Discovery of a relation between black hole mass and soft X-ray time lags in active galactic nuclei
By B. Marco, G. Ponti, M. Cappi, Mauro Dadina, P. Uttley, E. Cackett, A. C. Fabian, G. Miniutti. 2011
196 citations recorded by the source corpus.
We carried out a systematic analysis of time lags between X-ray energy bands in a large sample (32 sources) of unabsorbed, radio quiet active galactic nuclei (AGN), observed by XMM-Newton. The analysis of X-ray lags (up to the highest/shortest frequencies/time-scales), is performed in the Fourier-frequency domain, between energy bands where the soft excess (soft band) and the primary power law (hard band) dominate the emission. We report a total of 15 out of 32 sources displaying a high-frequency soft lag in their light curves. All 15 are at a significance level exceeding 97 per cent and 11 are at a level exceeding 99 per cent. Of these soft lags, seven have not been previously reported in the literature, thus this work significantly increases the number of known sources with a soft/negative lag. The characteristic time-scales of the soft/negative lag are relatively short (with typical frequencies and amplitudes of ν ∼ 0.07-4 × 10−3 Hz and τ ∼ 10-600 s, respectively), and show a highly significant (≳4σ) correlation with the black hole mass. The measured correlations indicate that soft lags are systematically shifted to lower frequencies and higher absolute amplitudes as the mass of the source increases. To first approximation, all the sources in the sample are consistent with having similar mass-scaled lag properties. These results strongly suggest the existence of a mass-scaling law for the soft/negative lag, that holds for AGN spanning a large range of masses (about 2.5 orders of magnitude), thus supporting the idea that soft lags originate in the innermost regions of AGN and are powerful tools for testing their physics and geometry.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/4a2f40b8b7a9f55ae7d36db7bab799dffdade7f6
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Astronomy and Astrophysics
In Nuclear and High Energy Physics
Citations in the corpus
- X-ray reverberation around accreting black holes (2014, methodology): “The unique line-of-sight argument is also inconsistent with the ubiquity of the soft lag in NLS1 sources (De Marco et al. 2013).”
- Active galactic nuclei: what’s in a name? (2017, background): “…BHXRBs; the fact that the inner/outer disk and the BLR directly respond to continuum variations as inferred from results of X-ray (Fabian et al. 2009; Zoghbi et al. 2012; De Marco et al. 2013; Kara et al. 2016) and UV/optical reverberation mapping (e.g. Peterson et al. 2004; Edelson et al. 2015).”
- A global look at X-ray time lags in seyfert galaxies (2016, methodology): “This reverberation lag-mass scaling relationship has been shown for the soft lags (De Marco et al. 2013), and for a few sources with iron K lags as well (Kara et al. 2013c).”