Dissecting galaxies: spatial and spectral separation of emission excited by star formation and AGN activity

Davies, R. L.; Groves, Brent; Kewley, Lisa J.; Dopita, Michael A.; Hampton, Elise; Shastri, P.; Scharwächter, J.; Sutherland, Ralph S.; Kharb, P.; Bhatt, H. C.; Jin, Chichuan; Banfield, Julie; Zaw, I.; James, Bethan L.; Juneau, Stéphanie; Srivastava, Shweta

doi:10.1093/mnras/stw1754

Cited by 72 publications

(77 citation statements)

References 80 publications

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“…Combined with the fact that the SE emission is systematically brighter than the NW emission, the NLR is inclined such that the bicone is in front of the nuclear disk towards the SE and behind the disk towards the NW until it breaks through at larger radii. This interpretation is consistent with previous studies of NGC 5728 using HST narrow band imaging (Wilson et al 1993) and lower spatial resolution IFU observations (Davies et al 2016).…”

Section: Nlr Morphologysupporting

confidence: 93%

The multiphase gas structure and kinematics in the circumnuclear region of NGC 5728

Shimizu

Davies

Lutz

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We report on our combined analysis of HST, VLT/MUSE, VLT/SINFONI, and ALMA observations of the local Seyfert 2 galaxy, NGC 5728 to investigate in detail the feeding and feedback of the AGN. The datasets simultaneously probe the morphology, excitation, and kinematics of the stars, ionized gas, and molecular gas over a large range of spatial scales (10 pc-10 kpc). NGC 5728 contains a large stellar bar which is driving gas along prominent dust lanes to the inner 1 kpc where the gas settles into a circumnuclear ring. The ring is strongly star forming and contains a substantial population of young stars as indicated by the lowered stellar velocity dispersion and gas excitation consistent with HII regions. We model the kinematics of the ring using the velocity field of the CO (2-1) emission and stars and find it is consistent with a rotating disk. The outer regions of the disk, where the dust lanes meet the ring, show signatures of inflow at a rate of 1 M yr −1 . Inside the ring, we observe three molecular gas components corresponding to the circular rotation of the outer ring, a warped disk, and the nuclear stellar bar. The AGN is driving an ionized gas outflow that reaches a radius of 250 pc with a mass outflow rate of 0.08 M yr −1 consistent with its luminosity and scaling relations from previous studies. While we observe distinct holes in CO emission which could be signs of molecular gas removal, we find that largely the AGN is not disrupting the structure of the circumnuclear region.

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Section: Nlr Morphologysupporting

confidence: 93%

The multiphase gas structure and kinematics in the circumnuclear region of NGC 5728

Shimizu

Davies

Lutz

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…The non-gravitational kinematics are commonly detected in the broad component of both [O III] and Hα, which are revealed by their large velocity dispersion compared to the stellar velocity dispersion and/or their large velocity offset with respect to the systemic velocity of the host galaxy. While the broad components of [O III] and Hα show qualitatively similar non-gravitational kinematics, the absolute value of velocity and velocity dispersion of Hα are relatively smaller than those of [O III]. We find a clear sign of gravitational kinematics (i.e., Keple- Davies et al 2016, Woo et al 2017 6.2. Driving mechanism of the outflows While it is clear that the ionized gas outflows of our sample are mainly due to AGN activity (see Section 5.2), we further investigate the driving mechanism of the outflows.…”

Section: Estimated Energeticssupporting

confidence: 46%

The Limited Impact of Outflows: Integral-field Spectroscopy of 20 Local AGNs

Bae

Woo

Karouzos

et al. 2017

ApJ

112

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To investigate AGN outflows as a tracer of AGN feedback on star-formation, we perform integral-field spectroscopy of 20 type 2 AGNs at z<0.1, which are luminous AGNs with the [O III] luminosity >10 41.5 erg s −1 , and exhibit strong outflow signatures in the [O III] kinematics. By decomposing the emission-line profile, we obtain the maps of the narrow and broad components of [O III] and Hα lines, respectively. The broad components in both [O III] and Hα represent the non-gravitational kinematics, i.e., gas outflows, while the narrow components, especially in Hα, represent the gravitational kinematics, i.e., rotational disk. By using the integrated spectra within the flux-weighted size of the narrow-line region, we estimate the energetics of the gas outflows. The ionized gas mass is 1.0-38.5×105 M , and the mean mass outflow rate is 4.6±4.3 M yr −1 , which is a factor of ∼260 higher than the mean mass accretion rate 0.02±0.01 M yr −1 . The mean energy injection rate of the sample is 0.8±0.6% of the AGN bolometric luminosity, while the momentum flux is (5.4±3.6)×L bol /c on average, except for two most kinematically energetic AGNs with low L bol , which are possibly due to the dynamical timescale of the outflows. The estimated outflow energetics are consistent with the theoretical expectations for energy-conserving outflows from AGNs, yet we find no supporting evidence of instantaneous quenching of star formation due to the outflows.

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“…For AGNs of low to intermediate luminosity (on average), the broadening from outflows may not be as strong as for more luminous quasars (e.g., Greene & Ho 2005). A final discrimination of the relative importance of the mechanisms for emission line broadening may require spatially resolved kinematics (e.g., Davies et al 2016). …”

Section: Shift Of High-redshift Sfgs and Agns On The Kex Diagrammentioning

confidence: 99%

A New Diagnostic Diagram of Ionization Sources for High-redshift Emission Line Galaxies

Zhang

Hao

2018

ApJ

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We propose a new diagram, the kinematics-excitation (KEx) diagram, which uses the [O III] λ5007/Hβ line ratio and the [O III] λ5007emission line width (σ [O III] ) to diagnose the ionization source and physical properties of active galactic nuclei (AGNs) and star-forming galaxies (SFGs). The KEx diagram is a suitable tool to classify emission line galaxies at intermediate redshift because it uses only the [O III] λ5007 and Hβ emission lines. We use the main galaxy sample of SDSS DR7 and the Baldwin−Phillips−Terlevich (BPT) diagnostic to calibrate the diagram at low redshift. The diagram can be divided into three regions: the KEx-AGN region, which consists mainly of pure AGNs, the KEx-composite region, which is dominated by composite galaxies, and the KEx-SFG region, which contains mostly SFGs. LINERs strongly overlap with the composite and AGN regions. AGNs are separated from SFGs in this diagram mainly because they preferentially reside in luminous and massive galaxies and have higher [O III]/Hβ than SFGs. The separation between AGNs and SFGs is even cleaner thanks to the additional 0.15/0.12dex offset in σ [O III] at fixed luminosity/stellar mass. We apply the KEx diagram to 7866 galaxies at 0.3<z<1 in the DEEP2 Galaxy Redshift Survey, and compare it to an independent X-ray classification scheme using Chandra observations. X-ray AGNs are mostly located in the KEx-AGN region, while X-ray SFGs are mostly located in the KEx-SFG region. Almost all Type 1 AGNs lie in the KEx-AGN region. These tests support the reliability of this classification diagram for emission line galaxies at intermediate redshift.At z∼2, the demarcation line between SFGs and AGNs is shifted by ∼0.3dex toward higher values of σ [O III] due to evolution effects.

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Dissecting galaxies: spatial and spectral separation of emission excited by star formation and AGN activity

Cited by 72 publications

References 80 publications

The multiphase gas structure and kinematics in the circumnuclear region of NGC 5728

The multiphase gas structure and kinematics in the circumnuclear region of NGC 5728

The Limited Impact of Outflows: Integral-field Spectroscopy of 20 Local AGNs

A New Diagnostic Diagram of Ionization Sources for High-redshift Emission Line Galaxies

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