Accretion geometry of the neutron star low mass X-ray binary Cyg X-2 from X-ray polarization measurements-Reference-Cited by-同舟云学术

Accretion geometry of the neutron star low mass X-ray binary Cyg X-2 from X-ray polarization measurements

Published:2022-12-20 Issue:3 Volume:519 Page:3681-3690
ISSN:0035-8711
Container-title:Monthly Notices of the Royal Astronomical Society
language:en
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Author:

Farinelli R¹^ORCID,Fabiani S²,Poutanen J³⁴,Ursini F⁵,Ferrigno C⁶,Bianchi S⁵,Cocchi M⁷,Capitanio F²,De Rosa A²,Gnarini A⁵,Kislat F⁸,Matt G⁵,Mikusincova R⁵,Muleri F²,Agudo I⁹,Antonelli L A¹⁰¹¹,Bachetti M⁷,Baldini L¹²¹³,Baumgartner W H¹⁴,Bellazzini R¹²,Bongiorno S D¹⁴,Bonino R¹⁵¹⁶,Brez A¹²,Bucciantini N¹⁷¹⁸¹⁹,Castellano S¹²,Cavazzuti E²⁰,Ciprini S¹¹²¹,Costa E²,Del Monte E²,Di Gesu L²⁰,Di Lalla N²²,Di Marco A²,Donnarumma I²⁰,Doroshenko V²³,Dovčiak M²⁴,Ehlert S R¹⁴,Enoto T²⁵,Evangelista Y²,Ferrazzoli R²,Garcia J A²⁶,Gunji S²⁷,Hayashida K²⁸,Heyl J²⁹,Iwakiri W³⁰,Jorstad S G³¹³²,Karas V²⁴,Kitaguchi T²⁵,Kolodziejczak J J¹⁴,Krawczynski H³³,La Monaca F²,Latronico L¹⁵,Liodakis I³⁴,Maldera S¹⁵,Manfreda A¹²,Marin F³⁵,Marscher A P³¹,Marshall H L³⁶,Mitsuishi I³⁷,Mizuno T³⁸,Ng C-Y³⁹,O’Dell S L¹⁴,Omodei N²²,Oppedisano C¹⁵,Papitto A¹⁰,Pavlov G G⁴⁰,Peirson A L²²,Perri M¹⁰¹¹,Pesce-Rollins M¹²,Petrucci P O⁴¹,Pilia M⁷,Possenti A⁷,Puccetti S¹¹,Ramsey B D¹⁴,Rankin J²,Ratheesh A²,Romani R W²²,Sgrò C¹²,Slane P⁴²,Soffitta P²,Spandre G¹²,Tamagawa T²⁵,Tavecchio F⁴³,Taverna R⁴⁴,Tawara Y³⁷,Tennant A F¹⁴,Thomas N E¹⁴,Tombesi F²¹⁴⁵⁴⁶,Trois A⁷,Tsygankov S S³⁴,Turolla R⁴⁴⁴⁷,Vink J⁴⁸,Weisskopf M C¹⁴,Wu K⁴⁷,Xie F²⁴⁹,Zane S⁴⁷

Affiliation:

1. INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna , Via P. Gobetti 101, I-40129 Bologna, Italy

2. INAF – IAPS , via del Fosso del Cavaliere 100, I-00113 Roma, Italy

3. Department of Physics and Astronomy , FI-20014 University of Turku, Finland

4. Space Research Institute of the Russian Academy of Sciences , Profsoyuznaya Str. 84/32, 117997 Moscow, Russia

5. Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre , Via della Vasca Navale 84, I-00146 Roma, Italy

6. Department of Astronomy, University of Geneva , Ch. d’Ecogia 16, CH-1290 Versoix, Geneva, Switzerland

7. INAF – Osservatorio Astronomico di Cagliari , via della Scienza 5, I-09047 Selargius (CA), Italy

8. University of New Hampshire, Department of Physics & Astronomy and Space Science Center , 8 College Rd, Durham, NH 03824, USA

9. Instituto de Astrofísica de Andalucía-CSIC , Glorieta de la Astronomía s/n, E-18008 Granada, Spain

10. INAF Osservatorio Astronomico di Roma , Via Frascati 33, I-00078 Monte Porzio Catone (RM), Italy

11. Space Science Data Center, Agenzia Spaziale Italiana , Via del Politecnico snc, I-00133 Roma, Italy

12. Istituto Nazionale di Fisica Nucleare , Sezione di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy

13. Dipartimento di Fisica, Università di Pisa , Largo B. Pontecorvo 3, I-56127 Pisa, Italy

14. NASA Marshall Space Flight Center , Huntsville, AL 35812, USA

15. Istituto Nazionale di Fisica Nucleare , Sezione di Torino, Via Pietro Giuria 1, I-10125 Torino, Italy

16. Dipartimento di Fisica, Università degli Studi di Torino , Via Pietro Giuria 1, I-10125 Torino, Italy

17. INAF Osservatorio Astrofisico di Arcetri , Largo Enrico Fermi 5, I-50125 Firenze, Italy

18. Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze , Via Sansone 1, I-50019 Sesto Fiorentino (FI), Italy

19. Istituto Nazionale di Fisica Nucleare, Sezione di Firenze , Via Sansone 1, I-50019 Sesto Fiorentino (FI), Italy

20. ASI - Agenzia Spaziale Italiana , Via del Politecnico snc, I-00133 Roma, Italy

21. Istituto Nazionale di Fisica Nucleare , Sezione di Roma ‘Tor Vergata’, Via della Ricerca Scientifica 1, I-00133 Roma, Italy

22. Department of Physics and Kavli Institute for Particle Astrophysics and Cosmology, Stanford University , Stanford, California 94305, USA

23. Institut für Astronomie und Astrophysik, Universität Tübingen , Sand 1, D-72076 Tübingen, Germany

24. Astronomical Institute of the Czech Academy of Sciences , Boční II 1401/1, 14100 Praha 4, Czech Republic

25. RIKEN Cluster for Pioneering Research , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan

26. California Institute of Technology , Pasadena, CA 91125, USA

27. Yamagata University , 1-4-12 Kojirakawa-machi, Yamagata-shi 990-8560, Japan

28. Osaka University , 1-1 Yamadaoka, Suita, Osaka 565-0871, Japan

29. University of British Columbia , Vancouver, BC V6T 1Z4, Canada

30. Department of Physics, Faculty of Science and Engineering , Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan

31. Institute for Astrophysical Research, Boston University , 725 Commonwealth Avenue, Boston, MA 02215, USA

32. Department of Astrophysics, St. Petersburg State University , Universitetsky pr. 28, Petrodvoretz, 198504 St. Petersburg, Russia

33. Physics Department and McDonnell Center for the Space Sciences, Washington University in St. Louis, St. Louis , MO 63130, USA

34. Finnish Centre for Astronomy with ESO , FI-20014 University of Turku, Finland

35. Université de Strasbourg , CNRS, Observatoire Astronomique de Strasbourg, UMR 7550, F-67000 Strasbourg, France

36. MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, MA 02139, USA

37. Graduate School of Science, Division of Particle and Astrophysical Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan

38. Hiroshima Astrophysical Science Center, Hiroshima University , 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan

39. Department of Physics, The University of Hong Kong , Pokfulam, Hong Kong

40. Department of Astronomy and Astrophysics, Pennsylvania State University , University Park, PA 16802, USA

41. Université Grenoble Alpes , CNRS, IPAG, F-38000 Grenoble, France

42. Center for Astrophysics, Harvard & Smithsonian , 60 Garden St, Cambridge, MA 02138, USA

43. INAF Osservatorio Astronomico di Brera , Via E. Bianchi 46, I-23807 Merate (LC), Italy

44. Dipartimento di Fisica e Astronomia, Università degli Studi di Padova , Via Marzolo 8, I-35131 Padova, Italy

45. Dipartimento di Fisica, Università degli Studi di Roma ‘Tor Vergata’ , Via della Ricerca Scientifica 1, I-00133 Roma, Italy

46. Department of Astronomy, University of Maryland , College Park, Maryland 20742, USA

47. Mullard Space Science Laboratory, University College London , Holmbury St Mary, Dorking, Surrey RH5 6NT, UK

48. Anton Pannekoek Institute for Astronomy & GRAPPA, University of Amsterdam , Science Park 904, NL-1098 XH Amsterdam, The Netherlands

49. Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology , Guangxi University, Nanning 530004, China

Abstract

ABSTRACT We report spectro-polarimetric results of an observational campaign of the bright neutron star low-mass X-ray binary Cyg X-2 simultaneously observed by IXPE, NICER, and INTEGRAL. Consistently with previous results, the broad-band spectrum is characterized by a lower-energy component, attributed to the accretion disc with kTin ≈ 1 keV, plus unsaturated Comptonization in thermal plasma with temperature kTe = 3 keV and optical depth τ ≈ 4, assuming a slab geometry. We measure the polarization degree in the 2–8 keV band P = 1.8 ± 0.3 per cent and polarization angle ϕ = 140° ± 4°, consistent with the previous X-ray polarimetric measurements by OSO-8 as well as with the direction of the radio jet which was earlier observed from the source. While polarization of the disc spectral component is poorly constrained with the IXPE data, the Comptonized emission has a polarization degree P = 4.0 ± 0.7 per cent and a polarization angle aligned with the radio jet. Our results strongly favour a spreading layer at the neutron star surface as the main source of the polarization signal. However, we cannot exclude a significant contribution from reflection off the accretion disc, as indicated by the presence of the iron fluorescence line.

Funder

National Aeronautics and Space Administration

Marshall Space Flight Center

Italian Space Agency

Istituto Nazionale di Astrofisica

Russian Science Foundation

Academy of Finland

Publisher

Oxford University Press (OUP)

Subject

Space and Planetary Science,Astronomy and Astrophysics

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