X‐Ray Spectral Variability and Rapid Variability of the Soft X‐Ray Spectrum Seyfert 1 Galaxies Arakelian 564 and Ton S180

Edelson, R.; Turner, T. J.; Pounds, K. A.; Vaughan, S.; Markowitz, A.; Marshall, Herman L.; Dobbie, P. D.; Warwick, R. S.

doi:10.1086/323779

Cited by 410 publications

(397 citation statements)

References 46 publications

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“…The fast variations therefore appear be associated mainly with the harder X-rays. This is supported by the finding that the X-ray variation power density spectrum flattens with increasing energy in NGC 7469 , Akn 564, and Ton S180 (Edelson et al 2002a).…”

Section: Discussionmentioning

confidence: 58%

X-Ray versus Optical Variations in the Seyfert 1 Nucleus NGC 3516: A Puzzling Disconnectedness

Maoz¹,

Markowitz²,

Edelson³

et al. 2002

The Astronomical Journal

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We present optical broadband (B and R) observations of the Seyfert 1 nucleus NGC 3516 obtained at Wise Observatory from 1997 March to 2002 March, contemporaneously with X-ray 2-10 keV measurements with RXTE. With these data we increase the temporal baseline of this data set to 5 years, more than triple the coverage we have previously presented for this object. Analysis of the new data does not confirm the 100 day lag of X-ray behind optical variations tentatively reported in our previous work. Indeed, excluding the first year's data, which drove the previous result, there is no significant correlation at any lag between the X-ray and optical bands. We also find no correlation at any lag between optical flux and various X-ray hardness ratios. We conclude that the close relation observed between the bands during the first year of our program was either a fluke or perhaps the result of the exceptionally bright state of NGC 3516 in 1997, to which it has yet to return. Reviewing the results of published joint X-ray and UV-optical Seyfert monitoring programs, we speculate that there are at least two components or mechanisms contributing to the X-ray continuum emission up to 10 keV: a soft component that is correlated with UV-optical variations on timescales e1 day and whose presence can be detected when the source is observed at low enough energies ($1 keV), is unabsorbed, or is in a sufficiently bright phase, and a hard component whose variations are uncorrelated with the UV-optical.

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Section: Discussionmentioning

confidence: 58%

X-Ray versus Optical Variations in the Seyfert 1 Nucleus NGC 3516: A Puzzling Disconnectedness

Maoz¹,

Markowitz²,

Edelson³

et al. 2002

The Astronomical Journal

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“…Edelson et al 2002;Nandra et al 1997 and references therein), where S 2 is the observed variance of the time series with N bins, i.e.…”

Section: Variability Characterisationmentioning

confidence: 99%

TheXMM-Newtonserendipitous survey

Rosen

Webb

Watson

et al. 2016

A&A

313

150

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Context. Thanks to the large collecting area (3 × ∼1500 cm 2 at 1.5 keV) and wide field of view (30 across in full field mode) of the X-ray cameras on board the European Space Agency X-ray observatory XMM-Newton, each individual pointing can result in the detection of up to several hundred X-ray sources, most of which are newly discovered objects. Since XMM-Newton has now been in orbit for more than 15 yr, hundreds of thousands of sources have been detected. Aims. Recently, many improvements in the XMM-Newton data reduction algorithms have been made. These include enhanced source characterisation and reduced spurious source detections, refined astrometric precision of sources, greater net sensitivity for source detection, and the extraction of spectra and time series for fainter sources, both with better signal-to-noise. Thanks to these enhancements, the quality of the catalogue products has been much improved over earlier catalogues. Furthermore, almost 50% more observations are in the public domain compared to 2XMMi-DR3, allowing the XMM-Newton Survey Science Centre to produce a much larger and better quality X-ray source catalogue. Methods. The XMM-Newton Survey Science Centre has developed a pipeline to reduce the XMM-Newton data automatically. Using the latest version of this pipeline, along with better calibration, a new version of the catalogue has been produced, using XMM-Newton X-ray observations made public on or before 2013 December 31. Manual screening of all of the X-ray detections ensures the highest data quality. This catalogue is known as 3XMM. Results. In the latest release of the 3XMM catalogue, 3XMM-DR5, there are 565 962 X-ray detections comprising 396 910 unique X-ray sources. Spectra and lightcurves are provided for the 133 000 brightest sources. For all detections, the positions on the sky, a measure of the quality of the detection, and an evaluation of the X-ray variability is provided, along with the fluxes and count rates in 7 X-ray energy bands, the total 0.2-12 keV band counts, and four hardness ratios. With the aim of identifying the detections, a cross correlation with 228 catalogues of sources detected in all wavebands is also provided for each X-ray detection. Conclusions. 3XMM-DR5 is the largest X-ray source catalogue ever produced. Thanks to the large array of data products associated with each detection and each source, it is an excellent resource for finding new and extreme objects.Key words. catalogs -astronomical databases: miscellaneous -surveys -X-rays: general Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.The catalogue is available at http://cdsarc.u-strasbg.fr/ viz-bin/VizieR?-meta.foot&-source=IX/46

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“…Subsequently, better quality lightcurves have provided stronger evidence of a linear rms-flux relation in AGN (in Akn 564, Edelson et al 2002;and MCG-6-30-15, Vaughan et al 2003). With the excellent quality of the present XMM-Newton lightcurve, together with the high variability of this source, we examine the rms-flux relation of NGC 4051 in similar detail.…”

Section: The Rms-flux Relationshipmentioning

confidence: 99%

Combined long and short timescale X-ray variability of NGC 4051 with RXTE and XMM-Newton

McHardy¹,

Papadakis²,

Uttley³

et al. 2004

Nuclear Physics B - Proceedings Supplements

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We present a comprehensive examination of the X-ray variability of the narrow line Seyfert 1 (NLS1) galaxy NGC 4051, one of the most variable AGN in the sky. We combine over 6.5 years of frequent monitoring observations by RXTE with a > 100 ks continuous observation by XMM-Newton and so present an overall 2-10 keV powerspectral density (PSD) covering an unprecedent frequency range of over 6.5 decades from < 10 −8 to > 10 −2 Hz. The combined RXTE and XMM-Newton PSD is a very good match to the PSD of the galactic black hole binary system (GBH) Cyg X-1 when in a 'high', rather than 'low', state providing the first definite confirmation of an AGN in a 'high' state. We also find that a bending powerlaw, rather than a sharply broken powerlaw, besides being more physical, is a much better description of the high state PSD of Cyg X-1 and is also a better description of the PSD of NGC 4051.At low frequencies the PSD of NGC 4051 has a slope of -1.1 bending, at a frequency ν B = 8 +4 −3 × 10 −4 Hz, to a slope of α H ∼ −2. Although ν B does not depend on photon energy, α H is steeper at lower energies. If ν B scales with mass, we imply a black hole mass of 3 +2 −1 × 10 5 M ⊙ in NGC 4051, which is consistent with the recently reported reverberation value of 5 +6 −3 × 10 5 M ⊙ . Hence NGC 4051 is emitting at ∼ 30% L Edd . NGC 4051 follows the same rms-flux relationship as GBHs, consistent with higher Fourier frequencies being associated with smaller radii.From the cross-powerspectra and cross-correlation functions between XMMNewton lightcurves in different energy bands, we note that the higher energy photons lag the lower energy ones. We also note that the lag is greater for variations of longer Fourier period and increases with the energy separation of the bands. Variations in different wavebands are very coherent at long Fourier periods but the coherence decreases at shorter periods and as the energy separation between bands increases. This behaviour is again similar to that of GBHs, and of MCG-6-30-15, and suggests a radial distribution of frequencies and photon energies with higher energies and higher frequencies being associated with smaller radii.Combining our observations with observations from the literature we find it is not possible to fit all AGN to the same linear scaling of break timescale with black hole mass. However broad line AGN are consistent with a linear scaling of break timescale with mass from Cyg X-1 in its low state and NLS1 galaxies scale better with Cyg X-1 in its high state. We suggest that the relationship between black hole mass and break timescale is a function of at least one other underlying parameter which may be accretion rate or black hole spin or both.

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X‐Ray Spectral Variability and Rapid Variability of the Soft X‐Ray Spectrum Seyfert 1 Galaxies Arakelian 564 and Ton S180

Cited by 410 publications

References 46 publications

X-Ray versus Optical Variations in the Seyfert 1 Nucleus NGC 3516: A Puzzling Disconnectedness

X-Ray versus Optical Variations in the Seyfert 1 Nucleus NGC 3516: A Puzzling Disconnectedness

TheXMM-Newtonserendipitous survey

Combined long and short timescale X-ray variability of NGC 4051 with RXTE and XMM-Newton

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