{"title":"关于候选白矮星脉冲星ZTF J190132.9+145808.7的X射线效率","authors":"Aya Bamba, Yukikatsu Terada, Kazumi Kashiyama, Shota Kisaka, Takahiro Minami, Tadayuki Takahashi","doi":"10.1093/pasj/psae041","DOIUrl":null,"url":null,"abstract":"Strongly magnetized, rapidly rotating massive white dwarfs (WDs) emerge as potential outcomes of double degenerate mergers. These WDs can act as sources of non-thermal emission and cosmic rays, gethering attention as WD pulsars. In this context, we studied the X-ray emissions from ZTF J190132.9+145808.7 (hereafter ZTF J1901+14), a notable massive isolated WD in the Galaxy, using the Chandra X-ray observatory. Our results showed 3.5σ level evidence of X-ray signals, although it is marginal. Under the assumption of a photon index of 2, we derived its intrinsic flux to be 2.3 (0.9–4.7) × 10−15 erg cm−2 s−1 and luminosity 4.6 (2.0–9.5) × 1026 erg s−1 for a 0.5–7 keV band in the $90\\%$ confidence range, given its distance of 41 pc. We derived the X-ray efficiency (η) concerning the spin-down luminosity to be 0.012 (0.0022–0.074), a value comparable to that of ordinary neutron star pulsars. The inferred X-ray luminosity may be compatible with curvature radiation from sub-TeV electrons accelerated within open magnetic fields in the magnetosphere of ZTF J1901+14. Conducting more extensive X-ray observations is crucial to confirm whether ZTF J1901+14-like isolated WDs are also significant sources of X-rays and sub-TeV electron cosmic rays, similar to other WD pulsars in accreting systems.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":null,"pages":null},"PeriodicalIF":2.2000,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On the X-ray efficiency of the white dwarf pulsar candidate ZTF J190132.9+145808.7\",\"authors\":\"Aya Bamba, Yukikatsu Terada, Kazumi Kashiyama, Shota Kisaka, Takahiro Minami, Tadayuki Takahashi\",\"doi\":\"10.1093/pasj/psae041\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Strongly magnetized, rapidly rotating massive white dwarfs (WDs) emerge as potential outcomes of double degenerate mergers. These WDs can act as sources of non-thermal emission and cosmic rays, gethering attention as WD pulsars. In this context, we studied the X-ray emissions from ZTF J190132.9+145808.7 (hereafter ZTF J1901+14), a notable massive isolated WD in the Galaxy, using the Chandra X-ray observatory. Our results showed 3.5σ level evidence of X-ray signals, although it is marginal. Under the assumption of a photon index of 2, we derived its intrinsic flux to be 2.3 (0.9–4.7) × 10−15 erg cm−2 s−1 and luminosity 4.6 (2.0–9.5) × 1026 erg s−1 for a 0.5–7 keV band in the $90\\\\%$ confidence range, given its distance of 41 pc. We derived the X-ray efficiency (η) concerning the spin-down luminosity to be 0.012 (0.0022–0.074), a value comparable to that of ordinary neutron star pulsars. The inferred X-ray luminosity may be compatible with curvature radiation from sub-TeV electrons accelerated within open magnetic fields in the magnetosphere of ZTF J1901+14. Conducting more extensive X-ray observations is crucial to confirm whether ZTF J1901+14-like isolated WDs are also significant sources of X-rays and sub-TeV electron cosmic rays, similar to other WD pulsars in accreting systems.\",\"PeriodicalId\":20733,\"journal\":{\"name\":\"Publications of the Astronomical Society of Japan\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.2000,\"publicationDate\":\"2024-05-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Publications of the Astronomical Society of Japan\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.1093/pasj/psae041\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ASTRONOMY & ASTROPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Publications of the Astronomical Society of Japan","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1093/pasj/psae041","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
摘要
强磁化、快速旋转的大质量白矮星(WDs)是双变性合并的潜在结果。这些白矮星可以作为非热辐射和宇宙射线的来源,作为白矮星脉冲星而受到关注。在这种情况下,我们利用钱德拉 X 射线天文台研究了银河系中一个著名的大质量孤立 WD--ZTF J190132.9+145808.7(以下简称 ZTF J1901+14)的 X 射线辐射。我们的研究结果显示了 3.5σ 级的 X 射线信号证据,尽管这种证据很微弱。在光子指数为2的假设下,我们推导出它的本征通量为2.3(0.9-4.7)×10-15 erg cm-2 s-1,光度为4.6(2.0-9.5)×1026 erg s-1,波段为0.5-7 keV,置信度范围为90%$,考虑到它的距离为41 pc。我们推导出有关自旋下降光度的X射线效率(η)为0.012(0.0022-0.074),这个值与普通中子星脉冲星的效率相当。推断出的X射线光度可能与ZTF J1901+14磁层中开放磁场内加速的亚TeV电子产生的曲率辐射相吻合。进行更广泛的X射线观测对于确认类似ZTF J1901+14的孤立WD是否也是X射线和亚TeV电子宇宙射线的重要来源至关重要,这一点与吸积系统中的其他WD脉冲星类似。
On the X-ray efficiency of the white dwarf pulsar candidate ZTF J190132.9+145808.7
Strongly magnetized, rapidly rotating massive white dwarfs (WDs) emerge as potential outcomes of double degenerate mergers. These WDs can act as sources of non-thermal emission and cosmic rays, gethering attention as WD pulsars. In this context, we studied the X-ray emissions from ZTF J190132.9+145808.7 (hereafter ZTF J1901+14), a notable massive isolated WD in the Galaxy, using the Chandra X-ray observatory. Our results showed 3.5σ level evidence of X-ray signals, although it is marginal. Under the assumption of a photon index of 2, we derived its intrinsic flux to be 2.3 (0.9–4.7) × 10−15 erg cm−2 s−1 and luminosity 4.6 (2.0–9.5) × 1026 erg s−1 for a 0.5–7 keV band in the $90\%$ confidence range, given its distance of 41 pc. We derived the X-ray efficiency (η) concerning the spin-down luminosity to be 0.012 (0.0022–0.074), a value comparable to that of ordinary neutron star pulsars. The inferred X-ray luminosity may be compatible with curvature radiation from sub-TeV electrons accelerated within open magnetic fields in the magnetosphere of ZTF J1901+14. Conducting more extensive X-ray observations is crucial to confirm whether ZTF J1901+14-like isolated WDs are also significant sources of X-rays and sub-TeV electron cosmic rays, similar to other WD pulsars in accreting systems.
期刊介绍:
Publications of the Astronomical Society of Japan (PASJ) publishes the results of original research in all aspects of astronomy, astrophysics, and fields closely related to them.