Average Quasar Spectra in the Context of Eigenvector 1

By J. Sulentic, P. Marziani, R. Zamanov, R. Bachev, M. Calvani, D. Dultzin-Hacyan. 2002

133 citations recorded by the source corpus.

Recent work has shown that it is possible to systematize quasar spectral diversity in a parameter space called "Eigenvector 1" (E1). We present median active galactic nucleus (AGN) spectra for fixed regions of the E1 (optical) parameter space [FWHM(Hβ) vs. equivalent width ratio R = W(Fe II λ4570)/W(Hβ)]. Comparison of the median spectra shows considerable differences. We suggest that an E1-driven approach to median/average spectra emphasizes significant differences between AGNs and offers more insights into AGN physics than a single-population median/average spectrum derived from a large and heterogeneous sample of sources. We find that the Hβ broad component line profile changes along the E1 sequence in FWHM, centroid shift, and profile asymmetry. While objects with FWHM(HβBC) ≲ 4000 km s-1 are well fitted by a Lorentz function, AGNs with FWHM(HβBC) ≳ 4000 km s-1 are better fitted if two broad-line components are used: a "classical" broad-line component and a very broad/redshifted component.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b341ff896593857a36e9c8a1e0841f2359deb02b

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Citations in the corpus

ANALYSIS OF OPTICAL Fe ii EMISSION IN A SAMPLE OF ACTIVE GALACTIC NUCLEUS SPECTRA (2010, methodology): “A similar subdivision of AGN samples was performed by Sulentic et al. (2002, 2009) and Zamfir et al. (2010), but for FWHM Hβ ≈ 4000 km s−1 as the limiting FWHM of the subdivision.”
Red and Reddened Quasars in the Sloan Digital Sky Survey (2003, methodology): “On the other hand, Sulentic et al. (2002) found that it was the radio-quiet quasars that tended to have the narrowest H emission lines and the largest soft X-ray excesses.”
The evolution of the broad-line region among SDSS quasars (2005, background): “It is also reported that the best-fit profile function may depend on the velocity width and other AGN properties (e.g., Sulentic et al. 2002).”
C IV λ1549 as an Eigenvector 1 Parameter for Active Galactic Nuclei (2007, background): “Sources with FWHM(H BC)P 4000 km s 1 show average profiles well fit by a Lorentzian function, while broader line sources show profiles that are frequently redward asymmetric and that require two Gaussians for a reasonable fit (Sulentic et al. 2002).”
Radio-loud Narrow-Line Type 1 Quasars (2006, methodology): “Spectra of high resolution and S/N would allow a search for similarities/differences in emission lines between radio-loud and radio-quiet NLS1s the same way it is now rigorously done for broad- and narrow-line objects (e.g., Veron et al. 2001, Sulentic et al. 2002, Bachev et al. 2004).”
A LARGE SYSTEMATIC SEARCH FOR CLOSE SUPERMASSIVE BINARY AND RAPIDLY RECOILING BLACK HOLES (2011, unknown): “The vast majority of our objects belong to their population B (FWHMHβ > 4, 000 km s −1, weak Fe ii lines; see Sulentic et al. 2002), whose dis- tribution of broad Hβ shifts shows some preference for redshifts and has extrema of ±3100 km s−1.”
An Optical Spectroscopic Atlas of Low-Redshift Active Galactic Nuclei (2003, methodology): “The sample presented here was already used to calculate average spectra in the eigenvector 1 context (Sulentic et al. 2002) and to search for objects with large shifts between H and [O iii] 5007 (Zamanov et al. 2002).”
A CATALOG OF QUASAR PROPERTIES FROM SLOAN DIGITAL SKY SURVEY DATA RELEASE 7 (2010, background): “It appears that the radioloud contours are more vertically elongated, broadly consistent with the phenomenological classification scheme based on the 4DE1 parameter space (e.g., Sulentic et al. 2000, 2002; Zamfir et al. 2010).”