X-Ray Dips and Polarization Angle Swings in GX 13+1
We present the result from the 2024 April observation of the low-mass X-ray binary GX 13+1 with the Imaging X-ray Polarimetry Explorer (IXPE), together with Neutron Star Interior Composition Explorer and Swift- X-Ray Telescope coordinated observations. Two light-curve dips were observed; during them...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/ada7f8 |
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| author | Alessandro Di Marco Fabio La Monaca Anna Bobrikova Luigi Stella Alessandro Papitto Juri Poutanen Maria Cristina Baglio Matteo Bachetti Vladislav Loktev Maura Pilia Daniele Rogantini |
| author_facet | Alessandro Di Marco Fabio La Monaca Anna Bobrikova Luigi Stella Alessandro Papitto Juri Poutanen Maria Cristina Baglio Matteo Bachetti Vladislav Loktev Maura Pilia Daniele Rogantini |
| author_sort | Alessandro Di Marco |
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| description | We present the result from the 2024 April observation of the low-mass X-ray binary GX 13+1 with the Imaging X-ray Polarimetry Explorer (IXPE), together with Neutron Star Interior Composition Explorer and Swift- X-Ray Telescope coordinated observations. Two light-curve dips were observed; during them, the harder Comptonized spectral component was dominant and the polarization degree (PD) higher than in the softer, off-dip intervals. Through a joint analysis of the three IXPE observations, which also included the dip from the first observation, we demonstrate that the polarization properties varied in response to the intensity and spectral hardness changes associated with the dips. The PD attained values up to ∼4%. The polarization angle (PA) showed a swing of ∼70 ^∘ across the dip and off-dip states, comparable to the continuous rotation seen during the first IXPE observation. We discuss these results in the context of models for polarized emission from the accretion disk and the boundary/spreading layer on the neutron star surface. We also draw attention to the role that an extended accretion disk corona or disk wind can play in generating high PDs and, possibly, swings of the PA. |
| format | Article |
| id | doaj-art-0cbd271f6a184a48a792b786ecf03946 |
| institution | Kabale University |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj-art-0cbd271f6a184a48a792b786ecf039462025-02-01T05:28:20ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019792L4710.3847/2041-8213/ada7f8X-Ray Dips and Polarization Angle Swings in GX 13+1Alessandro Di Marco0https://orcid.org/0000-0003-0331-3259Fabio La Monaca1https://orcid.org/0000-0001-8916-4156Anna Bobrikova2https://orcid.org/0009-0009-3183-9742Luigi Stella3https://orcid.org/0000-0002-0018-1687Alessandro Papitto4https://orcid.org/0000-0001-6289-7413Juri Poutanen5https://orcid.org/0000-0002-0983-0049Maria Cristina Baglio6https://orcid.org/0000-0003-1285-4057Matteo Bachetti7https://orcid.org/0000-0002-4576-9337Vladislav Loktev8https://orcid.org/0000-0001-6894-871XMaura Pilia9https://orcid.org/0000-0001-7397-8091Daniele Rogantini10https://orcid.org/0000-0002-5359-9497INAF Istituto di Astrofisica e Planetologia Spaziali , Via del Fosso del Cavaliere 100, 00133 Roma, Italy ; alessandro.dimarco@inaf.itINAF Istituto di Astrofisica e Planetologia Spaziali , Via del Fosso del Cavaliere 100, 00133 Roma, Italy ; alessandro.dimarco@inaf.it; Dipartimento di Fisica, Università degli Studi di Roma “Tor Vergata,” Via della Ricerca Scientifica 1, 00133 Rome, ItalyDepartment of Physics and Astronomy, 20014, University of Turku , FinlandINAF Osservatorio Astronomico di Roma , Via Frascati 33, 00078 Monte Porzio Catone (RM), ItalyINAF Osservatorio Astronomico di Roma , Via Frascati 33, 00078 Monte Porzio Catone (RM), ItalyDepartment of Physics and Astronomy, 20014, University of Turku , FinlandINAF Osservatorio Astronomico di Brera , Via Bianchi 46, I-23807 Merate (LC), ItalyINAF Osservatorio Astronomico di Cagliari , Via della Scienza 5, 09047 Selargius (CA), ItalyDepartment of Physics and Astronomy, 20014, University of Turku , FinlandINAF Osservatorio Astronomico di Cagliari , Via della Scienza 5, 09047 Selargius (CA), ItalyDepartment of Astronomy and Astrophysics, University of Chicago , Chicago, IL 60637, USAWe present the result from the 2024 April observation of the low-mass X-ray binary GX 13+1 with the Imaging X-ray Polarimetry Explorer (IXPE), together with Neutron Star Interior Composition Explorer and Swift- X-Ray Telescope coordinated observations. Two light-curve dips were observed; during them, the harder Comptonized spectral component was dominant and the polarization degree (PD) higher than in the softer, off-dip intervals. Through a joint analysis of the three IXPE observations, which also included the dip from the first observation, we demonstrate that the polarization properties varied in response to the intensity and spectral hardness changes associated with the dips. The PD attained values up to ∼4%. The polarization angle (PA) showed a swing of ∼70 ^∘ across the dip and off-dip states, comparable to the continuous rotation seen during the first IXPE observation. We discuss these results in the context of models for polarized emission from the accretion disk and the boundary/spreading layer on the neutron star surface. We also draw attention to the role that an extended accretion disk corona or disk wind can play in generating high PDs and, possibly, swings of the PA.https://doi.org/10.3847/2041-8213/ada7f8Stellar accretion disksNeutron starsPolarimetrySpectropolarimetryLow-mass x-ray binary stars |
| spellingShingle | Alessandro Di Marco Fabio La Monaca Anna Bobrikova Luigi Stella Alessandro Papitto Juri Poutanen Maria Cristina Baglio Matteo Bachetti Vladislav Loktev Maura Pilia Daniele Rogantini X-Ray Dips and Polarization Angle Swings in GX 13+1 The Astrophysical Journal Letters Stellar accretion disks Neutron stars Polarimetry Spectropolarimetry Low-mass x-ray binary stars |
| title | X-Ray Dips and Polarization Angle Swings in GX 13+1 |
| title_full | X-Ray Dips and Polarization Angle Swings in GX 13+1 |
| title_fullStr | X-Ray Dips and Polarization Angle Swings in GX 13+1 |
| title_full_unstemmed | X-Ray Dips and Polarization Angle Swings in GX 13+1 |
| title_short | X-Ray Dips and Polarization Angle Swings in GX 13+1 |
| title_sort | x ray dips and polarization angle swings in gx 13 1 |
| topic | Stellar accretion disks Neutron stars Polarimetry Spectropolarimetry Low-mass x-ray binary stars |
| url | https://doi.org/10.3847/2041-8213/ada7f8 |
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