Relativistic Fe K$\alpha$ Line Revealed in the Composite X-ray Spectrum of Narrow Line Seyfert 1 Galaxies --- do their black holes have averagely low or intermediate spins?

Abstract

While a broad profile of the Fe K$\alpha$ emission line is frequently found in the X-ray spectra of typical Seyfert galaxies, the situation is unclear in the case of Narrow Line Seyfert 1 galaxies (NLS1s)---an extreme subset which are generally thought to harbor less massive black holes with higher accretion rates. In this paper, the ensemble property of the Fe K$\alpha$ line in NLS1s is investigated by stacking the X-ray spectra of a large sample of 51 NLS1s observed with {\it XMM-Newton}. The composite X-ray spectrum reveals a prominent, broad emission feature over 4--7 keV, characteristic of the broad Fe K$\alpha$ line. In addition, there is an indication for a possible superimposing narrow (unresolved) line, either emission or absorption, corresponding to Fe XXVI or Fe XXV, respectively. The profile of the broad emission feature can well be fitted with relativistic broad-line models, with the line energy consistent either with 6.4 keV (i.e., neutral Fe) or with 6.67 keV (i.e., highly ionized Fe), in the case of the narrow line being emission and absorption, respectively. Interestingly, there are tentative indications for low or intermediate values of the average spins of the black holes ($a<0.84$), as inferred from the profile of the composite broad line. If the observed feature is indeed a broad line rather than resulting from partial covering absorption, our results suggest that a relativistic Fe line may in fact be common in NLS1s; and there are tentative indications that black holes in NLS1s may not spin very fast in general.

arXiv commentaccepted for publication in MNRAS

References in corpus (68)

• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database
• Foundations of Black Hole Accretion Disk Theory
• An XMM-Newton survey of broad iron lines in Seyfert galaxies
• ASCA observations of Seyfert 1 galaxies: II. Relativistic Iron K-alpha emission
• Broad iron lines in Active Galactic Nuclei
• Constraining Black Hole Spin Via X-ray Spectroscopy
• Black Hole Mass and Eddington Ratio as Drivers for the Observable Properties of Radio-Loud and Radio-Quiet QSOs
• The XMM-Newton Serendipitous Survey. V. The Second XMM-Newton Serendipitous Source Catalogue
• Relativistic X-ray Lines from the Inner Accretion Disks Around Black Holes
• A New Sample of Low-mass Black Holes in Active Galaxies
• A long hard look at MCG-6-30-15 with XMM-Newton
• The XMM-Newton wide-field survey in the COSMOS field: I. Survey description
• A Comprehensive Study of 2 000 Narrow Line Seyfert 1 Galaxies from the Sloan Digital Sky Survey: I. The Sample
• A Comprehensive Spectral and Variability Study of Narrow-Line Seyfert 1 Galaxies Observed by ASCA: II. Spectral Analysis and Correlations
• Cosmological black hole spin evolution by mergers and accretion
• Broad emission lines for negatively spinning black holes
• Active Galactic Nuclei with Candidate Intermediate-Mass Black Holes
• Narrow Line Seyfert 1 Galaxies and the Evolution of Galaxies & Active Galaxies
• A rapidly spinning supermassive black hole at the centre of NGC 1365
• The Evolution of Black Hole Mass and Spin in Active Galactic Nuclei
• Slim Disk Model for Soft X-Ray Excess and Variability of Narrow-Line Seyfert 1 Galaxies
• A spectrophotometric atlas of Narrow-Line Seyfert 1 galaxies
• CAIXA: a Catalogue of AGN In the XMM-Newton Archive I. Spectral analysis
• A Complete Sample of Soft X-ray Selected AGN: II. Statistical Analysis
• The Spin of Supermassive Black Holes
• An absorption origin for the X-ray spectral variability of MCG-6-30-15
• The Cores of the Fe K$\alpha$ Lines in Active Galactic Nuclei: an Extended Chandra High Energy Grating Sample
• The effect of radiation pressure on dusty absorbing gas around AGN
• Suzaku observations of the hard X-ray variability of MCG-6-30-15: the effects of strong gravity around a Kerr black hole
• A Complete Sample of Soft X-ray Selected AGN: I. The Data
• The Cores of the Fe K Lines in Seyfert I Galaxies Observed by the Chandra High Energy Grating
• On the Iwasawa-Taniguchi effect of radio-quiet AGN
• Narrow Components within the Fe Kalpha Profile of NGC 3516: Evidence for the Importance of General Relativistic Effects?
• Investigating the nature of narrow-line Seyfert 1 galaxies with high-energy spectral complexity
• FERO: Finding Extreme Relativistic Objects. I. Statistics of Relativistic Fe Kalpha lines in Radio-Quiet Type 1 AGN
• A Revised Broad-Line Region Radius and Black Hole Mass for the Narrow-Line Seyfert 1 NGC 4051
• An X-ray Baldwin effect for the narrow Fe K-alpha lines observed in Active Galactic Nuclei
• A Suzaku survey of Fe K lines in Seyfert 1 AGN
• Narrow-line Seyfert 1 Galaxies and the M_BH - sigma Relation
• Fe-K line probing of material around the AGN central engine with Suzaku
• The evolution of black-hole mass and angular momentum
• The Role of Secular Evolution in the Black Hole Growth of Narrow-Line Seyfert 1 Galaxies
• Narrow Iron K$\alpha$ Lines in Active Galactic Nuclei: Evolving Populations?
• Simultaneous NuSTAR and XMM-Newton 0.5-80 keV spectroscopy of the Narrow Line Seyfert 1 galaxy SWIFT J2127.4+5654
• The XMM-Newton HBS28 sample: studying the obscuration in hard X-ray selected AGNs
• Chandra High Energy Grating Observations of the Fe Ka Line Core in Type 2 Seyfert Galaxies: A Comparison with Type 1 Nuclei
• Fe XXV and Fe XXVI lines from low velocity, photoionised gas in the X-ray spectra of AGN
• XMM-Newton observations of the Narrow-Line Seyfert 1 galaxy Mrk 335 in an historical low X-ray flux state
• Supermassive black holes, pseudobulges, and the narrow-line Seyfert 1 galaxies
• A Very Radio-Loud Narrow-Line Seyfert 1: PKS 2004-447
• A new way to measure supermassive black hole spin in accretion disc dominated Active Galaxies
• An intermediate black hole spin in the NLS1 galaxy SWIFT J2127.4+5654: chaotic accretion or spin energy extraction?
• Chandra-SDSS Normal and Star-Forming Galaxies I: X-ray Source Properties of Galaxies Detected by Chandra in SDSS DR2
• XMM-Newton observations of the Lockman Hole: III. A relativistic Fe line in the mean X-ray spectra of type-1 and type-2 AGN
• X-Ray Properties of Narrow-Line Seyfert 1 Galaxies with Very Small Broad-Line Widths
• Ionized iron Kαlines in AGN X-ray spectra
• Evidence for relativistic features in the X-ray spectrum of Mrk 335
• Statistics of relativistically broadened Fe K-alpha lines in AGN
• Luminosity-dependent unification of Active Galactic Nuclei and the X-ray Baldwin effect
• Average Fe K-alpha emission from distant AGN
• Fe K emission from active galaxies in the COSMOS field
• Modeling the Fe K Line Profiles in Type I AGN with a Compton-Thick Disk Wind
• A comparison of hard X-ray photon indices and iron \ka emission lines in X-ray luminous narrow- and broad-line Seyfert 1 galaxies
• An AGN Sample with High X-ray-to-optical Flux Ratio from RASS II.Optical Emission Line Properties of Seyfert 1 Type AGN
• Rest-frame stacking of 2XMM catalog sources : Properties of the Fe Kalpha line
• The role of the Gamma-Eddington ratio relation on the X-ray Baldwin effect in Active Galactic Nuclei
• Relativistic reflection in the average X-ray spectrum of AGN in the Véron-Cetty & Véron catalogue

Cited by in corpus (16)

• X-ray spectral properties of the AGN sample in the northern XMM-XXL field
• The Radio Properties of Radio-Loud Narrow-Line Seyfert 1 Galaxies on Parsec Scales
• Detection of a possible X-ray Quasi-periodic Oscillation in the Active Galactic Nucleus 1H~0707-495
• The new class of FR0 radio galaxies
• Disk-Jet Connection in Active Supermassive Black Holes in the Standard Accretion Disk Regime
• Testing wind as an explanation for the spin problem in the continuum-fitting method
• Properties of the narrow line Seyfert 1 galaxies revisited
• Reconciling AGN-star formation, the Soltan argument, and Meier's paradox
• Dependence of the broad Fe K$\alpha$ line on the physical parameters of AGN
• Effect of accreting tidally disrupted stars on the spin evolution of $\sim 10^6{M}_{\odot }$ black holes
• Exploring the physics of the accretion and jet in nearby narrow-line Seyfert 1 galaxies
• X-ray spectral and temporal analysis of Narrow Line Seyfert 1 galaxy Was 61
• A Systematic Study of the Short-Term X-ray Variability of Seyfert Galaxies I. Diversity of the X-ray Rms Spectra
• A Suzaku sample of unabsorbed narrow-line and broad-line Seyfert 1 galaxies: II. Iron emission and absorption
• Broad Band X-ray Constraints on the Accreting Black Hole in Quasar 4C 74.26
• Estimate of SMBH Spin for Narrow-Line Seyfert 1 Galaxies