X-ray time delays in the narrow line Seyfert 1 galaxy PG 1244+026

作者：Alston W N^*; Done C; Vaughan S

来源：Monthly Notices of the Royal Astronomical Society, 2014, 439(2): 1548-1555.

DOI：10.1093/mnras/stu005

• galaxies: active
• galaxies: individual: PG 1244+026
• galaxies: Seyfert
• X-rays: galaxies

We analyse the X-ray time-lags in the narrow line Seyfert 1 (NLS1) galaxy PG 1244+026 (M-BH similar to 10(7) M-circle dot, L/L-Edd similar to 1). The time delay between the soft (0.3-0.7 keV) and harder (1.2-4.0 keV) variations shows the well-established switch from hard lags at low frequencies to soft lags at high frequencies. The low-frequency hard lags are qualitatively consistent with the propagation of fluctuations model, with some long-time-scale response of the reflection component. The high-frequency soft lag appears to extend over a wide frequency band, that we divide this into two narrow frequency ranges, and examine the lag as a function of energy for each of these. At high frequencies the soft excess emission is delayed with respect to the harder energy bands, without any corresponding strong, hard X-ray reflection signature. At even higher frequencies a soft lag is seen at the softest energies, as well as tentative evidence for an iron K alpha reverberation signal. These results point to the importance of reprocessing as well as reflection in determining the lags in NLS1s.

• 出版日期2014-4