用AstroSat和NuSTAR对SMC X-1进行脉冲相位分辨光谱分析

IF 10.5 4区物理与天体物理 Q1 ASTRONOMY & ASTROPHYSICS

Journal of High Energy Astrophysics Pub Date : 2025-09-11 DOI:10.1016/j.jheap.2025.100462

Pravat Dangal , Ranjeev Misra , Nand Kumar Chakradhari

{"title":"用AstroSat和NuSTAR对SMC X-1进行脉冲相位分辨光谱分析","authors":"Pravat Dangal , Ranjeev Misra , Nand Kumar Chakradhari","doi":"10.1016/j.jheap.2025.100462","DOIUrl":null,"url":null,"abstract":"<div><div>We report the results of pulse phase-averaged and phase-resolved analyses of the X-ray spectra of SMC X-1 within the 1 to 60 keV energy band during high superorbital phases, observed by AstroSat and NuSTAR. The phase-averaged spectra were well described by both the cutoff powerlaw and Comptonized blackbody models, including Fe emission lines and absorption features. The pulsar was found to be accreting in the Super-Eddington regime, with a mass accretion rate of ∼ (8.7 ± 0.26) × 1018 gm s−1. A prominent cyclotron absorption line at ∼ 46 keV (NuSTAR) is interpreted as the first harmonic, while weaker features at ∼ 23 keV (AstroSat) and 27 keV (NuSTAR) are likely the supressed fundamental cyclotron resonances. The 6.4 keV Fe line as well as cyclotron line exhibited a clear dependence on the double-peaked pulse profile. The negative correlation of Fe line's equivalent width with X-ray intensity suggests an origin in highly ionized accretion disk transitions, where fluorescence efficiency decreases with high ionization. The positive correlation of cyclotron absorption energy and optical depth with intensity likely arises from beam geometry or accretion dynamics. We estimate the magnetic moment of the neutron star to be within (2.44 ± 0.09 to 2.86 ± 0.08) × 1030 G m3, the Alfven radius (RA) within (1.77 ± 0.07 to 1.79 ± 0.07) × 108 cm and the Co-rotation radius (R<math><msub><mrow></mrow><mrow><mi>c</mi><mi>o</mi></mrow></msub></math>) ∼ (1.2 ± 0.09) × 108 cm. Since RA > R<math><msub><mrow></mrow><mrow><mi>c</mi><mi>o</mi></mrow></msub></math>, a possible Super-Keplerian Inhibition may potentially induce spin-down episodes—a phenomenon not yet observed in SMC X-1.</div></div>","PeriodicalId":54265,"journal":{"name":"Journal of High Energy Astrophysics","volume":"49 ","pages":"Article 100462"},"PeriodicalIF":10.5000,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Pulse-phase resolved spectroscopy of SMC X-1 with AstroSat and NuSTAR\",\"authors\":\"Pravat Dangal , Ranjeev Misra , Nand Kumar Chakradhari\",\"doi\":\"10.1016/j.jheap.2025.100462\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>We report the results of pulse phase-averaged and phase-resolved analyses of the X-ray spectra of SMC X-1 within the 1 to 60 keV energy band during high superorbital phases, observed by AstroSat and NuSTAR. The phase-averaged spectra were well described by both the cutoff powerlaw and Comptonized blackbody models, including Fe emission lines and absorption features. The pulsar was found to be accreting in the Super-Eddington regime, with a mass accretion rate of ∼ (8.7 ± 0.26) × 1018 gm s−1. A prominent cyclotron absorption line at ∼ 46 keV (NuSTAR) is interpreted as the first harmonic, while weaker features at ∼ 23 keV (AstroSat) and 27 keV (NuSTAR) are likely the supressed fundamental cyclotron resonances. The 6.4 keV Fe line as well as cyclotron line exhibited a clear dependence on the double-peaked pulse profile. The negative correlation of Fe line's equivalent width with X-ray intensity suggests an origin in highly ionized accretion disk transitions, where fluorescence efficiency decreases with high ionization. The positive correlation of cyclotron absorption energy and optical depth with intensity likely arises from beam geometry or accretion dynamics. We estimate the magnetic moment of the neutron star to be within (2.44 ± 0.09 to 2.86 ± 0.08) × 1030 G m3, the Alfven radius (RA) within (1.77 ± 0.07 to 1.79 ± 0.07) × 108 cm and the Co-rotation radius (R<math><msub><mrow></mrow><mrow><mi>c</mi><mi>o</mi></mrow></msub></math>) ∼ (1.2 ± 0.09) × 108 cm. Since RA > R<math><msub><mrow></mrow><mrow><mi>c</mi><mi>o</mi></mrow></msub></math>, a possible Super-Keplerian Inhibition may potentially induce spin-down episodes—a phenomenon not yet observed in SMC X-1.</div></div>\",\"PeriodicalId\":54265,\"journal\":{\"name\":\"Journal of High Energy Astrophysics\",\"volume\":\"49 \",\"pages\":\"Article 100462\"},\"PeriodicalIF\":10.5000,\"publicationDate\":\"2025-09-11\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of High Energy Astrophysics\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2214404825001430\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ASTRONOMY & ASTROPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of High Energy Astrophysics","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2214404825001430","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}

引用次数: 0

摘要

本文报道了AstroSat和NuSTAR观测到的SMC X-1高超轨道相位1 ~ 60kev能量带x射线谱的脉冲相位平均和相位分辨分析结果。截断幂律和复合黑体模型都很好地描述了相平均光谱，包括铁发射线和吸收特征。该脉冲星的吸积速率为~（8.7±0.26）× 1018 gm s−1。在~ 46 keV （NuSTAR）的一个突出的回旋加速器吸收线被解释为第一谐波，而在~ 23 keV （AstroSat）和27 keV （NuSTAR）的较弱特征可能是被抑制的基本回旋加速器共振。6.4 keV铁谱线和回旋加速器谱线对双峰脉冲谱线有明显的依赖性。铁谱线的等效宽度与x射线强度呈负相关，表明其起源是高电离的吸积盘跃迁，荧光效率随着高电离而降低。回旋加速器吸收能量和光深与强度的正相关关系可能是由光束几何形状或吸积动力学引起的。我们估计中子星的磁矩在（2.44±0.09 ~ 2.86±0.08）× 1030 G m3之间，阿尔芬半径（RA）在（1.77±0.07 ~ 1.79±0.07）× 108 cm之间，共旋转半径（Rco）在（1.2±0.09）× 108 cm之间。自RA >； Rco以来，可能的超级开普勒抑制可能潜在地诱导自旋下降事件-这一现象尚未在SMC X-1中观察到。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

查看原文本刊更多论文

Pulse-phase resolved spectroscopy of SMC X-1 with AstroSat and NuSTAR

We report the results of pulse phase-averaged and phase-resolved analyses of the X-ray spectra of SMC X-1 within the 1 to 60 keV energy band during high superorbital phases, observed by AstroSat and NuSTAR. The phase-averaged spectra were well described by both the cutoff powerlaw and Comptonized blackbody models, including Fe emission lines and absorption features. The pulsar was found to be accreting in the Super-Eddington regime, with a mass accretion rate of ∼ (8.7 ± 0.26) × 10¹⁸ gm s⁻¹. A prominent cyclotron absorption line at ∼ 46 keV (NuSTAR) is interpreted as the first harmonic, while weaker features at ∼ 23 keV (AstroSat) and 27 keV (NuSTAR) are likely the supressed fundamental cyclotron resonances. The 6.4 keV Fe line as well as cyclotron line exhibited a clear dependence on the double-peaked pulse profile. The negative correlation of Fe line's equivalent width with X-ray intensity suggests an origin in highly ionized accretion disk transitions, where fluorescence efficiency decreases with high ionization. The positive correlation of cyclotron absorption energy and optical depth with intensity likely arises from beam geometry or accretion dynamics. We estimate the magnetic moment of the neutron star to be within (2.44 ± 0.09 to 2.86 ± 0.08) × 10³⁰ G m³, the Alfven radius (R_A) within (1.77 ± 0.07 to 1.79 ± 0.07) × 10⁸ cm and the Co-rotation radius (R

_{c o}

) ∼ (1.2 ± 0.09) × 10⁸ cm. Since R_A > R

_{c o}

, a possible Super-Keplerian Inhibition may potentially induce spin-down episodes—a phenomenon not yet observed in SMC X-1.

求助全文

通过发布文献求助，成功后即可免费获取论文全文。去求助

来源期刊

Journal of High Energy Astrophysics Earth and Planetary Sciences-Space and Planetary Science

CiteScore

9.70

自引率

5.30%

发文量

审稿时长

65 days

期刊介绍： The journal welcomes manuscripts on theoretical models, simulations, and observations of highly energetic astrophysical objects both in our Galaxy and beyond. Among those, black holes at all scales, neutron stars, pulsars and their nebula, binaries, novae and supernovae, their remnants, active galaxies, and clusters are just a few examples. The journal will consider research across the whole electromagnetic spectrum, as well as research using various messengers, such as gravitational waves or neutrinos. Effects of high-energy phenomena on cosmology and star-formation, results from dedicated surveys expanding the knowledge of extreme environments, and astrophysical implications of dark matter are also welcomed topics.