Investigation of a small X-ray flaring event in NLS1 galaxy NGC 4051

Abstract

We performed a detailed broadband spectral and timing analysis of a small flaring event of ~120 ks in a narrow-line Seyfert 1 galaxy NGC 4051 using simultaneous XMM-Newton and NuSTAR observations. The ~300 ks long NuSTAR observation and the overlapping XMM-Newton exposure were segregated into pre-flare, flare, and post-flare segments. During the flare, the NuSTAR count rate peaked at 2.5 times the mean count rate before the flare. Using various physical and phenomenological models, we examined the 0.3-50 keV X-ray spectrum, which consists of a primary continuum, reprocessed emission, warm absorber and ultra-fast outflows in different timescales. The mass of the central black hole is estimated to be >1.32*10^5 solar mass from the spectral analysis. The absence of correlation between flux in 6-7 keV and 10-50 keV bands suggests different origins of the iron emission line and the Compton hump. From the spectral analysis, we found that the reflection fraction drops significantly during the flare, accompanied by an increase in the coronal height above the disc. The spectrum became soft during the flare supporting the "softer when brighter" nature of the source. After the alleviation of the flare, the coronal height drops and the corona heats up. This indicates that there could be inflation of the corona during the flare. We found no significant change in the inner accretion disc or the seed photon temperature. These results suggest that the flaring event occurred due to the change in the coronal properties rather than any notable change in the accretion disc.

14 pages, 14 figures, Accepted for publication in MNRAS

References in corpus (16)

• HI4PI: A full-sky HI survey based on EBHIS and GASS
• BAT AGN Spectroscopic Survey - V. X-ray properties of the Swift/BAT 70-month AGN catalog
• Radio-loud Narrow-Line Type 1 Quasars
• The Hard X-ray Spectrum as a Probe for Black-Hole Growth in Radio-Quiet Active Galactic Nuclei
• Ionized outflows from active galactic nuclei as the essential elements of feedback
• 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
• Effects of Downscattering on the Continuum and Line Spectra in Powerful Wind Environment. Monte Carlo Simulations, Analytical Results and Data Analysis
• The $L_{\mathrm{x}}$-$L_{\mathrm{uv}}$-$L_{\mathrm{radio}}$ relation and corona-disk-jet connection in optically selected radio-loud quasars
• Black hole magnetosphere with small scale flux tubes--II. Stability and dynamics
• Acceleration and cooling of the corona during X-ray flares from the Seyfert galaxy I Zw 1
• Long term X-Ray Observations of Seyfert 1 Galaxy Ark 120: On the origin of soft-excess
• Nature of the Warm Absorber Outflow in NGC 4051
• More than softer-when-brighter: the X-Ray powerlaw spectral variability in NGC 4051
• Complex optical/UV and X-ray variability in Seyfert 1 galaxy Mrk 509
• Detection of a High-Temperature Blackbody Hump in Black Hole Spectra. The strongly redshifted annihilation line

Cited by in corpus (2)

• Detection of X-ray/UV delay in NGC 4051 using AstroSat observations
• Extracting the X-ray reverberation response functions from the AGN light curves using an autoencoder