Long Term Spectral Variability of Seyfert Galaxies from RXTE Color-Flux Diagrams

Abstract

We present results from RXTE data obtained during a systematic monitoring program of four Seyfert galaxies (NGC5548, NGC5506, MCG-6-30-15 and NGC4051). We studied the variability of three hardness ratios derived from the light curves in four energy bands. All the objects show similar spectral variations in all ratios. In order to interpret the results we computed the hardness ratios corresponding to a simple spectral model of a power law plus iron line plus reflection component, considering two possibilities: a)variations with constant line equivalent width and reflection parameter R and b) variations with constant line and reflection flux. The overall, mean observed trends can be explained by spectral slope variations and a constant flux Fe line and reflection component, although the existence of a line component which is variable on short time scales cannot be excluded. Finally, we find that the data are not consistent with an increase of R with flux for individual sources, indicating that, as a single source varies, softer spectra do not correspond to larger R values.

24 pages, 8 figures, accepted for publication in ApJ

References in corpus (2)

• Measuring the broadband power spectra of active galactic nuclei with RXTE
• Ubiquitous variability of X-ray absorbing column densities in Seyfert 2 Galaxies

Cited by in corpus (36)

• A light bending model for the X-ray temporal and spectral properties of accreting black holes
• First X-ray-Based Statistical Tests for Clumpy-Torus Models: Eclipse Events from 230 Years of Monitoring of Seyfert AGN
• Correlations between X-ray and radio spectral properties of accreting black holes
• A long, hard look at MCG-6-30-15 with XMM-Newton II: detailed EPIC analysis and modelling
• The long term X-ray spectral variability of AGN
• X-ray Absorption and Reflection in Active Galactic Nuclei
• An Expanded RXTE Survey of X-ray Variability in Seyfert 1 Galaxies
• Connection between the Accretion Disk and Jet in the Radio Galaxy 3C 111
• Observatory science with eXTP
• A self-consistent hybrid Comptonization model for broad-band spectra of accreting supermassive black holes
• Suzaku Observation of a Hard Excess in 1H 0419-577: Detection of a Compton-Thick Partial-Covering Absorber
• Long-Term X-Ray and TeV variability of Mrk 501
• The recent X-ray history of NGC 5506
• On the origin of the X-rays and the nature of accretion in NGC 4261
• Blazar nuclei in radio-loud narrow-line Seyfert 1?
• X-ray Characteristics of NGC 3516: A View through the Complex Absorber
• Twelve and a Half Years of Observations of Centaurus A with RXTE
• Long-Term, Continuous Monitoring of the Broad Line Radio Galaxies 3C 390.3 and 3C 120 With the Rossi X-Ray Timing Explorer
• X-ray Variability Characteristics of the Seyfert 1 Galaxy NGC 3783
• Spectral Analysis of the Accretion Flow in NGC 1052 with Suzaku
• X-ray to UV Variability Correlation in MCG-6-30-15
• Long-term monitoring of PKS0558-504 with Swift: the disc-corona link
• Gravitational effects on the high energy emission of accreting black holes
• The polyhedral nature of LINERs: An XMM-Newton view of LINERs in radio galaxies
• The nature of a broad line radio galaxy: Simultaneous RXTE and Chandra HETG observations of 3C 382
• Constraining black hole masses in low-accreting AGN using X-ray spectra
• Reflection at large distance from the central engine in Seyferts
• The long time-scale X-ray variability of the radio-quiet quasar PG 0804+761
• Spectral Signature of Wind Generation From The Post-Shock Region in GRS1915+105 Accretion Disk
• Exploring the disc/jet interaction in the radio-loud quasar 4C +74.26 with Suzaku
• Correlated spectral and temporal changes in 3C 390.3: a new link between AGN and Galactic Black Hole Binaries?
• Long-Term X-Ray spectral variability of the radio-loud NLS1 galaxy PKS 0558-504
• Extended Corona Models of X-ray Reverberation in the AGN 1H~0707-495 and IRAS 13224-3809
• Possible X-ray diagnostic for jet/disk dominance in Type 1 AGN
• Long-Term X-Ray monitoring of NGC6251: Evidence for a jet-dominated radio galaxy
• Models for the X-ray spectra and variability of luminous accreting black holes