A Complete Sample of Soft X-Ray-selected AGNs. II. Statistical Analysis

By D. Grupe. 2004

167 citations recorded by the source corpus.

Direct correlations and a principal component analysis (PCA) are presented for a complete sample of 110 soft X-ray–selected AGNs, of which about half are narrow-line Seyfert 1 galaxies (NLS1's). The direct correlation analyses show that narrower FWHM(Hβ) correlates with steeper X-ray spectrum, stronger optical Fe II emission, weaker [O III] emission and stronger short-term X-ray variability. This direct correlation analysis and the PCA confirm the Boroson & Green (1992) eigenvector 1 relationship for AGNs: Fe II strength anticorrelates with [O III] line strength. Eigenvector 1 is well correlated with the Eddington luminosity ratio L/LEdd, while eigenvector 2 shows a very good correlation with the mass of the central black hole MBH and the mass accretion rate . The Eddington ratio L/LEdd correlates with the X-ray spectral index αX and the black home mass MBH anticorrelates with the X-ray variability χ2/ν. The Eddington ratio L/LEdd may be interpreted as the age of an AGN: AGNs with steep X-ray spectra, strong Fe II, and weak [O III] are AGNs in an early phase of their evolution. In this hypothesis, NLS1's are young AGNs.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/c4117ef4e80311984959d380d5da1108d223faf9

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In Astronomy and Astrophysics

1. R. Maiolino
2. S. Komossa
3. K. Leighly
4. A. Marconi
5. Tohru Nagao
6. D. Grupe
7. Wolfgang J. Duschl
8. K. Page

Citations in the corpus

• The Effect of Radiation Pressure on Virial Black Hole Mass Estimates and the Case of Narrow-Line Seyfert 1 Galaxies (2008, background): “Many different authors have undertaken the task of measuring virial BH masses in NLS1 galaxies and found that they are small compared to broad line AGNs with similar luminosities (e.g. Grupe 2004).”
• A Comprehensive Study of 2000 Narrow Line Seyfert 1 Galaxies from the Sloan Digital Sky Survey. I. The Sample (2006, result): “For instance, Puchnarewicz et al. (1992) found that about 50% of their soft X-ray–selected AGNs were NLS1s; a similar result was also obtained by Grupe (2004).”
• On the Nature of Seyfert Galaxies with High [O III] λ5007 Blueshifts (2008, background): “NLS1 galaxies are a subclass of AGN with extreme emission-line and continuum prop- erties which appear to be in part driven by their high Eddington ratios, low black hole masses, and other parameters (e.g., Osterbrock & Pogge 1985, Boroson 2002, Grupe 2004; see Komossa 2008 for a review).”
• Radio-loud Narrow-Line Type 1 Quasars (2006, methodology): “…1992, Pounds et al. 1995, Wang et al. 1996, Boller et al. 1996, Laor et al. 1997, Czerny et al. 1997, Marziani et al. 2001, Boroson 2002, Simkin & Roychowdhury 2003, Xu et al. 2003, Kawaguchi 2003, Wang & Netzer 2003, Grupe 2004, Grupe & Mathur 2004, Botte et al. 2004, Collin & Kawaguchi 2004).”
• THE SIMULTANEOUS OPTICAL-TO-X-RAY SPECTRAL ENERGY DISTRIBUTION OF SOFT X-RAY SELECTED ACTIVE GALACTIC NUCLEI OBSERVED BY SWIFT (2010, methodology): “This correlation is similar to those found previously by Grupe (2004) and Shemmer et al. (2008) who reported strong correlations between the Eddington ratio L/LEdd and 11Note that this result may be an artifact of assuming a single power law to fit the whole X-ray spectrum.”