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<p>Magnetars are the most strongly magnetized compact objects known in the Universe and are regarded as one of the primary engines powering a variety of enigmatic, high-energy transients. However, our understanding of magnetars remains highly limited, constrained by observational sample size and radiative variability. XTE J1810–197, which re-entered a radio-active phase in 2018, is one of only six known radio-pulsating magnetars. Leveraging the distinctive capability for simultaneous dual-frequency observations, we utilized the Shanghai Tianma Radio Telescope (TMRT) to monitor this magnetar continuously at both 2.25 and 8.60 GHz, capturing its entire evolution from radio activation to quenching. This enabled precise characterization of the evolution in its integrated profile, spin frequency, flux density, and spectral index (<i>α</i>, defined by <i>S</i> ∝ <i>f</i><sup><i>α</i></sup>). The first time derivative of its spin frequency <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\dot v\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mover> <mi>v</mi> <mo>˙</mo> </mover> </mrow> </math></EquationSource> </InlineEquation> passed through four distinct phases—rapid decrease, violent oscillation, steady decline, and stable recovery—before returning to its pre-outburst value concomitant with the cessation of radio emission. Remarkably, both the amplitudes and the characteristic time-scales of these <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\dot v\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mover> <mi>v</mi> <mo>˙</mo> </mover> </mrow> </math></EquationSource> </InlineEquation> variations match those observed during the previous outburst that began in 2003, providing the first demonstration that post-outburst rotational evolution and radiative behavior in a magnetar are repeatable. A twisted-magnetosphere model can qualitatively account for this repeatability as well as for the progressive narrowing and abrupt disappearance of the radio pulse radiation, thereby receiving strong observational support.</p>

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Does the radio-active phase of XTE J1810–197 recur following the same evolutionary pattern?

  • 期刊论文

  • 发表日期：

    2026年3月11日

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  • Zhipeng Huang,
  • Zhen Yan,
  • Zhiqiang Shen,
  • Hao Tong,
  • Mingyu Ge,
  • Zhifu Gao,
  • Yajun Wu,
  • Rongbing Zhao,
  • Jie Liu,
  • Rui Wang,
  • Xiaowei Wang,
  • Fan Yang,
  • Chuyuan Zhang,
  • Zhenlong Liao,
  • Yangyang Lin

摘要

Magnetars are the most strongly magnetized compact objects known in the Universe and are regarded as one of the primary engines powering a variety of enigmatic, high-energy transients. However, our understanding of magnetars remains highly limited, constrained by observational sample size and radiative variability. XTE J1810–197, which re-entered a radio-active phase in 2018, is one of only six known radio-pulsating magnetars. Leveraging the distinctive capability for simultaneous dual-frequency observations, we utilized the Shanghai Tianma Radio Telescope (TMRT) to monitor this magnetar continuously at both 2.25 and 8.60 GHz, capturing its entire evolution from radio activation to quenching. This enabled precise characterization of the evolution in its integrated profile, spin frequency, flux density, and spectral index (α, defined by S ∝ fα). The first time derivative of its spin frequency \(\dot v\) v ˙ passed through four distinct phases—rapid decrease, violent oscillation, steady decline, and stable recovery—before returning to its pre-outburst value concomitant with the cessation of radio emission. Remarkably, both the amplitudes and the characteristic time-scales of these \(\dot v\) v ˙ variations match those observed during the previous outburst that began in 2003, providing the first demonstration that post-outburst rotational evolution and radiative behavior in a magnetar are repeatable. A twisted-magnetosphere model can qualitatively account for this repeatability as well as for the progressive narrowing and abrupt disappearance of the radio pulse radiation, thereby receiving strong observational support.