The detection of a short hard X-ray burst and an associated bright soft X-ray source by the Swift satellite in 2020 October heralded a new magnetar in outburst, SGR J1830−0645. Pulsations at a period of ∼10.4 s were detected in prompt follow-up X-ray observations. We present here the analysis of the Swift/Burst Alert Telescope burst, of XMM-Newton and the Nuclear Spectroscopic Telescope Array observations performed at the outburst peak, and of a Swift/X-ray Telescope monitoring campaign over the subsequent month. The burst was single-peaked, lasted ∼6 ms, and released a fluence of ≈5 10⁻⁹ erg cm⁻² (15–50 keV). The spectrum of the X-ray source at the outburst peak was well described by an absorbed double-blackbody model plus a power-law component detectable up to ∼25 keV. The unabsorbed X-ray flux decreased from ∼5 10⁻¹¹ to ∼2.5 10⁻¹¹ erg cm⁻² s⁻¹ one month later (0.3–10 keV). Based on our timing analysis, we estimate a dipolar magnetic field ≈5.5 10¹⁴ G at pole, a spin-down luminosity ≈2.4 10³² erg s⁻¹, and a characteristic age ≈24 kyr. The spin modulation pattern appears highly pulsed in the soft X-ray band, and becomes smoother at higher energies. Several short X-ray bursts were detected during our campaign. No evidence for periodic or single-pulse emission was found at radio frequencies in observations performed with the Sardinia Radio Telescope and Parkes. According to magneto-thermal evolutionary models, the real age of SGR J1830−0645 is close to the characteristic age, and the dipolar magnetic field at birth was slightly larger, ∼10¹⁵ G.

斯威夫特卫星在2020年10月探测到短时硬X射线爆发和相关的亮软X射线源，这预示着爆发的新磁星SGR J1830−0645。在快速的后续X射线观察中发现了大约10.4 s的脉动。我们在此介绍对爆发高峰时进行的Swift / Burst Alert望远镜爆发，XMM-Newton和核光谱望远镜阵列观测的分析，以及接下来一个月的Swift / X射线望远镜监视活动。爆发是单峰的，持续约6毫秒，并释放出≈510 ^-9 erg cm ^-2的能量密度（15–50 keV）。吸收峰双黑体模型加上可检测到约25 keV的幂律分量很好地描述了爆发峰处的X射线源光谱。一个月后（0.3–10 keV），未吸收的X射线通量从〜5 10 ^-11降至〜2.5 10 ^-11 erg cm ^-2 s ^-1。根据我们的时序分析，我们估计极点处的双极磁场≈5.510 ¹⁴ G，向下旋转的光度≈2.410 ³² erg s ^-1，且特征年龄约等于24岁。自旋调制模式在软X射线带中表现为高度脉冲，并在较高能量下变得更平滑。在我们的竞选活动中，发现了几次短暂的X射线爆发。在撒丁岛射电望远镜和帕克斯进行的观测中，没有发现周期性或单脉冲发射的证据。根据磁热演化模型，SGR J1830-0645的真实年龄接近的特点年龄和出生时的偶极磁场略大，~10 ¹⁵ G.