On the Nature of Seyfert Galaxies with High [O III] λ5007 Blueshifts

By S. Komossa, Dong Xu, Hongyan Zhou, T. Storchi-Bergmann, L. Binette. 2008

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We have studied the properties of Seyfert galaxies with high [O III] λ5007 blueshifts (“blue outliers”), originally identified because of their strong deviation from the MBH − σ relation of normal, narrow-line Seyfert 1 (NLS1) and broad-line Seyfert 1 (BLS1) galaxies. These blue outliers turn out to be important test beds for models of the narrow-line region (NLR), for mechanisms of driving large-scale outflows, for links between NLS1 galaxies and radio galaxies, and for orientation-dependent NLS1 models. We report the detection of a strong correlation of line blueshift with ionization potential in each galaxy, including the measurement of coronal lines with radial velocities up to 500-1000 km s−1, and we confirm a strong correlation between [O III] blueshift and line width. All [O III] blue outliers have narrow widths of their broad Balmer lines and high Eddington ratios. While the presence of nonshifted low-ionization lines signifies the presence of a classical outer quiescent NLR in blue outliers, we also report the absence of any second, nonblueshifted [O III] component from a classical inner NLR. These results place tight constraints on NLR models. We favor a scenario in which the NLR clouds are entrained in a decelerating wind, which explains the strong stratification and the absence of a zero-blueshift inner NLR of blue outliers. The origin of the wind remains speculative at this time (collimated radio plasma, thermal winds, or radiatively accelerated clouds). It is perhaps linked to the high Eddington ratios of blue outliers. Similar, less powerful winds could be present in all Seyfert galaxies, but would generally only affect the coronal line region (CLR), or level off even before reaching the CLR. Similarities between blue outliers in NLS1 galaxies and (compact) radio sources are briefly discussed.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/6c1c1355bc323618f94f59b736d3ba66f6189446

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Citations in the corpus

INSPIRALLING SUPERMASSIVE BLACK HOLES: A NEW SIGNPOST FOR GALAXY MERGERS (2008, background): “AGN Outflows and Jets Velocity shifts of [O III] emission lines can also be explained by a strong, decelerating wind in the inner NLR of the AGN (Komossa et al. 2008a).”
Discovery of extreme [O III] λ5007 Å outflows in high-redshift red quasars (2015, background): “…in known type 2 quasars, especially in those with the strongest outflow signatures (Zakamska & Greene 2014), presumably due to the well-known but poorly understood stratification of the narrow-line region (e.g. Whittle 1985b; De Robertis & Osterbrock 1986; Veilleux 1991b; Komossa et al. 2008).”
A CATALOG OF QUASAR PROPERTIES FROM SLOAN DIGITAL SKY SURVEY DATA RELEASE 7 (2010, background): “Since the [OIII] λλ4959,5007 lines frequently show asymmetric blue wings (e.g., Heckman et al. 1981; Greene & Ho 2005a; Komossa et al. 2008) and sometimes even more dramatic 9 Hewett & Wild (2010) provided improved redshifts for SDSS quasars.”
Kiloparsec-scale outflows are prevalent among luminous AGN: outflows and feedback in the context of the overall AGN population (2014, background): “…[SDSS]; York et al. 2000) have enabled the study of NLR kinematics in hundreds to tens of thousands of AGN (e.g., Boroson 2005; Greene & Ho 2005; Komossa et al. 2008; Zhang et al. 2011; Wang et al. 2011; Mullaney et al. 2013) that can constrain both the ubiquity ofthese outflow features and…”
Galaxy Zoo Green Peas: discovery of a class of compact extremely star-forming galaxies (2009, methodology): “This careful fitting can decrease the galaxy host mass measurement, placing the Narrow Line Seyfert 1 on the MBH-σ relation (Komossa et al. 2008).”
Narrow-line region gas kinematics of 24 264 optically selected AGN: the radio connection (2013, background): “…1 AGNs with narrow Balmer lines (i.e. <4000 km s−1) and, in particular, NLS1s show a tendency to have more prominent [O III] λ5007 blue wings or blueshifts compared to BLS1s (e.g. Marziani et al. 2003; Komossa et al. 2008) – a feature previously attributed to the higher Eddington ratios of NLS1s.”