A MODEL FOR TYPE 2 CORONAL LINE FOREST (CLiF) AGNs

Storchi‐Bergmann

Monthly Notices of the Royal Astronomical Society

et al. 2017

We use the Gemini Near-Infrared Integral Field Spectrograph (NIFS) to map the stellar kinematics of the inner few hundred parsecs of a sample of 16 nearby Seyfert galaxies, at a spatial resolution of tens of parsecs and spectral resolution of 40 km s −1. We find that the line-of-sight (LOS) velocity fields for most galaxies are well reproduced by rotating disc models. The kinematic position angle (PA) derived for the LOS velocity field is consistent with the large-scale photometric PA. The residual velocities are correlated with the hard X-ray luminosity, suggesting that more luminous active galactic nuclei have a larger impact in the surrounding stellar dynamics. The central velocity dispersion values are usually higher than the rotation velocity amplitude, what we attribute to the strong contribution of bulge kinematics in these inner regions. For 50 per cent of the galaxies, we find an inverse correlation between the velocities and the h 3 Gauss-Hermitte moment, implying red wings in the blueshifted side and blue wings in the redshifted side of the velocity field, attributed to the movement of the bulge stars lagging the rotation. Two of the 16 galaxies (NGC 5899 and Mrk 1066) show an S-shape zero velocity line, attributed to the gravitational potential of a nuclear bar. Velocity dispersion (σ) maps show rings of low-σ values (∼50-80 km s −1) for four objects and 'patches' of low σ for six galaxies at 150-250 pc from the nucleus, attributed to young/ intermediate age stellar populations.

Section: Introductionmentioning

confidence: 74%

Gemini NIFS survey of feeding and feedback processes in nearby active galaxies – I. Stellar kinematics

Storchi‐Bergmann

Monthly Notices of the Royal Astronomical Society

et al. 2017

“…and Hβ emission, so this correlation may be partly or entirely a consequence of orientation effects (c.f. Rose et al 2015;Glidden et al 2016). The theoretical grids published by Davies et al (2016a) show that the objects with highest [Fe VII] are located in the region of highest ionization parameter.…”

Section: Nuclear Classificationsmentioning

confidence: 99%

Probing the Physics of Narrow-line Regions in Active Galaxies. IV. Full Data Release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7)

Childress

Dopita

Shastri

et al. 2017

ApJS

We present the second and final data release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). Data are presented for 63 new galaxies not included in the first data release, and we provide 2D emission-line fitting products for the full S7 sample of 131 galaxies. The S7 uses the WiFeS instrument on the ANU 2.3m telescope to obtain spectra with a spectral resolution of R = 7000 in the red (540 -700 nm) and R = 3000 in the blue (350 -570 nm), over an integral field of 25 × 38 arcsec 2 with 1 × 1 arcsec 2 spatial pixels. The S7 contains both the largest sample of active galaxies and the highest spectral resolution of any comparable integral field survey to date. The emission-line fitting products include line fluxes, velocities and velocity dispersions across the WiFeS field of view, and an artificial neural network has been used to determine the optimal number of Gaussian kinematic components for emission-lines in each spaxel. Broad Balmer lines are subtracted from the spectra of nuclear spatial pixels in Seyfert 1 galaxies before fitting the narrow lines. We bin nuclear spectra and measure reddening-corrected nuclear fluxes of strong narrow lines for each galaxy. The nuclear spectra are classified on optical diagnostic diagrams, where the strength of the coronal line [Fe VII] λ6087 is shown to be correlated with [O III]/ Hβ. Maps revealing gas excitation and kinematics are included for the entire sample, and we provide notes on the newly observed objects.

“…The inner wall of the AGN dust torus is usually heavily irradiated, and just lie at the sublimation radius of the most refractive dust (Krolik & Kriss 1995). From certain viewing angles, this photo-ionized gas can produce spectra with many coronal lines (Rose et al 2015;Glidden et al 2016). The [Fe VII] line luminosity from SDSS1115+0544 is comparable to that of Seyfert galaxies (Nagao et al 2000;Gelbord et al 2009), but its [Fe VII]/[O III] ratio of 0.4 is much higher than AGNs.…”

Section: Coronal Fe Linesmentioning

confidence: 99%

Rapid “Turn-on” of Type-1 AGN in a Quiescent Early-type Galaxy SDSS1115+0544

Yan

Wang

Jiang

et al. 2019

ApJ

We present a detailed study of a transient in the center of SDSS1115+0544 based on the extensive UV, optical, mid-IR light curves (LC) and spectra over 1200 days. The host galaxy is a quiescent early type galaxy at z = 0.0899 with a blackhole mass of 2 × 10 7 M . The transient underwent a 2.5 magnitude brightening over ∼ 120 days, reaching a peak V -band luminosity (extinction corrected) of −20.9 magnitude, then fading 0.5 magnitude over 200 days, settling into a plateau of > 600 days. Following the optical brightening are the significant mid-IR flares at 3.4 and 4.5µm, with a peak time delay of ∼ 180 days. The mid-IR LCs are explained as the echo of UV photons by a dust medium with a radius of 5 × 10 17 cm, consistent with E(B − V) of 0.58 inferred from the spectra. This event is very energetic with an extinction corrected L bol ∼ 4 × 10 44 erg s −1 . Optical spectra over 400 days in the plateau phase revealed newly formed broad Hα, β emission with a FWHM of ∼ 3750 km s −1 and narrow coronal lines such as [Fe VII], [Ne V]. This flare also has a steeply rising UV continuum, detected by multi-epoch Swift data at +700 to +900 days post optical peak. The broad Balmer lines and the UV continuum do not show significant temporal variations. The slow evolving LCs over 1200 days, the constant Balmer lines and UV continuum at late-times rule out TDE and SN IIn as the physical model for this event. We propose that this event is a "turn-on" AGN, transitioning from a quiescent state to a type 1 AGN with a sub-Eddington accretion rate of 0.017M /yr. This change occurred on a very short time scale of ∼ 120 − 200 days. The discovery of such a rapid "turn-on" AGN poses challenges to accretion disk theories and may indicate such event is not extremely rare.