The flux-dependent X-ray time lags in NGC 4051

@article{Alston2013TheFX,
  title={The flux-dependent X-ray time lags in NGC 4051},
  author={William N. Alston and Simon Vaughan and Phil Uttley},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2013},
  volume={435},
  pages={1511-1519}
}
We present an analysis of the X-ray time lags for the highly variable Seyfert 1 galaxy NGC 4051, based on a series of XMM-Newton observations taken in 2009. We investigate the Fourier frequency dependent time lags in the light curves between the 0.3-1.0 keV and 2.0-5.0 keV energy bands as a function of source flux, including simultaneous modelling of the resulting lag-frequency spectra. We find the shape of the lag-frequency spectra to vary significantly and systematically with source flux. We… 

Figures and Tables from this paper

The long term X-ray time-lags of NGC 4051

We present the long term, frequency-dependent, X-ray time lags of the Seyfert galaxy NGC 4051. We used Rossi X-ray Timing Explorer light curves in the 2-4, 4-7 and 7-10 keV bands and we measured the

X-ray time delays from the Seyfert 2 galaxy IRAS 18325−5926

Using new XMM-Newtonobservations we detect hard X-ray time lags in the rapid variability of the Compton-thin Seyfert 2 galaxy IRAS 18325 5926. The higher-energy X-ray variations lag behind correlated

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

We analyse the X-ray time-lags in the narrow line Seyfert 1 (NLS1) galaxy PG 1244+026 (MBH ∼ 107 M⊙, L/LEdd ∼ 1). The time delay between the soft (0.3–0.7 keV) and harder (1.2–4.0 keV) variations

Measuring light echoes in NGC 4051

Five archived X-ray observations of NGC 4051, taken using the NuSTAR observatory, have been analysed, revealing lags between flux variations in bands covering a wide range of X-ray photon energy. In

The remarkable X-ray variability of IRAS 13224–3809 – I. The variability process

We present a detailed X-ray timing analysis of the highly variable narrow-line Seyfert 1 (NLS1) galaxy IRAS 13224–3809. The source was recently monitored for 1.5 Ms with XMM–Newton, which, combined

The changing X-ray time lag in MCG-6-30-15

MCG-6-30-15 is one of the most observed Narrow Line Seyfert 1 galaxies in the X-ray band. In this paper we examine the X-ray time lags in this source using a total of 600 ks in observations (440 ks

Timing the warm absorber in NGC 4051

We investigated, using spectral-timing analysis, the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results on the extensive ~ 600

X-ray time lags in AGN: inverse-Compton scattering and spherical corona model

We develop a physically motivated, spherical corona model to investigate the frequency-dependent time lags in AGN. The model includes the effects of Compton up-scattering between the disc UV photons

Theoretical modelling of the AGN iron-line vs continuum time-lags in the lamp-post geometry

Context: Theoretical modelling of time-lags between variations in the Fe K$\alpha$ emission and the X-ray continuum might shed light on the physics and geometry of the X-ray emitting region in active

X-ray timing analysis of the quasar PG 1211+143

We report on a timing analysis of a new ~630ks XMM-Newton observation of the quasar, PG 1211+143. We find a well-defined X-ray power spectrum with a well-detected bend at ~7e-5 Hz, consistent with

References

SHOWING 1-10 OF 42 REFERENCES

Frequency-dependent Time Lags in the X-Ray Emission of the Seyfert Galaxy NGC 7469

We report the discovery of time lags in the cross spectra of the X-ray light curves of the Seyfert galaxy NGC 7469. This behavior is common in Galactic black hole and neutron star binaries and is in

The discovery of non-linear X-ray variability in NGC 4051

We present a power spectral analysis of the 0.1--2 keV X-ray light curves of NGC 4051. Two long ROSAT observations have been analysed and the power spectra are shown to have significantly different

On the X-ray time-lags in the black hole candidates

ABSTRA C T It is shown that the energy dependence of the time-lags in Cygnus X-1 excludes any significant contribution of the standard reflected component to the observed lags. The conclusion is

Twelve years of X-ray and optical variability in the Seyfert galaxy NGC 4051

We discuss the origin of the optical variations in the narrow-line Seyfert 1 galaxy NGC 4051 and present the results of a cross-correlation study using X-ray and optical light curves spanning more

Revealing the X-ray source in IRAS 13224−3809 through flux-dependent reverberation lags

IRAS 13224−3809 was observed in 2011 for 500 ks with the XMM-Newton observatory. We detect highly significant X-ray lags between soft (0.3-1 keV) and hard (1.2-5 keV) energies. The hard band lags the

DIRECT MEASUREMENT OF THE X-RAY TIME-DELAY TRANSFER FUNCTION IN ACTIVE GALACTIC NUCLEI

The origin of the observed time lags, in nearby active galactic nuclei (AGNs), between hard and soft X-ray photons is investigated using new XMM-Newton data for the narrow-line Seyfert I galaxy Ark

Spectral variability and reverberation time delays in the Suzaku X‐ray spectrum of NGC 4051

Long-exposure Suzaku X-ray observations of the nearby active galaxy NGC 4051 from 2005 and 2008 are analysed, in an attempt to reach a self-consistent understanding of both the spectral variability

Relativistic iron K X-ray reverberation in NGC 4151

Recent X-ray observations have enabled the study of reverberation delays in active galactic nuclei (AGN) for the first time. All the detections so far are in sources with a strong soft excess, and

Discovery of a relation between black hole mass and soft X-ray time lags in active galactic nuclei

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

Spectral-timing evidence for a very high state in the narrow-line Seyfert 1 Ark 564

We use a 100 ks long XMM-Newton observation of the narrow-line Seyfert 1 galaxy Ark 564 and combine it with the month-long monitoring of the same source produced by ASCA, to calculate the phase lags