Investigation of the Nonthermal X-Ray Emission from the Supernova Remnant CTB 37B Hosting the Magnetar CXOU J171405.7-381031
We present a detailed X-ray investigation of a region (S1) exhibiting nonthermal X-ray emission within the supernova remnant (SNR) CTB 37B hosting the magnetar CXOU J171405.7−381031. Previous analyses modeled this emission with a power law (PL), inferring various values for the photon index (Γ) and...
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad938c |
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| author | Chanho Kim Jaegeun Park Hongjun An Kaya Mori Stephen P. Reynolds Samar Safi-Harb Shuo Zhang |
| author_facet | Chanho Kim Jaegeun Park Hongjun An Kaya Mori Stephen P. Reynolds Samar Safi-Harb Shuo Zhang |
| author_sort | Chanho Kim |
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| description | We present a detailed X-ray investigation of a region (S1) exhibiting nonthermal X-ray emission within the supernova remnant (SNR) CTB 37B hosting the magnetar CXOU J171405.7−381031. Previous analyses modeled this emission with a power law (PL), inferring various values for the photon index (Γ) and absorbing column density ( N _H ). Based on these, S1 was suggested to be an SNR shell, a background pulsar wind nebula, or an interaction region between the SNR and a molecular cloud. Our analysis of a larger data set favors a steepening (broken or curved PL) spectrum over a straight PL, with the best-fit broken power-law (BPL) parameters of Γ = 1.23 ± 0.23 and 2.24 ± 0.16 below and above a break at 5.57 ± 0.52 keV, respectively. However, a simple PL or srcut model cannot be definitively ruled out. For the BPL model, the inferred N _H = (4.08 ± 0.72) × 10 ^22 cm ^−2 towards S1 is consistent with that of the SNR, suggesting a physical association. The BPL-inferred spectral break ΔΓ ≈ 1 and hard Γ can be naturally explained by a nonthermal bremsstrahlung (NTB) model. We present an evolutionary NTB model that reproduces the observed spectrum, which indicates the presence of subrelativistic electrons within S1. However, alternate explanations for S1, an unrelated PWN or the SNR shock with unusually efficient acceleration, cannot be ruled out. We discuss these explanations and their implications for gamma-ray emission from CTB 37B and describe future observations that could settle the origin of S1. |
| format | Article |
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| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-d3d7d3876e144df6a22ed22c1d76d2cd2024-12-11T08:35:00ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01977216310.3847/1538-4357/ad938cInvestigation of the Nonthermal X-Ray Emission from the Supernova Remnant CTB 37B Hosting the Magnetar CXOU J171405.7-381031Chanho Kim0https://orcid.org/0000-0003-0226-9524Jaegeun Park1https://orcid.org/0000-0002-9103-506XHongjun An2https://orcid.org/0000-0002-6389-9012Kaya Mori3https://orcid.org/0000-0002-9709-5389Stephen P. Reynolds4https://orcid.org/0000-0002-5365-5444Samar Safi-Harb5https://orcid.org/0000-0001-6189-7665Shuo Zhang6https://orcid.org/0000-0002-2967-790XDepartment of Astronomy and Space Science, Chungbuk National University , Cheongju, 28644, Republic of Korea ; hjan@cbnu.ac.krDepartment of Astronomy and Space Science, Chungbuk National University , Cheongju, 28644, Republic of Korea ; hjan@cbnu.ac.krDepartment of Astronomy and Space Science, Chungbuk National University , Cheongju, 28644, Republic of Korea ; hjan@cbnu.ac.krColumbia Astrophysics Laboratory , 550 West 120th Street, New York, NY 10027, USAPhysics Department, NC State University , Raleigh, NC 27695, USADepartment of Physics and Astronomy, University of Manitoba , Winnipeg, MB R3T 2N2, CanadaDepartment of Physics and Astronomy, Michigan State University , East Lansing, MI 48824, USAWe present a detailed X-ray investigation of a region (S1) exhibiting nonthermal X-ray emission within the supernova remnant (SNR) CTB 37B hosting the magnetar CXOU J171405.7−381031. Previous analyses modeled this emission with a power law (PL), inferring various values for the photon index (Γ) and absorbing column density ( N _H ). Based on these, S1 was suggested to be an SNR shell, a background pulsar wind nebula, or an interaction region between the SNR and a molecular cloud. Our analysis of a larger data set favors a steepening (broken or curved PL) spectrum over a straight PL, with the best-fit broken power-law (BPL) parameters of Γ = 1.23 ± 0.23 and 2.24 ± 0.16 below and above a break at 5.57 ± 0.52 keV, respectively. However, a simple PL or srcut model cannot be definitively ruled out. For the BPL model, the inferred N _H = (4.08 ± 0.72) × 10 ^22 cm ^−2 towards S1 is consistent with that of the SNR, suggesting a physical association. The BPL-inferred spectral break ΔΓ ≈ 1 and hard Γ can be naturally explained by a nonthermal bremsstrahlung (NTB) model. We present an evolutionary NTB model that reproduces the observed spectrum, which indicates the presence of subrelativistic electrons within S1. However, alternate explanations for S1, an unrelated PWN or the SNR shock with unusually efficient acceleration, cannot be ruled out. We discuss these explanations and their implications for gamma-ray emission from CTB 37B and describe future observations that could settle the origin of S1.https://doi.org/10.3847/1538-4357/ad938cSupernova remnantsMagnetarsGamma-ray sourcesX-ray sourcesNon-thermal radiation sourcesHigh energy astrophysics |
| spellingShingle | Chanho Kim Jaegeun Park Hongjun An Kaya Mori Stephen P. Reynolds Samar Safi-Harb Shuo Zhang Investigation of the Nonthermal X-Ray Emission from the Supernova Remnant CTB 37B Hosting the Magnetar CXOU J171405.7-381031 The Astrophysical Journal Supernova remnants Magnetars Gamma-ray sources X-ray sources Non-thermal radiation sources High energy astrophysics |
| title | Investigation of the Nonthermal X-Ray Emission from the Supernova Remnant CTB 37B Hosting the Magnetar CXOU J171405.7-381031 |
| title_full | Investigation of the Nonthermal X-Ray Emission from the Supernova Remnant CTB 37B Hosting the Magnetar CXOU J171405.7-381031 |
| title_fullStr | Investigation of the Nonthermal X-Ray Emission from the Supernova Remnant CTB 37B Hosting the Magnetar CXOU J171405.7-381031 |
| title_full_unstemmed | Investigation of the Nonthermal X-Ray Emission from the Supernova Remnant CTB 37B Hosting the Magnetar CXOU J171405.7-381031 |
| title_short | Investigation of the Nonthermal X-Ray Emission from the Supernova Remnant CTB 37B Hosting the Magnetar CXOU J171405.7-381031 |
| title_sort | investigation of the nonthermal x ray emission from the supernova remnant ctb 37b hosting the magnetar cxou j171405 7 381031 |
| topic | Supernova remnants Magnetars Gamma-ray sources X-ray sources Non-thermal radiation sources High energy astrophysics |
| url | https://doi.org/10.3847/1538-4357/ad938c |
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