论文标题
2019年更换外观AGN IRAS23226-3843的爆发
The outburst of the changing-look AGN IRAS23226-3843 in 2019
论文作者
论文摘要
IRAS23226-3843先前已根据X射线和光谱变化归类为更换AGN。与2017年的观察相比，2019年，Swift观察结果表明，与2017年的观察相比，X射线和紫外线通量的重新爆发。我们对Swift，XMM-Newton和Nustar观察结果进行了后续的X射线和光谱（SALT和SAAAO 1.9m望远镜），从2019年到2021年至2021年。从2019年到2021年。 X射线和光学连续体分别在两个月内分别为5和1.6。这对应于在校正宿主星系贡献后光学后的3倍。 Balmer和FEII发射线强度显示出可比的可变性幅度。 Halpha的配置文件从1997年和1999年的蓝峰形象变化为2017年和2019年的双重峰值概况。但是，尽管2019年的强度有很大的强度变化，但在郊外的一年中，双重强度的变化很大。 X射线。在2019年的最大状态下，采用了深层XMM-NEWTON/NUSTAR频谱。该频谱在质量上与2017年拍摄的频谱非常相似，但高于10倍。柔软的X射线乐队显得毫无功能。软过量通过构造模型很好地建模。宽带拟合幂律连续体，构成软过量和银河吸收，可与Epic-PN和Nustar频谱组合良好。此外，我们在X射线中看到了复杂而宽的Fe K发射线轮廓。 IRAS23226-3843中的更换外观很可能是由增生率变化引起的 - 基于数周至数月的时间尺度的短期变化。
IRAS23226-3843 has previously been classified as a changing-look AGN based on X-ray and optical spectral variations. In 2019, Swift observations revealed a strong rebrightening in X-ray and UV fluxes in comparison to observations in 2017. We took follow-up Swift, XMM-Newton, and NuSTAR observations together with optical spectra (SALT and SAAO 1.9m telescope) from 2019 until 2021. IRAS23226-3843 showed a strong X-ray and optical outburst in 2019. It varied in the X-ray and optical continuum by a factor of 5 and 1.6, respectively, within two months. This corresponds to a factor of 3 in the optical after correction for the host galaxy contribution. The Balmer and FeII emission-line intensities showed comparable variability amplitudes. The Halpha profiles changed from a blue-peaked profile in the years 1997 and 1999 to a broad double-peaked profile in 2017 and 2019. However, there were no major profile variations in the extremely broad double-peaked profiles despite the strong intensity variations in 2019. One year after the outburst, the optical spectral type changed and became a Seyfert type 2 in 2020. Blue outflow components are present in the Balmer lines and in the Fe band in the X-rays. A deep broadband XMM-Newton/NuSTAR spectrum was taken during the maximum state in 2019. This spectrum is qualitatively very similar to a spectrum taken in 2017, but by a factor of 10 higher. The soft X-ray band appears featureless. The soft excess is well modeled with a Comptonization model. A broadband fit with a power-law continuum, Comptonized soft excess, and Galactic absorption gives a good fit to the combined EPIC-pn and NuSTAR spectrum. In addition, we see a complex and broadened Fe K emission-line profile in the X-rays. The changing-look character in IRAS23226-3843 is most probably caused by changes in the accretion rate -- based on the short-term variations on timescales of weeks to months.
