A correlation between the spectral and timing properties of AGN (2009)
Papadakis, I. E., Sobolewska, M., Arevalo, P., Markowitz, A., McHardy, I. M., Miller, L., ...
We present the results from a combined study of the average X-ray spectral and timing properties of 14 nearby AGN. For 11 of the sources in the sample, we used all the available data from the RXTE...
Correlation and time delays of the X-ray and optical emission of the Seyfert Galaxy NGC3783 (2009)
Arevalo, P., Uttley, P., Lira, P., Breedt, E., McHardy, I. M., Churazov, E.
We present simultaneous X-ray and optical B and V band light curves of the Seyfert Galaxy NGC3783 spanning 2 years. The flux in all bands is highly variable and the fluctuations are significantly...
X-ray Variability of the Seyfert 1 Markarian 335: Power Spectrum and Time Lags (2008)
Arevalo, P., McHardy, I. M., Summons, D. P.
To investigate further the comparison between AGN and black hole X-ray binaries, we have studied the main X-ray variability properties of the Seyfert 1 Galaxy Markarian 335. We put particular...
Fourier-resolved energy spectra of the Narrow Line Seyfert 1 Mkn 766 (2008)
Arevalo, P., McHardy, I. M., Markowitz, A., Papadakis, I. E., Turner, T. J., Miller, L., ...
We compute Fourier-resolved X-ray spectra of the Seyfert 1 Markarian 766 to study the shape of the variable components contributing to the 0.3-10 keV energy spectrum and their time-scale dependence....
McHardy, I. M., Arevalo, P., Uttley, P., Papadakis, I. E., Summons, D. P., Brinkmann, W., ...
We present a power spectral analysis of a 100 ksec XMM-Newton observation of the narrow line Seyfert 1 galaxy Ark~564. When combined with earlier RXTE and ASCA observations, these data produce a...
Timing evidence in determining the accretion state of the Seyfert galaxy NGC 3783 (2007)
Summons, D. P., Arevalo, P., McHardy, I. M., Uttley, P., Bhaskar, A.
Previous observations with the Rossi X-ray Timing Explorer (RXTE) have suggested that the power spectral density (PSD) of NGC 3783 flattens to a slope near zero at low frequencies, in a similar...
The Energy-dependent X-ray Timing Characteristics of the Narrow Line Seyfert 1 Mkn 766 (2006)
Markowitz, A., Papadakis, I. E., Arevalo, P., Turner, T. J., Miller, L., Reeves, J. N.
We present the energy-dependent power spectral density (PSD) and cross-spectral properties of Mkn 766, obtained from combining data obtained during an XMM-Newton observation spanning six revolutions...
Spectral-timing evidence for a Very High State in the Narrow Line Seyfert 1 Ark 564 (2006)
Arevalo, P., Papadakis, I. E., Uttley, P., McHardy, I. M., Brinkmann, W.
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...
Fluctuating-Accretion Model for AGN and BHXRB Variability (2006)
We model, phenomenologically, fluctuations in the accretion flow to explain the variability properties observed in X-ray light curves of accreting black hole systems. We show how the information...
The fluctuating accretion model of Lyubarskii (1997) and its extension by Kotov et al. (2001), seeks to explain the spectral-timing properties of the X-ray variability of accreting black holes in...
X-ray to UV Variability Correlation in MCG-6-30-15 (2004)
Arevalo, P., Papadakis, I., Kuhlbrodt, B., Brinkmann, W.
We used a ~300 ks long XMM-Newton observation of the Seyfert 1 galaxy MCG-6-30-15 to study the correlation between the 0.2-10 keV X-ray and the 3000-4000 A bands. We found a significant correlation...
X-ray variability of the Narrow Line Seyfert 1 Galaxy PKS 0558-504 (2003)
Brinkmann, W., Arevalo, P., Gliozzi, M., Ferrero, E.
We present results from several XMM-Newton observations of the radio loud Narrow-line Seyfert 1 galaxy (NLS1) PKS 0558-504. We find evidence for strong and persistent X-ray variability, both on short...