Separating line emission from star formation, shocks, and AGN ionization in NGC 1068

D'Agostino, Joshua; Kewley, Lisa J.; Groves, Brent; Medling, Anne M.; Teodoro, Enrico M. Di; Dopita, Michael A.; Thomas, Amberyn; Sutherland, Ralph S.; García‐Burillo, S.

doi:10.1093/mnras/stz1611

Cited by 43 publications

(18 citation statements)

References 82 publications

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“…Using Hα as a star-formation rate indicator in AGN host galaxies is a well known challenge, and high-redshift data typically lack the diagnostic power to carefully decompose the relative constributions to the Hα luminosity from AGN photoionisation, star formation photoionisation and shocks (Davies et al 2014a,b;D'Agostino et al 2019). Previous work using IFU data on AGN host galaxies presented low [N ii]/Hα emission-line ratios as evidence that the Hα emission is star-formation dominated in off-nuclear regions for those specific targets (e.g., Cano-Díaz et al 2012;Cresci et al 2015b;Carniani et al 2016); however, we re-assess this for one of these literature sources (our ID 6) in § 4.4.1.…”

Section: Comparison Of Star-formation Rates From Fir and Hαmentioning

confidence: 99%

“…Based on (1) the discrepancy between star-formation rates inferred from Hα compared to those from FIR; (2) the different sizes and distributions of the FIR (tracing obscured star formation) compared to the Hα distribution and; (3) the challenges in decoupling the contribution of star-formation from the AGN contribution to producing the Hα emission, we conclude that Hα emission alone is not a reliable tracer of the star-formation in the AGN host galaxies in our sample. These challenges can be overcome, at least to some degree, in IFU observations of local AGN since the high spatial resolution observations can result in maps of multiple emissionline ratio diagnostics (e.g., Venturi et al 2018;D'Agostino et al 2019). However, with the current observational facilities this is rarely possible for high-z systems and caution, and a careful case-by-case assessment is required when using Hα emission to trace star-formation in high-z AGN host galaxies.…”

Section: Spatially-resolved Comparison Of Hα and Fir Emissionmentioning

confidence: 99%

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KASHz: No evidence for ionised outflows instantaneously suppressing star formation in moderate luminosity AGN at z ∼ 1.4–2.6

Scholtz

Harrison

Rosario

et al. 2020

Monthly Notices of the Royal Astronomical Society

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As part of our KMOS AGN Survey at High-redshift (KASHz), we present spatiallyresolved VLT/KMOS and VLT/SINFONI spectroscopic data and ALMA 870µm continuum imaging of eight z=1.4-2.6 moderate AGN (L 2−10kev = 10 42 −10 45 ergs s −1 ). We map [O iii], Hα and rest-frame FIR emission to search for any spatial anti-correlation between ionised outflows (traced by the [O iii] line) and star formation (SF; traced by Hα and FIR), that has previously been claimed for some high-z AGN and used as evidence for negative and/or positive AGN feedback. Firstly, we conclude that Hα is unreliable to map SF inside our AGN host galaxies based on: (i) SF rates inferred from attenuation-corrected Hα can lie below those inferred from FIR; (ii) the FIR continuum is more compact than the Hα emission by a factor of ∼ 2 on average; (iii) in half of our sample, we observe significant spatial offsets between the FIR and Hα emission, with an average offset of 1.4 ± 0.6 kpc. Secondly, for the five targets with outflows we find no evidence for a spatial anti-correlation between outflows and SF using either Hα or FIR as a tracer. This holds for our re-analysis of a famous z=1.6 X-ray AGN ('XID 2028') where positive and negative feedback has been previously claimed. Based on our results, any instantaneous impact on SF by ionised outflows must be subtle, either occurring on scales below our resolution, or on long timescales.

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Section: Comparison Of Star-formation Rates From Fir and Hαmentioning

confidence: 99%

Section: Spatially-resolved Comparison Of Hα and Fir Emissionmentioning

confidence: 99%

KASHz: No evidence for ionised outflows instantaneously suppressing star formation in moderate luminosity AGN at z ∼ 1.4–2.6

Scholtz

Harrison

Rosario

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…The high velocity range is more sensitive to shock excitation, as observed in optical emission lines (e.g. Ho et al 2014;D'Agostino et al 2019b;Riffel et al 2020a). We exclude from these diagrams spaxels where the emission lines are not detected at a 3σ continuum level.…”

Section: Emission-line Ratio Diagnostic Diagramsmentioning

confidence: 99%

“…Wylezalek et al 2020). We follow a similar procedure used in the optical by D'Agostino et al (2019b) to separate the contributions of star formation, shocks, and AGN ionisation (see also D'Agostino et al 2019a) and define an emission-line ratio function (f elr ) by We present, in Figure 11, the density plot of f elr vs. W80 (corrected for instrumental broadening) for all spaxels with H2 2.1218 µm/Brγ [Fe ii]1.2570 µm/Paβ measurements from all galaxies. In green, we show the line ratios from the HLR region in the diagnostic diagram (Figs.…”

Section: Gas Excitationmentioning

confidence: 99%

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

Riffel

Storchi‐Bergmann

Riffel

et al. 2017

Monthly Notices of the Royal Astronomical Society

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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.

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“…Spatially resolved measurements of electron temperature and density are important to constrain the AGN contribution to gas ionization and to infer the gas physical conditions. Observational data that enable measurements of weak auroral lines, from which e can be estimated, and spatially resolved studies of e in AGN are seldom found in the literature (but see Revalski et al 2018;Dahmer-Hahn et al 2019;D'Agostino et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Chemical abundances in Seyfert galaxies – V. The discovery of shocked emission outside the AGN ionization axis

Riffel

Dors

Armah

et al. 2020

Monthly Notices of the Royal Astronomical Society: Letters

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We present maps for the electron temperature in the inner kpc of three luminous Seyfert galaxies: Mrk 79, Mrk 348, and Mrk 607 obtained from Gemini Multi-Object Spectrograph-integral field unit observations at spatial resolutions of ∼110–280 pc. We study the distributions of electron temperature in active galaxies and find temperatures varying in the range from ∼8000 to $\gtrsim 30\, 000\,$K. Shocks due to gas outflows play an important role in the observed temperature distributions of Mrk 79 and Mrk 348, while standard photoionization models reproduce the derived temperature values for Mrk 607. In Mrk 79 and Mrk 348, we find direct evidence for shock ionization with overall orientation orthogonal to the ionization axis, where shocks can be easily observed as the active galactic nuclei radiation field is shielded by the nuclear dusty torus. This also indicates that even when the ionization cones are narrow, the shocks can be much wider angle.

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Separating line emission from star formation, shocks, and AGN ionization in NGC 1068

Cited by 43 publications

References 82 publications

KASHz: No evidence for ionised outflows instantaneously suppressing star formation in moderate luminosity AGN at z ∼ 1.4–2.6

KASHz: No evidence for ionised outflows instantaneously suppressing star formation in moderate luminosity AGN at z ∼ 1.4–2.6

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

Chemical abundances in Seyfert galaxies – V. The discovery of shocked emission outside the AGN ionization axis

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