X-Ray Polarization of the Magnetar 1E 1841−045
We report on IXPE and NuSTAR observations beginning 40 days after the 2024 outburst onset of magnetar 1E 1841−045, marking the first IXPE observation of a magnetar in an enhanced state. Our spectropolarimetric analysis indicates that both a blackbody (BB) plus double power-law (PL) and a double blac...
Saved in:
| Main Authors: | , , , , , , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Astrophysical Journal Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/2041-8213/adbffa |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850139104437600256 |
|---|---|
| author | Rachael Stewart George A. Younes Alice K. Harding Zorawar Wadiasingh Matthew G. Baring Michela Negro Tod E. Strohmayer Wynn C. G. Ho Mason Ng Zaven Arzoumanian Hoa Dinh Thi Niccolò Di Lalla Teruaki Enoto Keith Gendreau Chin-Ping Hu Alex van Kooten Chryssa Kouveliotou Alexander McEwen |
| author_facet | Rachael Stewart George A. Younes Alice K. Harding Zorawar Wadiasingh Matthew G. Baring Michela Negro Tod E. Strohmayer Wynn C. G. Ho Mason Ng Zaven Arzoumanian Hoa Dinh Thi Niccolò Di Lalla Teruaki Enoto Keith Gendreau Chin-Ping Hu Alex van Kooten Chryssa Kouveliotou Alexander McEwen |
| author_sort | Rachael Stewart |
| collection | DOAJ |
| description | We report on IXPE and NuSTAR observations beginning 40 days after the 2024 outburst onset of magnetar 1E 1841−045, marking the first IXPE observation of a magnetar in an enhanced state. Our spectropolarimetric analysis indicates that both a blackbody (BB) plus double power-law (PL) and a double blackbody plus power-law spectral model fit the phase-averaged intensity data well, with a hard PL tail (Γ = 1.19 and 1.35, respectively) dominating above ≈5 keV. For the former model, we find the soft PL (the dominant component at soft energies) exhibits a polarization degree (PD) of ≈30% while the hard PL displays a PD of ≈40%. Similarly, the cool BB of the 2BB+PL model possesses a PD of ≈15% and a hard PL PD of ≈57%. For both models, each component has a polarization angle (PA) compatible with celestial north. Model-independent polarization analysis supports these results, wherein the PD increases from ≈15% to ≈70% in the 2–3 keV and 6–8 keV ranges, respectively, while the PA remains nearly constant. We find marginal evidence for phase-dependent variability of the polarization properties, namely a higher PD at phases coinciding with the hard X-ray pulse peak. We compare the hard X-ray PL to the expectation from resonant inverse Compton scattering (RICS) and secondary pair cascade synchrotron radiation from primary high-energy RICS photons; both present reasonable spectropolarimetric agreement with the data, albeit the latter does so more naturally. We suggest that the soft PL X-ray component may originate from a Comptonized corona in the inner magnetosphere. |
| format | Article |
| id | doaj-art-97cc80cae54e4005abdc3d658bfe150a |
| institution | OA Journals |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj-art-97cc80cae54e4005abdc3d658bfe150a2025-08-20T02:30:24ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019852L3510.3847/2041-8213/adbffaX-Ray Polarization of the Magnetar 1E 1841−045Rachael Stewart0https://orcid.org/0000-0002-0254-5915George A. Younes1https://orcid.org/0000-0002-7991-028XAlice K. Harding2https://orcid.org/0000-0001-6119-859XZorawar Wadiasingh3https://orcid.org/0000-0002-9249-0515Matthew G. Baring4https://orcid.org/0000-0003-4433-1365Michela Negro5https://orcid.org/0000-0002-6548-5622Tod E. Strohmayer6https://orcid.org/0000-0001-7681-5845Wynn C. G. Ho7https://orcid.org/0000-0002-6089-6836Mason Ng8https://orcid.org/0000-0002-0940-6563Zaven Arzoumanian9https://orcid.org/0009-0008-6187-8753Hoa Dinh Thi10https://orcid.org/0000-0001-9268-5577Niccolò Di Lalla11https://orcid.org/0000-0002-7574-1298Teruaki Enoto12https://orcid.org/0000-0003-1244-3100Keith Gendreau13https://orcid.org/0000-0001-7115-2819Chin-Ping Hu14https://orcid.org/0000-0001-8551-2002Alex van Kooten15https://orcid.org/0000-0002-3905-4853Chryssa Kouveliotou16https://orcid.org/0000-0003-1443-593XAlexander McEwen17https://orcid.org/0000-0001-5481-7559Department of Physics, The George Washington University , Washington, DC 20052, USAAstrophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA; Center for Space Sciences and Technology, University of Maryland , Baltimore County, Baltimore, MD 21250, USATheoretical Division, Los Alamos National Laboratory , Los Alamos, NM 87545, USAAstrophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA; Department of Astronomy, University of Maryland , College Park, MD 20742, USA; Center for Research and Exploration in Space Science and Technology , NASA/GSFC, Greenbelt, MD 20771, USADepartment of Physics and Astronomy—MS 108, Rice University , 6100 Main Street, Houston, TX 77251-1892, USADepartment of Physics & Astronomy, Louisiana State University , Baton Rouge, LA 70803, USAAstrophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USADepartment of Physics and Astronomy, Haverford College , 370 Lancaster Avenue, Haverford, PA 19041, USADepartment of Physics, McGill University , 3600 rue University, Montréal, QC H3A 2T8, Canada; Trottier Space Institute, McGill University , 3550 rue University, Montréal, QC H3A 2A7, CanadaAstrophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USADepartment of Physics and Astronomy—MS 108, Rice University , 6100 Main Street, Houston, TX 77251-1892, USAW. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University , Stanford, CA 94305, USARIKEN Cluster for Pioneering Research , 2-1 Hirosawa, Wako, Saitama 351-0198, JapanAstrophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USADepartment of Physics, National Changhua University of Education , Changhua 50007, TaiwanDepartment of Physics, The George Washington University , Washington, DC 20052, USADepartment of Physics, The George Washington University , Washington, DC 20052, USACenter for Space Sciences and Technology, University of Maryland , Baltimore County, Baltimore, MD 21250, USAWe report on IXPE and NuSTAR observations beginning 40 days after the 2024 outburst onset of magnetar 1E 1841−045, marking the first IXPE observation of a magnetar in an enhanced state. Our spectropolarimetric analysis indicates that both a blackbody (BB) plus double power-law (PL) and a double blackbody plus power-law spectral model fit the phase-averaged intensity data well, with a hard PL tail (Γ = 1.19 and 1.35, respectively) dominating above ≈5 keV. For the former model, we find the soft PL (the dominant component at soft energies) exhibits a polarization degree (PD) of ≈30% while the hard PL displays a PD of ≈40%. Similarly, the cool BB of the 2BB+PL model possesses a PD of ≈15% and a hard PL PD of ≈57%. For both models, each component has a polarization angle (PA) compatible with celestial north. Model-independent polarization analysis supports these results, wherein the PD increases from ≈15% to ≈70% in the 2–3 keV and 6–8 keV ranges, respectively, while the PA remains nearly constant. We find marginal evidence for phase-dependent variability of the polarization properties, namely a higher PD at phases coinciding with the hard X-ray pulse peak. We compare the hard X-ray PL to the expectation from resonant inverse Compton scattering (RICS) and secondary pair cascade synchrotron radiation from primary high-energy RICS photons; both present reasonable spectropolarimetric agreement with the data, albeit the latter does so more naturally. We suggest that the soft PL X-ray component may originate from a Comptonized corona in the inner magnetosphere.https://doi.org/10.3847/2041-8213/adbffaMagnetarsNeutron starsX-ray sourcesPulsarsPolarimetry |
| spellingShingle | Rachael Stewart George A. Younes Alice K. Harding Zorawar Wadiasingh Matthew G. Baring Michela Negro Tod E. Strohmayer Wynn C. G. Ho Mason Ng Zaven Arzoumanian Hoa Dinh Thi Niccolò Di Lalla Teruaki Enoto Keith Gendreau Chin-Ping Hu Alex van Kooten Chryssa Kouveliotou Alexander McEwen X-Ray Polarization of the Magnetar 1E 1841−045 The Astrophysical Journal Letters Magnetars Neutron stars X-ray sources Pulsars Polarimetry |
| title | X-Ray Polarization of the Magnetar 1E 1841−045 |
| title_full | X-Ray Polarization of the Magnetar 1E 1841−045 |
| title_fullStr | X-Ray Polarization of the Magnetar 1E 1841−045 |
| title_full_unstemmed | X-Ray Polarization of the Magnetar 1E 1841−045 |
| title_short | X-Ray Polarization of the Magnetar 1E 1841−045 |
| title_sort | x ray polarization of the magnetar 1e 1841 045 |
| topic | Magnetars Neutron stars X-ray sources Pulsars Polarimetry |
| url | https://doi.org/10.3847/2041-8213/adbffa |
| work_keys_str_mv | AT rachaelstewart xraypolarizationofthemagnetar1e1841045 AT georgeayounes xraypolarizationofthemagnetar1e1841045 AT alicekharding xraypolarizationofthemagnetar1e1841045 AT zorawarwadiasingh xraypolarizationofthemagnetar1e1841045 AT matthewgbaring xraypolarizationofthemagnetar1e1841045 AT michelanegro xraypolarizationofthemagnetar1e1841045 AT todestrohmayer xraypolarizationofthemagnetar1e1841045 AT wynncgho xraypolarizationofthemagnetar1e1841045 AT masonng xraypolarizationofthemagnetar1e1841045 AT zavenarzoumanian xraypolarizationofthemagnetar1e1841045 AT hoadinhthi xraypolarizationofthemagnetar1e1841045 AT niccolodilalla xraypolarizationofthemagnetar1e1841045 AT teruakienoto xraypolarizationofthemagnetar1e1841045 AT keithgendreau xraypolarizationofthemagnetar1e1841045 AT chinpinghu xraypolarizationofthemagnetar1e1841045 AT alexvankooten xraypolarizationofthemagnetar1e1841045 AT chryssakouveliotou xraypolarizationofthemagnetar1e1841045 AT alexandermcewen xraypolarizationofthemagnetar1e1841045 |