论文标题
一个非常年轻的无线电大磁铁
A very young radio-loud magnetar
论文作者
论文摘要
2020年3月，当Swift检测到9毫秒的硬X射线爆发和长期爆发时，发现了J1818.0-1607的磁铁Swift。迅速的X射线观测结果显示，旋转周期为1.36 s，很快通过发现无线电脉动证实。我们在这里报告了Swift爆发和后续X射线和无线电观察结果的分析。爆发平均光度为$ l _ {\ rm burt} \ sim2 \ times 10^{39} $ erg/s（在4.8 kpc）。 Simultaneous observations with XMM-Newton and NuSTAR three days after the burst provided a source spectrum well fit by an absorbed blackbody ($N_{\rm H} = (1.13\pm0.03) \times 10^{23}$ cm$^{-2}$ and $kT = 1.16\pm0.03$ keV) plus a power-law （$γ= 0.0 \ pm1.3 $）在1-20 kev频段中，其发光度为$ \ sim $$ 8 \ times10^{34} $ erg/s，以黑体发射为主。根据我们的定时分析，我们得出了偶性磁场$ b \ sim 7 \ times10^{14} $ g，旋转向下的光度$ \ dot {e} _ {\ rm rot} \ sim 1.4 \ sim 1.4 \ times10^{36} $ erg/s and and and and 240 yr的特征性年龄，当前已知。档案观测导致静态光度的上限$ <$ <$ <$ <$ <$ <times10^{33} $ erg/s，低于源特征时代磁铁冷却模型预期的值。除常规的脉冲发射外，X射线爆发在1.5 GHz的X射线爆发中检测到许多强和短无线电脉冲后，对Sardinia射电望远镜进行了1小时的无线电观察。它们以平均速率0.9分钟$^{ - 1} $发射，并占$ \ sim的$ 50％的50％。我们得出的结论是，Swift，J1818.0-1607是一种属于小型，多样化的年轻中子星的奇特磁铁，其性质跨越了旋转和磁性的脉冲星的特性。未来的观察将通过测量静止率来更好地估计年龄的估计。
The magnetar Swift ,J1818.0-1607 was discovered in March 2020 when Swift detected a 9 ms hard X-ray burst and a long-lived outburst. Prompt X-ray observations revealed a spin period of 1.36 s, soon confirmed by the discovery of radio pulsations. We report here on the analysis of the Swift burst and follow-up X-ray and radio observations. The burst average luminosity was $L_{\rm burst} \sim2\times 10^{39}$ erg/s (at 4.8 kpc). Simultaneous observations with XMM-Newton and NuSTAR three days after the burst provided a source spectrum well fit by an absorbed blackbody ($N_{\rm H} = (1.13\pm0.03) \times 10^{23}$ cm$^{-2}$ and $kT = 1.16\pm0.03$ keV) plus a power-law ($Γ=0.0\pm1.3$) in the 1-20 keV band, with a luminosity of $\sim$$8\times10^{34}$ erg/s, dominated by the blackbody emission. From our timing analysis, we derive a dipolar magnetic field $B \sim 7\times10^{14}$ G, spin-down luminosity $\dot{E}_{\rm rot} \sim 1.4\times10^{36}$ erg/s and characteristic age of 240 yr, the shortest currently known. Archival observations led to an upper limit on the quiescent luminosity $<$$5.5\times10^{33}$ erg/s, lower than the value expected from magnetar cooling models at the source characteristic age. A 1 hr radio observation with the Sardinia Radio Telescope taken about 1 week after the X-ray burst detected a number of strong and short radio pulses at 1.5 GHz, in addition to regular pulsed emission; they were emitted at an average rate 0.9 min$^{-1}$ and accounted for $\sim$50% of the total pulsed radio fluence. We conclude that Swift ,J1818.0-1607 is a peculiar magnetar belonging to the small, diverse group of young neutron stars with properties straddling those of rotationally and magnetically powered pulsars. Future observations will make a better estimation of the age possible by measuring the spin-down rate in quiescence.
