Nature of the Warm Absorber Outflow in NGC 4051

Abstract

The Narrow-line Seyfert 1 galaxy NGC 4051 is known to exhibit significant X-ray spectral/flux variations and have a number of emission/absorption features. X-ray observations have revealed that these absorption features are blueshifted, which indicates that NGC 4051 has warm absorber outflow. In order to constrain physical parameters of the warm absorber outflow, we analyze the archival data with the longest exposure taken by XMM-Newton in 2009. We calculate the root-mean-square (RMS) spectra with the grating spectral resolution for the first time. The RMS spectra have a sharp peak and several dips, which can be explained by variable absorption features and non-variable emission lines; a lower-ionized warm absorber (WA1: $\log \xi =1.5,v=-650{\mathrm{km}\mathrm{s}}^{-1}$) shows large variability, whereas higher-ionized warm absorbers (WA2: $\log \xi =2.5,v=-4100{\mathrm{km}\mathrm{s}}^{-1}$, WA3: $\log \xi =3.4,v=-6100{\mathrm{km}\mathrm{s}}^{-1}$) show little variability. WA1 shows the maximum variability at a timescale of $\sim 10^4$~s, suggesting that the absorber locates at $\sim 10^3$ times of the Schwarzschild radius. The depth of the absorption features due to WA1 and the observed soft X-ray flux are anti-correlated in several observational sequences, which can be explained by variation of partial covering fraction of the double-layer blobs that are composed of the Compton-thick core and the ionized layer ($=$WA1). WA2 and WA3 show little variability and presumably extend uniformly in the line of sight. The present result shows that NGC 4051 has two types of the warm absorber outflows; the static, high-ionized and extended line-driven disk winds, and the variable, low-ionized and clumpy double-layer blobs.

Accepted for MNRAS. Sorry for broken hyperref (citation of references is broken). Please find the published version

References in corpus (8)

• An XMM-Newton survey of broad iron lines in Seyfert galaxies
• A fast and long-lived outflow from the supermassive black hole in NGC 5548
• XMM-Newton study of the complex and variable spectrum of NGC 4051
• A Revised Broad-Line Region Radius and Black Hole Mass for the Narrow-Line Seyfert 1 NGC 4051
• Timing the warm absorber in NGC 4051
• High-resolution X-ray spectroscopy of the low and high states of the Seyfert 1 galaxy NGC 4051 with Chandra LETGS
• Interpretation of the X-ray Spectral Variation of 1H0707-495 with a Variable Double Partial Covering Model
• Origin of the Characteristic X-ray Spectral Variations of IRAS 13224$-$3809

Cited by in corpus (11)

• The soft X-ray excess: NLS1s vs. BLS1s
• Incoherent fast variability of X-ray obscurers. The case of NGC 3783
• Kinetic energy transfer from X-ray ultrafast outflows to mm/sub-mm cold molecular outflows in Seyfert galaxies
• Deep Chandra Observations of NGC 5728: Morphology and Spectral Properties of the Extended X-ray Emission
• Warm Absorbers in the Radiation-driven Fountain Model of Low-mass Active Galactic Nuclei
• A deep, multi-epoch Chandra HETG study of the ionized outflow from NGC 4051
• X-ray timing and spectral analysis of reverberating active galactic nuclei
• Investigation of a small X-ray flaring event in NLS1 galaxy NGC 4051
• Stellar wind variability in Cygnus X-1 from high-resolution excess variance spectroscopy with Chandra
• Simple interpretation of the seemingly complicated X-ray spectral variation of NGC 5548
• A broadband X-ray study of a sample of AGNs with [OIII] measured inclinations