Long-Term X-Ray spectral variability of the radio-loud NLS1 galaxy PKS 0558-504
arXiv:astro-ph/0611348 · doi:10.1086/510798
Abstract
We present X-ray observations of the Narrow-Line Seyfert 1 galaxy PKS 0558-504 obtained with RXTE during a 1-year monitoring campaign. This source, which is one of the very few radio-loud NLS1 galaxies, shows strong X-ray flux variability on time scales of weeks-months accompanied by spectral variability. The main goal of this study is to investigate the spectral variability with model-independent methods and time-resolved spectroscopy in order to shed light on the origin of the X-rays. The main results can be summarized as follows: 1) The flux typically changes by a factor of 1.5-2 on time scales of 10-30 days, with few extreme events where the flux increases by a factor of ~4 in 3 days. 2) We do not observe any large amplitude, flux related spectral variations. During the flux variations, the spectrum varies mainly in normalization and not in shape. We do observe some small amplitude spectral variations, which do not correlate with flux, although there is a hint of spectral hardening as the source brightens. 3) There is no evidence for reprocessing features such as the Fe Kalpha line or a Compton hump. We argue that PKS 0558-504 is a peculiar object that appears to be different from most of the radio-quiet and radio-loud AGN. If a jet is responsible for the bulk of the X-rays, it must operate in an unusual way. If instead a corona is responsible for the X-rays, the system might be a large-scale analog of the Galactic black holes in the transient intermediate state.
arXiv comment12 pages, 7 figures, accepted for publication in ApJ
References in corpus (39)
- First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Preliminary Maps and Basic Results
- Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei
- Towards a unified model for black hole X-ray binary jets
- On characterising the variability properties of X-ray light curves from active galaxies
- An Explanation for the soft X-ray excess in AGN
- In-flight Performance of the High Energy X-ray Timing Experiment on the Rossi X-ray Timing Explorer
- A Comprehensive Spectral and Variability Study of Narrow-Line Seyfert 1 Galaxies Observed by ASCA: II. Spectral Analysis and Correlations
- Radio-loud Narrow-Line Type 1 Quasars
- Eigenvector 1: An Optimal Correlation Space for Active Galactic Nuclei
- Narrow Line Seyfert 1 Galaxies and the Evolution of Galaxies & Active Galaxies
- Soft state of Cygnus X-1: stable disk and unstable corona
- GX 339-4: the distance, state transitions, hysteresis and spectral correlations
- A Comprehensive Spectral and Variability Study of Narrow-Line Seyfert 1 Galaxies Observed by ASCA: I. Observations and Time Series Analysis
- M-BH - sigma relation for a Complete Sample of Soft X-ray Selected AGNs
- A Complete Sample of Soft X-ray Selected AGN: II. Statistical Analysis
- ROSAT monitoring of persistent giant and rapid variability in the narrow-line Seyfert 1 galaxy IRAS 13224-3809
- Long-Term X-ray Spectral Variability in Seyfert 1 Galaxies
- Characteristic X-ray Variability of TeV Blazars: Probing the Link between the Jet and the Central Engine
- An Expanded RXTE Survey of X-ray Variability in Seyfert 1 Galaxies
- X-ray variability in a complete sample of Soft X-ray selected AGN
- Evidence for Ionised Accretion Discs in Five Narrow-Line Seyfert 1 Galaxies
- The nature of X-ray spectral variability in Seyfert Galaxies
- Patterns of energy-dependent variability from Comptonization
- ROSAT HRI Monitoring of Extreme X-ray Variability in the Narrow-Line Quasar PHL 1092
- X-ray Emission of Mkn 421: New Clues From Its Spectral Evolution. I. Temporal Analysis
- An RXTE Survey of Long-Term X-ray Variability in Seyfert 1 Galaxies
- Long-term spectral changes in the partial-covering candidate NLS1 1H 0707-495
- Long-Term X-Ray and TeV variability of Mrk 501
- Multiwavelength Observations of the Blazar Mrk 421 in December 2002 and January 2003
- Extreme X-ray Variability In The Narrow-Line QSO PHL 1092
- Long Term Spectral Variability of Seyfert Galaxies from RXTE Color-Flux Diagrams
- RXTE Observations of 3C273 between 1996 and 2000:Variability Timescale and Jet Power
- XMM-Newton Detection of a Comptonized Accretion Disc in the Quasar PKS0558-504
- A Rapid X-ray Flare in the Radio-loud Narrow Line Quasar PKS 0558-504
- Modeling the X-ray Contribution of X-ray Binary Jets
- XMM-Newton monitoring of X-ray variability in the quasar PKS 0558-504
- X-ray variability of the Narrow Line Seyfert 1 Galaxy PKS 0558-504
- The long time-scale X-ray variability of the radio-quiet quasar PG 0804+761
- Correlated spectral and temporal changes in 3C 390.3: a new link between AGN and Galactic Black Hole Binaries?
Cited by in corpus (9)
- A panchromatic view of PKS 0558-504: an ideal laboratory to study the disk-jet link
- A Suzaku sample of unabsorbed narrow-line and broad-line Seyfert 1 galaxies: I. X-ray spectral properties
- X-ray flux variability of active galactic nuclei observed using NuSTAR
- SDSS J075101.42+291419.1: A Super-Eddington Accreting Quasar with Extreme X-ray Variability
- 3D Spectroscopic Study of the Line Emitting Regions of Mrk 493
- A Chandra view of Naked Active Galactic Nuclei
- XMM-Newton long-look observation of the narrow line Seyfert 1 galaxy PKS0558-504; I: Spectral analysis
- Accretion disk/corona emission from a radio-loud narrow line Seyfert 1 galaxy PKS 0558-504
- Revisiting the Continuum Reverberation Lags in the AGN PKS 0558-504