We present near-infrared emission-line flux distributions, excitation and kinematics, as well as stellar kinematics, of the inner 520 × 520 pc2 of the Seyfert 2 galaxy NGC 5929. The observations were ...performed with Gemini's Near-Infrared Integral Field Spectrograph (NIFS) at a spatial resolution of ∼20 pc and spectral resolution of 40 km s− 1 in the J and K
l bands. The flux distributions of H2, Fe ii, P ii and H recombination lines are extended over most of the field of view, with the highest intensity levels observed along PA = 60/240°, and well correlated with the radio emission. The H2 and Fe ii line emission originated in thermal processes, mainly due to heating of the gas by X-rays from the central active galactic nucleus (AGN). The contribution of shocks due to the radio jet is observed at locations co-spatial with the radio hotspots at 0.50 arcsec north-east and 0.60 arcsec south-west of the nucleus, as evidenced by the emission-line ratio and gas kinematics. The stellar kinematics shows rotation with an amplitude at 250 pc from the nucleus of ∼200 km s− 1 after correcting for the inferred inclination of 18.3°. The stellar velocity dispersion obtained from the integrated K-band spectrum is σ* = 133 ± 8 km s− 1, which implies a mass for the supermassive black hole of
$M_\bullet = 5.2^{1.6}_{-1.2} \times 10^7\,{\rm M_{{\odot }}}$
, using the M
•–σ* relation. The gas kinematics present three components: (1) gas in the plane of the galaxy in counter-rotation relative to the stars; (2) an outflow perpendicular to the radio jet that seems to be due to an equatorial AGN outflow; and (3) turbulence of the gas observed in association with the radio hotspots, supporting an interaction of the radio jet with the gas of the disc. We estimated the masses of ionized gas and warm molecular gas to be ∼1.3 × 106 M⊙ and ∼470 M⊙, respectively.
ABSTRACT
We present a simple model for low-luminosity active galactic nucleus (LLAGN) feedback through winds produced by a hot accretion flow. The wind carries considerable energy and deposits it on ...the host galaxy at kiloparsec scales and beyond, heating the galactic gas and thereby quenching star formation. Our model predicts that the typical LLAGN can quench more than 10 per cent of star formation in its host galaxy. We find that long-lived LLAGN winds from supermassive black holes (SMBHs) with masses ≥108 M⊙ and mass accretion rates $\dot{M} \gt 10^{-3} \dot{M}_{\rm Edd}\ (0.002\,{\rm M}_{\odot }\,\mathrm{ yr}^{-1})$ can prevent gas collapse and significantly quench galactic star formation compared to a scenario without AGNs, if the wind persists over 1 Myr. For sustained wind production over time-scales of 10 Myr or longer, SMBHs with 108 M⊙ or larger masses have important feedback effects with $\dot{M} \gt 10^{-4} \dot{M}_{\rm Edd}\ (0.0002\,{\rm M}_{\odot }\, \mathrm{ yr}^{-1})$.
ABSTRACT
The prevalence of outflow and feedback signatures in active galactic nuclei (AGNs is a major unresolved question which large integral field unit (IFU) surveys now allow to address. In this ...paper, we present a kinematic analysis of the ionized gas in 2778 galaxies at z ∼ 0.05 observed by Sloan Digital Sky Survey-IV (SDSS-IV) Mapping Nearby Galaxies at Apache Point Observatory (MaNGA). Specifically, we measure the kinematics of the O iii λ5007 Å emission line in each spatial element and fit multiple Gaussian components to account for possible non-gravitational motions of gas. Comparing the kinematics of the ionized gas between 308 MaNGA-selected AGNs that have been previously identified through emission-line diagnostics and sources not classified as AGN, we find that while 25 per cent of MaNGA-selected AGN show O iii components with emission-line widths of >500 km s−1 in more than 10 per cent of their spaxels, only 7 per cent of MaNGA non-AGNs show a similar signature. Even the AGNs that do not show nuclear AGN photoionization signatures and that were only identified as AGN based on their larger scale photoionization signatures show similar kinematic characteristics. In addition to obscuration, another possibility is that outflow and mechanical feedback signatures are longer lived than the AGN itself. Our measurements demonstrate that high velocity gas is more prevalent in AGN compared to non-AGN and that outflow and feedback signatures in low-luminosity, low-redshift AGN may so far have been underestimated. We show that higher luminosity MaNGA-selected AGNs are able to drive larger scale outflows than lower luminosity AGN. But estimates of the kinetic coupling efficiencies are ≪1 per cent and suggest that the feedback signatures probed in this paper are unlikely to have a significant impact on the AGN host galaxies. However, continuous energy injection may still heat a fraction of the cool gas and delay or suppress star formation in individual galaxies even when the AGN is weak.
ABSTRACT
Henize 2–10 is a blue dwarf galaxy with intense star formation and one the most intriguing question about it is whether or not it hosts an accreting massive black hole. We use H and K-band ...integral field spectra of the inner 130 pc × 130 pc of He 2–10 to investigate the emission and kinematics of the gas at unprecedented spatial resolution. The observations were done using the Gemini Near-Infrared Integral Field Spectrograph (NIFS) operating with the ALTAIR adaptive optics module and the resulting spatial resolutions are 6.5 and 8.6 pc in the K and H bands, respectively. Most of the line emission is due to excitation of the gas by photoionization and shocks produced by the star forming regions. In addition, our data provide evidence of emission of gas excited by an active galactic nucleus located at the position of the radio and X-ray sources, as revealed by the analysis of the emission-line ratios. The emission lines from the ionized gas in the field present two kinematic components: one narrow with a velocity field suggesting a disc rotation and a broad component due to winds from the star forming regions. The molecular gas shows only the narrow component. The stellar velocity dispersion map presents an enhancement of about 7 km s−1 at the position of the black hole, consistent with a mass of $1.5^{+1.3}_{-1.3}\times 10^6$ M⊙.
Abstract
We present new evidence for AGN feedback in a subset of 69 quenched low-mass galaxies (M⋆ ≲ 5 × 109 M⊙, Mr > −19) selected from the first 2 yr of the Sloan Digital Sky Survey-IV Mapping ...Nearby Galaxies at APO (SDSS-IV MaNGA) survey. The majority (85 per cent) of these quenched galaxies appear to reside in a group environment. We find six galaxies in our sample that appear to have an active AGN that is preventing on-going star formation; this is the first time such a feedback mechanism has been observed in this mass range. Interestingly, five of these six galaxies have an ionized gas component that is kinematically offset from their stellar component, suggesting the gas is either recently accreted or outflowing. We hypothesize these six galaxies are low-mass equivalents to the ‘red geysers’ observed in more massive galaxies. Of the other 63 galaxies in the sample, we find 8 do appear for have some low level, residual star formation, or emission from hot, evolved stars. The remaining galaxies in our sample have no detectable ionized gas emission throughout their structures, consistent with them being quenched. This work shows the potential for understanding the detailed physical properties of dwarf galaxies through spatially resolved spectroscopy.
ABSTRACT
We present a 2D mapping of stellar population age components, emission-line fluxes, gas excitation, and kinematics within the inner ∼200 pc of the Seyfert 2 galaxy NGC 2110. We used the ...Gemini North Integral Field Spectrograph (NIFS) in the J and K bands at a spatial resolution of ∼22 pc. The unresolved nuclear continuum is originated in combined contributions of young stellar population (SP; age ≤ 100 Myr), a featureless AGN continuum and hot dust emission. The young-intermediate SP (100 < age ≤ 700 Myr) is distributed in a ring-shaped structure at ≈140 pc from the nucleus, which is roughly coincident with the lowest values of the stellar velocity dispersion. In the inner ≈115 pc the old SP (age > 2 Gyr) is dominant. The Fe ii $\lambda \, 1.2570\, \mu$m emission-line flux distribution is correlated with the radio emission and its kinematics comprise two components, one from gas rotating in the galaxy plane and another from gas in outflow within a bicone-oriented along north–south. These outflows seem to originate in the interaction of the radio jet with the ambient gas producing shocks that are the main excitation mechanism of the Fe ii emission. We estimate: (1) an ionized gas mass outflow rate of ∼0.5 M⊙ yr−1 at ∼70 pc from the nucleus; and (2) a kinetic power for the outflow of only 0.05 per cent of the AGN bolometric luminosity implying weak feedback effect on the galaxy.
ABSTRACT
In most galaxies, the fluxes of rotational H2 lines strongly correlate with star formation diagnostics such as polycyclic aromatic hydrocarbons (PAHs), suggesting that H2 emission from warm ...molecular gas is a minor by-product of star formation. We analyse the optical properties of a sample of 309 nearby galaxies derived from a parent sample of 2015 objects observed with the Spitzer Space Telescope. We find a correlation between the O iλ6300 emission-line flux and kinematics and the H2 S(3) 9.665 $\mu\mathrm{ m}$/PAH 11.3 $\mu\mathrm{ m}$. The O iλ6300 kinematics in active galactic nuclei (AGNs) cannot be explained only by gas motions due to the gravitational potential of their host galaxies, suggesting that AGN-driven outflows are important to the observed kinematics. While H2 excess also correlates with the fluxes and kinematics of ionized gas (probed by O iii), the correlation with O i is much stronger, suggesting that H2 and O i emissions probe the same phase or tightly coupled phases of the wind. We conclude that the excess of H2 emission seen in AGNs is produced by shocks due to AGN-driven outflows and in the same clouds that produce the O i emission. Our results provide an indirect detection of neutral and molecular winds and suggest a new way to select galaxies that likely host molecular outflows. Further ground- and space-based spatially resolved observations of different phases of the molecular gas (cold, warm, and hot) are necessary to test our new selection method.
ABSTRACT
Quasar-driven outflows must have made their most significant impact on galaxy formation during the epoch when massive galaxies were forming most rapidly. To study the impact of quasar ...feedback, we conducted rest-frame optical integral field spectrograph (IFS) observations of three extremely red quasars (ERQs) and one type-2 quasar at z = 2–3, obtained with the NIFS and OSIRIS instruments at the Gemini North and W. M. Keck Observatory with the assistance of laser-guided adaptive optics. We use the kinematics and morphologies of the O iii 5007 Å and H α 6563 Å emission lines redshifted into the near-infrared to gauge the extents, kinetic energies and momentum fluxes of the ionized outflows in the quasars host galaxies. For the ERQs, the galactic-scale outflows are likely driven by radiation pressure in a high column density environment or due to an adiabatic shock. The outflows in the ERQs carry a significant amount of energy ranging from 0.05 to 5 ${{\ \rm per\ cent}}$ of the quasar’s bolometric luminosity, powerful enough to have a significant impact on the quasar host galaxies. The outflows are resolved on kpc scales, the observed outflow sizes are generally smaller than other ionized outflows observed at high redshift. The high ratio between the momentum flux of the ionized outflow and the photon momentum flux from the quasar accretion disc and high nuclear obscuration makes these ERQs great candidates for transitional objects where the outflows are likely responsible for clearing material in the inner regions of each galaxy, unveiling the quasar accretion disc at optical wavelengths.
Abstract
In this paper, we investigate 2727 galaxies observed by MaNGA as of 2016 June to develop spatially resolved techniques for identifying signatures of active galactic nuclei (AGNs). We ...identify 303 AGN candidates. The additional spatial dimension imposes challenges in identifying AGNs due to contamination from diffuse ionized gas, extraplanar gas and photoionization by hot stars. We show that the combination of spatially resolved line diagnostic diagrams and additional cuts on H α surface brightness and H α equivalent width can distinguish between AGN-like signatures and high-metallicity galaxies with low-ionization nuclear emission-line regions-like spectra. Low-mass galaxies with high specific star formation rates are particularly difficult to diagnose and routinely show diagnostic line ratios outside of the standard star formation locus. We develop a new diagnostic – the distance from the standard diagnostic line in the line-ratio space – to evaluate the significance of the deviation from the star formation locus. We find 173 galaxies that would not have been selected as AGN candidates based on single-fibre spectral measurements but exhibit photoionization signatures suggestive of AGN activity in the Mapping Nearby Galaxies at APO resolved observations, underscoring the power of large integral field unit surveys. A complete census of these new AGN candidates is necessary to understand their nature and probe the complex co-evolution of supermassive black holes and their hosts.
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