as the off-pulse phases, the polarization degree (PD) of (24.5 ${\pm}$ 5.3)% and polarization angle (PA) of (78.1 ${\pm}$ 6.2){\deg} is detected at 4.6${\sigma}$ significance level, consistent with the PA observed in the optical band. In a single on-pulse window, a hint of polarization is measured at 3.8${\sigma}$ with polarization degree of (50.0 ${\pm}$ 13.1)% and polarization angle of (6.2 ${\pm}$ 7.4){\deg}. A 'simultaneous' PSR/PWN analysis finds two bins at the edges of the pulse exceeding 3${\sigma}$ PD significance, with PD of (68 ${\pm}$ 20)% and (62 ${\pm}$ 20)%; intervening bins at 2-3${\sigma}$ significance have lower PD, hinting at additional polarization structure., Comment: 10 pages, 7 figures, 4 tables, author's version of the paper accepted for publication in ApJ
Published: 2024

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

Author: Bobrikova, Anna, Forsblom, Sofia V., Di Marco, Alessandro, La Monaca, Fabio, Poutanen, Juri, Ng, Mason, Ravi, Swati, Loktev, Vladislav, Kajava, Jari J. E., Ursini, Francesco, Veledina, Alexandra, Rogantini, Daniele, Salmi, Tuomo, Bianchi, Stefano, Capitanio, Fiamma, Done, Chris, Fabiani, Sergio, Gnarini, Andrea, Heyl, Jeremy, Kaaret, Philip, Matt, Giorgio, Muleri, Fabio, Nitindala, Anagha P., Rankin, John, Weisskopf, Martin C., Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Doroshenko, Victor, Dovciak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Ratheesh, Ajay J., Roberts, Oliver, Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Weakly magnetized neutron stars in X-ray binaries show complex phenomenology with several spectral components that can be associated with the accretion disk, boundary and/or spreading layer, a corona, and a wind. Spectroscopic information alone is, however, not enough to disentangle these components. Additional information about the nature of the spectral components and in particular the geometry of the emission region can be provided by X-ray polarimetry. One of the objects of the class, a bright, persistent, and rather peculiar galactic Type I X-ray burster was observed with the Imaging X-ray Polarimetry Explorer (IXPE) and the X-ray Multi-Mirror Mission Newton (XMM-Newton). Using the XMM-Newton data we estimated the current state of the source as well as detected strong absorption lines associated with the accretion disk wind. IXPE data showed the source to be significantly polarized in the 2-8 keV energy band with the overall polarization degree (PD) of 1.4% at a polarization angle (PA) of -2 degrees (errors at 68% confidence level). During the two-day long observation, we detected rotation of the PA by about 70 degrees with the corresponding changes in the PD from 2% to non-detectable and then up to 5%. These variations in polarization properties are not accompanied by visible changes in spectroscopic characteristics. The energy-resolved polarimetric analysis showed a significant change in polarization, from being strongly dependent on energy at the beginning of the observation to being almost constant with energy in the later parts of the observation. As a possible interpretation, we suggest the presence of a constant component of polarization, strong wind scattering, or different polarization of the two main spectral components with individually peculiar behavior. The rotation of the PA suggests a 30-degree misalignment of the neutron star spin from the orbital axis., Comment: 12 pages, 12 figures
Published: 2024
Full Text: View/download PDF

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

Author: Errando, Manel, Liodakis, Ioannis, Marscher, Alan P., Marshall, Herman L., Middei, Riccardo, Negro, Michela, Peirson, Abel Lawrence, Perri, Matteo, Puccetti, Simonetta, Rabinowitz, Pazit L., Agudo, Iván, Jorstad, Svetlana G., Savchenko, Sergey S., Blinov, Dmitry, Bourbah, Ioakeim G., Kiehlmann, Sebastian, Kontopodis, Evangelos, Mandarakas, Nikos, Romanopoulos, Stylianos, Skalidis, Raphael, Vervelaki, Anna, Aceituno, Francisco José, Bernardos, Maria I., Bonnoli, Giacomo, Casanova, Víctor, Agís-González, Beatriz, Husillos, César, Marchini, Alessandro, Sota, Alfredo, Kouch, Pouya M., Lindfors, Elina, Casadio, Carolina, Escudero, Juan, Myserlis, Ioannis, Imazawa, Ryo, Sasada, Mahito, Fukazawa, Yasushi, Kawabata, Koji S., Uemura, Makoto, Mizuno, Tsunefumi, Nakaoka, Tatsuya, Akitaya, Hiroshi, Gurwell, Mark, Keating, Garrett K., Rao, Ramprasad, Ingram, Adam, Massaro, Francesco, Antonelli, Lucio Angelo, Bonino, Raffaella, Cavazzuti, Elisabetta, Chen, Chien-Ting, Cibrario, Nicolò, Ciprini, Stefano, De Rosa, Alessandra, Di Gesu, Laura, Di Pierro, Federico, Donnarumma, Immacolata, Ehlert, Steven R., Fenu, Francesco, Gau, Ephraim, Karas, Vladimir, Kim, Dawoon E., Krawczynski, Henric, Laurenti, Marco, Lisalda, Lindsey, López-Coto, Rubén, Madejski, Grzegorz, Marin, Frédéric, Marinucci, Andrea, Mitsuishi, Ikuyuki, Muleri, Fabio, Pacciani, Luigi, Paggi, Alessandro, Petrucci, Pierre-Olivier, Cavero, Nicole Rodriguez, Romani, Roger W., Tavecchio, Fabrizio, Tugliani, Stefano, Wu, Kinwah, Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Costa, Enrico, Del Monte, Ettore, Di Lalla, Niccolò, Di Marco, Alessandro, Doroshenko, Victor, Dovčiak, Michal, Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Kaaret, Philip, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Matt, Giorgio, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Observations of linear polarization in the 2-8 keV energy range with the Imaging X-ray Polarimetry Explorer (IXPE) explore the magnetic field geometry and dynamics of the regions generating non-thermal radiation in relativistic jets of blazars. These jets, particularly in blazars whose spectral energy distribution peaks at X-ray energies, emit X-rays via synchrotron radiation from high-energy particles within the jet. IXPE observations of the X-ray selected BL Lac-type blazar 1ES 1959+650 in 2022 May 3-4 showed a significant linear polarization degree of $\Pi_\mathrm{x} = 8.0\% \pm 2.3\%$ at an electric-vector position angle $\psi_\mathrm{x} = 123^\circ \pm 8^\circ$. However, in 2022 June 9-12, only an upper limit of $\Pi_\mathrm{x} \leq 5.1\%$ could be derived (at the 99% confidence level). The degree of optical polarization at that time $\Pi_\mathrm{O} \sim 5\%$ is comparable to the X-ray measurement. We investigate possible scenarios for these findings, including temporal and geometrical depolarization effects. Unlike some other X-ray selected BL Lac objects, there is no significant chromatic dependence of the measured polarization in 1ES 1959+650, and its low X-ray polarization may be attributed to turbulence in the jet flow with dynamical timescales shorter than 1 day., Comment: 16 pages, 4 figures, accepted for publication in The Astrophysical Journal
Published: 2024
Full Text: View/download PDF

14. X-ray Polarimetry as a Tool to Constrain Orbital Parameters in X-Ray Binaries

Author: Rankin, John, Kravtsov, Vadim, Muleri, Fabio, Poutanen, Juri, Marin, Frédéric, Capitanio, Fiamma, Matt, Giorgio, Costa, Enrico, Di Marco, Alessandro, Fabiani, Sergio, La Monaca, Fabio, Marra, Lorenzo, and Soffitta, Paolo
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: X-ray binary systems consist of a companion star and a compact object in close orbit. Thanks to their copious X-ray emission, these objects have been studied in detail using X-ray spectroscopy and timing. The inclination of these systems is a major uncertainty in the determination of the mass of the compact object using optical spectroscopic methods. In this paper, we present a new method to constrain the inclination of X-ray binaries, which is based on the modeling of the polarization of X-rays photons produced by a compact source and scattered off the companion star. We describe our method and explore the potential of this technique in the specific case of the low mass X-ray binary GS 1826-238 observed by the Imaging X-ray Polarimetry Explorer (IXPE) observatory., Comment: 9 pages, 8 figures, accepted for publication in ApJ
Published: 2023

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

Author: Saade, M. Lynne, Kaaret, Philip, Gnarini, Andrea, Poutanen, Juri, Ursini, Francesco, Bianchi, Stefano, Bobrikova, Anna, La Monaca, Fabio, Di Marco, Alessandro, Capitanio, Fiamma, Veledina, Alexandra, Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesù, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Doroshenko, Victor, Dovciak, Michal, Ehlert, Steven R., Emote, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizudo, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Oliver, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Zwartz, Douglas Z., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tenant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the first X-ray polarimetric study of the dipping accreting neutron star 4U 1624$-$49 with the Imaging X-ray Polarimetry Explorer (IXPE). We report a detection of polarization in the non-dip time intervals with a confidence level of 99.99%. We find an average polarization degree (PD) of $3.1\pm0.7$% and a polarization angle of $81\pm6$ degrees east of north in the 2-8 keV band. We report an upper limit on the PD of 22% during the X-ray dips with 95% confidence. The PD increases with energy, reaching from $3.0\pm0.9$% in the 4-6 keV band to $6\pm2$% in the 6-8 keV band. This indicates the polarization likely arises from Comptonization. The high PD observed is unlikely to be produced by Comptonization in the boundary layer or spreading layer alone. It can be produced by the addition of an extended geometrically thin slab corona covering part of the accretion disk, as assumed in previous models of dippers, and/or a reflection component from the accretion disk.
Published: 2023

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

Author: Churazov, Eugene, Khabibullin, Ildar, Barnouin, Thibault, Bucciantini, Niccolò, Costa, Enrico, Di Gesu, Laura, Di Marco, Alessandro, Ferrazzoli, Riccardo, Forman, William, Kaaret, Philip, Kim, Dawoon E., Kolodziejczak, Jeffery J., Kraft, Ralph, Marin, Frédéric, Matt, Giorgio, Negro, Michela, Romani, Roger W., Silvestri, Stefano, Soffitta, Paolo, Sunyaev, Rashid, Svoboda, Jiri, Vikhlinin, Alexey, Weisskopf, Martin C., Xie, Fei, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Lalla, Niccolò, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, García, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report the discovery of X-ray polarization from the X-ray-bright filament. G0.13-0.11 in the Galactic center (GC) region. This filament features a bright, hard X-ray source that is most plausibly a pulsar wind nebula (PWN) and an extended and structured diffuse component. Combining the polarization signal from IXPE with the imaging/spectroscopic data from Chandra, we find that X-ray emission of G0.13-0.11 is highly polarized PD=$57(\pm18)$% in the 3-6 keV band, while the polarization angle is PA=$21^\circ(\pm9^\circ)$. This high degree of polarization proves the synchrotron origin of the X-ray emission from G0.13-0.11. In turn, the measured polarization angle implies that the X-ray emission is polarized approximately perpendicular to a sequence of nonthermal radio filaments that may be part of the GC Radio Arc. The magnetic field on the order of $100\,{\rm\mu G}$ appears to be preferentially ordered along the filaments. The above field strength is the fiducial value that makes our model self-consistent, while the other conclusions are largely model independent., Comment: Accepted for publication in A&A
Published: 2023
Full Text: View/download PDF

17. Tracking the X-ray Polarization of the Black Hole Transient Swift J1727.8-1613 during a State Transition

Author: Ingram, Adam, Bollemeijer, Niek, Veledina, Alexandra, Dovciak, Michal, Poutanen, Juri, Egron, Elise, Russell, Thomas D., Trushkin, Sergei A., Negro, Michela, Ratheesh, Ajay, Capitanio, Fiamma, Connors, Riley, Neilsen, Joseph, Kraus, Alexander, Iacolina, Maria Noemi, Pellizzoni, Alberto, Pilia, Maura, Carotenuto, Francesco, Matt, Giorgio, Mastroserio, Guglielmo, Kaaret, Philip, Bianchi, Stefano, Garcia, Javier A., Bachetti, Matteo, Wu, Kinwah, Costa, Enrico, Ewing, Melissa, Kravtsov, Vadim, Krawczynski, Henric, Loktev, Vladislav, Marinucci, Andrea, Marra, Lorenzo, Mikusincova, Romana, Nathan, Edward, Parra, Maxime, Petrucci, Pierre-Olivier, Righini, Simona, Soffitta, Paolo, Steiner, James F., Svoboda, Jiri, Tombesi, Francesco, Tugliani, Stefano, Ursini, Francesco, Yang, Yi-Jung, Zane, Silvia, Zhang, Wenda, Agudo, Ivan, Antonelli, Lucio A., Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on an observational campaign on the bright black hole X-ray binary Swift J1727.8$-$1613 centered around five observations by the Imaging X-ray Polarimetry Explorer (IXPE). These observations track for the first time the evolution of the X-ray polarization of a black hole X-ray binary across a hard to soft state transition. The 2--8 keV polarization degree decreased from $\sim$4\% to $\sim$3\% across the five observations, but the polarization angle remained oriented in the North-South direction throughout. Based on observations with the Australia Telescope Compact Array (ATCA), we find that the intrinsic 7.25 GHz radio polarization aligns with the X-ray polarization. Assuming the radio polarization aligns with the jet direction (which can be tested in the future with higher spatial resolution images of the jet), our results imply that the X-ray corona is extended in the disk plane, rather than along the jet axis, for the entire hard intermediate state. This in turn implies that the long ($\gtrsim$10 ms) soft lags that we measure with the Neutron star Interior Composition ExploreR (NICER) are dominated by processes other than pure light-crossing delays. Moreover, we find that the evolution of the soft lag amplitude with spectral state does not follow the trend seen for other sources, implying that Swift J1727.8$-$1613 is a member of a hitherto under-sampled sub-population., Comment: Accepted for publication in ApJ. 21 pages, 8 figures
Published: 2023

18. X-Ray Polarized View on the Accretion Geometry in the X-Ray Binary Circinus X-1

Author: Rankin, John, La Monaca, Fabio, Di Marco, Alessandro, Poutanen, Juri, Bobrikova, Anna, Kravtsov, Vadim, Muleri, Fabio, Pilia, Maura, Veledina, Alexandra, Fender, Rob, Kaaret, Philip, Kim, Dawoon E., Marinucci, Andrea, Marshall, Herman L., Papitto, Alessandro, Tennant, Allyn F., Tsygankov, Sergey S., Weisskopf, Martin C., Wu, Kinwah, Zane, Silvia, Ambrosino, Filippo, Farinelli, Ruben, Gnarini, Andrea, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, di Lalla, Niccolò, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marscher, Alan P., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Cir X-1 is a neutron star X-ray binary characterized by strong variations in flux during its eccentric $\sim$16.6 days orbit. There are also strong variations in the spectral state, and historically it has 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 $1.6\%\pm0.3\%$ and $1.4\%\pm0.3\%$ at polarization angles of $37^\circ\pm5^\circ$ and $-12^\circ\pm7^\circ$, respectively. Thus we observed a rotation of the polarization angle by $49^\circ\pm8^\circ$ 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 $67^\circ\pm11^\circ$ 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., Comment: 15 pages, 6 figures, Accepted for publication in ApJL
Published: 2023
Full Text: View/download PDF

19. X-ray Polarization Reveals the Precessions of the Neutron Star in Hercules X-1

Author: Heyl, Jeremy, Doroshenko, Victor, González-Caniulef, Denis, Caiazzo, Ilaria, Poutanen, Juri, Mushtukov, Alexander, Tsygankov, Sergey S., Kirmizibayrak, Demet, Bachetti, Matteo, Pavlov, George G., Forsblom, Sofia V., Malacaria, Christian, Suleimanov, Valery F., Agudo, Iván, Antonelli, Lucio Angelo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Di Marco, Alessandro, Donnarumma, Immacolata, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Peirson, Abel Lawrence, Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: In an accreting X-ray pulsar, a neutron star accretes matter from a stellar companion through an accretion disk. The high magnetic field of the rotating neutron star disrupts the inner edge of the disc, funneling the gas to flow onto the magnetic poles on its surface. Hercules X-1 is in many ways the prototypical X-ray pulsar; it shows persistent X-ray emission and it resides with its companion HZ Her, a two-solar-mass star, at about 7~kpc from Earth. Its emission varies on three distinct timescales: the neutron star rotates every 1.2~seconds, it is eclipsed by its companion each 1.7~days, and the system exhibits a superorbital period of 35~days which has remained remarkably stable since its discovery. Several lines of evidence point to the source of this variation as the precession of the accretion disc, the precession of the neutron star or both. Despite the many hints over the past fifty years, the precession of the neutron star itself has yet not been confirmed or refuted. We here present X-ray polarization measurements with the Imaging X-ray Polarimetry Explorer (IXPE) which probe the spin geometry of the neutron star. These observations provide direct evidence that the 35-day-period is set by the free precession of the neutron star crust, which has the important implication that its crust is somewhat asymmetric fractionally by a few parts per ten million. Furthermore, we find indications that the basic spin geometry of the neutron star is altered by torques on timescale of a few hundred days., Comment: 37 pages
Published: 2023

20. The detection of polarized x-ray emission from the magnetar 1E 2259+586

Author: Heyl, Jeremy, Taverna, Roberto, Turolla, Roberto, Israel, Gian Luca, Ng, Mason, Kirmizibayrak, Demet, González-Caniulef, Denis, Caiazzo, Ilaria, Zane, Silvia, Ehlert, Steven R., Negro, Michela, Agudo, Iván, Antonelli, Lucio Angelo, Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel Lawrence, Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on IXPE, NICER and XMM-Newton observations of the magnetar 1E 2259+586. We find that the source is significantly polarized at about or above 20% for all phases except for the secondary peak where it is more weakly polarized. The polarization degree is strongest during the primary minimum which is also the phase where an absorption feature has been identified previously (Pizzocaro et al. 2019). The polarization angle of the photons are consistent with a rotating vector model with a mode switch between the primary minimum and the rest of the rotation of the neutron star. We propose a scenario in which the emission at the source is weakly polarized (as in a condensed surface) and, as the radiation passes through a plasma arch, resonant cyclotron scattering off of protons produces the observed polarized radiation. This confirms the magnetar nature of the source with a surface field greater than about 1015 G, Comment: 13 pages, 13 figures, 5 tables
Published: 2023

21. 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

22. Discovery of a variable energy-dependent X-ray polarization in the accreting neutron star GX 5-1

Author: Fabiani, Sergio, Capitanio, Fiamma, Iaria, Rosario, Poutanen, Juri, Gnarini, Andrea, Ursini, Francesco, Farinelli, Ruben, Bobrikova, Anna, Steiner, James F., Svoboda, Jiri, Anitra, Alessio, Baglio, Maria C., Carotenuto, Francesco, Del Santo, Melania, Ferrigno, Carlo, Lewis, Fraser, Russell, David M., Russell, Thomas D., Eijnden, Jakob van den, Cocchi, Massimo, Di Marco, Alessandro, La Monaca, Fabio, Liu, Kuan, Rankin, John, Weisskopf, Martin C., Xie, Fei, Bianchi, Stefano, Burderi, Luciano, Di Salvo, Tiziana, Egron, Elise, Illiano, Giulia, Kaaret, Philip, Matt, Giorgio, Mikušincová, Romana, Muleri, Fabio, Papitto, Alessandro, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on the coordinated observations of the neutron star low-mass X-ray binary (NS-LMXB) \gx in X-rays (IXPE, NICER, Nustar and INTEGRAL), optical (REM and LCO), near-infrared (REM), mid-infrared (VLT VISIR), and radio (ATCA). This Z-source was observed by \IXPE twice in March-April 2023 (Obs. 1 and 2). In the radio band, the source was detected, but only upper-limits to the linear polarization were obtained at a $3\sigma$ level of $6.1\%$ at 5.5 GHz and $5.9\%$ at 9 GHz in Obs.~1 and $12.5\%$ at 5.5~GHz and $20\%$ at 9~GHz in Obs.~2. The mid-IR, near-IR and optical observations suggest the presence of a compact jet which peaks in the mid- or far-IR. The X-ray polarization degree was found to be $3.7\% \pm 0.4 \%$ (at $90\%$ confidence level) during Obs.~1 when the source was in the horizontal branch of the Z-track and $1.8\% \pm 0.4 \%$ during Obs.~2 when the source was in the normal-flaring branch. These results confirm the variation of polarization degree as a function of the position of the source in the color-color diagram as for previously observed Z-track sources (Cyg~X-2 and XTE~1701$-$462). Evidence for a variation of the polarization angle $\sim 20^\circ$ with energy is found in both observations, likely related to the different, non-orthogonal polarization angles of the disk and Comptonization components which peak at different energies., Comment: Submitted to Astronomy and Astrophysics on 06 July 2023. Accepted on 21 November 2023
Published: 2023

23. Magnetic Field Properties inside the Jet of Mrk 421: Multiwavelength Polarimetry Including the Imaging X-ray Polarimetry Explorer

Author: Kim, Dawoon E., Di Gesu, Laura, Liodakis, Ioannis, Marscher, Alan P., Jorstad, Svetlana G., Midde, Riccardo, Marshall, Herman L., Pacciani, Luigi, Agudo, Iván, Tavecchio, Fabrizio, Cibrario, Nicolò, Tugliani, Stefano, Bonino, Raffaella, Negro, Michela, Puccetti, Simonetta, Tombesi, Francesco, Costa, Enrico, Donnarumma, Immacolata, Soffitta, Paolo, Mizuno, Tsunefumi, Fukazawa, Yasushi, Kawabata, Koji S., Nakaoka, Tatsuya, Uemura, Makoto, Imazawa, Ryo, Sasada, Mahito, Akitaya, Hiroshi, Aceituno, Francisco Josè, Bonnoli, Giacomo, Casanova, Vìctor, Myserlis, Ioannis, Sievers, Albrecht, Angelakis, Emmanouil, Kraus, Alexander, Cheong, Whee Yeon, Jeong, Hyeon-Woo, Kang, Sincheol, Kim, Sang-Hyun, Lee, Sang-Sung, Agìs-Gonzàlez, Beatriz, Sota, Alfredo, Escudero, Juan, Gurwell, Mark, Keating, Garrett K., Rao, Ramprasad, Kouch, Pouya M., Lindfors, Elina, Bourbah, Ioakeim G., Kiehlmann, Sebastian, Kontopodis, Evangelos, Mandarakas, Nikos, Romanopoulos, Stylianos, Skalidis, Raphael, Vervelaki, Anna, Savchenko, Sergey S., Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Lalla, Niccolò, Di Marco, Alessandro, Doroshenko, Victor, Dovčiak, 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., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver, Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Doug, Tamagawa, Toru, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., 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 conducted a polarimetry campaign from radio to X-ray wavelengths of the high-synchrotron-peak (HSP) blazar Mrk 421, including Imaging X-ray Polarimetry Explorer (IXPE) measurements on 2022 December 6-8. We detected X-ray polarization of Mrk 421 with a degree of $\Pi_{\rm X}$=14$\pm$1$\%$ and an electric-vector position angle $\psi_{\rm X}$=107$\pm$3$^{\circ}$ in the 2-8 keV band. From the time variability analysis, we find a significant episodic variation in $\psi_{\rm X}$. During 7 months from the first IXPE pointing of Mrk 421 in 2022 May, $\psi_{\rm X}$ varied across the range of 0$^{\circ}$ to 180$^{\circ}$, while $\Pi_{\rm X}$ maintained similar values within $\sim$10-15$\%$. Furthermore, a swing in $\psi_{\rm X}$ in 2022 June was accompanied by simultaneous spectral variations. The results of the multiwavelength polarimetry show that the X-ray polarization degree was generally $\sim$2-3 times greater than that at longer wavelengths, while the polarization angle fluctuated. Additionally, based on radio, infrared, and optical polarimetry, we find that rotation of $\psi$ occurred in the opposite direction with respect to the rotation of $\psi_{\rm X}$ over longer timescales at similar epochs. The polarization behavior observed across multiple wavelengths is consistent with previous IXPE findings for HSP blazars. This result favors the energy-stratified shock model developed to explain variable emission in relativistic jets. The accompanying spectral variation during the $\psi_{\rm X}$ rotation can be explained by a fluctuation in the physical conditions, e.g., in the energy distribution of relativistic electrons. The opposite rotation direction of $\psi$ between the X-ray and longer-wavelength polarization accentuates the conclusion that the X-ray emitting region is spatially separated from that at longer wavelengths., Comment: 17 pages, 13 figures, 4 tables; Accepted for publication in A&A
Published: 2023
Full Text: View/download PDF

24. An X-rays-to-radio investigation of the nuclear polarization from the radio-galaxy Centaurus A

Author: Marin, Frédéric, Barnouin, Thibault, Ehlert, Steven R., Peirson, Abel Lawrence, Lopez-Rodriguez, Enrique, Petropoulou, Maria, Wu, Kinwah, and Martí-Vidal, Iván
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, J.2.3, J.2.9
Abstract: Centaurus A is one of the closest radio-galaxies to Earth. Its proximity allowed us to extensively study its active galactic nucleus but the core emission mechanism remains elusive because of local strong dust and gas obscuration. The capability of polarimetry to shave-off contaminating emission has been exploited without success in the near-infrared by previous studies but the very recent measurement of the 2 - 8 keV polarization by the Imaging X-ray Polarimetry Explorer (IXPE) brought the question back to the fore. To determine what is the prevalent photon generation mechanism to the multi-wavelength emission from the core of Centaurus A, we retrieved from the archives the panchromatic polarization measurements of the central compact component. We built the total and polarized flux spectral energy distributions of the core and demonstrated that synchrotron self-Compton models nicely fit the polarized flux from the radio to the X-ray band. The linear polarization of the synchrotron continuum is perpendicular to the jet radio axis from the optical to the radio band, and parallel to it at higher energies. The observed smooth rotation of the polarization angle in the ultraviolet band is attributed to synchrotron emission from regions that are getting closer to the particle acceleration site, where the orientation of the jet's magnetic fields become perpendicular to the jet axis. This phenomenon support the shock acceleration mechanism for particle acceleration in Centaurus A, in line with IXPE observations of several high-synchrotron peak blazars., Comment: 10 pages, 6 figures, accepted for publication in MNRAS
Published: 2023

25. X-ray Polarization of the BL Lac Type Blazar 1ES 0229+200

Author: Ehlert, Steven R., Liodakis, Ioannis, Middei, Riccardo, Marscher, Alan P., Tavecchio, Fabrizio, Agudo, Iván, Kouch, Pouya M., Lindfors, Elina, Nilsson, Kari, Myserlis, Ioannis, Gurwell, Mark, Rao, Ramprasad, Aceituno, Francisco Jose, Bonnoli, Giacomo, Casanova, Victor, Agiz-Gonzalez, Beatriz, Escudero, Juan, Santos, Jorge Otero, Sota, Alfredo, Angelakis, Emmanouil, Kraus, Alexander, Keating, Garrett K., Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., 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 polarization measurements in the $2-8 \thinspace \mathrm{keV}$ 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 $\Pi_{X} = 17.9 \pm 2.8 \%$ at an electric-vector position angle $\psi_X = 25.0 \pm 4.6^{\circ}$ using a spectropolarimetric 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 time scales (hours) or longer time scales (days). The contemporaneous polarization degree at optical wavelengths was $>$7$\times$ 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., Comment: 17 Pages, 6 Figures, Resubmitted to ApJ after addressing referee comments
Published: 2023

26. The Polarized Cosmic Hand: IXPE Observations of PSR B1509-58/MSH 15-52

Author: Romani, Roger W., Wong, Josephine, Di Lalla, Niccolo, Omodei, Nicola, Xie, Fei, Ng, C. -Y., Ferrazzoli, Riccardo, Di Marco, Alessandro, Bucciantini, Niccolo, Pilia, Maura, Slane, Patrick, Weisskopf, Martin C., Johnston, Simon, Burgay, Marta, Wei, Deng, Yang, Yi-Jung, Zhang, Shumeng, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Cibrario, Nicolo, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Liodakis, Ioannis, Kaaret, Philip, Karas, Vladimir, Kim, Dawoon E., Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Madejski, Grzegorz, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Middei, Riccardo, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, O'Dell, Stephen L., Oppedisano, Chiara, Pacciani, Luigi, Papitto, Alessandro, Pavlov, George G., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Sgro, Carmelo, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey, Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We describe IXPE polarization observations of the Pulsar Wind Nebula (PWN) MSH15-52, 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., Comment: To appear in the Astrophysical Journal
Published: 2023

27. Discovery of X-ray Polarization from the Black Hole Transient Swift J1727.8-1613

Author: Veledina, Alexandra, Muleri, Fabio, Dovciak, Michal, Poutanen, Juri, Ratheesh, Ajay, Capitanio, Fiamma, Matt, Giorgio, Soffitta, Paolo, Tennant, Allyn F., Negro, Michela, Kaaret, Philip, Costa, Enrico, Ingram, Adam, Svoboda, Jiri, Krawczynski, Henric, Bianchi, Stefano, Steiner, James F., Garcia, Javier A., Kravtsov, Vadim, Nitindala, Anagha P., Ewing, Melissa, Mastroserio, Guglielmo, Marinucci, Andrea, Ursini, Francesco, Tombesi, Francesco, Tsygankov, Sergey S., Yang, Yi-Jung, Weisskopf, Martin C., Trushkin, Sergei A., Egron, Elise, Iacolina, Maria Noemi, Pilia, Maura, Marra, Lorenzo, Mikusincova, Romana, Nathan, Edward, Parra, Maxime, Petrucci, Pierre-Olivier, Podgorny, Jakub, Tugliani, Stefano, Zane, Silvia, Zhang, Wenda, Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Thomas, Nicholas E., Trois, Alessio, Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
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 degrees (errors at 68% confidence level; this translates to about 20-sigma 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 sub-mm wavelengths. Since the sub-mm 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., Comment: 10 pages, 3 figures, submitted
Published: 2023

28. First X-ray polarization measurement confirms the low black-hole spin in LMC X-3

Author: Svoboda, Jiří, Dovčiak, Michal, Steiner, James F., Muleri, Fabio, Ingram, Adam, Yilmaz, Anastasiya, Cavero, Nicole Rodriguez, Marra, Lorenzo, Poutanen, Juri, Veledina, Alexandra, Mojaver, Mehrnoosh Rahbardar, Bianchi, Stefano, Garcia, Javier, Kaaret, Philip, Krawczynski, Henric, Matt, Giorgio, Podgorný, Jakub, Weisskopf, Martin C., Kislat, Fabian, Petrucci, Pierre-Olivier, Brigitte, Maimouna, Bursa, Michal, Fabiani, Sergio, Hu, Kun, Chun, Sohee, Mastroserio, Guglielmo, Mikušincová, Romana, Ratheesh, Ajay, Romani, Roger W., Soffitta, Paolo, Ursini, Francesco, Zane, Silvia, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven, Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimír, Kitaguchi, Takao, Kolodziejczak, Jeffery, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George, Peirson, Abel, Perri, Matteo, Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Roberts, Oliver, Sgro, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena
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 the X-ray spectro-polarimetric 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 of 3.2% +- 0.6% and a constant polarization angle -42 deg +- 6 deg 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 of the polarization degree 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., Comment: 14 pages, 8 figures, submitted to ApJ
Published: 2023
Full Text: View/download PDF

29. A remarkably stable accretion disc in the Seyfert galaxy MCG-5-23-16

Author: Serafinelli, Roberto, Marinucci, Andrea, De Rosa, Alessandra, Bianchi, Stefano, Middei, Riccardo, Matt, Giorgio, Reeves, James N., Braito, Valentina, Tombesi, Francesco, Gianolli, Vittoria E., Ingram, Adam, Marin, Frédéric, Petrucci, Pierre-Olivier, Tagliacozzo, Daniele, and Ursini, Francesco
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract: MCG-5-23-16 is a Seyfert 1.9 galaxy at redshift z=0.00849. We analyse here the X-ray spectra obtained with XMM-Newton and NuSTAR data, which are the first contemporaneous observations with these two X-ray telescopes. Two reflection features, producing a narrow core and a broad component of the Fe K$\alpha$, are clearly detected in the data. The analysis of the broad iron line shows evidence of a truncated disc with inner radius $R_{\rm in}=40^{+23}_{-16}$ $R_g$ and an inclination of $41^{+9}_{-10}$ $^\circ$. The high quality of the NuSTAR observations allows us to measure a high energy cut-off at $E_{\rm cut}=131^{+10}_{-9}$ keV. We also analyse the RGS spectrum, finding that the soft X-ray emission is produced by two photoionised plasma emission regions, with different ionisation parameters and similar column densities. Remarkably, the source only shows moderate continuum flux variability, keeping the spectral shape roughly constant in a time scale of $\sim20$ years., Comment: 9 pages, 5 figures, 2 tables. Accepted for publication in MNRAS
Published: 2023

30. Forgotten treasures in the HST/FOC UV imaging polarimetric archives of active galactic nuclei. I. Pipeline and benchmarking against NGC~1068 and exploring IC~5063

Author: Barnouin, Thibault, Marin, Frédéric, Lopez-Rodriguez, Enrique, Huber, Léo, and Kishimoto, Makoto
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, 85-04 (Primary), 85-08, 85A25 (Secondary), J.2, I.4.1, I.4.7, I.6.4
Abstract: Over its 13 years of operation (1990 -- 2002), the Faint Object Camera (FOC) on board the Hubble Space Telescope (HST) observed 26 individual active galactic nuclei (AGNs) in ultraviolet (UV) imaging polarimetry. However, not all of the observations have been reduced and analyzed or set within a standardized framework. We plan to reduce and analyze the AGN observations that have been neglected in the FOC archives using a consistent, novel, and open-access reduction pipeline of our own. We then extend the method to the full AGN sample, thus leading to potential discoveries in the near future. We developed a new pipeline in Python that will be able to reduce all the FOC observations in imaging polarimetry in a homogeneous way. Most of the previously published reduced observations are dispersed throughout the literature, with the range of different analyses and approaches making it difficult to fully interpret the FOC AGN sample. By standardizing the method, we have enabled a coherent comparison among the different observational sets. In this first paper of a series exploring the full HST/FOC AGN sample, we present an exhaustively detailed account of how to properly reduce the observational data. Current progress in data-analysis is implemented in and has provided state-of-the-art UV polarimetric maps. We compare our new maps to the benchmark AGN case of NGC~1068 and successfully reproduce the main results previously published, while pushing the polarimetric exploration of this AGN futher, thanks to a finer resolution and a higher signal-to-noise ratio (S/N) than previously reported. We also present, for the first time, an optical polarimetric map of the radio-loud AGN IC~5063 and we examine the complex interactions between the AGN outflows and the surrounding interstellar medium (ISM)., Comment: 17 pages, 19 figures, to be published in Astronomy & Astrophysics
Published: 2023
Full Text: View/download PDF

31. Magnetic structures and turbulence in SN 1006 revealed with imaging X-ray polarimetry

Author: Zhou, Ping, Prokhorov, Dmitry, Ferrazzoli, Riccardo, Yang, Yi-Jung, Slane, Patrick, Vink, Jacco, Silvestri, Stefano, Bucciantini, Niccolò, Reynoso, Estela, Moffett, David, Soffitta, Paolo, Swartz, Doug, Kaaret, Philip, Baldini, Luca, Costa, Enrico, Ng, C. -Y., Kim, Dawoon E., Doroshenko, Victor, Ehlert, Steven R., Heyl, Jeremy, Marin, Frédéric, Mizuno, Tsunefumi, Pesce-Rollins, Melissa, Sgrò, Carmelo, Tamagawa, Toru, Weisskopf, Martin C., Xie, Fei, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Di Marco, Alessandro, Donnarumma, Immacolata, Dovčiak, Michal, Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Kislat, Fabian, Karas, Vladimir, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Negro, Michela, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver, Romani, Roger W., Spandre, Gloria, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Wu, Kinwah, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Young supernova remnants (SNRs) strongly modify surrounding magnetic fields, which in turn play an essential role in accelerating cosmic rays (CRs). 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 SN1006 from a 1 Ms observation with the Imaging X-ray Polarimetry Explorer (IXPE). We found an average polarization degree of $22.4\pm 3.5\%$ and an average polarization angle of $-45.4\pm 4.5^\circ$ (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 turbulence in SN 1006 and CR acceleration is environment-dependent., Comment: 15 pages, 4 Figures, 2 Tables; accepted for publication in The Astrophysical Journal
Published: 2023

32. IXPE and XMM-Newton observations of the Soft Gamma Repeater SGR 1806-20

Author: Turolla, Roberto, Taverna, Roberto, Israel, Gian Luca, Muleri, Fabio, Zane, Silvia, Bachetti, Matteo, Heyl, Jeremy, Di Marco, Alessandro, Gau, Ephraim, Krawczynski, Henric, Ng, Mason, Possenti, Andrea, Poutanen, Juri, Baldini, Luca, Matt, Giorgio, Negro, Michela, Agudo, Ivan, Antonelli, Lucio Angelo, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo', Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting J., Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo', Donnarumma, Immacolata, Doroshenko, Victor, Doviak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffrey, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Ng, Stephen Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Puccetti, Simonetta, Ramsey, Brian, Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgro', Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Tawara, Yuzuru, Tennant, Allyn F., Thomas, N., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
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 {\gamma}-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\pm 10.5% and PA=-17.6\pm 15 deg 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 proposed for the bright magnetar 4U 0142+61., Comment: 11 pages, 3 figures, accepted for publication in ApJ
Published: 2023

33. IXPE and multi-wavelength observations of blazar PG 1553+113 reveal an orphan optical polarization swing

Author: Middei, Riccardo, Perri, Matteo, Puccetti, Simonetta, Liodakis, Ioannis, Di Gesu, Laura, Marscher, Alan P., Cavero, Nicole Rodriguez, Tavecchio, Fabrizio, Donnarumma, Immacolata, Laurenti, Marco, Jorstad, Svetlana G., Agudo, Iván, Marshall, Herman L., Pacciani, Luigi, Kim, Dawoon E., Aceituno, Francisco José, Bonnoli, Giacomo, Casanova, Víctor, Agís-González, Beatriz, Sota, Alfredo, Casadio, Carolina, Escudero, Juan, Myserlis, Ioannis, Sievers, Albrecht, Kouch, Pouya M., Lindfors, Elina, Gurwell, Mark, Keating, Garrett K., Rao, Ramprasad, Kang, Sincheol, Lee, Sang-Sung, Kim, Sang-Hyun, Cheong, Whee Yeon, Jeong, Hyeon-Woo, Angelakis, Emmanouil, Kraus, Alexander, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Lalla, Niccolò, Di Marco, Alessandro, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, García, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, 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: 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 $(10\pm2)\%$ along an electric-vector position angle of $\psi_X=86^{\circ}\pm8^{\circ}$. At the same time, the radio and optical polarization degrees are lower by a factor of $\sim$3. During our IXPE pointing, we observed the first orphan optical polarization swing of the IXPE era, as the optical angle of PG 1553+113 underwent a smooth monotonic rotation by about 125$^\circ$, with a rate of $\sim$17 degrees per day. 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 co-spatial. Our spectro-polarimetric results provide further evidence that the steady-state X-ray emission in blazars originates in a shock-accelerated and energy-stratified electron population., Comment: Accepted for pubblication in The Astrophysical Journal Letters. 3 Figures, 13 pages
Published: 2023

34. Spectral and polarization properties of reflected X-ray emission from black-hole accretion discs for a distant observer: the lamp-post model

Author: Podgorný, Jakub, Dovčiak, Michal, Goosmann, René, Marin, Frédéric, Matt, Giorgio, Różańska, Agata, and Karas, Vladimír
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Rebirth of X-ray polarimetric instruments will have a significant impact on our knowledge of compact accreting sources. The properties of inner-accreting regions of active galactic nuclei (AGNs) or X-ray binary systems (XRBs), such as black-hole spin, their disc inclination and orientation, shape and size of their corona, can be polarimetrically studied, parallelly to the well-known X-ray spectroscopic and timing techniques. In this work, we provide a new spectropolarimetric numerical estimate of X-rays in the lamp-post coronal model for a distant observer, including a polarized reflected radiation from the accretion disc. The local disc reflection was simulated using the codes TITAN and STOKES and includes variable disc ionization as well as Monte Carlo treatment of Compton multiple scatterings. We introduce a relativistic code KYNSTOKES based on our well-tested KY package that accounts for all relativistic effects on radiation near a black hole, apart from the returning radiation, and adds a possibility of polarized coronal emission. We study the spectrum, polarization degree and polarization angle at spatial infinity for various global system parameters and we demonstrate the difference at infinity, if analytical local reflection computations are used. We newly predict that in the hard X-rays the reflected component can be 25% polarized and the total emission can be 9% polarized in the most favourable, yet realistic configurations of radio-quiet AGNs. Thus, the relativistic disc reflection remains important for the interpretation of X-ray polarimetric observations., Comment: 25 pages, 23 figures, 2 tables. Accepted for publication in MNRAS. Figures 6, 7, 9, 10, 15, 16 corrected
Published: 2023
Full Text: View/download PDF

35. Discovery of strongly variable X-ray polarization in the neutron star low-mass X-ray binary transient XTE J1701$-$462

Author: Cocchi, Massimo, Gnarini, Andrea, Fabiani, Sergio, Ursini, Francesco, Poutanen, Juri, Capitanio, Fiamma, Bobrikova, Anna, Farinelli, Ruben, Paizis, Adamantia, Sidoli, Lara, Veledina, Alexandra, Bianchi, Stefano, Di Marco, Alessandro, Ingram, Adam, Kajava, Jari J. E., La Monaca, Fabio, Matt, Giorgio, Malacaria, Christian, Mikušincová, Romana, Rankin, John, Zane, Silvia, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monta, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract: After about 16 years since its first outburst, the transient neutron star low-mass X-ray binary XTE J1701$-$462 turned on again in September 2022, allowing for the first study of its X-ray polarimetric characteristics by a dedicated observing program with the Imaging X-ray Polarimeter Explorer (IXPE). Polarimetric studies of XTE J1701$-$462 have been expected to improve our understanding of accreting weakly magnetized neutron stars, in particular, the physics and the geometry of the hot inner regions close to the compact object. The IXPE data of two triggered observations were analyzed using time-resolved spectroscopic and polarimetric techniques, following the source along its Z-track of the color-color diagram. During the first pointing on 2022 September 29, an average 2-8 keV polarization degree of 4.6$\pm$ 0.4\% was measured, the highest value found up to now for this class of sources. Conversely, only a $\sim$0.6\% average degree was obtained during the second pointing ten days later. The polarimetric signal appears to be strictly related to the higher energy blackbody component associated with the boundary layer (BL) emission and its reflection from the inner accretion disk, and it is as strong as 6.1\% and 1.2\% ($>95\%$ significant) above 3-4 keV for the two measurements, respectively. The variable polarimetric signal is apparently related to the spectral characteristics of XTE J1701$-$462, which is the strongest when the source was in the horizontal branch of its Z-track and the weakest in the normal branch. These IXPE results provide new important observational constraints on the physical models and geometry of the Z-sources. Here, we discuss the possible reasons for the presence of strong and variable polarization among these sources., Comment: 7 pages, 8 figures; published in A&A 674, L10 (2023)
Published: 2023
Full Text: View/download PDF

36. First detection of X-ray polarization from the accreting neutron star 4U 1820-303

Author: Di Marco, Alessandro, La Monaca, Fabio, Poutanen, Juri, Russell, Thomas D., Anitra, Alessio, Farinelli, Ruben, Mastroserio, Guglielmo, Muleri, Fabio, Xie, Fei, Bachetti, Matteo, Burderi, Luciano, Carotenuto, Francesco, Del Santo, Melania, Di Salvo, Tiziana, Dovciak, Michal, Gnarini, Andrea, Iaria, Rosario, Kajava, Jari J. E., Liu, Kuan, Middei, Riccardo, O'Dell, Stephen L., Pilia, Maura, Rankin, John, Sanna, Andrea, Eijnden, Jakob van den, Weisskopf, Martin C., Bobrikova, Anna, Capitanio, Fiamma, Costa, Enrico, Kaaret, Philip, Marino, Alessio, Soffitta, Paolo, Ursini, Francesco, Ambrosino, Filippo, Cocchi, Massimo, Fabiani, Sergio, Marshall, Herman L., Matt, Giorgio, Motta, Sara Elisa, Papitto, Alessandro, Stella, Luigi, Tarana, Antonella, Zane, Silvia, Agudo, Ivan, Antonelli, Lucio A., Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, Ng, Chi-Yung, Omodei, Nicola, Oppedisano, Chiara, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, and Wu, Kinwah
Subjects: Astrophysics - High Energy Astrophysical Phenomena
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 (ATCA). The IXPE observations of 4U 1820-303 were coordinated with Swift-XRT, NICER, and NuSTAR 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) deg in the 4-7 keV energy range, and a polarization degree of 10(2)% and a polarization angle of -67(7) deg 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 about 90 deg 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 99.97% upper limit of 50% at 7.25 GHz.
Published: 2023
Full Text: View/download PDF

37. X-ray polarization properties of partially ionized equatorial obscurers around accreting compact objects

Author: Podgorný, Jakub, Marin, Frédéric, and Dovčiak, Michal
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the expected X-ray polarization signal resulting from distant reprocessing material around black holes. Using a central isotropic power-law emission at the center of the simulated model, we add distant equatorial and axially symmetric media that are covering the central accreting sources. We include partial ionization and partial transparency effects, and the impact of various polarization and steepness of the primary radiation spectrum. The results are obtained with the Monte Carlo code STOKES that considers both line and continuum processes and computes the effects of scattering and absorption inside static homogenous wedge-shaped and elliptical toroidal structures, varying in relative size, composition and distance to the source. We provide first order estimates for parsec-scale reprocessing in Compton-thin and Compton-thick active galactic nuclei, as well as winds around accreting stellar-mass compact objects, for observer's inclinations above and below the grazing angle. The resulting reprocessed polarization can reach tens of % with either parallel or perpendicular orientation with respect to the axis of symmetry, depending on subtle details of the geometry, density and ionization structure. We also show how principal parameters constrained from X-ray spectroscopy or polarimetry in other wavelengths can lift the shown degeneracies in X-ray polarization. We provide an application example of the broad modelling discussion by revisiting the recent IXPE 2-8 keV X-ray polarimetric observation of the accreting stellar-mass black hole in Cygnus X-3 from the perspective of partial transparency and ionization of the obscuring outflows., Comment: 23 pages, 21 figures. Accepted for publication in MNRAS. Figures 2 (and caption), 5, 8, 9, A4 corrected
Published: 2023

38. Complex variations of X-ray polarization in the X-ray pulsar LS V +44 17/RX J0440.9+4431

Author: Doroshenko, Victor, Poutanen, Juri, Heyl, Jeremy, Tsygankov, Sergey S., Caiazzo, Ilaria, Turolla, Roberto, Veledina, Alexandra, Weisskopf, Martin C., Forsblom, Sofia V., González-Caniulef, Denis, Loktev, Vladislav, Malacaria, Christian, Mushtukov, Alexander A., Suleimanov, Valery F., Lutovinov, Alexander A., Mereminskiy, Ilya A., Molkov, Sergey V., Salganik, Alexander, Santangelo, Andrea, Berdyugin, Andrei V., Kravtsov, Vadim, Nitindala, Anagha P., Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Di Marco, Alessandro, Donnarumma, Immacolata, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, García, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Vink, Jacco, Wu, Kinwah, Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on Imaging X-ray polarimetry explorer (IXPE) observations of the Be-transient X-ray pulsar LS V +44 17/RX J0440.9+4431 made at two luminosity levels during the giant outburst in January--February 2023. Considering the observed spectral variability and changes in the pulse profiles, the source was likely caught in supercritical and subcritical states with significantly different emission-region geometry, associated with the presence of accretion columns and hot spots, respectively. We focus here on the pulse-phase-resolved polarimetric analysis and find that the observed dependencies of the polarization degree and polarization angle (PA) on the pulse phase are indeed drastically different for the two observations. The observed differences, if interpreted within the framework of the rotating vector model (RVM), imply dramatic variations in the spin axis inclination, the position angle, and the magnetic colatitude by tens of degrees within the space of just a few days. We suggest that the apparent changes in the observed PA phase dependence are predominantly related to the presence of an unpulsed polarized component in addition to the polarized radiation associated with the pulsar itself. We then show that the observed PA phase dependence in both observations can be explained with a single set of RVM parameters defining the pulsar's geometry. We also suggest that the additional polarized component is likely produced by scattering of the pulsar radiation in the equatorial disk wind., Comment: 10 pages, 7 figures, accepted in A&A
Published: 2023
Full Text: View/download PDF

39. X-ray polarimetry of the accreting pulsar GX 301-2

Author: Suleimanov, Valery F., Forsblom, Sofia V., Tsygankov, Sergey S., Poutanen, Juri, Doroshenko, Victor, Doroshenko, Rosalia, Capitanio, Fiamma, Di Marco, Alessandro, González-Caniulef, Denis, Heyl, Jeremy, La Monaca, Fabio, Lutovinov, Alexander A., Molkov, Sergey V., Malacaria, Christian, Mushtukov, Alexander A., Shtykovsky, Andrey E., Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Donnarumma, Immacolata, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Rollins, Melissa Pesce, Petrucci, Pierre Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The phase- and energy-resolved polarization measurements of accreting X-ray pulsars (XRPs) allow us to test different theoretical models of their emission, and they also provide an avenue to determine the emission region geometry. We present the results of the observations of the XRP GX 301-2 performed with the Imaging X-ray Polarimetry Explorer (IXPE). A persistent XRP, GX 301-2 has one of the longest spin periods known: $\sim$680s. A massive hyper-giant companion star Wray 977 supplies mass to the neutron star via powerful stellar winds. We did not detect significant polarization in the phase-averaged data when using spectro-polarimetric analysis, with the upper limit on the polarization degree (PD) of 2.3% (99% confidence level). Using the phase-resolved spectro-polarimetric analysis, we obtained a significant detection of polarization (above 99% confidence level) in two out of nine phase bins and a marginal detection in three bins, with a PD ranging between $\sim$3% and $\sim$10% and a polarization angle varying in a very wide range from $\sim$0 degree to $\sim$160 degree. Using the rotating vector model, we obtained constraints on the pulsar geometry using both phase-binned and unbinned analyses, finding excellent agreement. Finally, we discuss possible reasons for a low observed polarization in GX 301-2., Comment: 10 pages, 10 figures, accepted for publication in A&A
Published: 2023
Full Text: View/download PDF

40. X-ray Polarization of BL Lacertae in Outburst

Author: Peirson, Abel L., Negro, Michela, Liodakis, Ioannis, Middei, Riccardo, Kim, Dawoon E., Marscher, Alan P., Marshall, Herman L., Pacciani, Luigi, Romani, Roger W., Wu, Kinwah, Di Marco, Alessandro, Di Lalla, Niccolo, Omodei, Nicola, Jorstad, Svetlana G., Agudo, Ivan, Kouch, Pouya M., Lindfors, Elina, Aceituno, Francisco Jose, Bernardos, Maria I., Bonnoli, Giacomo, Casanova, Victor, Garcia-Comas, Maya, Agis-Gonzalez, Beatriz, Husillos, Cesar, Marchini, Alessandro, Sota, Alfredo, Casadio, Carolina, Escudero, Juan, Myserlis, Ioannis, Sievers, Albrecht, Gurwell, Mark, Rao, Ramprasad, Imazawa, Ryo, Sasada, Mahito, Fukazawa, Yasushi, Kawabata, Koji S., Uemura, Makoto, Mizuno, Tsunefumi, Nakaoka, Tatsuya, Akitaya, Hiroshi, Cheong, Whee Yeon, Jeong, Hyeon-Woo, Kang, Sincheol, Kim, Sang-Hyun, Lee, Sang-Sung, Angelakis, Emmanouil, Kraus, Alexander, Cibrario, Nicolo, Donnarumma, Immacolata, Poutanen, Juri, Tavecchio, Fabrizio, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Doroshenko, Victor, Dovciak, 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, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Madejski, Grzegorz, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Muleri, Fabio, Ng, C. -Y., O'Dell, Stephen L., Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., 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, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
Abstract: We report the first $> 99\%$ confidence detection of X-ray polarization in BL Lacertae. During a recent X-ray/$\gamma$-ray outburst, a 287 ksec observation (2022 November 27-30) was taken using the Imaging X-ray Polarimetry Explorer ({\it IXPE}), together with contemporaneous multiwavelength observations from the Neil Gehrels {\it Swift} observatory and {\it XMM-Newton} in soft X-rays (0.3--10~keV), {\it 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 {\it 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 $\Pi_{2-4{\rm keV}} = 21.7^{+5.6}_{-7.9}\%$ and electric vector polarization angle $\psi_{2-4{\rm keV}} = -28.7 \pm 8.7^{\circ}$ in the time bin with highest estimated synchrotron flux contribution. We discuss possible implications of our observations, including previous {\it IXPE} BL Lacertae pointings, tentatively concluding that synchrotron self-Compton emission dominates over hadronic emission processes during the observed epochs., Comment: Accepted to ApJL. 16 pages, 8 figures
Published: 2023
Full Text: View/download PDF

41. Discovery of X-ray polarization angle rotation in active galaxy Mrk 421

Author: Di Gesu, Laura, Marshall, Herman L., Ehlert, Steven R., Kim, Dawoon E., Donnarumma, Immacolata, Tavecchio, Fabrizio, Liodakis, Ioannis, Kiehlmann, Sebastian, Agudo, Iván, Jorstad, Svetlana G., Muleri, Fabio, Marscher, Alan P., Puccetti, Simonetta, Middei, Riccardo, Perri, Matteo, Pacciani, Luigi, Negro, Michela, Romani, Roger W., Di Marco, Alessandro, Blinov, Dmitry, Bourbah, Ioakeim G., Kontopodis, Evangelos, Mandarakas, Nikos, Romanopoulos, Stylianos, Skalidis, Raphael, Vervelaki, Anna, Casadio, Carolina, Escudero, Juan, Myserlis, Ioannis, Gurwell, Mark, Rao, Ramprasad, Keating, Garrett, Kouch, Pouya M., Lindfors, Elina, Aceituno, Francisco Josè, Bernardos, Maria I., Bonnoli, Giacomo, Casanova, Vìctor, Garcìa-Comas, Maya, Agìs-Gonzàlez, Beatriz, Husillos, Cèsar, Marchini, Alessandro, Sota, Alfredo, Imazawa, Ryo, Sasada, Mahito, Fukazawa, Yasushi, Kawabata, Koji S., Uemura, Makoto, Mizuno, Tsunefumi, Nakaoka, Tatsuya, Akitaya, Hiroshi, Savchenko, Sergey S., Vasilyev, Andrey A., Gòmez, Josè L., Antonelli, Lucio A., Barnouin, Thibault, Bonino, Raffaella, Cavazzuti, Elisabetta, Costamante, Luigi, Chen, Chien-Ting, Cibrario, Nicolò, De Rosa, Alessandra, Di Pierro, Federico, Errando, Manel, Kaaret, Philip, Karas, Vladimir, Krawczynski, Henric, Lisalda, Lindsey, Madejski, Grzegorz, Malacaria, Christian, Marin, Frédéric, Marinucci, Andrea, Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, O'Dell, Stephen L., Paggi, Alessandro, Peirson, Abel L., Petrucci, Pierre-Olivier, Ramsey, Brian D., Tennant, Allyn F., Wu, Kinwah, Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Ciprini, Stefano, Costa, Enrico, Del Monte, Ettore, Di Lalla, Niccolò, Doroshenko, Victor, Dovčiak, Michal, Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Ng, C. -Y., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Taverna, Roberto, Tawara, Yuzuru, Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The magnetic field conditions in astrophysical relativistic jets can be probed by multiwavelength polarimetry, which has been recently extended to X-rays. For example, one can track how the magnetic field changes in the flow of the radiating particles by observing rotations of the electric vector position angle $\Psi$. Here we report the discovery of a $\Psi_{\mathrm x}$ rotation in the X-ray band in the blazar Mrk 421 at an average flux state. Across the 5 days of Imaging X-ray Polarimetry Explorer (IXPE) observations of 4-6 and 7-9 June 2022, $\Psi_{\mathrm x}$ rotated in total by $\geq360^\circ$. Over the two respective date ranges, we find constant, within uncertainties, rotation rates ($80 \pm 9$ and $91 \pm 8 ^\circ/\rm day$) and polarization degrees ($\Pi_{\mathrm x}=10\%\pm1\%$). Simulations of a random walk of the polarization vector indicate that it is unlikely that such rotation(s) are produced by a stochastic process. The X-ray emitting site does not completely overlap the radio/infrared/optical emission sites, as no similar rotation of $\Psi$ was observed in quasi-simultaneous data at longer wavelengths. We propose that the observed rotation was caused by a helical magnetic structure in the jet, illuminated in the X-rays by a localized shock propagating along this helix. The optically emitting region likely lies in a sheath surrounding an inner spine where the X-ray radiation is released.
Published: 2023

42. The First X-ray Polarization Observation of the Black Hole X-ray Binary 4U 1630-47 in the Steep Power Law State

Author: Cavero, Nicole Rodriguez, Marra, Lorenzo, Krawczynski, Henric, Dovčiak, Michal, Bianchi, Stefano, Steiner, James F., Svoboda, Jiri, Capitanio, Fiamma, Matt, Giorgio, Negro, Michela, Ingram, Adam, Veledina, Alexandra, Taverna, Roberto, Karas, Vladimir, Ursini, Francesco, Podgorný, Jakub, Ratheesh, Ajay, Suleimanov, Valery, Mikušincová, Romana, Zane, Silvia, Kaaret, Philip, Muleri, Fabio, Poutanen, Juri, Malacaria, Christian, Petrucci, Pierre-Olivier, Gau, Ephraim, Hu, Kun, Chun, Sohee, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, García, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Soffitta, Paolo, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena
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{\deg}.3 +/- 0{\deg}.9 East of North (all errors at 1{\sigma} 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., Comment: 14 pages, 2 tables, 6 figures
Published: 2023

43. X-ray Polarization of the Black Hole X-ray Binary 4U 1630-47 Challenges Standard Thin Accretion Disk Scenario

Author: Ratheesh, Ajay, Dovčiak, Michal, Krawczynski, Henric, Podgorný, Jakub, Marra, Lorenzo, Veledina, Alexandra, Suleimanov, Valery, Cavero, Nicole Rodriguez, Steiner, James, Svoboda, Jiri, Marinucci, Andrea, Bianchi, Stefano, Negro, Michela, Matt, Giorgio, Tombesi, Francesco, Poutanen, Juri, Ingram, Adam, Taverna, Roberto, West, Andrew, Karas, Vladimir, Ursini, Francesco, Soffitta, Paolo, Capitanio, Fiamma, Viscolo, Domenico, Manfreda, Alberto, Muleri, Fabio, Parra, Maxime, Beheshtipour, Banafsheh, Chun, Sohee, Cibrario, Niccolò, Di Lalla, Niccolò, Fabiani, Sergio, Hu, Kun, Kaaret, Philip, Loktev, Vladislav, Mikušincová, Romana, Mizuno, Tsunefumi, Omodei, Nicola, Petrucci, Pierre-Olivier, Puccetti, Simonetta, Rankin, John, Zane, Silvia, Zhang, Sixuan, Agudo, Iván, Antonelli, Lucio, Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne, Bellazzini, Ronaldo, Bongiorno, Stephen, Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Marco, Alessandro, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven, Enoto, Teruaki, Evangelista, Yuri, Ferrazzoli, Riccardo, Garcia, Javier, Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Marin, Frédéric, Marscher, Alan, Marshall, Herman, Massaro, Francesco, Mitsuishi, Ikuyuki, Ng, C. -Y., O'Dell, Stephen, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George, Peirson, Abel, Perri, Matteo, Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Ramsey, Brian, Roberts, Oliver, Romani, Roger, Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Douglas, Tamagawa, Toru, Tavecchio, Fabrizio, Tawara, Yuzuru, Tennant, Allyn, Thomas, Nicholas, Trois, Alessio, Tsygankov, Sergey, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin, Wu, Kinwah, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: 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 $\approx50\sigma$ confidence level) of an unexpectedly high polarization, rising from $\sim6\%$ at $2$ keV to $\sim10\%$ at $8$ keV, cannot be easily reconciled with standard models of thin accretion discs. 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 disc, covered by a partially-ionized atmosphere flowing away at mildly relativistic velocities., Comment: Published in ApJ (https://doi.org/10.3847/1538-4357/ad226e)
Published: 2023
Full Text: View/download PDF

44. X-ray polarization evidence for a 200 years-old flare of Sgr A$^*$

Author: Marin, Frédéric, Churazov, Eugene, Khabibullin, Ildar, Ferrazzoli, Riccardo, Di Gesu, Laura, Barnouin, Thibault, Di Marco, Alessandro, Middei, Riccardo, Vikhlinin, Alexey, Costa, Enrico, Soffitta, Paolo, Muleri, Fabio, Sunyaev, Rashid, Forman, William, Kraft, Ralph, Bianchi, Stefano, Donnarumma, Immacolata, Petrucci, Pierre-Olivier, Enoto, Teruaki, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Lalla, Niccolò, Doroshenko, Victor, Dovciak, Michal, Ehlert, Steven R., Evangelista, Yuri, Fabiani, Sergio, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Ingram, Adam, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, Ng, C. -Y., O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Doug, Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., 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, Astrophysics - Astrophysics of Galaxies, J.2.3, J.2.9
Abstract: The center of the Milky Way Galaxy hosts a $\sim$4 million solar mass black hole (Sgr A$^*$) that is currently very quiescent with a luminosity many orders of magnitude below those of active galactic nuclei. Reflection of X-rays from Sgr A$^*$ by dense gas in the Galactic Center region offers a means to study its past flaring activity on times scales of hundreds and thousands of years. The shape of the X-ray continuum and the strong fluorescent iron line observed from giant molecular clouds in the vicinity of Sgr A$^*$ are consistent with the reflection scenario. If this interpretation is correct, the reflected continuum emission should be polarized. Here we report observations of polarized X-ray emission in the direction of the Galactic center molecular clouds using the Imaging X-ray Polarimetry Explorer (IXPE). We measure a polarization degree of 31\% $\pm$ 11\%, and a polarization angle of $-$48$^\circ$ $\pm$ 11$^\circ$. The polarization angle is consistent with Sgr A$^*$ being the primary source of the emission, while the polarization degree implies that some 200 years ago the X-ray luminosity of Sgr A$^*$ was briefly comparable to a Seyfert galaxy., Comment: 24 pages, 5 figures, 4 tables, author's version of the paper accepted for publication in Nature
Published: 2023
Full Text: View/download PDF

45. A polarimetrically oriented X-ray stare at the accreting pulsar EXO 2030+375

Author: Malacaria, Christian, Heyl, Jeremy, Doroshenko, Victor, Tsygankov, Sergey S., Poutanen, Juri, Forsblom, Sofia V., Capitanio, Fiamma, Di Marco, Alessandro, Du, Yujia, Ducci, Lorenzo, La Monaca, Fabio, Lutovinov, Alexander A., Marshall, Herman L., Mereminskiy, Ilya A., Molkov, Sergey V., Ng, Mason, Petrucci, Pierre-Olivier, Santangelo, Andrea, Shtykovsky, Andrey E., Suleimanov, Valery F., Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Dovciak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak1, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Accreting X-ray pulsars (XRPs) are presumably ideal targets for polarization measurements, as their high magnetic field strength is expected to polarize the emission up to a polarization degree of ~80%. However, such expectations are being challenged by recent observations of XRPs with the Imaging X-ray Polarimeter Explorer (IXPE). Here we report on the results of yet another XRP, EXO 2030+375, observed with IXPE and contemporarily monitored with Insight-HXMT and SRG/ART-XC. In line with recent results obtained with IXPE for similar sources, analysis of the EXO 2030+375 data returns a low polarization degree of 0%-3% in the phase-averaged study and variation in the range 2%-7% in the phase-resolved study. Using the rotating vector model we constrain the geometry of the system and obtain a value for the magnetic obliquity of ~$60^{\circ}$. Considering also the estimated pulsar inclination of ~$130^{\circ}$, this indicates that the magnetic axis swings close to the observer line of sight. Our joint polarimetric, spectral and timing analysis hint to a complex accreting geometry where magnetic multipoles with asymmetric topology and gravitational light bending significantly affect the observed source behavior., Comment: A&A accepted. Proofs version
Published: 2023
Full Text: View/download PDF

46. Vela pulsar wind nebula x-rays are polarized to near the synchrotron limit

Author: Xie, Fei, Di Marco, Alessandro, La Monaca, Fabio, Liu, Kuan, Muleri, Fabio, Bucciantini, Niccolò, Romani, Roger W., Costa, Enrico, Rankin, John, Soffitta, Paolo, Bachetti, Matteo, Di Lalla, Niccolò, Fabiani, Sergio, Ferrazzoli, Riccardo, Gunji, Shuichi, Latronico, Luca, Negro, Michela, Omodei, Nicola, Pilia, Maura, Trois, Alessio, Watanabe, Eri, Agudo, Iván, Antonelli, Lucio A., Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Ciprini, Stefano, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Donnarumma, Immacolata, Doroshenko, Victor, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Garcia, Javier A., Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Ng, C. -Y., O'Dell, Stephen L., Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Poutanen, Juri, Puccetti, Simonetta, Ramsey, Brian D., Ratheesh, Ajay, Sgró, Carmelo, Slane, Patrick, Spandre, Gloria, Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicolas E., Tombesi, Francesco, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Pulsar wind nebulae are formed when outflows of relativistic electrons and positrons hit the surrounding supernova remnant or interstellar medium at a shock front. The Vela pulsar wind nebula is powered by a young pulsar (B0833-45, age 11 kyr) and located inside an extended structure called Vela X, itself inside the supernova remnant. Previous X-ray observations revealed two prominent arcs, bisected by a jet and counter jet. Radio maps have shown high linear polarization of 60 per cent in the outer regions of the nebula. Here we report X-ray observation of the inner part of the nebula, where polarization can exceed 60 per cent at the leading edge, which approaches the theoretical limit of what can be produced by synchrotron emission. We infer that, in contrast with the case of the supernova remnant, the electrons in the pulsar wind nebula are accelerated with little or no turbulence in a highly uniform magnetic field., Comment: 27 pages, 8 figures, 4 tables, author's version of the paper accepted for publication in Nature
Published: 2023
Full Text: View/download PDF

47. The first X-ray polarimetric observation of the black hole binary LMC X-1

Author: Podgorny, Jakub, Marra, Lorenzo, Muleri, Fabio, Cavero, Nicole Rodriguez, Ratheesh, Ajay, Dovciak, Michal, Mikusincova, Romana, Brigitte, Maimouna, Steiner, James F., Veledina, Alexandra, Bianchi, Stefano, Krawczynski, Henric, Svoboda, Jiri, Kaaret, Philip, Matt, Giorgio, Garcia, Javier A., Petrucci, Pierre-Olivier, Lutovinov, Alexander A., Semena, Andrey N., Di Marco, Alessandro, Negro, Michela, Weisskopf, Martin C., Ingram, Adam, Poutanen, Juri, Beheshtipour, Banfsheh, Chun, Sohee, Hu, Kun, Mizuno, Tsunefumi, Sixuan, Zhang, Tombesi, Francesco, Zane, Silvia, Agudo, Ivan, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolo, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolo, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., La Monaca, Fabio, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frederic, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Roberts, Oliver J., Romani, Roger W., Sgro, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Doug A., Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Trois, Alessio, Tsygankov, Sergey S., Turolla, Roberto, Vink, Jacco, Wu, Kinwah, and Xie, Fei
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on an X-ray polarimetric observation of the high-mass X-ray binary LMC X-1 in the high/soft state, obtained by the Imaging X-ray Polarimetry Explorer (IXPE) in October 2022. The measured polarization is below the minimum detectable polarization of 1.1 per cent (at the 99 per cent confidence level). Simultaneously, the source was observed with the NICER, NuSTAR and SRG/ART-XC instruments, which enabled spectral decomposition into a dominant thermal component and a Comptonized one. The low 2-8 keV polarization of the source did not allow for strong constraints on the black-hole spin and inclination of the accretion disc. However, if the orbital inclination of about 36 degrees is assumed, then the upper limit is consistent with predictions for pure thermal emission from geometrically thin and optically thick discs. Assuming the polarization degree of the Comptonization component to be 0, 4, or 10 per cent, and oriented perpendicular to the polarization of the disc emission (in turn assumed to be perpendicular to the large scale ionization cone orientation detected in the optical band), an upper limit to the polarization of the disc emission of 1.0, 0.9 or 0.9 per cent, respectively, is found (at the 99 per cent confidence level)., Comment: 12 pages, 9 figures, 4 tables. Accepted for publication in MNRAS
Published: 2023

48. IXPE observations of the quintessential wind-accreting X-ray pulsar Vela X-1

Author: Forsblom, Sofia V., Poutanen, Juri, Tsygankov, Sergey S., Bachetti, Matteo, Di Marco, Alessandro, Doroshenko, Victor, Heyl, Jeremy, La Monaca, Fabio, Malacaria, Christian, Marshall, Herman L., Muleri, Fabio, Mushtukov, Alexander A., Pilia, Maura, Rogantini, Daniele, Suleimanov, Valery F., Taverna, Roberto, Xi, Fei, Agudo, Iván, Antonelli, Lucio A., Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Donnarumma, Immacolata, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Sunyaev, Rashid A., Swartz, Doug, Tamagawa, Toru, Tavecchio, Fabrizio, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena
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 (IXPE). 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 spectro-polarimetric analysis of the phase-averaged data for Vela X-1 reveals a polarization degree (PD) of 2.3$\pm$0.4% at the polarization angle (PA) of -47.3$\pm$5.4 deg. 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 deg difference in the PA compared to the data in the 2-3 keV range. The phase-resolved spectro-polarimetric analysis finds a PD in the range 0-9% with the PA varying between -80 and 40 deg., Comment: 12 pages, 7 figures, ApJ Letters, submitted
Published: 2023
Full Text: View/download PDF

49. Cygnus X-3 revealed as a Galactic ultraluminous X-ray source by IXPE

Author: Veledina, Alexandra, Muleri, Fabio, Poutanen, Juri, Podgorný, Jakub, Dovčiak, Michal, Capitanio, Fiamma, Churazov, Eugene, De Rosa, Alessandra, Di Marco, Alessandro, Forsblom, Sofia, Kaaret, Philip, Krawczynski, Henric, La Monaca, Fabio, Loktev, Vladislav, Lutovinov, Alexander A., Molkov, Sergey V., Mushtukov, Alexander A., Ratheesh, Ajay, Cavero, Nicole Rodriguez, Steiner, James F., Sunyaev, Rashid A., Tsygankov, Sergey S., Zdziarski, Andrzej A., Bianchi, Stefano, Bright, Joe S., Bursov, Nikolaj, Costa, Enrico, Egron, Elise, Garcia, Javier A., Green, David A., Gurwell, Mark, Ingram, Adam, Kajava, Jari J. E., Kale, Ruta, Kraus, Alex, Malyshev, Denys, Marin, Frédéric, Matt, Giorgio, McCollough, Michael, Mereminskiy, Ilia A., Nizhelsky, Nikolaj, Piano, Giovanni, Pilia, Maura, Pittori, Carlotta, Rao, Ramprasad, Righini, Simona, Soffitta, Paolo, Shevchenko, Anton, Svoboda, Jiri, Tombesi, Francesco, Trushkin, Sergei, Tsybulev, Peter, Ursini, Francesco, Weisskopf, Martin C., Wu, Kinwah, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Donnarumma, Immacolata, Doroshenko, Victor, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Gunji, Shuichi, Hayashida, Kiyoshi, Heyl, Jeremy, Iwakiri, Wataru, Jorstad, Svetlana G., Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marinucci, Andrea, Marscher, Alan P., Marshall, Herman L., Massaro, Francesco, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Roberts, Oliver, Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Spandre, Gloria, Swartz, Doug, Tamagawa, Toru, Tavecchio, Fabrizio, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Trois, Alessio, Turolla, Roberto, Vink, Jacco, Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract: The accretion of matter by compact objects can be inhibited by radiation pressure if the luminosity exceeds the critical value, known as the Eddington limit. Discovery of ultraluminous X-ray sources has shown that accretion can proceed even when the apparent luminosity significantly exceeds this limit. High apparent luminosity might be produced thanks to geometric beaming of the radiation by an outflow. The outflow half-opening angle, which determines the amplification due to beaming, has never been robustly constrained. Using the Imaging X-ray Polarimetry Explorer, we made the measurement of X-ray polarization in the Galactic X-ray binary Cyg X-3. We find high, over 20%, nearly energy-independent linear polarization, orthogonal to the direction of the radio ejections. These properties unambiguously indicate the presence of a collimating outflow in the X-ray binary Cyg~X-3 and constrain its half-opening angle, <15 degrees. Thus, the source can be used as a laboratory for studying the super-critical accretion regime. This finding underscores the importance of X-ray polarimetry in advancing our understanding of accreting sources., Comment: 52 pages, 14 figures, 3 tables. Author version of the article published in Nature Astronomy
Published: 2023
Full Text: View/download PDF

50. X-ray pulsar GRO J1008$-$57 as an orthogonal rotator

Author: Tsygankov, Sergey S., Doroshenko, Victor, Mushtukov, Alexander A., Poutanen, Juri, Di Marco, Alessandro, Heyl, Jeremy, La Monaca, Fabio, Forsblom, Sofia, Malacaria, Christian, Marshall, Herman L., Suleimanov, Valery F., Svoboda, Jiri, Taverna, Roberto, Ursini, Francesco, Agudo, Iván, Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccolò, Capitanio, Fiamma, Castellano, Simone, Cavazzuti, Elisabetta, Chen, Chien-Ting, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, Di Gesu, Laura, Di Lalla, Niccolò, Donnarumma, Immacolata, Dovčiak, Michal, Ehlert, Steven R., Enoto, Teruaki, Evangelista, Yuri, Fabiani, Sergio, Ferrazzoli, Riccardo, Garcia, Javier A., Gunji, Shuichi, Hayashida, Kiyoshi, Iwakiri, Wataru, Jorstad, Svetlana G., Kaaret, Philip, Karas, Vladimir, Kislat, Fabian, Kitaguchi, Takao, Kolodziejczak, Jeffery J., Krawczynski, Henric, Latronico, Luca, Liodakis, Ioannis, Maldera, Simone, Manfreda, Alberto, Marin, Frédéric, Marinucci, Andrea, Marscher, Alan P., Massaro, Francesco, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Negro, Michela, Ng, Chi-Yung, O'Dell, Stephen L., Omodei, Nicola, Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel Lawrence, Perri, Matteo, Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Puccetti, Simonetta, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Roberts, Oliver J., Romani, Roger W., Sgrò, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Swartz, Douglas A., Tamagawa, Toru, Tavecchio, Fabrizio, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicholas E., Tombesi, Francesco, Trois, Alessio, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract: X-ray polarimetry is a unique way to probe the geometrical configuration of highly magnetized accreting neutron stars (X-ray pulsars). GRO J1008$-$57 is the first transient X-ray pulsar observed at two different flux levels by the Imaging X-ray Polarimetry Explorer (IXPE) during its outburst in November 2022. We find the polarization properties of GRO J1008$-$57 to be independent of its luminosity, with the polarization degree varying between nondetection and about 15% over the pulse phase. Fitting the phase-resolved spectro-polarimetric data with the rotating vector model allowed us to estimate the pulsar inclination (130 deg, which is in good agreement with the orbital inclination), the position angle (75 deg) of the pulsar spin axis, and the magnetic obliquity (74 deg). This makes GRO J1008$-$57 the first confidently identified nearly orthogonal rotator among X-ray pulsars. We discuss our results in the context of the neutron star atmosphere models and theories of the axis alignment of accreting pulsars., Comment: 11 pages, 7 figures, A&A, in press
Published: 2023
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Publication Type

Journal

Database

Publisher

235 results on '"Marin, Frederic"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources