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Start Over Author "Kravtsov, A." Publication Type Electronic Resources
1,284 results on '"Kravtsov, A."'

1. Orbital variability of polarized X-ray radiation reflected from a companion star in X-ray binaries

Author

Ahlberg, Varpu, Kravtsov, Vadim, Poutanen, Juri, Ahlberg, Varpu, Kravtsov, Vadim, and Poutanen, Juri

Abstract

The reflection of X-ray radiation produced near a compact object from its stellar companion contributes to the orbital variability of polarization in X-ray binaries. The X-rays are reflected mainly via Thomson scattering resulting in a high polarization. The orbital variability of the polarization strongly depends on the inclination and the orbital parameters allowing us to constrain them. To explore this phenomenon, we present analytical single-scattering models for the polarized reflection. We find that while diluted by the direct emission, the reflection can produce a polarization degree of about 1$\%$ in the case of a large reflection albedo. We fitted the orbital variations of the X-ray polarization observed by the Imaging X-ray Polarimetry Explorer from an accreting weakly magnetized neutron star `clocked burster' GS 1826$-$238 and found that the amplitude of the variations is too large to be primarily caused by the companion star. The polarized reflection is more significant if the compact object is obscured from the observer, and thus it should be more easily observable in certain high-inclination targets., Comment: 8 pages, 10 figures, submitted to A&A

Published
2024

2. The enigmatic double-peaked stripped-envelope SN 2023aew

Author

Kangas, Tuomas, Kuncarayakti, Hanindyo, Nagao, Takashi, Kotak, Rubina, Kankare, Erkki, Fraser, Morgan, Stevance, Heloise, Mattila, Seppo, Maeda, Kei'ichi, Stritzinger, Maximilian, Lundqvist, Peter, Elias-Rosa, Nancy, Ferrari, Lucía, Folatelli, Gastón, Frohmaier, Christopher, Galbany, Lluís, Kawabata, Miho, Koutsiona, Eleni, Müller-Bravo, Tomás E., Piscarreta, Lara, Pursiainen, Miika, Singh, Avinash, Taguchi, Kenta, Teja, Rishabh Singh, Valerin, Giorgio, Pastorello, Andrea, Benetti, Stefano, Cai, Yong-Zhi, Charalampopoulos, Panagiotis, Gutiérrez, Claudia P., Kravtsov, Timo, Reguitti, Andrea, Kangas, Tuomas, Kuncarayakti, Hanindyo, Nagao, Takashi, Kotak, Rubina, Kankare, Erkki, Fraser, Morgan, Stevance, Heloise, Mattila, Seppo, Maeda, Kei'ichi, Stritzinger, Maximilian, Lundqvist, Peter, Elias-Rosa, Nancy, Ferrari, Lucía, Folatelli, Gastón, Frohmaier, Christopher, Galbany, Lluís, Kawabata, Miho, Koutsiona, Eleni, Müller-Bravo, Tomás E., Piscarreta, Lara, Pursiainen, Miika, Singh, Avinash, Taguchi, Kenta, Teja, Rishabh Singh, Valerin, Giorgio, Pastorello, Andrea, Benetti, Stefano, Cai, Yong-Zhi, Charalampopoulos, Panagiotis, Gutiérrez, Claudia P., Kravtsov, Timo, and Reguitti, Andrea

Abstract

We present optical and near-infrared photometry and spectroscopy of SN 2023aew and our findings on its remarkable properties. This event, initially resembling a Type IIb supernova (SN), rebrightened dramatically $\sim$80 d after discovery, at which time its spectrum transformed into that of a SN Ic. The slowly-evolving spectrum specifically resembled a post-peak SN Ic with relatively low line velocities even during the second rise. The second peak, reached $\sim$107 d after discovery, is both more luminous ($M_r = -18.75\pm0.04$ mag) and much broader than those of typical SNe Ic or Ic-BL. Blackbody fits to SN 2023aew indicate that the photosphere shrinks throughout its observed evolution, and the second peak is caused by an increasing temperature. Bumps in the light curve after the second peak suggest interaction with circumstellar matter (CSM) or possibly accretion. We consider several scenarios for producing the unprecedented behavior of SN 2023aew. Two separate SNe, either unrelated or from the same binary system, require either an incredible coincidence or extreme fine-tuning. A pre-SN eruption followed by a SN requires an extremely powerful, SN-like eruption (consistent with $\sim$10$^{51}$ erg) and is also disfavored. We therefore consider only the first peak a true stellar explosion. The observed evolution is difficult to reproduce if the second peak is dominated by interaction with a distant CSM shell. A delayed internal heating mechanism is more likely, but emerging embedded interaction with a CSM disk should be accompanied by CSM lines in the spectrum and is difficult to hide long enough. A magnetar central engine requires a delayed onset to explain the long time between the peaks. Delayed fallback accretion onto a black hole may present the most promising scenario, but we cannot definitively establish the power source., Comment: 21 pages + 13 appendix pages, 16 figures + 5 appendix figures. Submitted to A&A

Published
2024

3. The fast transient AT 2023clx in the nearby LINER galaxy NGC 3799, as a tidal disruption event of a very low-mass star

Author

Charalampopoulos, P., Kotak, R., Wevers, T., Leloudas, G., Kravtsov, T., Ramsden, P., Reynolds, T. M., Aamer, A., Anderson, J. P., Arcavi, I., Cai, Y. -Z., Chen, T. -W., Dennefeld, M., Galbany, L., Gromadzki, M., Gutiérrez, C. P., Ihanec, N., Kangas, T., Kankare, E., Kool, E., Lawrence, A., Makrygianni, L., Mattila, S., Müller-Bravo, T. E., Nicholl, M., Onori, F., Pursiainen, M., Sahu, A., Smartt, S. J., Sollerman, J., Wang, Y., Young, D. R., Charalampopoulos, P., Kotak, R., Wevers, T., Leloudas, G., Kravtsov, T., Ramsden, P., Reynolds, T. M., Aamer, A., Anderson, J. P., Arcavi, I., Cai, Y. -Z., Chen, T. -W., Dennefeld, M., Galbany, L., Gromadzki, M., Gutiérrez, C. P., Ihanec, N., Kangas, T., Kankare, E., Kool, E., Lawrence, A., Makrygianni, L., Mattila, S., Müller-Bravo, T. E., Nicholl, M., Onori, F., Pursiainen, M., Sahu, A., Smartt, S. J., Sollerman, J., Wang, Y., and Young, D. R.

Abstract

We present an extensive analysis of the optical and UV properties of AT2023clx, the closest TDE to date, that occurred in the nucleus of the interacting LINER galaxy, NGC3799 (z=0.01107). From several standard methods, we estimate the mass of the central SMBH to be ~ 10^6 Msol. After correcting for the host reddening (E(B-V) = 0.177 mag) we measured its peak absolute g-band magnitude to be -18.25\pm0.05 mag, and its peak bolometric luminosity to be L_pk=(3.24\pm0.36)x10^43erg/s, making AT2023clx an intermediate luminosity TDE. The first distinctive feature of AT2023clx is that it rose to peak within only 10.4\pm2.5 days, making it the fastest rising TDE to date. Our SMBH mass estimate rules out the possibility of an intermediate mass BH as the reason of the fast rise. Dense spectral follow-up revealed a blue continuum that cools slowly and broad Balmer and HeII lines as well as weak HeI emission, features that are typically seen in TDEs. A flat Balmer decrement (~ 1.58) suggests that the lines are collisionally excited rather than being produced via photoionisation, as in typical active galactic nuclei. A second distinctive feature, seen for the first time in TDE spectra, is a sharp, narrow emission peak at a rest wavelength of ~6353 A. This feature is clearly visible up to 10d post-peak; we attribute it to clumpy material preceding the bulk outflow, and manifested as a high-velocity component of Ha (-9584km/s). The third distinctive feature is a break observed in the near-UV light curves that is reflected as a dip in the temperature evolution around ~18-28 days post-peak. Combining these findings, we propose a scenario for AT2023clx involving the disruption of a very low-mass star (<=0.1Msol) with an outflow launched in our line-of-sight with disruption properties that led to circularisation and prompt and efficient accretion disc formation, observed through a low-density photosphere., Comment: Submitted to A&A. Comments are welcome!

Published
2024

4. Pulsar Scintillation Studies with LOFAR: II. Dual-frequency scattering study of PSR??J0826+2637 with LOFAR and NenuFAR

Author

Wu, Z, A Coles, W, W Verbiest, J, Moochickal Ambalappat, K, Tiburzi, C, Grie??meier, J, A Main, R, Liu, Y, Kramer, M, Wucknitz, O, Porayko, N, Os??owski, S, Bak Nielsen, A, Y Donner, J, Hoeft, M, Br??ggen, M, Vocks, C, Dettmar, R, Theureau, G, Serylak, M, Kondratiev, V, W McKee, J, Shaifullah, G, P Kravtsov, I, V Zakharenko, V, Ulyanov, O, O Konovalenko, O, Zarka, P, Cecconi, B, E Koopmans, L, Corbel, S, Ziwei Wu, William A Coles, Joris P W Verbiest, Krishnakumar Moochickal Ambalappat, Caterina Tiburzi, Jean-Mathias Grie??meier, Robert A Main, Yulan Liu, Michael Kramer, Olaf Wucknitz, Nataliya Porayko, Stefan Os??owski, Ann-Sofie Bak Nielsen, Julian Y Donner, Matthias Hoeft, Marcus Br??ggen, Christian Vocks, Ralf-J??rgen Dettmar, Gilles Theureau, Maciej Serylak, Vladislav Kondratiev, James W McKee, Golam Shaifullah, Ihor P Kravtsov, Vyacheslav V Zakharenko, Oleg Ulyanov, Olexandr O Konovalenko, Philippe Zarka, Baptiste Cecconi, L??on V E Koopmans, St??phane Corbel, Wu, Z, A Coles, W, W Verbiest, J, Moochickal Ambalappat, K, Tiburzi, C, Grie??meier, J, A Main, R, Liu, Y, Kramer, M, Wucknitz, O, Porayko, N, Os??owski, S, Bak Nielsen, A, Y Donner, J, Hoeft, M, Br??ggen, M, Vocks, C, Dettmar, R, Theureau, G, Serylak, M, Kondratiev, V, W McKee, J, Shaifullah, G, P Kravtsov, I, V Zakharenko, V, Ulyanov, O, O Konovalenko, O, Zarka, P, Cecconi, B, E Koopmans, L, Corbel, S, Ziwei Wu, William A Coles, Joris P W Verbiest, Krishnakumar Moochickal Ambalappat, Caterina Tiburzi, Jean-Mathias Grie??meier, Robert A Main, Yulan Liu, Michael Kramer, Olaf Wucknitz, Nataliya Porayko, Stefan Os??owski, Ann-Sofie Bak Nielsen, Julian Y Donner, Matthias Hoeft, Marcus Br??ggen, Christian Vocks, Ralf-J??rgen Dettmar, Gilles Theureau, Maciej Serylak, Vladislav Kondratiev, James W McKee, Golam Shaifullah, Ihor P Kravtsov, Vyacheslav V Zakharenko, Oleg Ulyanov, Olexandr O Konovalenko, Philippe Zarka, Baptiste Cecconi, L??on V E Koopmans, and St??phane Corbel

Abstract

Interstellar scattering (ISS) of radio pulsar emission can be used as a probe of the ionized interstellar medium (IISM) and causes corruptions in pulsar timing experiments. Two types of ISS phenomena (intensity scintillation and pulse broadening) are caused by electron density fluctuations on small scales (< 0.01 au). Theory predicts that these are related, and both have been widely employed to study the properties of the IISM. Larger scales (similar to 1 - 100 au) cause measurable changes in dispersion and these can be correlated with ISS observations to estimate the fluctuation spectrum over a very wide scale range. IISM measurements can often be modelled by a homogeneous power-law spatial spectrum of electron density with the Kolmogorov (-11/3) spectral exponent. Here, we aim to test the validity of using the Kolmogorov exponent with PSR J0826+2637. We do so using observations of intensity scintillation, pulse broadening and dispersion variations across a wide fractional bandwidth (20-180 MHz). We present that the frequency dependence of the intensity scintillation in the high-frequency band matches the expectations of a Kolmogorov spectral exponent, but the pulse broadening in the low-frequency band does not change as rapidly as predicted with this assumption. We show that this behaviour is due to an inhomogeneity in the scattering region, specifically that the scattering is dominated by a region of transverse size similar to 40 au. The power spectrum of the electron density, however, maintains the Kolmogorov spectral exponent from spatial scales of 5 x 10(-6) au to similar to 100 au.

Published
2023

5. Hybrid modelling of time-variant heterogeneous objects

Author

Kravtsov, Denis

Subjects
005.3, Computer Science and Informatics
Abstract

The physical world consists of a wide range of objects of a diverse constitution. Past research was mainly focussed on the modelling of simple homogeneous objects of a uniform constitution. Such research resulted in the development of a number of advanced theoretical concepts and practical techniques for describing such physical objects. As a result, the process of modelling and animating certain types of homogeneous objects became feasible. In fact most physical objects are not homogeneous but heterogeneous in their constitution and it is thus important that one is able to deal with such heterogeneous objects that are composed of diverse materials and may have complex internal structures. Heterogeneous object modelling is still a very new and evolving research area, which is likely to prove useful in a wide range of application areas. Despite its great promise, heterogeneous object modelling is still at an embryonic state of development and there is a dearth of extant tools that would allow one to work with static and dynamic heterogeneous objects. In addition, the heterogeneous nature of the modelled objects makes it appealing to employ a combination of different representations resulting in the creation of hybrid models. In this thesis we present a new dynamic Implicit Complexes (IC) framework incorporating a number of existing representations and animation techniques. This framework can be used for the modelling of dynamic multidimensional heterogeneous objects. We then introduce an Implicit Complexes Application Programming Interface (IC API). This IC API is designed to provide various applications with a unified set of tools allowing these to model time-variant heterogeneous objects. We also present a new Function Representation (FRep) API, which is used for the integration of FReps into complex time-variant hybrid models. This approach allows us to create a practical multilevel modelling system suited for complex multidimensional hybrid modelling of dynamic heterogeneous objects. We demonstrate the advantages of our approach through the introduction of a novel set of tools tailored to problems encountered in simulation applications, computer animation and computer games. These new tools empower users and amplify their creativity by allowing them to overcome a large number of extant modelling and animation problems, which were previously considered difficult or even impossible to solve.

Published
2011

6. Methodological Approach in the Simulation of the Robustness Boundaries of Tribosystems under the Conditions of Boundary Lubrication

Author

Al-Quraan, Tareq M. A., Alfaqs, Fadi, Alrefo, Ibrahim F. S., Vojtov, Viktor, Voitov, Anton, Kravtsov, Andrey, Miroshnyk, Oleksandr, Kondratiev, Andrii, Kučera, Pavel, Píštěk, Václav, Al-Quraan, Tareq M. A., Alfaqs, Fadi, Alrefo, Ibrahim F. S., Vojtov, Viktor, Voitov, Anton, Kravtsov, Andrey, Miroshnyk, Oleksandr, Kondratiev, Andrii, Kučera, Pavel, and Píštěk, Václav

Abstract

In the presented work, a methodical approach was developed for determining rational operation modes of tribosystems, taking into account their design. This approach makes it possible in the designing stage, according to the predicted operating modes, to calculate the limits and margins of stable work in operation. The definition of the robustness of the tribosystem and the criteria for assessing the robustness are formulated based on the theory of stability of technical systems. It is shown that such a methodical approach allows for determining the modes of the rational operation of the designed structures without damaging the friction surfaces. Experimental studies have proven that not all designs of tribosystems lose stability due to the appearance of friction surface burrs. There are designs where the loss of stability occurs upon the appearance of accelerated wear. The developed criteria take into account two options for the loss of stability. An experimental verification of the modes of loss of stability of tribosystems was performed by the appearance of a burr or the beginning of accelerated wear with the calculated values of the robustness criteria. The obtained results allow us to conclude that the modeling error is within 8.3–18.7%, which is a satisfactory result in the study of friction and wear processes. Robustness criteria is based on the coefficient of friction RRf and wear rate RRI, and must be used when designing new constructions of tribosystems. Theoretical calculations of such criteria and the dependence of their change on changing the predicted operating modes will allow for justifying rational operating modes within their stability.

Published
2023

7. Distance learning expert and leader

Author

Kukharenko, Vladimir N., Shunevych, Bohdan I., Kravtsov, Hennadiy M., Kukharenko, Vladimir N., Shunevych, Bohdan I., and Kravtsov, Hennadiy M.

Abstract

The paper deals with the theoretical foundations of training experts and leaders of distance learning in order to improve their training program. An expert is a specialist who has an experience in developing distance courses, conducting distance learning classes and has and uses the skills of a content curator. Leaders create the conditions for innovative changes that allow people and organizations to share their vision and move in its direction, contribute to the management and implementation of ideas. The paper describes the basic skills to be developed by an expert and a leader, provides typical mistakes of distance course developers. Training of experts and leaders was based on the distance course ”Distance Course Examination” for experienced developers of distance learning courses and administrators of distance learning systems from different organizations. During the training, students analyzed the purpose of learning according to the Bloom’s taxonomy and its accessibility, the complexity of the text and its design, tasks and learning activities, test quality and evaluation system as well as other elements responsible for the quality of learning. During the pilot training, the results were obtained in the form of reports of students about the examination of the distance course as well as analysis of this work was done. 47 teachers of educational institutions of Ukraine were trained and only 12 teachers successfully completed their training. Based on the results of training and taking into account the experience of emergency training during the pandemic and military actions in Ukraine, the course program has been refined. It is planned to use a team of experts, ”playing” coaches and new methods for conducting distance learning. Particular attention is paid to training experts, leaders and measuring their competencies.

Published
2023

8. Observation of $K^{+} \to \pi^{+}\pi^{0}\pi^{0}\gamma$ decay

Author

Filippov, S. N., Gushchin, E. N., Khudyakov, A. A., Kravtsov, V. I., Kudenko, Yu G., Kulik, A. V., Polyarush, A. Yu., Artamonov, A. V., Donskov, S. V., Filin, A. P., Gorin, A. M., Inyakin, A. V., Khaustov, G. V., Kholodenko, S. A., Kolosov, V. N., Kurshetsov, V. F., Lishin, V. A., Medynsky, M. V., Obraztsov, V. F., Okhotnikov, A. V., Polyakov, V. A., Romanovsky, V. I., Rykalin, V. I., Sadovsky, A. S., Samoylenko, V. D., Tiurin, I. S., Uvarov, V. A., Yushchenko, O. P., Bychkov, V. N., Kekelidze, G. D., Lysan, V. M., Zalikhanov, B. Zh., Filippov, S. N., Gushchin, E. N., Khudyakov, A. A., Kravtsov, V. I., Kudenko, Yu G., Kulik, A. V., Polyarush, A. Yu., Artamonov, A. V., Donskov, S. V., Filin, A. P., Gorin, A. M., Inyakin, A. V., Khaustov, G. V., Kholodenko, S. A., Kolosov, V. N., Kurshetsov, V. F., Lishin, V. A., Medynsky, M. V., Obraztsov, V. F., Okhotnikov, A. V., Polyakov, V. A., Romanovsky, V. I., Rykalin, V. I., Sadovsky, A. S., Samoylenko, V. D., Tiurin, I. S., Uvarov, V. A., Yushchenko, O. P., Bychkov, V. N., Kekelidze, G. D., Lysan, V. M., and Zalikhanov, B. Zh.

Abstract

The $K^{+} \to \pi^{+}\pi^{0}\pi^{0}\gamma$ decay is observed by the OKA collaboration. The branching ratio is measured to be $(4.1 \pm 0.9(stat) \pm 0.4(syst))\times 10^{-6}$. The branching ratio and $\gamma$ energy spectrum are consistent with ChPT prediction., Comment: arXiv admin note: text overlap with arXiv:2310.16429

Published
2023

9. Searches for the light invisible axion-like particle in $K^{+}\to\pi^{+}\pi^{0}a$ decay

Author

Sadovsky, A. S., Filin, A. P., Akimenko, S. A., Artamonov, A. V., Blik, A. M., Donskov, S. V., Gorin, A. M., Inyakin, A. V., Khaustov, G. V., Kholodenko, S. A., Kolosov, V. N., Kurshetsov, V. F., Lishin, V. A., Medynsky, M. V., Obraztsov, V. F., Okhotnikov, A. V., Polyakov, V. A., Romanovsky, V. I., Rykalin, V. I., Samoylenko, V. D., Tiurin, I. S., Uvarov, V. A., Yushchenko, O. P., Filippov, S. N., Gushchin, E. N., Khudyakov, A. A., Kravtsov, V. I., Kudenko, Yu G., Kulik, A. V., Polyarush, A. Yu., Bychkov, V. N., Kekelidze, G. D., Lysan, V. M., Zalikhanov, B. Zh., Sadovsky, A. S., Filin, A. P., Akimenko, S. A., Artamonov, A. V., Blik, A. M., Donskov, S. V., Gorin, A. M., Inyakin, A. V., Khaustov, G. V., Kholodenko, S. A., Kolosov, V. N., Kurshetsov, V. F., Lishin, V. A., Medynsky, M. V., Obraztsov, V. F., Okhotnikov, A. V., Polyakov, V. A., Romanovsky, V. I., Rykalin, V. I., Samoylenko, V. D., Tiurin, I. S., Uvarov, V. A., Yushchenko, O. P., Filippov, S. N., Gushchin, E. N., Khudyakov, A. A., Kravtsov, V. I., Kudenko, Yu G., Kulik, A. V., Polyarush, A. Yu., Bychkov, V. N., Kekelidze, G. D., Lysan, V. M., and Zalikhanov, B. Zh.

Abstract

A high statistics data sample of the $K^{+}$ decays is recorded by the OKA collaboration. A missing mass analysis is performed to search for a light invisible pseudoscalar axion-like particle (ALP) $a$ in the decay $K^{+} \to \pi^{+} \pi^{0} a$. No signal is observed, the upper limits for the branching ratio of the decay are calculated. The $90\%$ confidence level upper limit is changing from $2.5\cdot10^{-6}$ to $2\cdot10^{-7}$ for the ALP mass from 0 to 200 MeV/$c^{2}$, except for the region of $\pi^{0}$ mass, where the upper limit is $4.4\cdot10^{-6}$., Comment: 6 pages, 6 figures

Published
2023
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10. 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, Zane, Silvia, 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

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

11. Modeling molecular hydrogen in low metallicity galaxies

Author

Polzin, Ava, Kravtsov, Andrey V., Semenov, Vadim A., Gnedin, Nickolay Y., Polzin, Ava, Kravtsov, Andrey V., Semenov, Vadim A., and Gnedin, Nickolay Y.

Abstract

We use a suite of hydrodynamics simulations of the interstellar medium (ISM) within a galactic disk, which include radiative transfer, a non-equilibrium model of molecular hydrogen, and a realistic model for star formation and feedback, to study the structure of the ISM and H$_2$ abundance as a function of local ISM properties. We show that the star formation rate and structure of the ISM are sensitive to the metallicity of the gas with a progressively smoother density distribution with decreasing metallicity. In addition to the well-known trend of the HI-H$_2$ transition shifting to higher densities with decreasing metallicity, the maximum achieved molecular fraction in the interstellar medium drops drastically at $Z \lesssim 0.2 \, Z_\odot$ as the formation time of H$_2$ becomes much longer than a typical lifetime of dense regions of the ISM. We present accurate fitting formulae for both volumetric and projected $f_\mathrm{H_2}$ measured on different scales as a function of gas metallicity, UV radiation field, and gas density. We show that when the formulae are applied to the patches in the simulated galaxy the overall molecular gas mass is reproduced to better than a factor of $\lesssim 1.5$ across the entire range of metallicities and scales. We also show that the presented fit is considerably more accurate than any of the previous $f_\mathrm{H_2}$ models and fitting formulae in the low-metallicity regime. The fit can thus be used for modeling molecular gas in low-resolution simulations and semi-analytic models of galaxy formation in the dwarf and high-redshift regimes., Comment: 17 pages, 12 figures; submitted to ApJ

Published
2023

12. Modelling Stochastic Star Formation History of Dwarf Galaxies in GRUMPY

Author

Pan, Yue, Kravtsov, Andrey, Pan, Yue, and Kravtsov, Andrey

Abstract

We investigate the impact of bursty star formation on several galaxy scaling relations of dwarf galaxies using the $\texttt{GRUMPY}$ galaxy formation model. While this model reproduces the star formation rate (SFR)-stellar mass, stellar mass-gas mass, and stellar mass-metallicity relations, the scatter of these relations in the original model is smaller than observed. We explore the effects of additional stochasticity of SFR on the scaling relations using a model that reproduces the level of SFR burstiness in high-resolution zoom-in simulations. The additional SFR stochasticity increases the scatter in the SFR-stellar mass relation to a level similar to that exhibited by most nearby dwarf galaxies. The most extreme observed starbursting dwarfs, however, require higher levels of SFR stochasticity. We find that bursty star formation increases the scatter in the colour-magnitude distribution (CMD) for brighter dwarf galaxies $(M_V < -12)$ to the observed level, but not for fainter ones for which scatter remains significantly smaller than observed. This is due to the predominant old stellar populations in these faint model galaxies and their generally declining SFR over the past 10 Gyrs, rather than quenching caused by reionization. We examine the possibility that the colour scatter is due to scatter in metallicity, but show that the level of scatter required leads to an overestimation of scatter in the metallicity-mass relation. This illustrates that the scatter of observed scaling relations in the dwarf galaxy regime represents a powerful constraint on the properties of their star formation., Comment: 14 pages, 8 figures, submitted to MNRAS

Published
2023

13. In-situ vs accreted Milky Way globular clusters: a new classification method and implications for cluster formation

Author

Belokurov, Vasily, Kravtsov, Andrey, Belokurov, Vasily, and Kravtsov, Andrey

Abstract

We present a new scheme for the classification of the in-situ and accreted globular clusters (GCs). The scheme uses total energy $E$ and $z$-component of the orbital angular momentum and is calibrated using [Al/Fe] abundance ratio. We demonstrate that such classification results in the GC populations with distinct spatial, kinematic, and chemical abundance distributions. The in-situ GCs are distributed within the central 10 kpc of the Galaxy in a flattened configuration aligned with the MW disc, while the accreted GCs have a wide distribution of distances and a spatial distribution close to spherical. In-situ and accreted GCs have different $\rm [Fe/H]$ distributions with the well-known bimodality present only in the metallicity distribution of the in-situ GCs. Furthermore, the accreted and in-situ GCs are well separated in the plane of $\rm [Al/Fe]-[Mg/Fe]$ abundance ratios and follow distinct sequences in the age--$\rm [Fe/H]$ plane. The in-situ GCs in our classification show a clear disc spin-up signature -- the increase of median $V_\phi$ at metallicities $\rm [Fe/H]\approx -1.3\div -1$ similar to the spin-up in the in-situ field stars. This signature signals the MW's disc formation, which occurred $\approx 11.7-12.7$ Gyrs ago (or at $z\approx 3.1-5.3$) according to GC ages. In-situ GCs with metallicities of $\rm [Fe/H]\gtrsim -1.3$ were thus born in the Milky Way disc, while lower metallicity in-situ GCs were born during early, turbulent, pre-disc stages of the evolution of the Galaxy and are part of its Aurora stellar component., Comment: Submitted to MNRAS. Comments - in particular on the individual globular clusters you think we have misclassified - are welcome!

Published
2023

14. 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, Xie, Fei, 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

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

15. Taking the Milky Way for a spin: disc formation in the ARTEMIS simulations

Author

Dillamore, Adam M., Belokurov, Vasily, Kravtsov, Andrey, Font, Andreea S., Dillamore, Adam M., Belokurov, Vasily, Kravtsov, Andrey, and Font, Andreea S.

Abstract

We investigate the formation (spin-up) of galactic discs in the ARTEMIS simulations of Milky Way-mass galaxies. In almost all galaxies discs spin up at higher [Fe/H] than the Milky Way (MW). Those that contain an analogue of the Gaia Sausage-Enceladus (GSE) spin up at a lower average metallicity than those without. We identify six galaxies with spin-up metallicity similar to that of the MW, which form their discs $\sim 8-11$ Gyr ago. Five of these experience a merger similar to the GSE. The spin-up times correlate with the halo masses at early times: galaxies with early spin-up have larger virial masses at a lookback time $t_L=12$ Gyr. The fraction of stars accreted from outside the host galaxy is smaller in galaxies with earlier spin-ups. Accreted fractions small enough to be comparable to the MW are only found in galaxies with the earliest disc formation and large initial virial masses ($M_\mathrm{200c} \approx2\times10^{11}M_\odot$ at $t_L=12$ Gyr). We find that discs form when the halo's virial mass reaches a threshold of $M_\mathrm{200c}\approx(6\pm3)\times10^{11}M_\odot$, independent of the spin-up time. However, the failure to form a disc in other galaxies appears to be instead related to mergers at early times. We also find that discs form when the central potential is not particularly steep. Our results indicate that the MW assembled its mass and formed its disc earlier than the average galaxy of a similar mass., Comment: 9 pages, 7 figures, published in MNRAS

Published
2023
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16. Constraining the magnetic field geometry of the millisecond pulsar PSR~J0030+0451 from joint radio, thermal X-ray and $\gamma$-ray emission

Author

Pétri, J., Guillot, S., Guillemot, L., Cognard, I., Theureau, G., Grießmeier, J. -M., Bondonneau, L., González-Caniulef, D., Webb, N., Jankowski, F., Kravtsov, I. P., McKee, J. W., Carozzi, T. D., Cecconi, B., Serylak, M., Zarka, P., Pétri, J., Guillot, S., Guillemot, L., Cognard, I., Theureau, G., Grießmeier, J. -M., Bondonneau, L., González-Caniulef, D., Webb, N., Jankowski, F., Kravtsov, I. P., McKee, J. W., Carozzi, T. D., Cecconi, B., Serylak, M., and Zarka, P.

Abstract

With the advent of multi-wavelength electromagnetic observations of neutron stars, spanning many decades in photon energies, from radio wavelengths up to X-rays and $\gamma$-rays, it becomes possible to significantly constrain the geometry and the location of the associated emission regions. In this work, we use results from the modelling of thermal X-ray observations of PSR~J0030+0451 from the NICER mission and phase-aligned radio and $\gamma$-ray pulse profiles to constrain the geometry of an off-centred dipole able to reproduce the light-curves in these respective bands simultaneously. To this aim, we deduce a configuration with a simple dipole off-centred from the location of the centre of the thermal X-ray hot spots and show that the geometry is compatible with independent constraints from radio and $\gamma$-ray pulsations only, leading to a fixed magnetic obliquity of $\alpha \approx 75\deg$ and a line of sight inclination angle of $\zeta \approx 54\deg$. We demonstrate that an off-centred dipole cannot be rejected by accounting for the thermal X-ray pulse profiles. Moreover, the crescent shape of one spot is interpreted as the consequence of a small scale surface dipole on top of the large scale off-centred dipole., Comment: Accepted for publication in A&A

Published
2023
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17. ACNS Conference on Cloud and Immersive Technologies in Education: Report

Author

Papadakis, Stamatios, Kiv, Arnold E., Kravtsov, Hennadiy M., Osadchyi, Viacheslav V., Marienko, Maiia V., Pinchuk, Olha P., Shyshkina, Mariya P., Sokolyuk, Oleksandra M., Mintii, Iryna S., Vakaliuk, Tetiana A., Azarova, Larysa E., Kolgatina, Larisa S., Amelina, Svitlana M., Volkova, Nataliia P., Velychko, Vladyslav Ye., Striuk, Andrii M., Semerikov, Serhiy O., Papadakis, Stamatios, Kiv, Arnold E., Kravtsov, Hennadiy M., Osadchyi, Viacheslav V., Marienko, Maiia V., Pinchuk, Olha P., Shyshkina, Mariya P., Sokolyuk, Oleksandra M., Mintii, Iryna S., Vakaliuk, Tetiana A., Azarova, Larysa E., Kolgatina, Larisa S., Amelina, Svitlana M., Volkova, Nataliia P., Velychko, Vladyslav Ye., Striuk, Andrii M., and Semerikov, Serhiy O.

Abstract

This article serves as an introduction to a collection of selected papers presented at the ACNS Conference on Cloud and Immersive Technologies in Education (CITEd 2022), which took place in Kyiv, Ukraine, on December 21-22, 2022. The collection provides valuable insights into the latest advancements in cloud and immersive technologies in the field of education. The introductory text offers an overview of the conference events and provides concise summaries of the selected papers, offering a glimpse into the diverse topics and research areas covered. These selected papers reflect the cutting-edge research and innovative approaches showcased at CITEd 2022, making them a valuable resource for educators, researchers, and practitioners interested in exploring the potential of cloud and immersive technologies in education.

Published
2023

18. Nitrogen enrichment and clustered star formation at the dawn of the Galaxy

Author

Belokurov, Vasily, Kravtsov, Andrey, Belokurov, Vasily, and Kravtsov, Andrey

Abstract

Anomalously high nitrogen-to-oxygen abundance ratios [N/O] are observed in globular clusters (GCs), among the field stars of the Milky Way (MW), and even in the gas in a $z\approx 11$ galaxy. Using data from the APOGEE Data Release 17 and the Gaia Data Release 3, we present several independent lines of evidence that most of the MW's high-[N/O] stars were born in situ in massive bound clusters during the early, pre-disk evolution of the Galaxy. Specifically, we show that distributions of metallicity [Fe/H], energy, the angular momentum $L_z$, and distance of the low-metallicity high-[N/O] stars match the corresponding distributions of stars of the Aurora population and of the in-situ GCs. We also show that the fraction of in-situ field high-[N/O] stars, $f_{\rm N/O}$, increases rapidly with decreasing metallicity. During epochs when metallicity evolves from $\rm [Fe/H]=-1.5$ to $\rm [Fe/H]=-0.9$, the Galaxy spins up and transitions from a turbulent Aurora state to a coherently rotating disk. This transformation is accompanied by many qualitative changes. In particular, we show that high N/O abundances similar to those observed in GN-z11 were common before the spin-up ($\rm [Fe/H]\lesssim -1.5$) when up to $\approx 50\%-70\%$ of the in-situ stars formed in massive bound clusters. The dramatic drop of $f_{\rm N/O}$ at $\rm [Fe/H]\gtrsim -0.9$ indicates that after the disk emerges the fraction of stars forming in massive bound clusters decreases by two orders of magnitude., Comment: 18 pages, 13 figures, submitted to MNRAS

Published
2023
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19. Densities and mass assembly histories of the Milky Way satellites are not a challenge to $\Lambda$CDM

Author

Kravtsov, Andrey, Wu, Zewei, Kravtsov, Andrey, and Wu, Zewei

Abstract

We use the \texttt{GRUMPY} galaxy formation model based on a suite of zoom-in, high-resolution, dissipationless $\Lambda$ Cold Dark Matter ($\Lambda$CDM) simulations of the Milky Way (MW) sized haloes to examine total matter density within the half-mass radius of stellar distribution, $\rho_{\rm tot}( 10$, at these early epochs halos that survive as satellites to $z=0$ are located many virial radii away from the MW progenitors and thus do not have a chance to merge with it. Our results show that neither the densities estimated in observed Milky Way satellites nor their mass assembly histories pose a challenge to the $\Lambda$CDM model. In fact, the broad agreement between density trends with the stellar mass of the observed and model galaxies can be considered as yet another success of the model., Comment: 9 pages, 4 figures, 1 table. Submitted to MNRAS

Published
2023
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20. 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, Zane, Silvia, 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

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
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21. Peering into the tilted heart of Cyg X-1 with high-precision optical polarimetry

Author

Kravtsov, Vadim, Veledina, Alexandra, Berdyugin, Andrei V., Zdziarski, Andrzej A., Henson, Gary D., Piirola, Vilppu, Sakanoi, Takeshi, Kagitani, Masato, Berdyugina, Svetlana V., Poutanen, Juri, Kravtsov, Vadim, Veledina, Alexandra, Berdyugin, Andrei V., Zdziarski, Andrzej A., Henson, Gary D., Piirola, Vilppu, Sakanoi, Takeshi, Kagitani, Masato, Berdyugina, Svetlana V., and Poutanen, Juri

Abstract

We present the high-precision optical polarimetric observations of black hole X-ray binary Cyg X-1, spanning several cycles of its 5.6 day orbital period. Week-long observations on two telescopes located in opposite hemispheres allowed us to track the evolution of the polarization within one orbital cycle with the highest temporal resolution to date. Using the field stars, we determine the interstellar polarization in the source direction and subsequently its intrinsic polarization. The optical polarization angle is aligned with that in the X-rays as recently obtained with the Imaging X-ray Polarimetry Explorer. Furthermore, it is consistent, within the uncertainties, with the position angle of the radio ejections. We show that the intrinsic PD is variable with the orbital period with the amplitude of $\sim$0.2% and discuss various sites of its production. Assuming the polarization arises from a single Thomson scattering of the primary star radiation by the matter that follows the black hole in its orbital motion, we constrain the inclination of the binary orbit $i>120^\circ$ and its eccentricity $e<0.08$. The asymmetric shape of the orbital profiles of Stokes parameters implies also the asymmetry of the scattering matter distribution about the orbital plane, which may arise from the tilted accretion disk. We compare our data to the polarimetric observations made over 1975-1987 and find good, within $1^\circ$, agreement between the intrinsic polarization angles. On the other hand, the PD decreased by 0.4% over half a century, suggesting the presence of secular changes in the geometry of accreting matter., Comment: 12 pages, 18 figures

Published
2023
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22. The broad-lined Type-Ic supernova SN 2022xxf with extraordinary two-humped light curves

Author

Kuncarayakti, H., Sollerman, J., Izzo, L., Maeda, K., Yang, S., Schulze, S., Angus, C. R., Aubert, M., Auchettl, K., Della Valle, M., Dessart, L., Hinds, K., Kankare, E., Kawabata, M., Lundqvist, P., Nakaoka, T., Perley, D., Raimundo, S. I., Strotjohann, N. L., Taguchi, K., Cai, Y. -Z., Charalampopoulos, P., Fang, Q., Fraser, M., Gutierrez, C. P., Imazawa, R., Kangas, T., Kawabata, K. S., Kotak, R., Kravtsov, T., Matilainen, K., Mattila, S., Moran, S., Murata, I., Salmaso, I., Anderson, J. P., Ashall, C., Bellm, E. C., Benetti, S., Chambers, K. C., Chen, T. -W., Coughlin, M., De Colle, F., Fremling, C., Galbany, L., Gal-Yam, A., Gromadzki, M., Groom, S. L., Hajela, A., Inserra, C., Kasliwal, M. M., Mahabal, A. A., Martin-Carrillo, A., Moore, T., Muller-Bravo, T. E., Nicholl, M., Ragosta, F., Riddle, R. L., Sharma, Y., Srivastav, S., Stritzinger, M. D., Wold, A., Young, D. R., Kuncarayakti, H., Sollerman, J., Izzo, L., Maeda, K., Yang, S., Schulze, S., Angus, C. R., Aubert, M., Auchettl, K., Della Valle, M., Dessart, L., Hinds, K., Kankare, E., Kawabata, M., Lundqvist, P., Nakaoka, T., Perley, D., Raimundo, S. I., Strotjohann, N. L., Taguchi, K., Cai, Y. -Z., Charalampopoulos, P., Fang, Q., Fraser, M., Gutierrez, C. P., Imazawa, R., Kangas, T., Kawabata, K. S., Kotak, R., Kravtsov, T., Matilainen, K., Mattila, S., Moran, S., Murata, I., Salmaso, I., Anderson, J. P., Ashall, C., Bellm, E. C., Benetti, S., Chambers, K. C., Chen, T. -W., Coughlin, M., De Colle, F., Fremling, C., Galbany, L., Gal-Yam, A., Gromadzki, M., Groom, S. L., Hajela, A., Inserra, C., Kasliwal, M. M., Mahabal, A. A., Martin-Carrillo, A., Moore, T., Muller-Bravo, T. E., Nicholl, M., Ragosta, F., Riddle, R. L., Sharma, Y., Srivastav, S., Stritzinger, M. D., Wold, A., and Young, D. R.

Abstract

We report on our study of supernova (SN) 2022xxf based on observations obtained during the first four months of its evolution. The light curves (LCs) display two humps of similar maximum brightness separated by 75 days, unprecedented for a broad-lined (BL) Type Ic supernova (SN IcBL). SN 2022xxf is the most nearby SN IcBL to date (in NGC 3705, $z = 0.0037$, at a distance of about 20 Mpc). Optical and near-infrared photometry and spectroscopy are used to identify the energy source powering the LC. Nearly 50 epochs of high signal-to-noise-ratio spectroscopy were obtained within 130 days, comprising an unparalleled dataset for a SN IcBL, and one of the best-sampled SN datasets to date. The global spectral appearance and evolution of SN 2022xxf points to typical SN Ic/IcBL, with broad features (up to $\sim14000$ km s$^{-1}$) and a gradual transition from the photospheric to the nebular phase. However, narrow emission lines (corresponding to $\sim1000-2500$ km s$^{-1}$) are present in the spectra from the time of the second rise, suggesting slower-moving circumstellar material (CSM). These lines are subtle, in comparison to the typical strong narrow lines of CSM-interacting SNe, for example, Type IIn, Ibn, and Icn, but some are readily noticeable at late times such as in Mg I $\lambda$5170 and [O I] $\lambda$5577. Unusually, the near-infrared spectra show narrow line peaks in a number of features formed by ions of O and Mg. We infer the presence of CSM that is free of H and He. We propose that the radiative energy from the ejecta-CSM interaction is a plausible explanation for the second LC hump. This interaction scenario is supported by the color evolution, which progresses to the blue as the light curve evolves along the second hump, and the slow second rise and subsequent rapid LC drop. (Abstract abridged), Comment: Accepted version

Published
2023
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23. Pulsar Scintillation Studies with LOFAR: II. Dual-frequency scattering study of PSR J0826+2637 with LOFAR and NenuFAR

Author

Wu, Ziwei, Coles, William A., Verbiest, Joris P. W., Ambalappat, Krishnakumar Moochickal, Tiburzi, Caterina, Grießmeier, Jean-Mathias, Main, Robert A., Liu, Yulan, Kramer, Michael, Wucknitz, Olaf, Porayko, Nataliya, Osłowski, Stefan, Nielsen, Ann-Sofie Bak, Donner, Julian Y., Hoeft, Matthias, Brüggen, Marcus, Vocks, Christian, Dettmar, Ralf-Jürgen, Theureau, Gilles, Serylak, Maciej, Kondratiev, Vladislav, McKee, James W., Shaifullah, Golam M., Kravtsov, Ihor P., Zakharenko, Vyacheslav V., Ulyanov, Oleg, Konovalenko, Olexandr O., Zarka, Philippe, Cecconi, Baptiste, Koopmans, Léon V. E., Corbel, Stéphane, Wu, Ziwei, Coles, William A., Verbiest, Joris P. W., Ambalappat, Krishnakumar Moochickal, Tiburzi, Caterina, Grießmeier, Jean-Mathias, Main, Robert A., Liu, Yulan, Kramer, Michael, Wucknitz, Olaf, Porayko, Nataliya, Osłowski, Stefan, Nielsen, Ann-Sofie Bak, Donner, Julian Y., Hoeft, Matthias, Brüggen, Marcus, Vocks, Christian, Dettmar, Ralf-Jürgen, Theureau, Gilles, Serylak, Maciej, Kondratiev, Vladislav, McKee, James W., Shaifullah, Golam M., Kravtsov, Ihor P., Zakharenko, Vyacheslav V., Ulyanov, Oleg, Konovalenko, Olexandr O., Zarka, Philippe, Cecconi, Baptiste, Koopmans, Léon V. E., and Corbel, Stéphane

Abstract

Interstellar scattering (ISS) of radio pulsar emission can be used as a probe of the ionised interstellar medium (IISM) and causes corruptions in pulsar timing experiments. Two types of ISS phenomena (intensity scintillation and pulse broadening) are caused by electron density fluctuations on small scales (< 0.01 AU). Theory predicts that these are related, and both have been widely employed to study the properties of the IISM. Larger scales ($\sim$1-100\,AU) cause measurable changes in dispersion and these can be correlated with ISS observations to estimate the fluctuation spectrum over a very wide scale range. IISM measurements can often be modeled by a homogeneous power-law spatial spectrum of electron density with the Kolmogorov ($-11/3$) spectral exponent. Here we aim to test the validity of using the Kolmogorov exponent with PSR~J0826+2637. We do so using observations of intensity scintillation, pulse broadening and dispersion variations across a wide fractional bandwidth (20 -- 180\,MHz). We present that the frequency dependence of the intensity scintillation in the high frequency band matches the expectations of a Kolmogorov spectral exponent but the pulse broadening in the low frequency band does not change as rapidly as predicted with this assumption. We show that this behavior is due to an inhomogeneity in the scattering region, specifically that the scattering is dominated by a region of transverse size $\sim$40\,AU. The power spectrum of the electron density, however, maintains the Kolmogorov spectral exponent from spatial scales of 5$\times10^{-6}$\,AU to $\sim$100\,AU., Comment: Accepted for publication in MNRAS, typo fixed

Published
2023
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24. Observation of the electromagnetic field effect via charge-dependent directed flow in heavy-ion collisions at the Relativistic Heavy Ion Collider

Author

STAR Collaboration, Abdulhamid, M. I., Aboona, B. E., Adam, J., Adams, J. R., Agakishiev, G., Aggarwal, I., Aggarwal, M. M., Ahammed, Z., Aitbaev, A., Alekseev, I., Alpatov, E., Aparin, A., Aslam, S., Atchison, J., Averichev, G. S., Bairathi, V., Cap, J. G. Ball, Barish, K., Bhagat, P., Bhasin, A., Bhatta, S., Bhosale, S. R., Bordyuzhin, I. G., Brandenburg, J. D., Brandin, A. V., Cai, X. Z., Caines, H., Sánchez, M. Calderón de la Barca, Cebra, D., Ceska, J., Chakaberia, I., Chan, B. K., Chang, Z., Chatterjee, A., Chen, D., Chen, J., Chen, J. H., Chen, Z., Cheng, J., Cheng, Y., Choudhury, S., Christie, W., Chu, X., Crawford, H. J., Dale-Gau, G., Das, A., Dash, A. P., Daugherity, M., Dedovich, T. G., Deppner, I. M., Derevschikov, A. A., Dhamija, A., Dixit, P., Dong, X., Drachenberg, J. L., Duckworth, E., Dunlop, J. C., Engelage, J., Eppley, G., Esumi, S., Evdokimov, O., Eyser, O., Fatemi, R., Fazio, S., Feng, C. J., Feng, Y., Finch, E., Fisyak, Y., Flor, F. A., Fu, C., Gao, T., Geurts, F., Ghimire, N., Gibson, A., Gopal, K., Gou, X., Grosnick, D., Gupta, A., Hamed, A., Han, Y., Harasty, M. D., Harris, J. W., Harrison-Smith, H., He, W., He, X. H., He, Y., Hu, C., Hu, Q., Hu, Y., Huang, H., Huang, H. Z., Huang, S. L., Huang, T., Huang, X., Huang, Y., Humanic, T. J., Isenhower, D., Isshiki, M., Jacobs, W. W., Jalotra, A., Jena, C., Ji, Y., Jia, J., Jin, C., Ju, X., Judd, E. G., Kabana, S., Kalinkin, D., Kang, K., Kapukchyan, D., Kauder, K., Keane, D., Kechechyan, A., Kiselev, A., Knospe, A. G., Ko, H. S., Kochenda, L., Korobitsin, A. A., Kraeva, A. Yu., Kravtsov, P., Kumar, L., Labonte, M. C., Lacey, R., Landgraf, J. M., Lebedev, A., Lednicky, R., Lee, J. H., Leung, Y. H., Lewis, N., Li, C., Li, H-S., Li, W., Li, X., Li, Y., Li, Z., Liang, X., Liang, Y., Lin, T., Lin, Y., Liu, C., Liu, F., Liu, G., Liu, H., Liu, L., Liu, T., Liu, X., Liu, Y., Liu, Z., Ljubicic, T., Lomicky, O., Longacre, R. S., Loyd, E. M., Lu, T., Lukow, N. S., Luo, X. F., Luong, V. B., Ma, L., Ma, R., Ma, Y. G., Magdy, N., Mallick, D., Margetis, S., Matis, H. S., McNamara, G., Mi, K., Minaev, N. G., Mohanty, B., Mondal, M. M., Mooney, I., Morozov, D. A., Mudrokh, A., Nagy, M. I., Nain, A. S., Nam, J. D., Nasim, M., Nedorezov, E., Neff, D., Nelson, J. M., Nemes, D. B., Nie, M., Nigmatkulov, G., Niida, T., Nogach, L. V., Nonaka, T., Odyniec, G., Ogawa, A., Oh, S., Okorokov, V. A., Okubo, K., Page, B. S., Pak, R., Pandav, A., Panebratsev, Y., Pani, T., Parfenov, P., Paul, A., Perkins, C., Pokhrel, B. R., Posik, M., Povarov, A., Protzman, T., Pruthi, N. K., Putschke, J., Qin, Z., Qiu, H., Quintero, A., Racz, C., Radhakrishnan, S. K., Rana, A., Ray, R. L., Ritter, H. G., Robertson, C. W., Rogachevsky, O. V., Aguilar, M. A. Rosales, Roy, D., Ruan, L., Sahoo, A. K., Sahoo, N. R., Sako, H., Salur, S., Samigullin, E., Sato, S., Schaefer, B. C., Schmidke, W. B., Schmitz, N., Seger, J., Seto, R., Seyboth, P., Shah, N., Shahaliev, E., Shanmuganathan, P. V., Shao, T., Sharma, M., Sharma, N., Sharma, R., Sharma, S. R., Sheikh, A. I., Shen, D., Shen, D. Y., Shen, K., Shi, S. S., Shi, Y., Shou, Q. Y., Si, F., Singh, J., Singha, S., Sinha, P., Skoby, M. J., Söhngen, Y., Song, Y., Srivastava, B., Stanislaus, T. D. S., Stewart, D. J., Strikhanov, M., Stringfellow, B., Su, Y., Sun, C., Sun, X., Sun, Y., Surrow, B., Svirida, D. N., Sweger, Z. W., Tamis, A. C., Tang, A. H., Tang, Z., Taranenko, A., Tarnowsky, T., Thomas, J. H., Tlusty, D., Todoroki, T., Tokarev, M. V., Trentalange, S., Tribedy, P., Tripathy, S. K., Tsai, O. D., Tsang, C. Y., Tu, Z., Tyler, J., Ullrich, T., Underwood, D. G., Upsal, I., Van Buren, G., Vasiliev, A. N., Verkest, V., Videbæk, F., Vokal, S., Voloshin, S. A., Wang, F., Wang, G., Wang, J. S., Wang, J., Wang, X., Wang, Y., Wang, Z., Webb, J. C., Weidenkaff, P. C., Westfall, G. D., Wieman, H., Wilks, G., Wissink, S. W., Wu, J., Wu, X., Xi, B., Xiao, Z. G., Xie, G., Xie, W., Xu, H., Xu, N., Xu, Q. H., Xu, Y., Xu, Z., Yan, G., Yan, Z., Yang, C., Yang, Q., Yang, S., Yang, Y., Ye, Z., Yi, L., Yip, K., Yu, Y., Zha, W., Zhang, C., Zhang, D., Zhang, J., Zhang, S., Zhang, W., Zhang, X., Zhang, Y., Zhang, Z. J., Zhang, Z., Zhao, F., Zhao, J., Zhao, M., Zhou, C., Zhou, J., Zhou, S., Zhou, Y., Zhu, X., Zurek, M., Zyzak, M., STAR Collaboration, Abdulhamid, M. I., Aboona, B. E., Adam, J., Adams, J. R., Agakishiev, G., Aggarwal, I., Aggarwal, M. M., Ahammed, Z., Aitbaev, A., Alekseev, I., Alpatov, E., Aparin, A., Aslam, S., Atchison, J., Averichev, G. S., Bairathi, V., Cap, J. G. Ball, Barish, K., Bhagat, P., Bhasin, A., Bhatta, S., Bhosale, S. R., Bordyuzhin, I. G., Brandenburg, J. D., Brandin, A. V., Cai, X. Z., Caines, H., Sánchez, M. Calderón de la Barca, Cebra, D., Ceska, J., Chakaberia, I., Chan, B. K., Chang, Z., Chatterjee, A., Chen, D., Chen, J., Chen, J. H., Chen, Z., Cheng, J., Cheng, Y., Choudhury, S., Christie, W., Chu, X., Crawford, H. J., Dale-Gau, G., Das, A., Dash, A. P., Daugherity, M., Dedovich, T. G., Deppner, I. M., Derevschikov, A. A., Dhamija, A., Dixit, P., Dong, X., Drachenberg, J. L., Duckworth, E., Dunlop, J. C., Engelage, J., Eppley, G., Esumi, S., Evdokimov, O., Eyser, O., Fatemi, R., Fazio, S., Feng, C. J., Feng, Y., Finch, E., Fisyak, Y., Flor, F. A., Fu, C., Gao, T., Geurts, F., Ghimire, N., Gibson, A., Gopal, K., Gou, X., Grosnick, D., Gupta, A., Hamed, A., Han, Y., Harasty, M. D., Harris, J. W., Harrison-Smith, H., He, W., He, X. H., He, Y., Hu, C., Hu, Q., Hu, Y., Huang, H., Huang, H. Z., Huang, S. L., Huang, T., Huang, X., Huang, Y., Humanic, T. J., Isenhower, D., Isshiki, M., Jacobs, W. W., Jalotra, A., Jena, C., Ji, Y., Jia, J., Jin, C., Ju, X., Judd, E. G., Kabana, S., Kalinkin, D., Kang, K., Kapukchyan, D., Kauder, K., Keane, D., Kechechyan, A., Kiselev, A., Knospe, A. G., Ko, H. S., Kochenda, L., Korobitsin, A. A., Kraeva, A. Yu., Kravtsov, P., Kumar, L., Labonte, M. C., Lacey, R., Landgraf, J. M., Lebedev, A., Lednicky, R., Lee, J. H., Leung, Y. H., Lewis, N., Li, C., Li, H-S., Li, W., Li, X., Li, Y., Li, Z., Liang, X., Liang, Y., Lin, T., Lin, Y., Liu, C., Liu, F., Liu, G., Liu, H., Liu, L., Liu, T., Liu, X., Liu, Y., Liu, Z., Ljubicic, T., Lomicky, O., Longacre, R. S., Loyd, E. M., Lu, T., Lukow, N. S., Luo, X. F., Luong, V. B., Ma, L., Ma, R., Ma, Y. G., Magdy, N., Mallick, D., Margetis, S., Matis, H. S., McNamara, G., Mi, K., Minaev, N. G., Mohanty, B., Mondal, M. M., Mooney, I., Morozov, D. A., Mudrokh, A., Nagy, M. I., Nain, A. S., Nam, J. D., Nasim, M., Nedorezov, E., Neff, D., Nelson, J. M., Nemes, D. B., Nie, M., Nigmatkulov, G., Niida, T., Nogach, L. V., Nonaka, T., Odyniec, G., Ogawa, A., Oh, S., Okorokov, V. A., Okubo, K., Page, B. S., Pak, R., Pandav, A., Panebratsev, Y., Pani, T., Parfenov, P., Paul, A., Perkins, C., Pokhrel, B. R., Posik, M., Povarov, A., Protzman, T., Pruthi, N. K., Putschke, J., Qin, Z., Qiu, H., Quintero, A., Racz, C., Radhakrishnan, S. K., Rana, A., Ray, R. L., Ritter, H. G., Robertson, C. W., Rogachevsky, O. V., Aguilar, M. A. Rosales, Roy, D., Ruan, L., Sahoo, A. K., Sahoo, N. R., Sako, H., Salur, S., Samigullin, E., Sato, S., Schaefer, B. C., Schmidke, W. B., Schmitz, N., Seger, J., Seto, R., Seyboth, P., Shah, N., Shahaliev, E., Shanmuganathan, P. V., Shao, T., Sharma, M., Sharma, N., Sharma, R., Sharma, S. R., Sheikh, A. I., Shen, D., Shen, D. Y., Shen, K., Shi, S. S., Shi, Y., Shou, Q. Y., Si, F., Singh, J., Singha, S., Sinha, P., Skoby, M. J., Söhngen, Y., Song, Y., Srivastava, B., Stanislaus, T. D. S., Stewart, D. J., Strikhanov, M., Stringfellow, B., Su, Y., Sun, C., Sun, X., Sun, Y., Surrow, B., Svirida, D. N., Sweger, Z. W., Tamis, A. C., Tang, A. H., Tang, Z., Taranenko, A., Tarnowsky, T., Thomas, J. H., Tlusty, D., Todoroki, T., Tokarev, M. V., Trentalange, S., Tribedy, P., Tripathy, S. K., Tsai, O. D., Tsang, C. Y., Tu, Z., Tyler, J., Ullrich, T., Underwood, D. G., Upsal, I., Van Buren, G., Vasiliev, A. N., Verkest, V., Videbæk, F., Vokal, S., Voloshin, S. A., Wang, F., Wang, G., Wang, J. S., Wang, J., Wang, X., Wang, Y., Wang, Z., Webb, J. C., Weidenkaff, P. C., Westfall, G. D., Wieman, H., Wilks, G., Wissink, S. W., Wu, J., Wu, X., Xi, B., Xiao, Z. G., Xie, G., Xie, W., Xu, H., Xu, N., Xu, Q. H., Xu, Y., Xu, Z., Yan, G., Yan, Z., Yang, C., Yang, Q., Yang, S., Yang, Y., Ye, Z., Yi, L., Yip, K., Yu, Y., Zha, W., Zhang, C., Zhang, D., Zhang, J., Zhang, S., Zhang, W., Zhang, X., Zhang, Y., Zhang, Z. J., Zhang, Z., Zhao, F., Zhao, J., Zhao, M., Zhou, C., Zhou, J., Zhou, S., Zhou, Y., Zhu, X., Zurek, M., and Zyzak, M.

Abstract

The deconfined quark-gluon plasma (QGP) created in relativistic heavy-ion collisions enables the exploration of the fundamental properties of matter under extreme conditions. Non-central collisions can produce strong magnetic fields on the order of $10^{18}$ Gauss, which offers a probe into the electrical conductivity of the QGP. In particular, quarks and anti-quarks carry opposite charges and receive contrary electromagnetic forces that alter their momenta. This phenomenon can be manifested in the collective motion of final-state particles, specifically in the rapidity-odd directed flow, denoted as $v_1(\mathsf{y})$. Here we present the charge-dependent measurements of $dv_1/d\mathsf{y}$ near midrapidities for $\pi^{\pm}$, $K^{\pm}$, and $p(\bar{p})$ in Au+Au and isobar ($_{44}^{96}$Ru+$_{44}^{96}$Ru and $_{40}^{96}$Zr+$_{40}^{96}$Zr) collisions at $\sqrt{s_{\rm NN}}=$ 200 GeV, and in Au+Au collisions at 27 GeV, recorded by the STAR detector at the Relativistic Heavy Ion Collider. The combined dependence of the $v_1$ signal on collision system, particle species, and collision centrality can be qualitatively and semi-quantitatively understood as several effects on constituent quarks. While the results in central events can be explained by the $u$ and $d$ quarks transported from initial-state nuclei, those in peripheral events reveal the impacts of the electromagnetic field on the QGP. Our data put valuable constraints on the electrical conductivity of the QGP in theoretical calculations.

Published
2023

25. 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, Soffitta, Paolo, 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

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

26. The merger of hard binaries in globular clusters as the primary channel for the formation of second generation stars

Author

Kravtsov, Valery, Dib, Sami, Calderon, Francisco A., Kravtsov, Valery, Dib, Sami, and Calderon, Francisco A.

Abstract

We have recently presented observational evidence which suggests that the origin of the second generation (G2) stars in globular clusters (GCs) is due to the binary-mediated collision of primordial (G1) low-mass main-sequence (MS) stars. This mechanism avoids both the mass budget problem and the need of external gas for dilution. Here, we report on another piece of evidence supporting this scenario: (1) the fraction of MS binaries is proportional to the fraction of G1 stars in GCs and, at the same time, (2) the smaller the fraction of G1 stars is, the more deficient binaries of higher mass ratio (q$>0.7$) are. They are, on average, harder than their smaller mass-ratio counterparts due to higher binding energy at a given primary mass. Then (2) implies that (1) is due to the merging\slash collisions of hard binaries rather than to their disruption. These new results complemented by the present-day data on binaries lead to the following conclusions: (i) the mass-ratio distribution of binaries, particularly short-period ones, with low-mass primaries, $M_{\rm P} < 1.5$ M$_{\sun}$, is strongly peaked close to q$=1.0$, whereas (ii) dynamical processes at high stellar density tend to destroy softer binaries and make hard (nearly) twin binaries to become even harder and favor their mergers and collisions. G2 stars formed this way gain mass that virtually doubles the primary one, $2M_{\rm P}$, at which the number of G1 stars is $\sim5$ times smaller than at $M_{\rm P}$ according to the slope of a Milky Way-like IMF at $M_{\rm MS} < 1.0$ M$_{\sun}$., Comment: 9 pages, 1 figure, 1 table; Accepted for publication in Monthly Notices of the Royal Astronomical Society

Published
2023

27. 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., Xie, Fei, 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

Abstract

We report on a 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). This is the first time it has been possible to trace 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 slowly decreased from $\sim$4\% to $\sim$3\% across the five observations, but remained in the North-South direction throughout. Using the Australia Telescope Compact Array (ATCA), we measure the intrinsic 7.25 GHz radio polarization to align in the same direction. Assuming the radio polarization aligns with the jet direction (which can be tested in the future with resolved jet images), this implies that the X-ray corona is extended in the disk plane, rather than along the jet axis, for the entire hard intermediate state. This in turn implies that the long ($\gtrsim$10 ms) soft lags that we measure with the Neutron star Interior Composition ExploreR (NICER) are dominated by processes other than pure light-crossing delays. Moreover, we find that the evolution of the soft lag amplitude with spectral state differs from the common trend seen for other sources, implying that Swift J1727.8$-$1613 is a member of a hitherto under-sampled sub-population., Comment: Submitted to ApJ. 20 pages, 8 figures

Published
2023

28. 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, Xie, Fei, 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

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
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29. Forbidden hugs in pandemic times:IV. Panchromatic evolution of three luminous red novae

Author

Pastorello, A., Valerin, G., Fraser, M., Reguitti, A., Elias-rosa, N., Filippenko, A. V., Rojas-bravo, C., Tartaglia, L., Reynolds, T. M., Valenti, S., Andrews, J. E., Ashall, C., Bostroem, K. A., Brink, T. G., Burke, J., Cai, Y.-z., Cappellaro, E., Coulter, D. A., Dastidar, R., Davis, K. W., Dimitriadis, G., Fiore, A., Foley, R. J., Fugazza, D., Galbany, L., Gangopadhyay, A., Geier, S., Gutiérrez, C. P., Haislip, J., Hiramatsu, D., Holmbo, S., Howell, D. A., Hsiao, E. Y., Hung, T., Jha, S. W., Kankare, E., Karamehmetoglu, E., Kilpatrick, C. D., Kotak, R., Kouprianov, V., Kravtsov, T., Kumar, S., Li, Z.-t., Lundquist, M. J., Lundqvist, P., Matilainen, K., Mazzali, P. A., Mccully, C., Misra, K., Morales-garoffolo, A., Moran, S., Morrell, N., Newsome, M., Padilla Gonzalez, E., Pan, Y.-c., Pellegrino, C., Phillips, M. M., Pignata, G., Piro, A. L., Reichart, D. E., Rest, A., Salmaso, I., Sand, D. J., Siebert, M. R., Smartt, S. J., Smith, K. W., Srivastav, S., Stritzinger, M. D., Taggart, K., Tinyanont, S., Yan, S.-y., Wang, L., Wang, X.-f., Williams, S. C., Wyatt, S., Zhang, T.-m., De Boer, T., Chambers, K., Gao, H., Magnier, E., Pastorello, A., Valerin, G., Fraser, M., Reguitti, A., Elias-rosa, N., Filippenko, A. V., Rojas-bravo, C., Tartaglia, L., Reynolds, T. M., Valenti, S., Andrews, J. E., Ashall, C., Bostroem, K. A., Brink, T. G., Burke, J., Cai, Y.-z., Cappellaro, E., Coulter, D. A., Dastidar, R., Davis, K. W., Dimitriadis, G., Fiore, A., Foley, R. J., Fugazza, D., Galbany, L., Gangopadhyay, A., Geier, S., Gutiérrez, C. P., Haislip, J., Hiramatsu, D., Holmbo, S., Howell, D. A., Hsiao, E. Y., Hung, T., Jha, S. W., Kankare, E., Karamehmetoglu, E., Kilpatrick, C. D., Kotak, R., Kouprianov, V., Kravtsov, T., Kumar, S., Li, Z.-t., Lundquist, M. J., Lundqvist, P., Matilainen, K., Mazzali, P. A., Mccully, C., Misra, K., Morales-garoffolo, A., Moran, S., Morrell, N., Newsome, M., Padilla Gonzalez, E., Pan, Y.-c., Pellegrino, C., Phillips, M. M., Pignata, G., Piro, A. L., Reichart, D. E., Rest, A., Salmaso, I., Sand, D. J., Siebert, M. R., Smartt, S. J., Smith, K. W., Srivastav, S., Stritzinger, M. D., Taggart, K., Tinyanont, S., Yan, S.-y., Wang, L., Wang, X.-f., Williams, S. C., Wyatt, S., Zhang, T.-m., De Boer, T., Chambers, K., Gao, H., and Magnier, E.

Published
2023

30. The broad-lined Type-Ic supernova SN 2022xxf and its extraordinary two-humped light curves I. Signatures of H/He-free interaction in the first four months

Author

Kuncarayakti, H., Sollerman, J., Izzo, L., Maeda, K., Yang, S., Schulze, S., Angus, C. R., Aubert, M., Auchettl, K., Della Valle, M., Dessart, L., Hinds, K., Kankare, E., Kawabata, M., Lundqvist, P., Nakaoka, T., Perley, D., Raimundo, S. I., Strotjohann, N. L., Taguchi, K., Cai, Y.-z., Charalampopoulos, P., Fang, Q., Fraser, M., Gutiérrez, C. P., Imazawa, R., Kangas, T., Kawabata, K. S., Kotak, R., Kravtsov, T., Matilainen, K., Mattila, S., Moran, S., Murata, I., Salmaso, I., Anderson, J. P., Ashall, C., Bellm, E. C., Benetti, S., Chambers, K. C., Chen, T.-w., Coughlin, M., De Colle, F., Fremling, C., Galbany, L., Gal-yam, A., Gromadzki, M., Groom, S. L., Hajela, A., Inserra, C., Kasliwal, M. M., Mahabal, A. A., Martin-carrillo, A., Moore, T., Müller-bravo, T. E., Nicholl, M., Ragosta, F., Riddle, R. L., Sharma, Y., Srivastav, S., Stritzinger, M. D., Wold, A., Young, D. R., Kuncarayakti, H., Sollerman, J., Izzo, L., Maeda, K., Yang, S., Schulze, S., Angus, C. R., Aubert, M., Auchettl, K., Della Valle, M., Dessart, L., Hinds, K., Kankare, E., Kawabata, M., Lundqvist, P., Nakaoka, T., Perley, D., Raimundo, S. I., Strotjohann, N. L., Taguchi, K., Cai, Y.-z., Charalampopoulos, P., Fang, Q., Fraser, M., Gutiérrez, C. P., Imazawa, R., Kangas, T., Kawabata, K. S., Kotak, R., Kravtsov, T., Matilainen, K., Mattila, S., Moran, S., Murata, I., Salmaso, I., Anderson, J. P., Ashall, C., Bellm, E. C., Benetti, S., Chambers, K. C., Chen, T.-w., Coughlin, M., De Colle, F., Fremling, C., Galbany, L., Gal-yam, A., Gromadzki, M., Groom, S. L., Hajela, A., Inserra, C., Kasliwal, M. M., Mahabal, A. A., Martin-carrillo, A., Moore, T., Müller-bravo, T. E., Nicholl, M., Ragosta, F., Riddle, R. L., Sharma, Y., Srivastav, S., Stritzinger, M. D., Wold, A., and Young, D. R.

Published
2023

31. Erratum: Azimuthal anisotropy at the relativistic heavy ion collider: the first and fourth harmonics [Phys. Rev. Lett. 92, 062301 (2004)]

Author

Adams, Joseph R., Adler, Clemens, Aggarwal, Madan Mohan, Ahammed, Zubayer, Amonett, John, Anderson, Bryon D., Anderson, Mike, Arkhipkin, Dmitry A., Averichev, Georgy S., Badyal, S. K., Balewski, Jan, Barannikova, Olga, Barnby, Lee Stuart, Baudot, Jérome, Bekele, Selemon, Belaga, Victoria Vladimirovna, Bellwied, Rene, Berger, Jens, Bezverkhny, B. I., Bhardwaj, S., Bhaskar, P., Bhati, Ashok Kumar, Bichsel, Hans, Billmeier, Anja, Bland, Leslie C., Blyth, Charles O., Bonner, Billy E., Botje, Michiel, Boucham, Abdelkrim, Brandin, Andrei V., Bravar, Alessandro, Cadman, R. V., Cai, Xiang-Zhou, Caines, Helen Louise, Calderón de la Barca Sánchez, Manuel, Carroll, J., Castillo Castellanos, Javier Ernesto, Castro, M., Cebra, Daniel A., Chaloupka, Petr, Chattopadhyay, S., Chen, H. F., Chen, Y., Chernenko, Sergey P., Cherney, Michael Gerard, Chikanian, Alexei, Choi, B., Christie, William, Coffin, Jean Pierre, Cormier, Thomas Michael, Cramer, John G., Crawford, Henry J., Csanád, Máté, Das, Debasish, Das, Supriya, Derevschikov, Anatoly A., Didenko, Lidia, Dietel, Thomas, Dong, W. J., Dong, X., Draper, James E., Du, F., Dubey, Anand Kumar, Dunin, V. B., Dunlop, James C., Dutta Majumdar, Mihir Ranjan, Eckardt, Volker, Efimov, Leonid G., Emelianov, V., Engelage, Jon M., Eppley, Geary Wareham, Erazmus, Barbara Ewa, Estienne, Magali Danielle, Fachini, Patricia, Faine, V., Faivre, Julien, Fatemi, Renee H., Filimonov, Kirill, Filip, Peter, Finch, Evan, Fisyak, Yuri V., Flierl, Dominik Bernhard, Foley, Kenneth John, Fu, J., Gagliardi, Carl A., Gagunashvili, N., Gans, J., Ganti, Murthy S., Gaudichet, L., Germain, Marie, Geurts, Frank, Ghazikhanian, Vahe, Ghosh, Premomoy, Gonzalez, Johan Enmanuel, Grachov, Oleg A., Grigoriev, Vladislav A., Gronstal, S., Grosnick, David P., Guedon, M., Guertin, Steven M., Gupta, Anik, Gushin, E., Gutierrez, Thomas Dominic, Hallman, Timothy J., Hardtke, David H., Harris, John W., Heinz, Mark Thomas, Henry, Thomas W., Heppelmann, Steven Francis, Herston, T., Hippolyte, Boris, Hirsch, Andrew S., Hjort, Eric, Hoffmann, Gerald W., Horsley, M., Huang, Huan Zhong, Huang, Shengli, Humanic, Thomas J., Igo, George J., Ishihara, A., Jacobs, Peter Martin, Jacobs, William W., Janik, Michał, Jiang, H., Johnson, I., Jones, Peter Graham, Judd, Eleanor G., Kabana, Sonia, Kaneta, Kaneta, Kaplan, Morton, Keane, Declan, Khodyrev, V. Yu., Kiryluk, Joanna, Kisiel, Adam Ryszard, Klay, Jennifer Lynn, Klein, Spencer Robert, Klyachko, A., Koetke, Donald D., Kollegger, Thorsten, Kopytine, M., Kotchenda, L., Kovalenko, A. D., Kramer, M., Kravtsov, Peter, Kravtsov, Vladimir I., Krueger, Keith William, Kuhn, Christian Claude, Kulikov, Anatoly I., Kumar, Ajay, Kunde, Gerd J., Kunz, Christopher Lee, Kutuev, R. Kh., Kuznetsov, A. A., Lamont, Matthew A. C., Landgraf, Jeffery M., Lange, S., Lansdell, Curtis Patrick Leon, Lasiuk, Brian, Laue, Frank, Lauret, Jerome, Lebedev, Alexei, Lednický, Richard, LeVine, Micheal J., Li, C., Li, Q., Lindenbaum, Sam J., Lisa, Michael A., Liu, F., Liu, L., Liu, Z., Liu, Q. J., Ljubicic, Tonko A., Llope, William Joseph, Long, H., Longacre, Ronald S., Lopez-Noriega, M., Love, William A., Ludlam, Thomas, Lynn, David, Ma, Jing-guo, Ma, R., Ma, Yu-Gang, Magestro, Daniel, Mahajan, Sanjay, Mangotra, Lalit K., Mahapatra, D. P., Majka, Richard Daniel, Manweiler, Robert W., Margetis, Spyridon, Markert, Christina, Martin, L., Marx, Jay N., Matis, Howard S., Matulenko, Yuri A., McShane, Tom S., Meissner, F., Melnick, Yu., Meščanin, Aleksei P., Messer, Matthias, Miller, M. L., Milosevich, Z., Minaev, Nikolai G., Mironov, Camelia, Mishra, Debadeepti, Mitchell, J., Mohanty, Bedangadas, Molnar, Levente, Moore, C. F., Mora-Corral, M. J., Morozov, Dmitry A., Morozov, V., de Moura, M. M., Munhoz, Marcelo Gameiro, Nandi, Basanta Kumar, Nayak, S. K., Nayak, Tapan Kumar, Nelson, John M., Nevski, P., Niida, Takafumi, Nikitin, Vladimir A., Nogach, Larisa V., Norman, B., Nurušev, Sandibek B., Odyniec, Grazyna Janina, Ogawa, Akio, Okorokov, Vitaly A., Oldenburg, Markus D., Olson, Douglas L., Paic, Guy, Pandey, S. U., Pal, Susanta Kumar, Panebratsev, Yuri, Panitkin, Sergei Yurievich, Pavlinov, A. I., Pawlak, Tomasz Jan, Perevoztchikov, V., Perkins, Chris, Peryt, Wiktor Stanislaw, Petrov, V. A., Phatak, S. C., Picha, R., Planinic, Mirko, Pluta, Jan Marian, Porile, Norbert T., Porter, Jeffrey Brent, Poskanzer, Arthur M., Potekhin, Maxim, Potrebenikova, E., Potukuchi, B. V. K. S., Prindle, Duncan J., Pruneau, Claude A., Putschke, Jörn H., Rai, Gulshan, Rakness, Gregory L., Raniwala, Rashmi, Raniwala, Sudhir, Ravel, Olivier, Ray, Robert L., Razin, Sergej V., Reichhold, Dennis Michael, Reid, Jeffrey G., Renault, G., Retiere, Fabrice, Ridiger, Alexey, Ritter, Hans Georg, Roberts, Jabus B., Rogachevski, O. V., Romero, Juan L., Rose, A., Roy, Christelle Sophie, Ruan, Lijuan, Sahoo, Raghunath, Sakrejda, Iwona, Salur, Sevil, Sandweiss, Jack H., Savin, Igor A., Schambach, Joachim, Scharenberg, Rolf Paul, Schmitz, Norbert, Schroeder, Lee S., Schweda, Kai, Seger, Janet Elizabeth, Seliverstov, D., Seyboth, Peter, Shahaliev, Ehtiram, Shao, M., Sharma, M., Shestermanov, Konstantin E., Shimanskii, S. S., Singaraju, Rama Narayana, Simon, F., Skoro, Goran P., Smirnov, Nikolai, Snellings, Raimond, Sood, Gopika, Sorensen, Paul Richard, Sowinski, James, Spinka, Harold. M., Srivastava, Brijesh Kumar, Stanislaus, S., Stock, Reinhard, Stolpovsky, Alexander, Strichanov, Michail Nikolaevič, Stringfellow, Blair, Struck, Christof, Suaide, Alexandre Alarcon do Passo, Sugarbaker, Evan R., Suire, Christophe Pierre, Šumbera, Michal, Surrow, Bernd, Symons, Timothy James MacNeil, Toledo, Alejandro Szanto de, Szarwas, Piotr, Tai, An, Takahashi, Jun, Tang, Aihong, Thein, Dylan, Thomas, James H., Tikhomirov, V., Todoroki, Takahito, Tokarev, Mikhail V., Tonjes, Marguerite Belt, Trainor, Thomas A., Trentalange, Stephen, Tribble, Robert E., Trivedi, M. D., Trofimov, V., Tsai, Oleg D., Ullrich, Thomas, Underwood, David G., Van Buren, Gene, VanderMolen, A. M., Vasiliev, Alexander Nikolaevich, Vasiliev, M., Vigdor, Steven E., Viyogi, Yogendra P., Voloshin, Sergei, Waggoner, William T., Wang, F., Wang, G., Wang, X. L., Wang, Z. M., Ward, H., Watson, J. W., Wells, R., Westfall, Gary D., Whitten, Charles A., Wieman, Howard, Willson, Robert, Wissink, Scott W., Witt, Richard, Wood, J., Wu, J., Xu, N., Xu, Z., Xu, Z. Z., Yamamoto, E., Yepes, Pablo P., Yurevich, Vladimir Yurevich, Zanevski, Y. V., Zborovský, Imrich, Zhang, Haitao, Zhang, W. M., Zhang, Z. P., Żołnierczuk, Piotr Adam, Zoulkarneev, R., Zoulkarneeva, J., Zubarev, A. N., Adams, Joseph R., Adler, Clemens, Aggarwal, Madan Mohan, Ahammed, Zubayer, Amonett, John, Anderson, Bryon D., Anderson, Mike, Arkhipkin, Dmitry A., Averichev, Georgy S., Badyal, S. K., Balewski, Jan, Barannikova, Olga, Barnby, Lee Stuart, Baudot, Jérome, Bekele, Selemon, Belaga, Victoria Vladimirovna, Bellwied, Rene, Berger, Jens, Bezverkhny, B. I., Bhardwaj, S., Bhaskar, P., Bhati, Ashok Kumar, Bichsel, Hans, Billmeier, Anja, Bland, Leslie C., Blyth, Charles O., Bonner, Billy E., Botje, Michiel, Boucham, Abdelkrim, Brandin, Andrei V., Bravar, Alessandro, Cadman, R. V., Cai, Xiang-Zhou, Caines, Helen Louise, Calderón de la Barca Sánchez, Manuel, Carroll, J., Castillo Castellanos, Javier Ernesto, Castro, M., Cebra, Daniel A., Chaloupka, Petr, Chattopadhyay, S., Chen, H. F., Chen, Y., Chernenko, Sergey P., Cherney, Michael Gerard, Chikanian, Alexei, Choi, B., Christie, William, Coffin, Jean Pierre, Cormier, Thomas Michael, Cramer, John G., Crawford, Henry J., Csanád, Máté, Das, Debasish, Das, Supriya, Derevschikov, Anatoly A., Didenko, Lidia, Dietel, Thomas, Dong, W. J., Dong, X., Draper, James E., Du, F., Dubey, Anand Kumar, Dunin, V. B., Dunlop, James C., Dutta Majumdar, Mihir Ranjan, Eckardt, Volker, Efimov, Leonid G., Emelianov, V., Engelage, Jon M., Eppley, Geary Wareham, Erazmus, Barbara Ewa, Estienne, Magali Danielle, Fachini, Patricia, Faine, V., Faivre, Julien, Fatemi, Renee H., Filimonov, Kirill, Filip, Peter, Finch, Evan, Fisyak, Yuri V., Flierl, Dominik Bernhard, Foley, Kenneth John, Fu, J., Gagliardi, Carl A., Gagunashvili, N., Gans, J., Ganti, Murthy S., Gaudichet, L., Germain, Marie, Geurts, Frank, Ghazikhanian, Vahe, Ghosh, Premomoy, Gonzalez, Johan Enmanuel, Grachov, Oleg A., Grigoriev, Vladislav A., Gronstal, S., Grosnick, David P., Guedon, M., Guertin, Steven M., Gupta, Anik, Gushin, E., Gutierrez, Thomas Dominic, Hallman, Timothy J., Hardtke, David H., Harris, John W., Heinz, Mark Thomas, Henry, Thomas W., Heppelmann, Steven Francis, Herston, T., Hippolyte, Boris, Hirsch, Andrew S., Hjort, Eric, Hoffmann, Gerald W., Horsley, M., Huang, Huan Zhong, Huang, Shengli, Humanic, Thomas J., Igo, George J., Ishihara, A., Jacobs, Peter Martin, Jacobs, William W., Janik, Michał, Jiang, H., Johnson, I., Jones, Peter Graham, Judd, Eleanor G., Kabana, Sonia, Kaneta, Kaneta, Kaplan, Morton, Keane, Declan, Khodyrev, V. Yu., Kiryluk, Joanna, Kisiel, Adam Ryszard, Klay, Jennifer Lynn, Klein, Spencer Robert, Klyachko, A., Koetke, Donald D., Kollegger, Thorsten, Kopytine, M., Kotchenda, L., Kovalenko, A. D., Kramer, M., Kravtsov, Peter, Kravtsov, Vladimir I., Krueger, Keith William, Kuhn, Christian Claude, Kulikov, Anatoly I., Kumar, Ajay, Kunde, Gerd J., Kunz, Christopher Lee, Kutuev, R. Kh., Kuznetsov, A. A., Lamont, Matthew A. C., Landgraf, Jeffery M., Lange, S., Lansdell, Curtis Patrick Leon, Lasiuk, Brian, Laue, Frank, Lauret, Jerome, Lebedev, Alexei, Lednický, Richard, LeVine, Micheal J., Li, C., Li, Q., Lindenbaum, Sam J., Lisa, Michael A., Liu, F., Liu, L., Liu, Z., Liu, Q. J., Ljubicic, Tonko A., Llope, William Joseph, Long, H., Longacre, Ronald S., Lopez-Noriega, M., Love, William A., Ludlam, Thomas, Lynn, David, Ma, Jing-guo, Ma, R., Ma, Yu-Gang, Magestro, Daniel, Mahajan, Sanjay, Mangotra, Lalit K., Mahapatra, D. P., Majka, Richard Daniel, Manweiler, Robert W., Margetis, Spyridon, Markert, Christina, Martin, L., Marx, Jay N., Matis, Howard S., Matulenko, Yuri A., McShane, Tom S., Meissner, F., Melnick, Yu., Meščanin, Aleksei P., Messer, Matthias, Miller, M. L., Milosevich, Z., Minaev, Nikolai G., Mironov, Camelia, Mishra, Debadeepti, Mitchell, J., Mohanty, Bedangadas, Molnar, Levente, Moore, C. F., Mora-Corral, M. J., Morozov, Dmitry A., Morozov, V., de Moura, M. M., Munhoz, Marcelo Gameiro, Nandi, Basanta Kumar, Nayak, S. K., Nayak, Tapan Kumar, Nelson, John M., Nevski, P., Niida, Takafumi, Nikitin, Vladimir A., Nogach, Larisa V., Norman, B., Nurušev, Sandibek B., Odyniec, Grazyna Janina, Ogawa, Akio, Okorokov, Vitaly A., Oldenburg, Markus D., Olson, Douglas L., Paic, Guy, Pandey, S. U., Pal, Susanta Kumar, Panebratsev, Yuri, Panitkin, Sergei Yurievich, Pavlinov, A. I., Pawlak, Tomasz Jan, Perevoztchikov, V., Perkins, Chris, Peryt, Wiktor Stanislaw, Petrov, V. A., Phatak, S. C., Picha, R., Planinic, Mirko, Pluta, Jan Marian, Porile, Norbert T., Porter, Jeffrey Brent, Poskanzer, Arthur M., Potekhin, Maxim, Potrebenikova, E., Potukuchi, B. V. K. S., Prindle, Duncan J., Pruneau, Claude A., Putschke, Jörn H., Rai, Gulshan, Rakness, Gregory L., Raniwala, Rashmi, Raniwala, Sudhir, Ravel, Olivier, Ray, Robert L., Razin, Sergej V., Reichhold, Dennis Michael, Reid, Jeffrey G., Renault, G., Retiere, Fabrice, Ridiger, Alexey, Ritter, Hans Georg, Roberts, Jabus B., Rogachevski, O. V., Romero, Juan L., Rose, A., Roy, Christelle Sophie, Ruan, Lijuan, Sahoo, Raghunath, Sakrejda, Iwona, Salur, Sevil, Sandweiss, Jack H., Savin, Igor A., Schambach, Joachim, Scharenberg, Rolf Paul, Schmitz, Norbert, Schroeder, Lee S., Schweda, Kai, Seger, Janet Elizabeth, Seliverstov, D., Seyboth, Peter, Shahaliev, Ehtiram, Shao, M., Sharma, M., Shestermanov, Konstantin E., Shimanskii, S. S., Singaraju, Rama Narayana, Simon, F., Skoro, Goran P., Smirnov, Nikolai, Snellings, Raimond, Sood, Gopika, Sorensen, Paul Richard, Sowinski, James, Spinka, Harold. M., Srivastava, Brijesh Kumar, Stanislaus, S., Stock, Reinhard, Stolpovsky, Alexander, Strichanov, Michail Nikolaevič, Stringfellow, Blair, Struck, Christof, Suaide, Alexandre Alarcon do Passo, Sugarbaker, Evan R., Suire, Christophe Pierre, Šumbera, Michal, Surrow, Bernd, Symons, Timothy James MacNeil, Toledo, Alejandro Szanto de, Szarwas, Piotr, Tai, An, Takahashi, Jun, Tang, Aihong, Thein, Dylan, Thomas, James H., Tikhomirov, V., Todoroki, Takahito, Tokarev, Mikhail V., Tonjes, Marguerite Belt, Trainor, Thomas A., Trentalange, Stephen, Tribble, Robert E., Trivedi, M. D., Trofimov, V., Tsai, Oleg D., Ullrich, Thomas, Underwood, David G., Van Buren, Gene, VanderMolen, A. M., Vasiliev, Alexander Nikolaevich, Vasiliev, M., Vigdor, Steven E., Viyogi, Yogendra P., Voloshin, Sergei, Waggoner, William T., Wang, F., Wang, G., Wang, X. L., Wang, Z. M., Ward, H., Watson, J. W., Wells, R., Westfall, Gary D., Whitten, Charles A., Wieman, Howard, Willson, Robert, Wissink, Scott W., Witt, Richard, Wood, J., Wu, J., Xu, N., Xu, Z., Xu, Z. Z., Yamamoto, E., Yepes, Pablo P., Yurevich, Vladimir Yurevich, Zanevski, Y. V., Zborovský, Imrich, Zhang, Haitao, Zhang, W. M., Zhang, Z. P., Żołnierczuk, Piotr Adam, Zoulkarneev, R., Zoulkarneeva, J., and Zubarev, A. N.

Published
2021

32. The mass and galaxy distribution around SZ-selected clusters

Author

Shin, T, Jain, B, Adhikari, S, Baxter, E, Chang, C, Pandey, S, Salcedo, A, Weinberg, D, Amsellem, A, Battaglia, N, Belyakov, M, Dacunha, T, Goldstein, S, Kravtsov, A, Varga, T, Abbott, T, Aguena, M, Alarcon, A, Allam, S, Amon, A, Andrade-Oliveira, F, Annis, J, Bacon, D, Bechtol, K, Becker, M, Bernstein, G, Bertin, E, Bocquet, S, Bond, J, Brooks, D, Buckley-Geer, E, Burke, D, Campos, A, Carnero Rosell, A, Carrasco Kind, M, Carretero, J, Chen, R, Choi, A, Costanzi, M, da Costa, L, Derose, J, Desai, S, de Vicente, J, Devlin, M, Diehl, H, Dietrich, J, Dodelson, S, Doel, P, Doux, C, Drlica-Wagner, A, Eckert, K, Elvin-Poole, J, Everett, S, Ferraro, S, Ferrero, I, Ferte, A, Flaugher, B, Frieman, J, Gallardo, P, Gatti, M, Gaztanaga, E, Gerdes, D, Gruen, D, Gruendl, R, Gutierrez, G, Harrison, I, Hartley, W, Hill, J, Hilton, M, Hinton, S, Hollowood, D, Hughes, J, James, D, Jarvis, M, Jeltema, T, Koopman, B, Krause, E, Kuehn, K, Kuropatkin, N, Lahav, O, Lima, M, Lokken, M, Maccrann, N, Madhavacheril, M, Maia, M, Mccullough, J, Mcmahon, J, Melchior, P, Menanteau, F, Miquel, R, Mohr, J, Moodley, K, Morgan, R, Myles, J, Nati, F, Navarro-Alsina, A, Niemack, M, Ogando, R, Page, L, Palmese, A, Partridge, B, Paz-Chinchon, F, Pereira, M, Pieres, A, Plazas Malagon, A, Prat, J, Raveri, M, Rodriguez-Monroy, M, Rollins, R, Romer, A, Rykoff, E, Salatino, M, Sanchez, C, Sanchez, E, Santiago, B, Scarpine, V, Schillaci, A, Secco, L, Serrano, S, Sevilla-Noarbe, I, Sheldon, E, Sherwin, B, Sifon, C, Smith, M, Soares-Santos, M, Staggs, S, Suchyta, E, Swanson, M, Tarle, G, Thomas, D, To, C, Troxel, M, Tutusaus, I, Vavagiakis, E, Weller, J, Wollack, E, Yanny, B, Yin, B, Zhang, Y, Shin T., Jain B., Adhikari S., Baxter E. J., Chang C., Pandey S., Salcedo A., Weinberg D. H., Amsellem A., Battaglia N., Belyakov M., Dacunha T., Goldstein S., Kravtsov A. V., Varga T. N., Abbott T. M. C., Aguena M., Alarcon A., Allam S., Amon A., Andrade-Oliveira F., Annis J., Bacon D., Bechtol K., Becker M. R., Bernstein G. M., Bertin E., Bocquet S., Bond J. R., Brooks D., Buckley-Geer E., Burke D. L., Campos A., Carnero Rosell A., Carrasco Kind M., Carretero J., Chen R., Choi A., Costanzi M., da Costa L. N., DeRose J., Desai S., de Vicente J., Devlin M. J., Diehl H. T., Dietrich J. P., Dodelson S., Doel P., Doux C., Drlica-Wagner A., Eckert K., Elvin-Poole J., Everett S., Ferraro S., Ferrero I., Ferte A., Flaugher B., Frieman J., Gallardo P. A., Gatti M., Gaztanaga E., Gerdes D. W., Gruen D., Gruendl R. A., Gutierrez G., Harrison I., Hartley W. G., Hill J. C., Hilton M., Hinton S. R., Hollowood D. L., Hughes J. P., James D. J., Jarvis M., Jeltema T., Koopman B. J., Krause E., Kuehn K., Kuropatkin N., Lahav O., Lima M., Lokken M., MacCrann N., Madhavacheril M. S., Maia M. A. G., McCullough J., McMahon J., Melchior P., Menanteau F., Miquel R., Mohr J. J., Moodley K., Morgan R., Myles J., Nati F., Navarro-Alsina A., Niemack M. D., Ogando R. L. C., Page L. A., Palmese A., Partridge B., Paz-Chinchon F., Pereira M. E. S., Pieres A., Plazas Malagon A. A., Prat J., Raveri M., Rodriguez-Monroy M., Rollins R. P., Romer A. K., Rykoff E. S., Salatino M., Sanchez C., Sanchez E., Santiago B., Scarpine V., Schillaci A., Secco L. F., Serrano S., Sevilla-Noarbe I., Sheldon E., Sherwin B. D., Sifon C., Smith M., Soares-Santos M., Staggs S. T., Suchyta E., Swanson M. E. C., Tarle G., Thomas D., To C., Troxel M. A., Tutusaus I., Vavagiakis E. M., Weller J., Wollack E. J., Yanny B., Yin B., Zhang Y., Shin, T, Jain, B, Adhikari, S, Baxter, E, Chang, C, Pandey, S, Salcedo, A, Weinberg, D, Amsellem, A, Battaglia, N, Belyakov, M, Dacunha, T, Goldstein, S, Kravtsov, A, Varga, T, Abbott, T, Aguena, M, Alarcon, A, Allam, S, Amon, A, Andrade-Oliveira, F, Annis, J, Bacon, D, Bechtol, K, Becker, M, Bernstein, G, Bertin, E, Bocquet, S, Bond, J, Brooks, D, Buckley-Geer, E, Burke, D, Campos, A, Carnero Rosell, A, Carrasco Kind, M, Carretero, J, Chen, R, Choi, A, Costanzi, M, da Costa, L, Derose, J, Desai, S, de Vicente, J, Devlin, M, Diehl, H, Dietrich, J, Dodelson, S, Doel, P, Doux, C, Drlica-Wagner, A, Eckert, K, Elvin-Poole, J, Everett, S, Ferraro, S, Ferrero, I, Ferte, A, Flaugher, B, Frieman, J, Gallardo, P, Gatti, M, Gaztanaga, E, Gerdes, D, Gruen, D, Gruendl, R, Gutierrez, G, Harrison, I, Hartley, W, Hill, J, Hilton, M, Hinton, S, Hollowood, D, Hughes, J, James, D, Jarvis, M, Jeltema, T, Koopman, B, Krause, E, Kuehn, K, Kuropatkin, N, Lahav, O, Lima, M, Lokken, M, Maccrann, N, Madhavacheril, M, Maia, M, Mccullough, J, Mcmahon, J, Melchior, P, Menanteau, F, Miquel, R, Mohr, J, Moodley, K, Morgan, R, Myles, J, Nati, F, Navarro-Alsina, A, Niemack, M, Ogando, R, Page, L, Palmese, A, Partridge, B, Paz-Chinchon, F, Pereira, M, Pieres, A, Plazas Malagon, A, Prat, J, Raveri, M, Rodriguez-Monroy, M, Rollins, R, Romer, A, Rykoff, E, Salatino, M, Sanchez, C, Sanchez, E, Santiago, B, Scarpine, V, Schillaci, A, Secco, L, Serrano, S, Sevilla-Noarbe, I, Sheldon, E, Sherwin, B, Sifon, C, Smith, M, Soares-Santos, M, Staggs, S, Suchyta, E, Swanson, M, Tarle, G, Thomas, D, To, C, Troxel, M, Tutusaus, I, Vavagiakis, E, Weller, J, Wollack, E, Yanny, B, Yin, B, Zhang, Y, Shin T., Jain B., Adhikari S., Baxter E. J., Chang C., Pandey S., Salcedo A., Weinberg D. H., Amsellem A., Battaglia N., Belyakov M., Dacunha T., Goldstein S., Kravtsov A. V., Varga T. N., Abbott T. M. C., Aguena M., Alarcon A., Allam S., Amon A., Andrade-Oliveira F., Annis J., Bacon D., Bechtol K., Becker M. R., Bernstein G. M., Bertin E., Bocquet S., Bond J. R., Brooks D., Buckley-Geer E., Burke D. L., Campos A., Carnero Rosell A., Carrasco Kind M., Carretero J., Chen R., Choi A., Costanzi M., da Costa L. N., DeRose J., Desai S., de Vicente J., Devlin M. J., Diehl H. T., Dietrich J. P., Dodelson S., Doel P., Doux C., Drlica-Wagner A., Eckert K., Elvin-Poole J., Everett S., Ferraro S., Ferrero I., Ferte A., Flaugher B., Frieman J., Gallardo P. A., Gatti M., Gaztanaga E., Gerdes D. W., Gruen D., Gruendl R. A., Gutierrez G., Harrison I., Hartley W. G., Hill J. C., Hilton M., Hinton S. R., Hollowood D. L., Hughes J. P., James D. J., Jarvis M., Jeltema T., Koopman B. J., Krause E., Kuehn K., Kuropatkin N., Lahav O., Lima M., Lokken M., MacCrann N., Madhavacheril M. S., Maia M. A. G., McCullough J., McMahon J., Melchior P., Menanteau F., Miquel R., Mohr J. J., Moodley K., Morgan R., Myles J., Nati F., Navarro-Alsina A., Niemack M. D., Ogando R. L. C., Page L. A., Palmese A., Partridge B., Paz-Chinchon F., Pereira M. E. S., Pieres A., Plazas Malagon A. A., Prat J., Raveri M., Rodriguez-Monroy M., Rollins R. P., Romer A. K., Rykoff E. S., Salatino M., Sanchez C., Sanchez E., Santiago B., Scarpine V., Schillaci A., Secco L. F., Serrano S., Sevilla-Noarbe I., Sheldon E., Sherwin B. D., Sifon C., Smith M., Soares-Santos M., Staggs S. T., Suchyta E., Swanson M. E. C., Tarle G., Thomas D., To C., Troxel M. A., Tutusaus I., Vavagiakis E. M., Weller J., Wollack E. J., Yanny B., Yin B., and Zhang Y.

Abstract

We present measurements of the radial profiles of the mass and galaxy number density around Sunyaev–Zel’dovich (SZ)-selected clusters using both weak lensing and galaxy counts. The clusters are selected from the Atacama Cosmology Telescope Data Release 5 and the galaxies from the Dark Energy Survey Year 3 data set. With signal-to-noise ratio of 62 (45) for galaxy (weak lensing) profiles over scales of about 0.2–20 h-1 Mpc, these are the highest precision measurements for SZ-selected clusters to date. Because SZ selection closely approximates mass selection, these measurements enable several tests of theoretical models of the mass and light distribution around clusters. Our main findings are: (1) The splashback feature is detected at a consistent location in both the mass and galaxy profiles and its location is consistent with predictions of cold dark matter N-body simulations. (2) The full mass profile is also consistent with the simulations. (3) The shapes of the galaxy and lensing profiles are remarkably similar for our sample over the entire range of scales, from well inside the cluster halo to the quasilinear regime. We measure the dependence of the profile shapes on the galaxy sample, redshift, and cluster mass. We extend the Diemer & Kravtsov model for the cluster profiles to the linear regime using perturbation theory and show that it provides a good match to the measured profiles. We also compare the measured profiles to predictions of the standard halo model and simulations that include hydrodynamics. Applications of these results to cluster mass estimation, cosmology, and astrophysics are discussed.

Published
2021

33. Black hole spin-orbit misalignment in the x-ray binary MAXI J1820+070

Author

Poutanen, J., Veledina, A., Berdyugin, A.V., Berdyugina, S.V., Jermak, H., Jonker, P.G., Kajava, J.J.E., Kosenkov, I.A., Kravtsov, V., Piirola, V., Shrestha, M., Perez Torres, M.A., Tsygankov, S.S., Poutanen, J., Veledina, A., Berdyugin, A.V., Berdyugina, S.V., Jermak, H., Jonker, P.G., Kajava, J.J.E., Kosenkov, I.A., Kravtsov, V., Piirola, V., Shrestha, M., Perez Torres, M.A., and Tsygankov, S.S.

Abstract

Contains fulltext : 247345.pdf (Publisher’s version ) (Closed access)

Published
2022

34. From dawn till disk: Milky Way's turbulent youth revealed by the APOGEE+Gaia data

Author

Belokurov, Vasily, Kravtsov, Andrey, Belokurov, Vasily, and Kravtsov, Andrey

Abstract

We use accurate estimates of aluminium abundance provided as part of the APOGEE Data Release 17 and Gaia Early Data Release 3 astrometry to select a highly pure sample of stars with metallicity $-1.5\lesssim {\rm [Fe/H]}\lesssim 0.5$ born in-situ in the Milky Way proper. We show that the low-metallicity ([Fe/H]$\lesssim -1.3$) in-situ component that we dub Aurora is kinematically hot with an approximately isotropic velocity ellipsoid and a modest net rotation. Aurora stars exhibit large scatter in metallicity and in a number of element abundance ratios. The median tangential velocity of the in-situ stars increases sharply with increasing metallicity between [Fe/H]$=-1.3$ and $-0.9$, the transition that we call the spin-up. The observed and theoretically expected age-metallicity correlations imply that this increase reflects a rapid formation of the Milky Way disk over $\approx 1-2$ Gyrs. The transformation of the stellar kinematics as a function of [Fe/H] is accompanied by a qualitative change in chemical abundances: the scatter drops sharply once the Galaxy builds up a disk during later epochs corresponding to [Fe/H]$>-0.9$. Results of galaxy formation models presented in this and other recent studies strongly indicate that the trends observed in the Milky Way reflect generic processes during the early evolution of progenitors of MW-sized galaxies: a period of chaotic pre-disk evolution, when gas is accreted along cold narrow filaments and when stars are born in irregular configurations, and subsequent rapid disk formation. The latter signals formation of a stable hot gaseous halo around the MW progenitor, which changes the mode of gas accretion and allows development of coherently rotating disk., Comment: Comments are welcome!

Published
2022

35. Stellar collisions in globular clusters: constraints on the IMF of the first generation of stars

Author

Dib, Sami, Kravtsov, Valery V., Haghi, Hosein, Zonoozi, Akram Hasani, Belinchón, José Antonio, Dib, Sami, Kravtsov, Valery V., Haghi, Hosein, Zonoozi, Akram Hasani, and Belinchón, José Antonio

Abstract

Globular clusters display an anti-correlation between the fraction of the first generation of stars ($N({\rm G1})/N({\rm tot})$) and the slope of the present-day mass function of the clusters ($\alpha_{pd}$), which is particularly significant for massive clusters. In the framework of the binary-mediated collision scenario for the formation of the second generation stars in globular clusters, we test the effect of a varying initial stellar mass function (IMF) of the G1 stars on the $(N({\rm G1})/N({\rm tot}))-\alpha_{pd}$ anti-correlation. We use a simple collision model which has only two inputs, the IMF of G1 stars and the fraction of G1 stars that coalesce to form G2 stars. We show that a variable efficiency of the collision process is necessary in order to explain the $(N({\rm G1})/N({\rm tot}))-\alpha_{pd}$ anti-correlation, however, the scatter in the anti-correlation can only be explained by variations in the IMF, and in particular by variations of the slope in the mass interval $\approx$ (0.1-0.5) M$_{\odot}$. Our results indicate that in order to explain the scatter in the $(N({\rm G1})/N({\rm tot}))-\alpha_{pd}$ relation, it is necessary to invoke variations of the slope in this mass range between $\approx -0.9$ and $\approx -1.9$. Interpreted in terms of a Kroupa-like broken power law, this translates into variations of the mean mass between $\approx 0.2$ and $0.55$ M$_{\odot}$. This level of variations is consistent with what is observed for young stellar clusters in the Milky Way and may reflect variations in the physical conditions of the globular clusters progenitor clouds at the time the G1 population has formed or to the occurrence of collisions between protostellar embryos before stars settle on the Main Sequence., Comment: Submitted. Comments are welcome

Published
2022

36. Stellar collisions in globular clusters: the origin of multiple stellar populations

Author

Kravtsov, Valery, Dib, Sami, Calderon, Francisco A., Belinchon, Jose A., Kravtsov, Valery, Dib, Sami, Calderon, Francisco A., and Belinchon, Jose A.

Abstract

Two generations of stars, G1 and G2, typically populate Galactic globular clusters (GCs). The origin of G2 stars is unclear. We uncover two empirical dependencies between GC characteristics, which can be explained by the formation of G2 Main-Sequence (MS) stars due to collision\merging of their primordial counterparts (G1). A similar genesis of both G2 stars and peculiar objects like LMXBs and millisecond pulsars is also implied. Indeed, we find a significant (at a confidence level > 99,9%) anti-correlation between the fraction of G1 red giants (N_{G1}/N_{tot}) and stellar encounter rates among 51 GCs. Moreover, a Milky Way-like initial mass function (IMF) requires at least ~50% of MS stars located in the mass range [0.1-0.5] M_sun. Unlike cluster mass loss, stellar collisions\merging retain these G1 stars by converting them into more massive G2 ones, with mainly M_ms > 0.5 M_sun. This process coupled with a decreasing relative mass loss with increasing GC masses implies a smaller (N_{G1}/N_{tot}) in more massive GCs with a shallower present day MF. From data for 35 GCs, we find that such an anti-correlation is significant at 98.3% confidence level (Spearman's correlation) for 12 most massive GCs (M_GC > 10^{5.3} M_sun) and it is at a confidence level of 89\% for the 12 least massive GCs (M_GC < 10^{5.1} M_sun). Other fractions of G1 and G2 stars observed at the bottom of the MS as compared with the red giant branch in a few GCs are consistent with the scenario proposed., Comment: 10 pages, 3 figures, 1 table; accepted for publication in MNRAS (slightly abridged abstract)

Published
2022
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37. Not so fuzzy: excluding FDM with sizes and stellar kinematics of ultra-faint dwarf galaxies

Author

Dalal, Neal, Kravtsov, Andrey, Dalal, Neal, and Kravtsov, Andrey

Abstract

We use observations of ultra-faint dwarf (UFD) galaxies to constrain the particle mass of ultra-light dark matter. Potential fluctuations created by wave interference in virialized "fuzzy" dark matter (FDM) halos dynamically heat stellar orbits in UFDs, some of which exhibit velocity dispersions of $\lesssim$ 3 km/s and sizes $\lesssim$ 40 pc. Using simulations of FDM halos, and existing measurements of sizes and stellar radial velocities in Segue 1 and Segue 2 UFDs, we derive a lower limit on the dark matter particle mass of $m_{fdm} > 3\times 10^{-19}$ eV at 99% confidence, marginalized over host halo circular velocity. This constraint is conservative as it is derived under the assumption that soliton heating is negligible, and that no other sources of non-FDM dynamical heating of stars operate to increase velocity dispersion. It can potentially be strengthened by future spectroscopic observations of additional stars in ultra-faint galaxies and by tightening theoretical constraints on the soliton size-halo mass relation. However, even the current conservative lower limit on the FDM mass makes this model indistinguishable from Cold Dark Matter at the scales probed by existing astronomical observations., Comment: 10 pages. Added references

Published
2022

38. Observation of Global Spin Alignment of $\phi$ and $K^{*0}$ Vector Mesons in Nuclear Collisions

Author

STAR Collaboration, Abdallah, M. S., Aboona, B. E., Adam, J., Adamczyk, L., Adams, J. R., Adkins, J. K., Agakishiev, G., Aggarwal, I., Aggarwal, M. M., Ahammed, Z., Aitbaev, A., Alekseev, I., Anderson, D. M., Aparin, A., Aschenauer, E. C., Ashraf, M. U., Atetalla, F. G., Averichev, G. S., Bairathi, V., Baker, W., Cap, J. G. Ball, Barish, K., Behera, A., Bellwied, R., Bhagat, P., Bhasin, A., Bielcik, J., Bielcikova, J., Bordyuzhin, I. G., Brandenburg, J. D., Brandin, A. V., Cai, X. Z., Caines, H., Sánchez, M. Calderón de la Barca, Cebra, D., Chakaberia, I., Chaloupka, P., Chan, B. K., Chang, F-H., Chang, Z., Chatterjee, A., Chattopadhyay, S., Chen, D., Chen, J., Chen, J. H., Chen, X., Chen, Z., Cheng, J., Choudhury, S., Christie, W., Chu, X., Crawford, H. J., Csanád, M., Daugherity, M., Dedovich, T. G., Deppner, I. M., Derevschikov, A. A., Dhamija, A., Di Carlo, L., Didenko, L., Dixit, P., Dong, X., Drachenberg, J. L., Duckworth, E., Dunlop, J. C., Engelage, J., Eppley, G., Esumi, S., Evdokimov, O., Ewigleben, A., Eyser, O., Fatemi, R., Fawzi, F. M., Fazio, S., Feng, C. J., Feng, Y., Finch, E., Fisyak, Y., Francisco, A., Fu, C., Gagliardi, C. A., Galatyuk, T., Geurts, F., Ghimire, N., Gibson, A., Gopal, K., Gou, X., Grosnick, D., Gupta, A., Guryn, W., Hamed, A., Han, Y., Harabasz, S., Harasty, M. D., Harris, J. W., Harrison, H., He, S., He, W., He, X. H., He, Y., Heppelmann, S., Herrmann, N., Hoffman, E., Holub, L., Hu, C., Hu, Q., Hu, Y., Huang, H., Huang, H. Z., Huang, S. L., Huang, T., Huang, X., Huang, Y., Humanic, T. J., Isenhower, D., Isshiki, M., Jacobs, W. W., Jena, C., Jentsch, A., Ji, Y., Jia, J., Jiang, K., Ju, X., Judd, E. G., Kabana, S., Kabir, M. L., Kagamaster, S., Kalinkin, D., Kang, K., Kapukchyan, D., Kauder, K., Ke, H. W., Keane, D., Kechechyan, A., Kelsey, M., Kikoła, D. P., Kimelman, B., Kincses, D., Kisel, I., Kiselev, A., Knospe, A. G., Ko, H. S., Kochenda, L., Korobitsin, A., Kosarzewski, L. K., Kramarik, L., Kravtsov, P., Kumar, L., Kumar, S., Elayavalli, R. Kunnawalkam, Kwasizur, J. H., Lacey, R., Lan, S., Landgraf, J. M., Lauret, J., Lebedev, A., Lednicky, R., Lee, J. H., Leung, Y. H., Lewis, N., Li, C., Li, W., Li, X., Li, Y., Liang, X., Liang, Y., Licenik, R., Lin, T., Lin, Y., Lisa, M. A., Liu, F., Liu, H., Liu, P., Liu, T., Liu, X., Liu, Y., Liu, Z., Ljubicic, T., Llope, W. J., Longacre, R. S., Loyd, E., Lu, T., Lukow, N. S., Luo, X. F., Ma, L., Ma, R., Ma, Y. G., Magdy, N., Mallick, D., Manukhov, S. L., Margetis, S., Markert, C., Matis, H. S., Mazer, J. A., Minaev, N. G., Mioduszewski, S., Mohanty, B., Mondal, M. M., Mooney, I., Morozov, D. A., Mukherjee, A., Nagy, M., Nam, J. D., Nasim, Md., Nayak, K., Neff, D., Nelson, J. M., Nemes, D. B., Nie, M., Nigmatkulov, G., Niida, T., Nishitani, R., Nogach, L. V., Nonaka, T., Nunes, A. S., Odyniec, G., Ogawa, A., Oh, S., Okorokov, V. A., Okubo, K., Page, B. S., Pak, R., Pan, J., Pandav, A., Pandey, A. K., Panebratsev, Y., Parfenov, P., Paul, A., Pawlik, B., Pawlowska, D., Perkins, C., Pluta, J., Pokhrel, B. R., Porter, J., Posik, M., Prozorova, V., Pruthi, N. K., Przybycien, M., Putschke, J., Qiu, H., Quintero, A., Racz, C., Radhakrishnan, S. K., Raha, N., Ray, R. L., Reed, R., Ritter, H. G., Robotkova, M., Romero, J. L., Roy, D., Ruan, L., Sahoo, A. K., Sahoo, N. R., Sako, H., Salur, S., Samigullin, E., Sandweiss, J., Sato, S., Schmidke, W. B., Schmitz, N., Schweid, B. R., Seck, F., Seger, J., Seto, R., Seyboth, P., Shah, N., Shahaliev, E., Shanmuganathan, P. V., Shao, M., Shao, T., Sharma, R., Sheikh, A. I., Shen, D. Y., Shi, S. S., Shi, Y., Shou, Q. Y., Sichtermann, E. P., Sikora, R., Singh, J., Singha, S., Sinha, P., Skoby, M. J., Smirnov, N., Söhngen, Y., Solyst, W., Song, Y., Spinka, H. M., Srivastava, B., Stanislaus, T. D. S., Stefaniak, M., Stewart, D. J., Strikhanov, M., Stringfellow, B., Suaide, A. A. P., Sumbera, M., Sun, X. M., Sun, X., Sun, Y., Surrow, B., Svirida, D. N., Sweger, Z. W., Szymanski, P., Tang, A. H., Tang, Z., Taranenko, A., Tarnowsky, T., Thomas, J. H., Timmins, A. R., Tlusty, D., Todoroki, T., Tokarev, M., Tomkiel, C. A., Trentalange, S., Tribble, R. E., Tribedy, P., Tripathy, S. K., Truhlar, T., Trzeciak, B. A., Tsai, O. D., Tu, Z., Ullrich, T., Underwood, D. G., Upsal, I., Van Buren, G., Vanek, J., Vasiliev, A. N., Vassiliev, I., Verkest, V., Videbæk, F., Vokal, S., Voloshin, S. A., Wang, F., Wang, G., Wang, J. S., Wang, P., Wang, X., Wang, Y., Wang, Z., Webb, J. C., Weidenkaff, P. C., Westfall, G. D., Wieman, H., Wissink, S. W., Witt, R., Wu, J., Wu, Y., Xi, B., Xiao, Z. G., Xie, G., Xie, W., Xu, H., Xu, N., Xu, Q. H., Xu, Y., Xu, Z., Yan, G., Yang, C., Yang, Q., Yang, S., Yang, Y., Ye, Z., Yi, L., Yip, K., Yu, Y., Zbroszczyk, H., Zha, W., Zhang, C., Zhang, D., Zhang, J., Zhang, S., Zhang, Y., Zhang, Z. J., Zhang, Z., Zhao, F., Zhao, J., Zhao, M., Zhou, C., Zhou, Y., Zhu, X., Zurek, M., Zyzak, M., STAR Collaboration, Abdallah, M. S., Aboona, B. E., Adam, J., Adamczyk, L., Adams, J. R., Adkins, J. K., Agakishiev, G., Aggarwal, I., Aggarwal, M. M., Ahammed, Z., Aitbaev, A., Alekseev, I., Anderson, D. M., Aparin, A., Aschenauer, E. C., Ashraf, M. U., Atetalla, F. G., Averichev, G. S., Bairathi, V., Baker, W., Cap, J. G. Ball, Barish, K., Behera, A., Bellwied, R., Bhagat, P., Bhasin, A., Bielcik, J., Bielcikova, J., Bordyuzhin, I. G., Brandenburg, J. D., Brandin, A. V., Cai, X. Z., Caines, H., Sánchez, M. Calderón de la Barca, Cebra, D., Chakaberia, I., Chaloupka, P., Chan, B. K., Chang, F-H., Chang, Z., Chatterjee, A., Chattopadhyay, S., Chen, D., Chen, J., Chen, J. H., Chen, X., Chen, Z., Cheng, J., Choudhury, S., Christie, W., Chu, X., Crawford, H. J., Csanád, M., Daugherity, M., Dedovich, T. G., Deppner, I. M., Derevschikov, A. A., Dhamija, A., Di Carlo, L., Didenko, L., Dixit, P., Dong, X., Drachenberg, J. L., Duckworth, E., Dunlop, J. C., Engelage, J., Eppley, G., Esumi, S., Evdokimov, O., Ewigleben, A., Eyser, O., Fatemi, R., Fawzi, F. M., Fazio, S., Feng, C. J., Feng, Y., Finch, E., Fisyak, Y., Francisco, A., Fu, C., Gagliardi, C. A., Galatyuk, T., Geurts, F., Ghimire, N., Gibson, A., Gopal, K., Gou, X., Grosnick, D., Gupta, A., Guryn, W., Hamed, A., Han, Y., Harabasz, S., Harasty, M. D., Harris, J. W., Harrison, H., He, S., He, W., He, X. H., He, Y., Heppelmann, S., Herrmann, N., Hoffman, E., Holub, L., Hu, C., Hu, Q., Hu, Y., Huang, H., Huang, H. Z., Huang, S. L., Huang, T., Huang, X., Huang, Y., Humanic, T. J., Isenhower, D., Isshiki, M., Jacobs, W. W., Jena, C., Jentsch, A., Ji, Y., Jia, J., Jiang, K., Ju, X., Judd, E. G., Kabana, S., Kabir, M. L., Kagamaster, S., Kalinkin, D., Kang, K., Kapukchyan, D., Kauder, K., Ke, H. W., Keane, D., Kechechyan, A., Kelsey, M., Kikoła, D. P., Kimelman, B., Kincses, D., Kisel, I., Kiselev, A., Knospe, A. G., Ko, H. S., Kochenda, L., Korobitsin, A., Kosarzewski, L. K., Kramarik, L., Kravtsov, P., Kumar, L., Kumar, S., Elayavalli, R. Kunnawalkam, Kwasizur, J. H., Lacey, R., Lan, S., Landgraf, J. M., Lauret, J., Lebedev, A., Lednicky, R., Lee, J. H., Leung, Y. H., Lewis, N., Li, C., Li, W., Li, X., Li, Y., Liang, X., Liang, Y., Licenik, R., Lin, T., Lin, Y., Lisa, M. A., Liu, F., Liu, H., Liu, P., Liu, T., Liu, X., Liu, Y., Liu, Z., Ljubicic, T., Llope, W. J., Longacre, R. S., Loyd, E., Lu, T., Lukow, N. S., Luo, X. F., Ma, L., Ma, R., Ma, Y. G., Magdy, N., Mallick, D., Manukhov, S. L., Margetis, S., Markert, C., Matis, H. S., Mazer, J. A., Minaev, N. G., Mioduszewski, S., Mohanty, B., Mondal, M. M., Mooney, I., Morozov, D. A., Mukherjee, A., Nagy, M., Nam, J. D., Nasim, Md., Nayak, K., Neff, D., Nelson, J. M., Nemes, D. B., Nie, M., Nigmatkulov, G., Niida, T., Nishitani, R., Nogach, L. V., Nonaka, T., Nunes, A. S., Odyniec, G., Ogawa, A., Oh, S., Okorokov, V. A., Okubo, K., Page, B. S., Pak, R., Pan, J., Pandav, A., Pandey, A. K., Panebratsev, Y., Parfenov, P., Paul, A., Pawlik, B., Pawlowska, D., Perkins, C., Pluta, J., Pokhrel, B. R., Porter, J., Posik, M., Prozorova, V., Pruthi, N. K., Przybycien, M., Putschke, J., Qiu, H., Quintero, A., Racz, C., Radhakrishnan, S. K., Raha, N., Ray, R. L., Reed, R., Ritter, H. G., Robotkova, M., Romero, J. L., Roy, D., Ruan, L., Sahoo, A. K., Sahoo, N. R., Sako, H., Salur, S., Samigullin, E., Sandweiss, J., Sato, S., Schmidke, W. B., Schmitz, N., Schweid, B. R., Seck, F., Seger, J., Seto, R., Seyboth, P., Shah, N., Shahaliev, E., Shanmuganathan, P. V., Shao, M., Shao, T., Sharma, R., Sheikh, A. I., Shen, D. Y., Shi, S. S., Shi, Y., Shou, Q. Y., Sichtermann, E. P., Sikora, R., Singh, J., Singha, S., Sinha, P., Skoby, M. J., Smirnov, N., Söhngen, Y., Solyst, W., Song, Y., Spinka, H. M., Srivastava, B., Stanislaus, T. D. S., Stefaniak, M., Stewart, D. J., Strikhanov, M., Stringfellow, B., Suaide, A. A. P., Sumbera, M., Sun, X. M., Sun, X., Sun, Y., Surrow, B., Svirida, D. N., Sweger, Z. W., Szymanski, P., Tang, A. H., Tang, Z., Taranenko, A., Tarnowsky, T., Thomas, J. H., Timmins, A. R., Tlusty, D., Todoroki, T., Tokarev, M., Tomkiel, C. A., Trentalange, S., Tribble, R. E., Tribedy, P., Tripathy, S. K., Truhlar, T., Trzeciak, B. A., Tsai, O. D., Tu, Z., Ullrich, T., Underwood, D. G., Upsal, I., Van Buren, G., Vanek, J., Vasiliev, A. N., Vassiliev, I., Verkest, V., Videbæk, F., Vokal, S., Voloshin, S. A., Wang, F., Wang, G., Wang, J. S., Wang, P., Wang, X., Wang, Y., Wang, Z., Webb, J. C., Weidenkaff, P. C., Westfall, G. D., Wieman, H., Wissink, S. W., Witt, R., Wu, J., Wu, Y., Xi, B., Xiao, Z. G., Xie, G., Xie, W., Xu, H., Xu, N., Xu, Q. H., Xu, Y., Xu, Z., Yan, G., Yang, C., Yang, Q., Yang, S., Yang, Y., Ye, Z., Yi, L., Yip, K., Yu, Y., Zbroszczyk, H., Zha, W., Zhang, C., Zhang, D., Zhang, J., Zhang, S., Zhang, Y., Zhang, Z. J., Zhang, Z., Zhao, F., Zhao, J., Zhao, M., Zhou, C., Zhou, Y., Zhu, X., Zurek, M., and Zyzak, M.

Abstract

The strong force, as one of the four fundamental forces at work in the universe, governs interactions of quarks and gluons, and binds together the atomic nucleus. Notwithstanding decades of progress since Yukawa first developed a description of the force between nucleons in terms of meson exchange, a full understanding of the strong interaction remains a major challenge in modern science. One remaining difficulty arises from the non-perturbative nature of the strong force, which leads to the phenomenon of quark confinement at distance scales on the order of the size of the proton. Here we show that in relativistic heavy-ion collisions, where quarks and gluons are set free over an extended volume, two species of produced vector (spin-1) mesons, namely $\phi$ and $K^{*0}$, emerge with a surprising pattern of global spin alignment. In particular, the global spin alignment for $\phi$ is unexpectedly large, while that for $K^{*0}$ is consistent with zero. The observed spin-alignment pattern and magnitude for the $\phi$ cannot be explained by conventional mechanisms, while a model with strong force fields accommodates the current data. This is the first time that the strong force field is experimentally supported as a key mechanism that leads to global spin alignment. We extract a quantity proportional to the intensity of the field of the strong force. Within the framework of the Standard Model, where the strong force is typically described in the quark and gluon language of Quantum Chromodynamics, the field being considered here is an effective proxy description. This is a qualitatively new class of measurement, which opens a new avenue for studying the behaviour of strong force fields via their imprint on spin alignment.

Published
2022

39. The optimum assessment of the information systems of shipboard hardware reliability in cloud services

Author

Kravtsova, Lyudmyla V., Zaytseva, Tatyana V., Bezbakh, Oleh M., Kravtsov, Hennadiy M., Kaminska, Nataliia H., Kravtsova, Lyudmyla V., Zaytseva, Tatyana V., Bezbakh, Oleh M., Kravtsov, Hennadiy M., and Kaminska, Nataliia H.

Abstract

The world wide pandemic situation revealed the problems in all spheres of human life which haven’t been faced before. Recently the world has changed greatly as well as the relationship between people and their professional activity. The great bunch of the workload, if basically acceptable, is done with the use of modern innovative technologies. Such problems have not trampled down the sphere of higher education as well. Distance learning, which was previously addressed to only as accompanying possibility of lessons conduct, nowadays is considered to be the only practicable form of conducting lectures, practical lessons, tests, i.e. it has become a usual daily practice for both teachers and students. Among the basic functional requirements to the electronic educational resources in the system of distance learning there are the visualization and interaction principles both when getting familiar with the theoretical material and when completing virtual laboratory and practical tasks. The Microsoft Office documents have become the most widespread elements among the electronic educational resources. That is why there is a pressing need in presenting the electronic MS Excel spreadsheets on the resource web-pages. The simple and convenient way to solve the problem of Excel documents introduction into the electronic resources of the distance learning systems is the use of cloud services. The services help to acquire the access to the information resources of any level and of any capacity with the possibility to allocate the rights of the users belonging to different groups in relation to the resources. For that purpose the availability of the Internet network access and web-browser would be enough \cite{Kravtsova2020}. The cloud calculation technologies introduction allows for the use of the programs that do not require special licensing, update versions monitoring and eliminates the need of software technical support as the provider himself exercises control over the funct

Published
2022

40. Optical polarization signatures of black hole X-ray binaries

Author

Kravtsov, Vadim, Berdyugin, Andrei V., Kosenkov, Ilia A., Veledina, Alexandra, Piirola, Vilppu, Qadir, Yasir Abdul, Berdyugina, Svetlana V., Sakanoi, Takeshi, Kagitani, Masato, Poutanen, Juri, Kravtsov, Vadim, Berdyugin, Andrei V., Kosenkov, Ilia A., Veledina, Alexandra, Piirola, Vilppu, Qadir, Yasir Abdul, Berdyugina, Svetlana V., Sakanoi, Takeshi, Kagitani, Masato, and Poutanen, Juri

Abstract

Polarimetry provides an avenue for probing the geometry and physical mechanisms producing optical radiation in many astrophysical objects, including stellar binary systems. We present the results of multiwavelength (BVR) polarimetric studies of a sample of historical black hole X-ray binaries, observed during their outbursts or in the quiescent (or near-quiescent) state. We surveyed both long- and short-period systems, located at different Galactic latitudes. We performed careful analysis of the interstellar polarization in the direction on the sources to reliably estimate the intrinsic source polarization. Intrinsic polarization was found to be small (<0.2 per cent) in sources observed in bright soft states (MAXI J0637−430 and 4U 1957+115). It was found to be significant in the rising hard state of MAXI J1820+070 at the level of ∼0.5 per cent and negligible in the decaying hard state and during its failed outbursts, while Swift J1357.2−0933 showed its absence in the rising hard state. Three (XTE J1118+480 , V4641 Sgr , V404 Cyg) sources observed during quiescence show no evidence of significant intrinsic polarization, while MAXI J1820+070 is the only black hole X-ray binary which showed substantial (>5 per cent) intrinsic quiescent-state polarization with a blue spectrum. The absence of intrinsic polarization at the optical wavelengths puts constraints on the potential contribution of non-stellar (jet, hot flow, accretion disc) components to the total spectra of black hole X-ray binaries.

Published
2022
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41. Black hole spin-orbit misalignment in the x-ray binary MAXI J1820+070

Author

Poutanen, Juri, Veledina, Alexandra, Berdyugin, Andrei, Berdyugina, Svetlana, Jermak, Helen, Jonker, Peter G., Kajava, Jari J. E., Kosenkov, Ilia A., Kravtsov, Vadim, Piirola, Vilppu, Shrestha, Manisha, Perez Torres, Manuel A., Tsygankov, Sergey S., Poutanen, Juri, Veledina, Alexandra, Berdyugin, Andrei, Berdyugina, Svetlana, Jermak, Helen, Jonker, Peter G., Kajava, Jari J. E., Kosenkov, Ilia A., Kravtsov, Vadim, Piirola, Vilppu, Shrestha, Manisha, Perez Torres, Manuel A., and Tsygankov, Sergey S.

Abstract

The observational signatures of black holes in x-ray binary systems depend on their masses, spins, accretion rate, and the misalignment angle between the black hole spin and the orbital angular momentum. We present optical polarimetric observations of the black hole x-ray binary MAXI J1820+070, from which we constrain the position angle of the binary orbital. Combining this with previous determinations of the relativistic jet orientation. which traces the black hole spin, and the inclination of the orbit, we determine a lower limit of 40 degrees on the spin-orbit misalignment angle. The misalignment must originate from either the binary evolution or black hole formation stages. If other x-ray binaries have similarly large misalignments, these would bias measurements of black hole masses and spins from x-ray observations.

Published
2022
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42. Beam Energy Dependence of Triton Production and Yield Ratio ($\mathrm{N}_t \times \mathrm{N}_p/\mathrm{N}_d^2$) in Au+Au Collisions at RHIC

Author

STAR Collaboration, Abdulhamid, M. I., Aboona, B. E., Adam, J., Adams, J. R., Agakishiev, G., Aggarwal, I., Aggarwal, M. M., Ahammed, Z., Aitbaev, A., Alekseev, I., Anderson, D. M., Aparin, A., Aslam, S., Atchison, J., Averichev, G. S., Bairathi, V., Baker, W., Cap, J. G. Ball, Barish, K., Bhagat, P., Bhasin, A., Bhatta, S., Bordyuzhin, I. G., Brandenburg, J. D., Brandin, A. V., Cai, X. Z., Caines, H., Calderón~de~la~Barca~Sánchez, M., Cebra, D., Ceska, J., Chakaberia, I., Chan, B. K., Chang, Z., Chatterjee, A., Chen, D., Chen, J., Chen, J. H., Chen, Z., Cheng, J., Cheng, Y., Choudhury, S., Christie, W., Chu, X., Crawford, H. J., Dale-Gau, G., Das, A., Daugherity, M., Dedovich, T. G., Deppner, I. M., Derevschikov, A. A., Dhamija, A., Di Carlo, L., Didenko, L., Dixit, P., Dong, X., Drachenberg, J. L., Duckworth, E., Dunlop, J. C., Engelage, J., Eppley, G., Esumi, S., Evdokimov, O., Ewigleben, A., Eyser, O., Fatemi, R., Fazio, S., Feng, C. J., Feng, Y., Finch, E., Fisyak, Y., Flor, F. A., Fu, C., Geurts, F., Ghimire, N., Gibson, A., Gopal, K., Gou, X., Grosnick, D., Gupta, A., Hamed, A., Han, Y., Harasty, M. D., Harris, J. W., Harrison-Smith, H., He, W., He, X. H., He, Y., Hu, C., Hu, Q., Hu, Y., Huang, H., Huang, H. Z., Huang, S. L., Huang, T., Huang, X., Huang, Y., Humanic, T. J., Isenhower, D., Isshiki, M., Jacobs, W. W., Jalotra, A., Jena, C., Ji, Y., Jia, J., Jin, C., Ju, X., Judd, E. G., Kabana, S., Kabir, M. L., Kalinkin, D., Kang, K., Kapukchyan, D., Kauder, K., Ke, H. W., Keane, D., Kechechyan, A., Kelsey, M., Kimelman, B., Kiselev, A., Knospe, A. G., Ko, H. S., Kochenda, L., Korobitsin, A. A., Kravtsov, P., Kumar, L., Kumar, S., Elayavalli, R. Kunnawalkam, Lacey, R., Landgraf, J. M., Lebedev, A., Lednicky, R., Lee, J. H., Leung, Y. H., Lewis, N., Li, C., Li, W., Li, X., Li, Y., Li, Z., Liang, X., Liang, Y., Lin, T., Liu, C., Liu, F., Liu, H., Liu, L., Liu, T., Liu, X., Liu, Y., Liu, Z., Ljubicic, T., Llope, W. J., Lomicky, O., Longacre, R. S., Loyd, E. M., Lu, T., Lukow, N. S., Luo, X. F., Luong, V. B., Ma, L., Ma, R., Ma, Y. G., Magdy, N., Mallick, D., Margetis, S., Matis, H. S., Mazer, J. A., McNamara, G., Mi, K., Minaev, N. G., Mohanty, B., Mondal, M. M., Mooney, I., Morozov, D. A., Mudrokh, A., Nagy, M. I., Nain, A. S., Nam, J. D., Nasim, Md., Neff, D., Nelson, J. M., Nemes, D. B., Nie, M., Nigmatkulov, G., Niida, T., Nishitani, R., Nogach, L. V., Nonaka, T., Odyniec, G., Ogawa, A., Oh, S., Okorokov, V. A., Okubo, K., Page, B. S., Pak, R., Pan, J., Pandav, A., Pandey, A. K., Panebratsev, Y., Pani, T., Parfenov, P., Paul, A., Perkins, C., Pokhrel, B. R., Posik, M., Protzman, T., Pruthi, N. K., Putschke, J., Qin, Z., Qiu, H., Quintero, A., Racz, C., Radhakrishnan, S. K., Raha, N., Ray, R. L., Ritter, H. G., Robertson, C. W., Rogachevsky, O. V., Aguilar, M. A. Rosales, Roy, D., Ruan, L., Sahoo, A. K., Sahoo, N. R., Sako, H., Salur, S., Samigullin, E., Sato, S., Schmidke, W. B., Schmitz, N., Seger, J., Seto, R., Seyboth, P., Shah, N., Shahaliev, E., Shanmuganathan, P. V., Shao, T., Sharma, M., Sharma, N., Sharma, R., Sharma, S. R., Sheikh, A. I., Shen, D. Y., Shen, K., Shi, S. S., Shi, Y., Shou, Q. Y., Si, F., Singh, J., Singha, S., Sinha, P., Skoby, M. J., Söhngen, Y., Song, Y., Srivastava, B., Stanislaus, T. D. S., Stewart, D. J., Strikhanov, M., Stringfellow, B., Su, Y., Sun, C., Sun, X., Sun, Y., Surrow, B., Svirida, D. N., Sweger, Z. W., Tamis, A., Tang, A. H., Tang, Z., Taranenko, A., Tarnowsky, T., Thomas, J. H., Tlusty, D., Todoroki, T., Tokarev, M. V., Tomkiel, C. A., Trentalange, S., Tribble, R. E., Tribedy, P., Tsai, O. D., Tsang, C. Y., Tu, Z., Ullrich, T., Underwood, D. G., Upsal, I., Van Buren, G., Vasiliev, A. N., Verkest, V., Videbæk, F., Vokal, S., Voloshin, S. A., Wang, F., Wang, G., Wang, J. S., Wang, X., Wang, Y., Wang, Z., Webb, J. C., Weidenkaff, P. C., Westfall, G. D., Wieman, H., Wilks, G., Wissink, S. W., Wu, J., Wu, X., Wu, Y., Xi, B., Xiao, Z. G., Xie, G., Xie, W., Xu, H., Xu, N., Xu, Q. H., Xu, Y., Xu, Z., Yan, G., Yan, Z., Yang, C., Yang, Q., Yang, S., Yang, Y., Ye, Z., Yi, L., Yip, K., Yu, N., Yu, Y., Zha, W., Zhang, C., Zhang, D., Zhang, J., Zhang, S., Zhang, X., Zhang, Y., Zhang, Z. J., Zhang, Z., Zhao, F., Zhao, J., Zhao, M., Zhou, C., Zhou, J., Zhou, S., Zhou, Y., Zhu, X., Zurek, M., Zyzak, M., STAR Collaboration, Abdulhamid, M. I., Aboona, B. E., Adam, J., Adams, J. R., Agakishiev, G., Aggarwal, I., Aggarwal, M. M., Ahammed, Z., Aitbaev, A., Alekseev, I., Anderson, D. M., Aparin, A., Aslam, S., Atchison, J., Averichev, G. S., Bairathi, V., Baker, W., Cap, J. G. Ball, Barish, K., Bhagat, P., Bhasin, A., Bhatta, S., Bordyuzhin, I. G., Brandenburg, J. D., Brandin, A. V., Cai, X. Z., Caines, H., Calderón~de~la~Barca~Sánchez, M., Cebra, D., Ceska, J., Chakaberia, I., Chan, B. K., Chang, Z., Chatterjee, A., Chen, D., Chen, J., Chen, J. H., Chen, Z., Cheng, J., Cheng, Y., Choudhury, S., Christie, W., Chu, X., Crawford, H. J., Dale-Gau, G., Das, A., Daugherity, M., Dedovich, T. G., Deppner, I. M., Derevschikov, A. A., Dhamija, A., Di Carlo, L., Didenko, L., Dixit, P., Dong, X., Drachenberg, J. L., Duckworth, E., Dunlop, J. C., Engelage, J., Eppley, G., Esumi, S., Evdokimov, O., Ewigleben, A., Eyser, O., Fatemi, R., Fazio, S., Feng, C. J., Feng, Y., Finch, E., Fisyak, Y., Flor, F. A., Fu, C., Geurts, F., Ghimire, N., Gibson, A., Gopal, K., Gou, X., Grosnick, D., Gupta, A., Hamed, A., Han, Y., Harasty, M. D., Harris, J. W., Harrison-Smith, H., He, W., He, X. H., He, Y., Hu, C., Hu, Q., Hu, Y., Huang, H., Huang, H. Z., Huang, S. L., Huang, T., Huang, X., Huang, Y., Humanic, T. J., Isenhower, D., Isshiki, M., Jacobs, W. W., Jalotra, A., Jena, C., Ji, Y., Jia, J., Jin, C., Ju, X., Judd, E. G., Kabana, S., Kabir, M. L., Kalinkin, D., Kang, K., Kapukchyan, D., Kauder, K., Ke, H. W., Keane, D., Kechechyan, A., Kelsey, M., Kimelman, B., Kiselev, A., Knospe, A. G., Ko, H. S., Kochenda, L., Korobitsin, A. A., Kravtsov, P., Kumar, L., Kumar, S., Elayavalli, R. Kunnawalkam, Lacey, R., Landgraf, J. M., Lebedev, A., Lednicky, R., Lee, J. H., Leung, Y. H., Lewis, N., Li, C., Li, W., Li, X., Li, Y., Li, Z., Liang, X., Liang, Y., Lin, T., Liu, C., Liu, F., Liu, H., Liu, L., Liu, T., Liu, X., Liu, Y., Liu, Z., Ljubicic, T., Llope, W. J., Lomicky, O., Longacre, R. S., Loyd, E. M., Lu, T., Lukow, N. S., Luo, X. F., Luong, V. B., Ma, L., Ma, R., Ma, Y. G., Magdy, N., Mallick, D., Margetis, S., Matis, H. S., Mazer, J. A., McNamara, G., Mi, K., Minaev, N. G., Mohanty, B., Mondal, M. M., Mooney, I., Morozov, D. A., Mudrokh, A., Nagy, M. I., Nain, A. S., Nam, J. D., Nasim, Md., Neff, D., Nelson, J. M., Nemes, D. B., Nie, M., Nigmatkulov, G., Niida, T., Nishitani, R., Nogach, L. V., Nonaka, T., Odyniec, G., Ogawa, A., Oh, S., Okorokov, V. A., Okubo, K., Page, B. S., Pak, R., Pan, J., Pandav, A., Pandey, A. K., Panebratsev, Y., Pani, T., Parfenov, P., Paul, A., Perkins, C., Pokhrel, B. R., Posik, M., Protzman, T., Pruthi, N. K., Putschke, J., Qin, Z., Qiu, H., Quintero, A., Racz, C., Radhakrishnan, S. K., Raha, N., Ray, R. L., Ritter, H. G., Robertson, C. W., Rogachevsky, O. V., Aguilar, M. A. Rosales, Roy, D., Ruan, L., Sahoo, A. K., Sahoo, N. R., Sako, H., Salur, S., Samigullin, E., Sato, S., Schmidke, W. B., Schmitz, N., Seger, J., Seto, R., Seyboth, P., Shah, N., Shahaliev, E., Shanmuganathan, P. V., Shao, T., Sharma, M., Sharma, N., Sharma, R., Sharma, S. R., Sheikh, A. I., Shen, D. Y., Shen, K., Shi, S. S., Shi, Y., Shou, Q. Y., Si, F., Singh, J., Singha, S., Sinha, P., Skoby, M. J., Söhngen, Y., Song, Y., Srivastava, B., Stanislaus, T. D. S., Stewart, D. J., Strikhanov, M., Stringfellow, B., Su, Y., Sun, C., Sun, X., Sun, Y., Surrow, B., Svirida, D. N., Sweger, Z. W., Tamis, A., Tang, A. H., Tang, Z., Taranenko, A., Tarnowsky, T., Thomas, J. H., Tlusty, D., Todoroki, T., Tokarev, M. V., Tomkiel, C. A., Trentalange, S., Tribble, R. E., Tribedy, P., Tsai, O. D., Tsang, C. Y., Tu, Z., Ullrich, T., Underwood, D. G., Upsal, I., Van Buren, G., Vasiliev, A. N., Verkest, V., Videbæk, F., Vokal, S., Voloshin, S. A., Wang, F., Wang, G., Wang, J. S., Wang, X., Wang, Y., Wang, Z., Webb, J. C., Weidenkaff, P. C., Westfall, G. D., Wieman, H., Wilks, G., Wissink, S. W., Wu, J., Wu, X., Wu, Y., Xi, B., Xiao, Z. G., Xie, G., Xie, W., Xu, H., Xu, N., Xu, Q. H., Xu, Y., Xu, Z., Yan, G., Yan, Z., Yang, C., Yang, Q., Yang, S., Yang, Y., Ye, Z., Yi, L., Yip, K., Yu, N., Yu, Y., Zha, W., Zhang, C., Zhang, D., Zhang, J., Zhang, S., Zhang, X., Zhang, Y., Zhang, Z. J., Zhang, Z., Zhao, F., Zhao, J., Zhao, M., Zhou, C., Zhou, J., Zhou, S., Zhou, Y., Zhu, X., Zurek, M., and Zyzak, M.

Abstract

We report the triton ($t$) production in mid-rapidity ($|y| <$ 0.5) Au+Au collisions at $\sqrt{s_\mathrm{NN}}$= 7.7--200 GeV measured by the STAR experiment from the first phase of the beam energy scan at the Relativistic Heavy Ion Collider (RHIC). The nuclear compound yield ratio ($\mathrm{N}_t \times \mathrm{N}_p/\mathrm{N}_d^2$), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity ($dN_{ch}/d\eta$) and follows a scaling behavior. The $dN_{ch}/d\eta$ dependence of the yield ratio is compared to calculations from coalescence and thermal models. Enhancements in the yield ratios relative to the coalescence baseline are observed in the 0\%-10\% most central collisions at 19.6 and 27 GeV, with a significance of 2.3$\sigma$ and 3.4$\sigma$, respectively, giving a combined significance of 4.1$\sigma$. The enhancements are not observed in peripheral collisions or model calculations without critical fluctuation, and decreases with a smaller $p_{T}$ acceptance. The physics implications of these results on the QCD phase structure and the production mechanism of light nuclei in heavy-ion collisions are discussed., Comment: 6 pages, 4 figures, Supplemental Material: http://link.aps.org/supplemental/10.1103/PhysRevLett.130.202301

Published
2022
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43. Pion, kaon, and (anti-)proton production in U+U Collisions at $\sqrt{s_{NN}}$ = 193 GeV measured with the STAR detector

Author

STAR Collaboration, Abdallah, M. S., Aboona, B. E., Adam, J., Adams, J. R., Adkins, J. K., Agakishiev, G., Aggarwal, I., Aggarwal, M. M., Ahammed, Z., Aitbaev, A., Alekseev, I., Anderson, D. M., Aparin, A., Atchison, J., Averichev, G. S., Bairathi, V., Baker, W., Cap, J. G. Ball, Barish, K., Bhagat, P., Bhasin, A., Bhatta, S., Bordyuzhin, I. G., Brandenburg, J. D., Brandin, A. V., Cai, X. Z., Caines, H., Sánchez, M. Calderón de la Barca, Cebra, D., Chakaberia, I., Chan, B. K., Chang, Z., Chattopadhyay, S., Chen, D., Chen, J., Chen, J. H., Chen, X., Chen, Z., Cheng, J., Choudhury, S., Christie, W., Chu, X., Crawford, H. J., Daugherity, M., Dedovich, T. G., Deppner, I. M., Derevschikov, A. A., Dhamija, A., Di Carlo, L., Didenko, L., Dixit, P., Dong, X., Drachenberg, J. L., Duckworth, E., Dunlop, J. C., Engelage, J., Eppley, G., Esumi, S., Evdokimov, O., Ewigleben, A., Eyser, O., Fatemi, R., Fawzi, F. M., Fazio, S., Feng, C. J., Feng, Y., Finch, E., Fisyak, Y., Francisco, A., Fu, C., Geurts, F., Ghimire, N., Gibson, A., Gopal, K., Gou, X., Grosnick, D., Gupta, A., Hamed, A., Han, Y., Harasty, M. D., Harris, J. W., Harrison, H., He, S., He, W., He, X. H., He, Y., Heppelmann, S., Hoffman, E., Hu, C., Hu, Q., Hu, Y., Huang, H., Huang, H. Z., Huang, S. L., Huang, T., Huang, X., Huang, Y., Humanic, T. J., Isenhower, D., Isshiki, M., Jacobs, W. W., Jena, C., Ji, Y., Jia, J., Jiang, K., Jin, C., Ju, X., Judd, E. G., Kabana, S., Kabir, M. L., Kalinkin, D., Kang, K., Kapukchyan, D., Kauder, K., Ke, H. W., Keane, D., Kechechyan, A., Kelsey, M., Kimelman, B., Kiselev, A., Knospe, A. G., Ko, H. S., Kochenda, L., Korobitsin, A. A., Kravtsov, P., Kumar, L., Kumar, S., Elayavalli, R. Kunnawalkam, Kwasizur, J. H., Lacey, R., Lan, S., Landgraf, J. M., Lebedev, A., Lednicky, R., Lee, J. H., Leung, Y. H., Lewis, N., Li, C., Li, W., Li, X., Li, Y., Li, Z., Liang, X., Liang, Y., Lin, T., Lin, Y., Liu, F., Liu, H., Liu, T., Liu, X., Liu, Y., Ljubicic, T., Llope, W. J., Longacre, R. S., Loyd, E., Lu, T., Lukow, N. S., Luo, X. F., Ma, L., Ma, R., Ma, Y. G., Magdy, N., Mallick, D., Manukhov, S. L., Margetis, S., Matis, H. S., Mazer, J. A., McNamara, G., Minaev, N. G., Mishra, D., Mohanty, B., Mondal, M. M., Mooney, I., Morozov, D. A., Nagy, M. I., Nain, A. S., Nam, J. D., Nasim, Md., Nayak, K., Neff, D., Nelson, J. M., Nemes, D. B., Nie, M., Nigmatkulov, G., Niida, T., Nishitani, R., Nogach, L. V., Nonaka, T., Nunes, A. S., Odyniec, G., Ogawa, A., Oh, S., Okorokov, V. A., Okubo, K., Page, B. S., Pak, R., Pan, J., Pandav, A., Pandey, A. K., Panebratsev, Y., Parfenov, P., Paul, A., Perkins, C., Pokhrel, B. R., Porter, J., Posik, M., Pruthi, N. K., Putschke, J., Qin, Z., Qiu, H., Quintero, A., Racz, C., Radhakrishnan, S. K., Raha, N., Ray, R. L., Ritter, H. G., Rogachevsky, O. V., Romero, J. L., Roy, D., Chowdhury, P. Roy, Ruan, L., Sahoo, A. K., Sahoo, N. R., Sako, H., Salur, S., Samigullin, E., Sato, S., Schmidke, W. B., Schmitz, N., Seger, J., Sergeeva, M., Seto, R., Seyboth, P., Shah, N., Shahaliev, E., Shanmuganathan, P. V., Shao, M., Shao, T., Sharma, R., Sheikh, A. I., Shen, D. Y., Shen, K., Shi, S. S., Shi, Y., Shou, Q. Y., Sichtermann, E. P., Singh, J., Singha, S., Sinha, P., Skoby, M. J., Söhngen, Y., Solyst, W., Song, Y., Srivastava, B., Stanislaus, T. D. S., Stewart, D. J., Strikhanov, M., Stringfellow, B., Sun, C., Sun, X. M., Sun, X., Sun, Y., Surrow, B., Svirida, D. N., Sweger, Z. W., Tang, A. H., Tang, Z., Taranenko, A., Tarnowsky, T., Thomas, J. H., Tlusty, D., Todoroki, T., Tokarev, M., Tomkiel, C. A., Trentalange, S., Tribble, R. E., Tribedy, P., Tripathy, S. K., Tsai, O. D., Tsang, C. Y., Tu, Z., Ullrich, T., Underwood, D. G., Upsal, I., Van Buren, G., Vasiliev, A. N., Verkest, V., Videbæk, F., Vokal, S., Voloshin, S. A., Wang, F., Wang, G., Wang, J. S., Wang, P., Wang, X., Wang, Y., Wang, Z., Webb, J. C., Weidenkaff, P. C., Westfall, G. D., Wielanek, D., Wieman, H., Wissink, S. W., Wu, J., Wu, Y., Xi, B., Xiao, Z. G., Xie, G., Xie, W., Xu, H., Xu, N., Xu, Q. H., Xu, Y., Xu, Z., Yan, G., Yan, Z., Yang, C., Yang, Q., Yang, S., Yang, Y., Ye, Z., Yi, L., Yip, K., Yu, Y., Zha, W., Zhang, C., Zhang, D., Zhang, J., Zhang, S., Zhang, Y., Zhang, Z. J., Zhang, Z., Zhao, F., Zhao, J., Zhao, M., Zhou, C., Zhou, J., Zhou, Y., Zhu, X., Zurek, M., Zyzak, M., STAR Collaboration, Abdallah, M. S., Aboona, B. E., Adam, J., Adams, J. R., Adkins, J. K., Agakishiev, G., Aggarwal, I., Aggarwal, M. M., Ahammed, Z., Aitbaev, A., Alekseev, I., Anderson, D. M., Aparin, A., Atchison, J., Averichev, G. S., Bairathi, V., Baker, W., Cap, J. G. Ball, Barish, K., Bhagat, P., Bhasin, A., Bhatta, S., Bordyuzhin, I. G., Brandenburg, J. D., Brandin, A. V., Cai, X. Z., Caines, H., Sánchez, M. Calderón de la Barca, Cebra, D., Chakaberia, I., Chan, B. K., Chang, Z., Chattopadhyay, S., Chen, D., Chen, J., Chen, J. H., Chen, X., Chen, Z., Cheng, J., Choudhury, S., Christie, W., Chu, X., Crawford, H. J., Daugherity, M., Dedovich, T. G., Deppner, I. M., Derevschikov, A. A., Dhamija, A., Di Carlo, L., Didenko, L., Dixit, P., Dong, X., Drachenberg, J. L., Duckworth, E., Dunlop, J. C., Engelage, J., Eppley, G., Esumi, S., Evdokimov, O., Ewigleben, A., Eyser, O., Fatemi, R., Fawzi, F. M., Fazio, S., Feng, C. J., Feng, Y., Finch, E., Fisyak, Y., Francisco, A., Fu, C., Geurts, F., Ghimire, N., Gibson, A., Gopal, K., Gou, X., Grosnick, D., Gupta, A., Hamed, A., Han, Y., Harasty, M. D., Harris, J. W., Harrison, H., He, S., He, W., He, X. H., He, Y., Heppelmann, S., Hoffman, E., Hu, C., Hu, Q., Hu, Y., Huang, H., Huang, H. Z., Huang, S. L., Huang, T., Huang, X., Huang, Y., Humanic, T. J., Isenhower, D., Isshiki, M., Jacobs, W. W., Jena, C., Ji, Y., Jia, J., Jiang, K., Jin, C., Ju, X., Judd, E. G., Kabana, S., Kabir, M. L., Kalinkin, D., Kang, K., Kapukchyan, D., Kauder, K., Ke, H. W., Keane, D., Kechechyan, A., Kelsey, M., Kimelman, B., Kiselev, A., Knospe, A. G., Ko, H. S., Kochenda, L., Korobitsin, A. A., Kravtsov, P., Kumar, L., Kumar, S., Elayavalli, R. Kunnawalkam, Kwasizur, J. H., Lacey, R., Lan, S., Landgraf, J. M., Lebedev, A., Lednicky, R., Lee, J. H., Leung, Y. H., Lewis, N., Li, C., Li, W., Li, X., Li, Y., Li, Z., Liang, X., Liang, Y., Lin, T., Lin, Y., Liu, F., Liu, H., Liu, T., Liu, X., Liu, Y., Ljubicic, T., Llope, W. J., Longacre, R. S., Loyd, E., Lu, T., Lukow, N. S., Luo, X. F., Ma, L., Ma, R., Ma, Y. G., Magdy, N., Mallick, D., Manukhov, S. L., Margetis, S., Matis, H. S., Mazer, J. A., McNamara, G., Minaev, N. G., Mishra, D., Mohanty, B., Mondal, M. M., Mooney, I., Morozov, D. A., Nagy, M. I., Nain, A. S., Nam, J. D., Nasim, Md., Nayak, K., Neff, D., Nelson, J. M., Nemes, D. B., Nie, M., Nigmatkulov, G., Niida, T., Nishitani, R., Nogach, L. V., Nonaka, T., Nunes, A. S., Odyniec, G., Ogawa, A., Oh, S., Okorokov, V. A., Okubo, K., Page, B. S., Pak, R., Pan, J., Pandav, A., Pandey, A. K., Panebratsev, Y., Parfenov, P., Paul, A., Perkins, C., Pokhrel, B. R., Porter, J., Posik, M., Pruthi, N. K., Putschke, J., Qin, Z., Qiu, H., Quintero, A., Racz, C., Radhakrishnan, S. K., Raha, N., Ray, R. L., Ritter, H. G., Rogachevsky, O. V., Romero, J. L., Roy, D., Chowdhury, P. Roy, Ruan, L., Sahoo, A. K., Sahoo, N. R., Sako, H., Salur, S., Samigullin, E., Sato, S., Schmidke, W. B., Schmitz, N., Seger, J., Sergeeva, M., Seto, R., Seyboth, P., Shah, N., Shahaliev, E., Shanmuganathan, P. V., Shao, M., Shao, T., Sharma, R., Sheikh, A. I., Shen, D. Y., Shen, K., Shi, S. S., Shi, Y., Shou, Q. Y., Sichtermann, E. P., Singh, J., Singha, S., Sinha, P., Skoby, M. J., Söhngen, Y., Solyst, W., Song, Y., Srivastava, B., Stanislaus, T. D. S., Stewart, D. J., Strikhanov, M., Stringfellow, B., Sun, C., Sun, X. M., Sun, X., Sun, Y., Surrow, B., Svirida, D. N., Sweger, Z. W., Tang, A. H., Tang, Z., Taranenko, A., Tarnowsky, T., Thomas, J. H., Tlusty, D., Todoroki, T., Tokarev, M., Tomkiel, C. A., Trentalange, S., Tribble, R. E., Tribedy, P., Tripathy, S. K., Tsai, O. D., Tsang, C. Y., Tu, Z., Ullrich, T., Underwood, D. G., Upsal, I., Van Buren, G., Vasiliev, A. N., Verkest, V., Videbæk, F., Vokal, S., Voloshin, S. A., Wang, F., Wang, G., Wang, J. S., Wang, P., Wang, X., Wang, Y., Wang, Z., Webb, J. C., Weidenkaff, P. C., Westfall, G. D., Wielanek, D., Wieman, H., Wissink, S. W., Wu, J., Wu, Y., Xi, B., Xiao, Z. G., Xie, G., Xie, W., Xu, H., Xu, N., Xu, Q. H., Xu, Y., Xu, Z., Yan, G., Yan, Z., Yang, C., Yang, Q., Yang, S., Yang, Y., Ye, Z., Yi, L., Yip, K., Yu, Y., Zha, W., Zhang, C., Zhang, D., Zhang, J., Zhang, S., Zhang, Y., Zhang, Z. J., Zhang, Z., Zhao, F., Zhao, J., Zhao, M., Zhou, C., Zhou, J., Zhou, Y., Zhu, X., Zurek, M., and Zyzak, M.

Abstract

We present the first measurements of transverse momentum spectra of $\pi^{\pm}$, $K^{\pm}$, $p(\bar{p})$ at midrapidity ($|y| < 0.1$) in U+U collisions at $\sqrt{s_{NN}}$ = 193 GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The centrality dependence of particle yields, average transverse momenta, particle ratios and kinetic freeze-out parameters are discussed. The results are compared with the published results from Au+Au collisions at $\sqrt{s_{NN}} =$ 200 GeV in STAR. The results are also compared to those from A Multi Phase Transport (AMPT) model., Comment: 17 pages, 14 figures and 7 tables; Replaced with the updated version published in Physical Review C

Published
2022
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44. Measurement of T-odd asymmetry in radiative K+ -> pi0 e+ nu gamma decay using OKA detector

Author

Polyarush, A. Yu., Akimenko, S. A., Artamonov, A. V., Bychkov, V. N., Donskov, S. V., Duka, V. A., Inyakin, A. V., Gorin, A. M., Gushchin, E. N., Filin, A. P., Filippov, S. N., Kekelidze, G. D., Kolosov, V. N., Kravtsov, V. I., Khaustov, G. V., Kholodenko, S. A., Khudyakov, A. A., Kudenko, Yu. G., Kulik, A. V., Kurshetsov, V. F., Lishin, V. A., Lysan, V. M., Medynsky, M. V., Obraztsov, V. F., Ohotnikov, A. V., Polyakov, V. A., Romanovsky, V. I., Rykalin, V. I., Sadovsky, A. S., Samoilenko, V. D., Tyurin, I. S., Tchikilev, O. G., Uvarov, V. A., Yushchenko, O. P., Zalikhanov, B. Zh., Polyarush, A. Yu., Akimenko, S. A., Artamonov, A. V., Bychkov, V. N., Donskov, S. V., Duka, V. A., Inyakin, A. V., Gorin, A. M., Gushchin, E. N., Filin, A. P., Filippov, S. N., Kekelidze, G. D., Kolosov, V. N., Kravtsov, V. I., Khaustov, G. V., Kholodenko, S. A., Khudyakov, A. A., Kudenko, Yu. G., Kulik, A. V., Kurshetsov, V. F., Lishin, V. A., Lysan, V. M., Medynsky, M. V., Obraztsov, V. F., Ohotnikov, A. V., Polyakov, V. A., Romanovsky, V. I., Rykalin, V. I., Sadovsky, A. S., Samoilenko, V. D., Tyurin, I. S., Tchikilev, O. G., Uvarov, V. A., Yushchenko, O. P., and Zalikhanov, B. Zh.

Abstract

The paper presents a measurement of the T-odd correlation in radiation decay \boldmath $K^+ \rightarrow \pi^{0} e^{+} \nu_{e} \gamma $ performed on the installation of the 101200 candidate events of the investigated decay were identified. Measured correlation $\xi_{\pi e \gamma}$ -is a mixed product of moments $e^{+}$, $\pi^{0}$, $\gamma$ in the kaon rest system, normalized by $M^{3}_{K}$. To assess the asymmetry of the distribution by $\xi_{\pi e \gamma}$ the value used is $A_{\xi}= \frac {N_{+}-N_{-}} {N_{+}+N_{-}}$, where $N_{+(-)}$ is the number of events with $\xi$ greater than (less than) zero. For the $A_{\xi}$ asymmetry, the value is obtained $A_{\xi} = (+0.1 \pm 3.9($stat.$) \pm1.7($syst.$))\times10^{-3}$ or $|A_{\xi}| < 5.4\times10^{-3} (90\%~ CL)$

Published
2022
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45. SN 2020wnt: a slow-evolving carbon-rich superluminous supernova with no O II lines and a bumpy light curve

Author

Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), European Commission, National Aeronautics and Space Administration (US), Gutiérrez, Claudia P., Pastorello, Andrea, Bersten, M. C., Benetti, Stefano, Orellana, M., Fiore, Achille, Karamehmetoglu, Emir, Kravtsov, T., Reguitti, Andrea, Reynolds, Thomas M., Valerin, Giorgio, Mazzali, Paolo A., Sullivan, Mark, Cai, Y-Z, Elias-Rosa, Nancy, Fraser, Morgan, Hsiao, E. Y., Kankare, E., Kotak, R., Kuncarayakti, Hanindyo, Li, Z., Mattila, Seppo, Mo, Jianhong, Morán, Sebastián, Ochner, Paolo, Shahbandeh, Melissa, Tomasella, Lina, Wang, X., Yan, S., Zhang, J., Zhang, T., Stritzinger, Maximilian, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), European Commission, National Aeronautics and Space Administration (US), Gutiérrez, Claudia P., Pastorello, Andrea, Bersten, M. C., Benetti, Stefano, Orellana, M., Fiore, Achille, Karamehmetoglu, Emir, Kravtsov, T., Reguitti, Andrea, Reynolds, Thomas M., Valerin, Giorgio, Mazzali, Paolo A., Sullivan, Mark, Cai, Y-Z, Elias-Rosa, Nancy, Fraser, Morgan, Hsiao, E. Y., Kankare, E., Kotak, R., Kuncarayakti, Hanindyo, Li, Z., Mattila, Seppo, Mo, Jianhong, Morán, Sebastián, Ochner, Paolo, Shahbandeh, Melissa, Tomasella, Lina, Wang, X., Yan, S., Zhang, J., Zhang, T., and Stritzinger, Maximilian

Abstract

We present the analysis of SN 2020wnt, an unusual hydrogen-poor superluminous supernova (SLSN-I), at a redshift of 0.032. The light curves of SN 2020wnt are characterized by an early bump lasting ∼5 d, followed by a bright main peak. The SN reaches a peak absolute magnitude of Mmaxr=−20.52±0.03 mag at ∼77.5 d from explosion. This magnitude is at the lower end of the luminosity distribution of SLSNe-I, but the rise-time is one of the longest reported to date. Unlike other SLSNe-I, the spectra of SN 2020wnt do not show O II, but strong lines of C II and Si II are detected. Spectroscopically, SN 2020wnt resembles the Type Ic SN 2007gr, but its evolution is significantly slower. Comparing the bolometric light curve to hydrodynamical models, we find that SN 2020wnt luminosity can be explained by radioactive powering. The progenitor of SN 2020wnt is likely a massive and extended star with a pre-SN mass of 80 M⊙ and a pre-SN radius of 15 R⊙ that experiences a very energetic explosion of 45 × 1051 erg, producing 4 M⊙ of 56Ni. In this framework, the first peak results from a post-shock cooling phase for an extended progenitor, and the luminous main peak is due to a large nickel production. These characteristics are compatible with the pair-instability SN scenario. We note, however, that a significant contribution of interaction with circumstellar material cannot be ruled out.

Published
2022

46. Forbidden hugs in pandemic times III. Observations of the luminous red nova AT 2021biy in the nearby galaxy NGC 4631

Author

Cai, Y-Z, Pastorello, A., Fraser, M., Wang, X-F, Filippenko, A., Reguitti, A., Patra, K. C., Goranskij, V. P., Barsukova, E. A., Brink, T. G., Elias-Rosa, N., Stevance, H. F., Zheng, W., Yang, Y., Atapin, K. E., Benetti, S., de Boer, T. J. L., Bose, S., Burke, J., Byrne, R., Cappellaro, E., Chambers, K. C., Chen, W-L, Emami, N., Gao, H., Hiramatsu, D., Howell, D. A., Huber, M. E., Kankare, E., Kelly, P. L., Kotak, R., Kravtsov, T., Lander, V. Yu, Li, Z-T, Lin, C-C, Lundqvist, P., Magnier, E. A., Malygin, E. A., Maslennikova, N. A., Matilainen, K., Mazzali, P. A., McCully, C., Mo, J., Moran, S., Newsome, M., Oparin, D., Gonzalez, E. Padilla, Reynolds, T. M., Shatsky, N., Smartt, S. J., Smith, K. W., Stritzinger, M. D., Tatarnikov, A. M., Terreran, G., Uklein, R., Valerin, G., Vallely, P. J., Vozyakova, O. V., Wainscoat, R., Yan, S-Y, Zhang, J-J, Zhang, T-M, Zheltoukhov, S. G., Dastidar, R., Fulton, M., Galbany, L., Gangopadhyay, A., Ge, H-W, Gutierrez, C. P., Lin, H., Misra, K., Ou, Z-W, Salmaso, Nico, Tartaglia, L., Xiao, L., Zhang, X-H, Cai, Y-Z, Pastorello, A., Fraser, M., Wang, X-F, Filippenko, A., Reguitti, A., Patra, K. C., Goranskij, V. P., Barsukova, E. A., Brink, T. G., Elias-Rosa, N., Stevance, H. F., Zheng, W., Yang, Y., Atapin, K. E., Benetti, S., de Boer, T. J. L., Bose, S., Burke, J., Byrne, R., Cappellaro, E., Chambers, K. C., Chen, W-L, Emami, N., Gao, H., Hiramatsu, D., Howell, D. A., Huber, M. E., Kankare, E., Kelly, P. L., Kotak, R., Kravtsov, T., Lander, V. Yu, Li, Z-T, Lin, C-C, Lundqvist, P., Magnier, E. A., Malygin, E. A., Maslennikova, N. A., Matilainen, K., Mazzali, P. A., McCully, C., Mo, J., Moran, S., Newsome, M., Oparin, D., Gonzalez, E. Padilla, Reynolds, T. M., Shatsky, N., Smartt, S. J., Smith, K. W., Stritzinger, M. D., Tatarnikov, A. M., Terreran, G., Uklein, R., Valerin, G., Vallely, P. J., Vozyakova, O. V., Wainscoat, R., Yan, S-Y, Zhang, J-J, Zhang, T-M, Zheltoukhov, S. G., Dastidar, R., Fulton, M., Galbany, L., Gangopadhyay, A., Ge, H-W, Gutierrez, C. P., Lin, H., Misra, K., Ou, Z-W, Salmaso, Nico, Tartaglia, L., Xiao, L., and Zhang, X-H

Abstract

We present an observational study of the luminous red nova (LRN) AT 2021biy in the nearby galaxy NGC 4631. The field of the object was routinely imaged during the pre-eruptive stage by synoptic surveys, but the transient was detected only at a few epochs from similar to 231 days before maximum brightness. The LRN outburst was monitored with unprecedented cadence both photometrically and spectroscopically. AT 2021biy shows a short-duration blue peak, with a bolometric luminosity of similar to 1.6 x 10(41) erg s(-1), followed by the longest plateau among LRNe to date, with a duration of 210 days. A late-time hump in the light curve was also observed, possibly produced by a shell-shell collision. AT 2021biy exhibits the typical spectral evolution of LRNe. Early-time spectra are characterised by a blue continuum and prominent H emission lines. Then, the continuum becomes redder, resembling that of a K-type star with a forest of metal absorption lines during the plateau phase. Finally, late-time spectra show a very red continuum (T-BB approximate to 2050 K) with molecular features (e.g., TiO) resembling those of M-type stars. Spectropolarimetric analysis indicates that AT 2021biy has local dust properties similar to those of V838 Mon in the Milky Way Galaxy. Inspection of archival Hubble Space Telescope data taken on 2003 August 3 reveals a similar to 20 M-circle dot progenitor candidate with log (L/L-circle dot)= 5.0 dex and T-eff = 5900 K at solar metallicity. The above luminosity and colour match those of a luminous yellow supergiant. Most likely, this source is a close binary, with a 17-24 M(circle dot)( )primary component.

Published
2022

47. SN 2020wnt:a slow-evolving carbon-rich superluminous supernova with no O II lines and a bumpy light curve

Author

Gutierrez, C. P., Pastorello, A., Bersten, M., Benetti, S., Orellana, M., Fiore, A., Karamehmetoglu, E., Kravtsov, T., Reguitti, A., Reynolds, T. M., Valerin, G., Mazzali, P., Sullivan, M., Cai, Y-Z, Elias-Rosa, N., Fraser, M., Hsiao, E. Y., Kankare, E., Kotak, R., Kuncarayakti, H., Li, Z., Mattila, S., Mo, J., Moran, S., Ochner, P., Shahbandeh, M., Tomasella, L., Wang, X., Yan, S., Zhang, J., Zhang, T., Stritzinger, M. D., Gutierrez, C. P., Pastorello, A., Bersten, M., Benetti, S., Orellana, M., Fiore, A., Karamehmetoglu, E., Kravtsov, T., Reguitti, A., Reynolds, T. M., Valerin, G., Mazzali, P., Sullivan, M., Cai, Y-Z, Elias-Rosa, N., Fraser, M., Hsiao, E. Y., Kankare, E., Kotak, R., Kuncarayakti, H., Li, Z., Mattila, S., Mo, J., Moran, S., Ochner, P., Shahbandeh, M., Tomasella, L., Wang, X., Yan, S., Zhang, J., Zhang, T., and Stritzinger, M. D.

Abstract

We present the analysis of SN 2020wnt, an unusual hydrogen-poor superluminous supernova (SLSN-I), at a redshift of 0.032. The light curves of SN 2020wnt are characterized by an early bump lasting similar to 5 d, followed by a bright main peak. The SN reaches a peak absolute magnitude of M-r(max) = -20.52 +/- 0.03 mag at similar to 77.5 d from explosion. This magnitude is at the lower end of the luminosity distribution of SLSNe-I, but the rise-time is one of the longest reported to date. Unlike other SLSNe-I, the spectra of SN 2020wnt do not show O II, but strong lines of C II and Si II are detected. Spectroscopically, SN 2020wnt resembles the Type Ic SN 2007gr, but its evolution is significantly slower. Comparing the bolometric light curve to hydrodynamical models, we find that SN 2020wnt luminosity can be explained by radioactive powering. The progenitor of SN 2020wnt is likely a massive and extended star with a pre-SN mass of 80 M-circle dot and a pre-SN radius of 15 R-circle dot that experiences a very energetic explosion of 45 x 10(51) erg, producing 4 M-circle dot of Ni-56. In this framework, the first peak results from a post-shock cooling phase for an extended progenitor, and the luminous main peak is due to a large nickel production. These characteristics are compatible with the pair-instability SN scenario. We note, however, that a significant contribution of interaction with circumstellar material cannot be ruled out.

Published
2022

48. X-ray Polarization Observations of BL Lacertae

Author

Middei, Riccardo, Liodakis, Ioannis, Perri, Matteo, Puccetti, Simonetta, Cavazzuti, Elisabetta, Di Gesu, Laura, Ehlert, Steven R., Madejski, Grzegorz, Marscher, Alan P., Marshall, Herman L., Muleri, Fabio, Negro, Michela, Jorstad, Svetlana G., Agís-González, Beatriz, Agudo, Iván, Bonnoli, Giacomo, Bernardos, Maria I., Casanova, Víctor, García-Comas, Maya, Husillos, César, Marchini, Alessandro, Sota, Alfredo, Kouch, Pouya M., 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, Myserlis, Ioannis, Hales, Antonio, Kameno, Seiji, Kneissl, Ruediger, Messias, Hugo, Nagai, Hiroshi, Blinov, Dmitry, Bourbah, Ioakeim G., Kiehlmann, Sebastian, Kontopodis, Evangelos, Mandarakas, Nikos, Romanopoulos, Stylianos, Skalidis, Raphael, Vervelaki, Anna, Masiero, Joseph R., Mawet, Dimitri, Millar-Blanchaer, Maxwell A., Panopoulou, Georgia V., Tinyanont, Samaporn, Berdyugin, Andrei V., Kagitani, Masato, Kravtsov, Vadim, Sakanoi, Takeshi, Imazawa, Ryo, Sasada, Mahito, Fukazawa, Yasushi, Kawabata, Koji S., Uemura, Makoto, Mizuno, Tsunefumi, Nakaoka, Tatsuya, Akitaya, Hiroshi, Gurwell, Mark, Rao, Ramprasad, Di Lalla, Niccoló, Cibrario, Nicoló, Donnarumma, Immacolata, Kim, Dawoon E., Omodei, Nicola, Pacciani, Luigi, 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, Niccoló, Capitanio, Fiamma, Castellano, Simone, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, 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, Karas, Vladimir, 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, Ng, C. -Y., O'Dell, Stephen L., Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Romani, Roger W., Sgró, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, 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., Wu, Kinwah, Xie, Fei, Zane, Silvia, Middei, Riccardo, Liodakis, Ioannis, Perri, Matteo, Puccetti, Simonetta, Cavazzuti, Elisabetta, Di Gesu, Laura, Ehlert, Steven R., Madejski, Grzegorz, Marscher, Alan P., Marshall, Herman L., Muleri, Fabio, Negro, Michela, Jorstad, Svetlana G., Agís-González, Beatriz, Agudo, Iván, Bonnoli, Giacomo, Bernardos, Maria I., Casanova, Víctor, García-Comas, Maya, Husillos, César, Marchini, Alessandro, Sota, Alfredo, Kouch, Pouya M., 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, Myserlis, Ioannis, Hales, Antonio, Kameno, Seiji, Kneissl, Ruediger, Messias, Hugo, Nagai, Hiroshi, Blinov, Dmitry, Bourbah, Ioakeim G., Kiehlmann, Sebastian, Kontopodis, Evangelos, Mandarakas, Nikos, Romanopoulos, Stylianos, Skalidis, Raphael, Vervelaki, Anna, Masiero, Joseph R., Mawet, Dimitri, Millar-Blanchaer, Maxwell A., Panopoulou, Georgia V., Tinyanont, Samaporn, Berdyugin, Andrei V., Kagitani, Masato, Kravtsov, Vadim, Sakanoi, Takeshi, Imazawa, Ryo, Sasada, Mahito, Fukazawa, Yasushi, Kawabata, Koji S., Uemura, Makoto, Mizuno, Tsunefumi, Nakaoka, Tatsuya, Akitaya, Hiroshi, Gurwell, Mark, Rao, Ramprasad, Di Lalla, Niccoló, Cibrario, Nicoló, Donnarumma, Immacolata, Kim, Dawoon E., Omodei, Nicola, Pacciani, Luigi, 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, Niccoló, Capitanio, Fiamma, Castellano, Simone, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, 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, Karas, Vladimir, 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, Ng, C. -Y., O'Dell, Stephen L., Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Peirson, Abel L., Pesce-Rollins, Melissa, Petrucci, Pierre-Olivier, Pilia, Maura, Possenti, Andrea, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Romani, Roger W., Sgró, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, 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., Wu, Kinwah, Xie, Fei, and Zane, Silvia

Abstract

Blazars are a class of jet-dominated active galactic nuclei with a typical double-humped spectral energy distribution. It is of common consensus the Synchrotron emission to be responsible for the low frequency peak, while the origin of the high frequency hump is still debated. The analysis of X-rays and their polarization can provide a valuable tool to understand the physical mechanisms responsible for the origin of high-energy emission of blazars. We report the first observations of BL Lacertae performed with the Imaging X-ray Polarimetry Explorer ({IXPE}), from which an upper limit to the polarization degree $\Pi_X<$12.6\% was found in the 2-8 keV band. We contemporaneously measured the polarization in radio, infrared, and optical wavelengths. Our multiwavelength polarization analysis disfavors a significant contribution of proton synchrotron radiation to the X-ray emission at these epochs. Instead, it supports a leptonic origin for the X-ray emission in BL Lac., Comment: 17 pages, 5 figures, accepted for publication in ApJL

Published
2022
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49. Performance characterization and near-realtime monitoring of MUSE adaptive optics modes at Paranal

Author

Wevers, T., Selman, F. J., Reyes, A., Vega, M., Hartke, J., Bian, F., Beltramo-Martin, O., Fétick, R., Kamann, S., Kolb, J., Kravtsov, T., Moya, C., Neichel, B., Oberti, S., Reyes, C., Valenti, E., Wevers, T., Selman, F. J., Reyes, A., Vega, M., Hartke, J., Bian, F., Beltramo-Martin, O., Fétick, R., Kamann, S., Kolb, J., Kravtsov, T., Moya, C., Neichel, B., Oberti, S., Reyes, C., and Valenti, E.

Abstract

The Multi Unit Spectroscopic Explorer (MUSE) is an integral field spectrograph on the Very Large Telescope Unit Telescope 4, capable of laser guide star assisted and tomographic adaptive optics using the GALACSI module. Its observing capabilities include a wide field (1 square arcmin), ground layer AO mode (WFM-AO) and a narrow field (7.5"x7.5"), laser tomography AO mode (NFM-AO). The latter has had several upgrades in the 4 years since commissioning, including an optimisation of the control matrices for the AO system and a new sub-electron noise detector for its infra-red low order wavefront sensor. We set out to quantify the NFM-AO system performance by analysing $\sim$230 spectrophotometric standard star observations taken over the last 3 years. To this end we expand upon previous work, designed to facilitate analysis of the WFM-AO system performance. We briefly describe the framework that will provide a user friendly, semi-automated way for system performance monitoring during science operations. We provide the results of our performance analysis, chiefly through the measured Strehl ratio and full width at half maximum (FWHM) of the core of the point spread function (PSF) using two PSF models, and correlations with atmospheric conditions. These results will feed into a range of applications, including providing a more accurate prediction of the system performance as implemented in the exposure time calculator, and the associated optimization of the scientific output for a given set of limiting atmospheric conditions., Comment: SPIE proceedings (2022), Observatory Operations: Strategies, Processes, and Systems IX

Published
2022
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50. Polarized Blazar X-rays imply particle acceleration in shocks

Author

Liodakis, Ioannis, Marscher, Alan P., Agudo, Iván, Berdyugin, Andrei V., Bernardos, Maria I., Bonnoli, Giacomo, Borman, George A., Casadio, Carolina, Casanova, Víctor, Cavazzuti, Elisabetta, Cavero, Nicole Rodriguez, Di Gesu, Laura, Di Lalla, Niccoló, Donnarumma, Immacolata, Ehlert, Steven R., Errando, Manel, Escudero, Juan, García-Comas, Maya, Agís-González, Beatriz, Husillos, César, Jormanainen, Jenni, Jorstad, Svetlana G., Kagitani, Masato, Kopatskaya, Evgenia N., Kravtsov, Vadim, Krawczynski, Henric, Lindfors, Elina, Larionova, Elena G., Madejski, Grzegorz M., Marin, Frédéric, Marchini, Alessandro, Marshall, Herman L., Morozova, Daria A., Massaro, Francesco, Masiero, Joseph R., Mawet, Dimitri, Middei, Riccardo, Millar-Blanchaer, Maxwell A., Myserlis, Ioannis, Negro, Michela, Nilsson, Kari, O'Dell, Stephen L., Omodei, Nicola, Pacciani, Luigi, Paggi, Alessandro, Panopoulou, Georgia V., Peirson, Abel L., Perri, Matteo, Petrucci, Pierre-Olivier, Poutanen, Juri, Puccetti, Simonetta, Romani, Roger W., Sakanoi, Takeshi, Savchenko, Sergey S., Sota, Alfredo, Tavecchio, Fabrizio, Tinyanont, Samaporn, Vasilyev, Andrey A., Weaver, Zachary R., Zhovtan, Alexey V., Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccoló, Capitanio, Fiamma, Castellano, Simone, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, 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, Karas, Vladimir, Kitaguchi, Takao, Kolodziejczak, Jeffery J., La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marinucci, Andrea, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Ng, Stephen C. -Y., Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Sgró, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Tamagawa, Toru, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicolas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, Zane, Silvia, Liodakis, Ioannis, Marscher, Alan P., Agudo, Iván, Berdyugin, Andrei V., Bernardos, Maria I., Bonnoli, Giacomo, Borman, George A., Casadio, Carolina, Casanova, Víctor, Cavazzuti, Elisabetta, Cavero, Nicole Rodriguez, Di Gesu, Laura, Di Lalla, Niccoló, Donnarumma, Immacolata, Ehlert, Steven R., Errando, Manel, Escudero, Juan, García-Comas, Maya, Agís-González, Beatriz, Husillos, César, Jormanainen, Jenni, Jorstad, Svetlana G., Kagitani, Masato, Kopatskaya, Evgenia N., Kravtsov, Vadim, Krawczynski, Henric, Lindfors, Elina, Larionova, Elena G., Madejski, Grzegorz M., Marin, Frédéric, Marchini, Alessandro, Marshall, Herman L., Morozova, Daria A., Massaro, Francesco, Masiero, Joseph R., Mawet, Dimitri, Middei, Riccardo, Millar-Blanchaer, Maxwell A., Myserlis, Ioannis, Negro, Michela, Nilsson, Kari, O'Dell, Stephen L., Omodei, Nicola, Pacciani, Luigi, Paggi, Alessandro, Panopoulou, Georgia V., Peirson, Abel L., Perri, Matteo, Petrucci, Pierre-Olivier, Poutanen, Juri, Puccetti, Simonetta, Romani, Roger W., Sakanoi, Takeshi, Savchenko, Sergey S., Sota, Alfredo, Tavecchio, Fabrizio, Tinyanont, Samaporn, Vasilyev, Andrey A., Weaver, Zachary R., Zhovtan, Alexey V., Antonelli, Lucio A., Bachetti, Matteo, Baldini, Luca, Baumgartner, Wayne H., Bellazzini, Ronaldo, Bianchi, Stefano, Bongiorno, Stephen D., Bonino, Raffaella, Brez, Alessandro, Bucciantini, Niccoló, Capitanio, Fiamma, Castellano, Simone, Ciprini, Stefano, Costa, Enrico, De Rosa, Alessandra, Del Monte, Ettore, 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, Karas, Vladimir, Kitaguchi, Takao, Kolodziejczak, Jeffery J., La Monaca, Fabio, Latronico, Luca, Maldera, Simone, Manfreda, Alberto, Marinucci, Andrea, Matt, Giorgio, Mitsuishi, Ikuyuki, Mizuno, Tsunefumi, Muleri, Fabio, Ng, Stephen C. -Y., Oppedisano, Chiara, Papitto, Alessandro, Pavlov, George G., Pesce-Rollins, Melissa, Pilia, Maura, Possenti, Andrea, Ramsey, Brian D., Rankin, John, Ratheesh, Ajay, Sgró, Carmelo, Slane, Patrick, Soffitta, Paolo, Spandre, Gloria, Tamagawa, Toru, Taverna, Roberto, Tawara, Yuzuru, Tennant, Allyn F., Thomas, Nicolas E., Tombesi, Francesco, Trois, Alessio, Tsygankov, Sergey, Turolla, Roberto, Vink, Jacco, Weisskopf, Martin C., Wu, Kinwah, Xie, Fei, and Zane, Silvia

Abstract

Most of the light from blazars, active galactic nuclei with jets of magnetized plasma that point nearly along the line of sight, is produced by high-energy particles, up to $\sim 1$ TeV. Although the jets are known to be ultimately powered by a supermassive black hole, how the particles are accelerated to such high energies has been an unanswered question. The process must be related to the magnetic field, which can be probed by observations of the polarization of light from the jets. Measurements of the radio to optical polarization - the only range available until now - probe extended regions of the jet containing particles that left the acceleration site days to years earlier (Jorstad et al., 2005; Marin et al., 2018; Blinov et al., 2021), and hence do not directly explore the acceleration mechanism, as could X-ray measurements. Here we report the detection of X-ray polarization from the blazar Markarian~501 (Mrk~501). We measure an X-ray linear polarization degree $\Pi_X \sim10\%$, a factor of $\sim2$ higher than the value at optical wavelengths, with a polarization angle parallel to the radio jet. This points to a shock front as the source of particle acceleration, and also implies that the plasma becomes increasingly turbulent with distance from the shock., Comment: 34 pages, 4 figures, 4 tables

Published
2022
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