Gauging the effect of feedback from Supermassive Black Holes on the host galaxies

Frequentemente associados à regulação da formação estelar nos núcleos galácticos ativos (AGN), os buracos negros supermassivos (SMBH) desempenham um papel fundamental na evolução das galáxias através de seus efeitos de feedback (retro-alimentação). Para investigar o impacto deste feedback no modo radiativo – causado por fótons energéticos durante o processo de acreção de matéria – analisamos, em um trabalho anterior, imagens de banda estreita obtidas com o Hubble Space Telescope (HST) de uma amostra de nove AGNs do tipo II com luminosidades bolométricas LBol > 1045 erg s−1 , no qual encontramos que o gás emissor de linhas estreitas (ENLR) se estende além do corpo da galáxia, sugerindo um feedback poderoso do AGN através da ejeção de gás a grandes distâncias do núcleo. No entanto, para verificar se há mesmo ejeção de gás nesses objetos, e quantificar o seu efeito sobre a galáxia, precisamos mapear a cinemática do gás, e assim calcular a taxa de ejeção de massa e a sua potência cinética. Para isto, observamos parte de nossa amostra usando observações de espectroscopia de campo integral com o instrumento Gemini GMOS-IFU, num total de oito objetos. A cinemática do gás foi obtida através do ajuste de componentes Gaussianas aos perfis das linhas de emissão do gás ionizado. Em geral, além de uma componente larga (broad), foram necessárias mais de duas componentes estreitas (narrow) para representar os perfis da NLR. Encontramos que a cinemática das componentes narrow é bem complexa, condizente com a presença de interações com galáxias vizinhas, previamente observado nas imagens do HST. Associamos a componente broad ao gás em outflow: esta componente possui valores de dispersão de velocidade de até 850 km s−1 , o que reforça a identificação dessa componente com o gás perturbado em ejeção. Utilizando apenas a componente broad, calculamos a taxa de massa de gás ionizado em outflow (M˙ out), encontrando valores de até 10 M yr−1 . A potência cinética do outflow (E˙ out) atinge valores máximos entre 1041 e 1043 erg s−1 , o que corresponde a eficiências de feedback de ∼ 0.001 − 0.1 % da LBol. Estes valores estão abaixo dos encontrados em simulações e modelos analíticos que reproduzem os efeitos da cessação da formação estelar durante a evolução das galáxias. Entretanto, nossos cálculos consideram somente a contribuição ao outflow do gás ionizado, que representa apenas uma fração da energia liberada pelo feedback. Investigamos também a relação de M˙ out e E˙ out com LBol, e o efeito das incertezas em algumas grandezas – como a densidade e a massa total do gás ionizado em outflow – nos valores finais de M˙ out e E˙ out.Often associated with the regulation of star formation in active galactic nuclei (AGN), supermassive black holes (SMBH) play a fundamental role in the evolution of galaxies through their feedback effects. To investigate the impact of this feedback in the radiative mode – caused by energetic photons during the process of accretion of matter – we analyzed, in a previous work, narrow-band images obtained with Hubble Space Telescope (HST) of a sample of nine type II AGNs with bolometric luminosities LBol > 1045 erg s−1 . There, we found that the gas emitting narrow lines (ENLR) extends beyond the body of the galaxy, suggesting a powerful AGN feedback through gas ejection to large distances from the nucleus. However, to check if there is even an outflow in these objects, and to quantify its effect on the galaxy, we need to map the gas kinematics, and then calculate the mass outflow rate and its kinetic power. For this, we observed part of our sample using integral field spectroscopy observations with the Gemini GMOS-IFU instrument, for a total of eight objects. The gas kinematics was obtained by fitting Gaussian components to the profiles of the emission lines of the ionized gas. In general, in addition to a broad component, more than two narrow components were required to represent the NLR profiles. We found that the kinematics of the narrow components are quite complex, consistent with the presence of interactions with nearby galaxies, previously observed in the HST images. We associate the broad component with the gas in outflow: this component has velocity dispersion values up to 850 km s−1 , which reinforces its identification with the disturbed gas in the outflowing winds. Using only the broad component, we calculate the mass outflow rate (M˙ out), finding values of up to 10 M yr−1 . The outflow kinetic power (E˙ out) reaches maximum values between 1041 and 1043 erg s−1 , which corresponds to feedback efficiencies of ∼ 0.001 − 0.1 % of LBol. These values are below those found in simulations and analytical models in order to quench star formation during the evolution of galaxies. However, our calculations consider only the contribution from the ionized gas to the outflow power, which represents only a fraction of the total power released by the feedback. We also investigated the relationship of M˙ out and E˙ out with LBol, and the effect of uncertainties on the values of some quantities – such as the electron density and the mass of the ionized gas in outflow – to the final values of M˙ out and E˙ out

Cold molecular gas outflow encasing the ionised one in the Seyfert galaxy NGC 3281

We present ALMA CO(2-1) observations of the Seyfert 2 galaxy NGC 3281 at $\sim$ 100 pc spatial resolution. This galaxy was previously known to present a bi-conical ionised gas outflow extending to 2 kpc from the nucleus. The analysis of the CO moment and channel maps, as well as kinematic modelling reveals two main components in the molecular gas: one rotating in the galaxy plane and another outflowing and extending up to $\sim$ 1.8 -- 2.6 kpc from the nucleus, partially encasing the ionised component. The mass of the outflowing molecular gas component is $M_{\mathrm{mol},\mathrm{out}}$ = $(2.5\pm1.6){\times}10^{6}$ $\rm{M_{\odot}}$, representing $\sim$ 1.7 -- 2 % of the total molecular gas seen in emission within the inner 2.3 kpc. The corresponding mass outflow rate and power are $\dot{M}_{\mathrm{mol},\mathrm{out}}$ = 0.12 -- 0.72 $\rm{M_{\odot} yr^{-1}}$ and $\dot{E}_{\mathrm{mol},\mathrm{out}}$ = (0.045 -- 1.6) ${\times} 10^{40}$ $\rm{erg s^{-1}}$, which translates to a kinetic coupling efficiency with the AGN power of only $10^{-4}$ -- 0.02 %. This value reaches up to 0.1 % when including both the feedback in the ionised and molecular gas, as well as considering that only part of the energy couples kinetically with the gas. Some of the non-rotating CO emission can also be attributed to inflow in the galaxy plane towards the nucleus. The similarity of the CO outflow -- encasing the ionised gas one and the X-ray emission -- to those seen in other sources, suggests that this may be a common property of galactic outflows.Comment: 13 pages, 11 figures. Accepted for publication in MNRA

Interactions between large-scale radio structures and gas in a sample of optically selected type 2 quasars

Context. The role of radio mode feedback in non radio-loud quasars needs to be explored in depth to determine its true importance. Its effects can be identified based on the evidence of interactions between the radio structures and the ambient ionised gas. Aims. We investigate this interaction in a sample of 13 optically selected type 2 quasars (QSO2) at z < 0.2 with the Very Large Array (VLA) FIRST Survey radio detections, none of which are radio-loud. The ranges of [OIII]λ5007 and monochromatic radio luminosities are log(L[OIII]/erg s−1 ) ∼ 42.08–42.79 and log(P1.4 GHz/erg s−1 Hz−1 ) ∼ 30.08−31.76. All of them show complex optical morphologies, with signs of distortion across tens of kpc due to mergers and interactions. Methods. We searched for evidence of interactions between the radio structures and the ionised gas by characterising and comparing their morphologies. The former was traced by narrow band Hα images obtained with the GTC 10.4 m Spanish telescope and the Osiris instrument. The latter is traced by VLA radio maps obtained with A and B configurations to achieve both high resolution and brightness sensitivity. Results. The radio luminosity has an active galatic nucleus (AGN) component in 11 our of 13 QSO2, which is spatially extended in our radio data in 9 of them (jets, lobes, or other). The relative contribution of the extended radio emission to the total P1.4 GHz is in most cases in the range from 30% to 90%. The maximum sizes are in the range of d R max of around a few to 500 kpc. The QSO2 undergoing interaction or merger events appear to be invariably associated with ionised gas spread over large spatial scales with maximum distances from the AGN in the range rmax ∼ 12−90 kpc. The morphology of the ionised gas at <30 kpc is strongly influenced by AGN related processes. Evidence for radio-gas interactions exist in 10 out of 13 QSO2; that is, in all but one with confirmed AGN radio components. The interactions are identified across different spatial scales, from the nuclear narrow line region up to tens of kpc. Conclusions. Although this sample cannot be considered representative of the general population of QSO2, it supports the idea that large-scale low to modest power radio sources can exist in radio-quiet QSO2, which can provide a source of feedback on scales of the spheroidal component of galaxies and well into the circumgalactic medium, in systems where radiative mode feedback is expected to dominate

AGNIFS survey of local AGN : GMOS-IFU data and outflows in 30 sources

We analyse optical data cubes of the inner kiloparsec of 30 local (z ≤ 0.02) active galactic nucleus (AGN) hosts that our research group, AGNIFS, has collected over the past decade via observations with the integral field units of the Gemini Multi-Object Spectrographs. Spatial resolutions range between 50 and 300 pc and spectral coverage is from 4800 or 5600 to 7000 Å, at velocity resolutions of ≈50 km s−1. We derive maps of the gas excitation and kinematics, and determine the AGN ionization axis – which has random orientation relative to the galaxy – and the kinematic major axes of the emitting gas. We find that rotation dominates the gas kinematics in most cases, but is disturbed by the presence of inflows and outflows. Outflows have been found in 21 nuclei, usually along the ionization axis. The gas velocity dispersion is traced by W80 (velocity width encompassing 80 per cent of the line flux), adopted as a tracer of outflows. In seven sources, W80 is enhanced perpendicularly to the ionization axis, indicating lateral expansion of the outflow. We have estimated mass-outflow rates M˙ and powers E˙, finding median values of log [M/˙ ( M yr−1)] = −2.1+1.6 −1.0 and log [E/˙ ( erg s−1)] = 38.5+1.8 −0.9, respectively. Both quantities show a mild correlation with the AGN luminosity (LAGN). E˙ is of the order of 0.01 LAGN for four sources, but much lower for the majority (nine) of the sources, with a median value of log [E/L AGN] = −5.34+3.2 −0.9, indicating that typical outflows in the local Universe are unlikely to significantly impact their host galaxy evolution

AGNIFS survey of local AGN : GMOS-IFU data and outflows in 30 sources

We analyse optical data cubes of the inner kiloparsec of 30 local (z ≤ 0.02) active galactic nucleus (AGN) hosts that our research group, AGNIFS, has collected over the past decade via observations with the integral field units of the Gemini Multi-Object Spectrographs. Spatial resolutions range between 50 and 300 pc and spectral coverage is from 4800 or 5600 to 7000 Å, at velocity resolutions of ≈50 km s−1. We derive maps of the gas excitation and kinematics, and determine the AGN ionization axis – which has random orientation relative to the galaxy – and the kinematic major axes of the emitting gas. We find that rotation dominates the gas kinematics in most cases, but is disturbed by the presence of inflows and outflows. Outflows have been found in 21 nuclei, usually along the ionization axis. The gas velocity dispersion is traced by W80 (velocity width encompassing 80 per cent of the line flux), adopted as a tracer of outflows. In seven sources, W80 is enhanced perpendicularly to the ionization axis, indicating lateral expansion of the outflow. We have estimated mass-outflow rates M˙ and powers E˙, finding median values of log [M/˙ ( M yr−1)] = −2.1+1.6 −1.0 and log [E/˙ ( erg s−1)] = 38.5+1.8 −0.9, respectively. Both quantities show a mild correlation with the AGN luminosity (LAGN). E˙ is of the order of 0.01 LAGN for four sources, but much lower for the majority (nine) of the sources, with a median value of log [E/L AGN] = −5.34+3.2 −0.9, indicating that typical outflows in the local Universe are unlikely to significantly impact their host galaxy evolution

Gauging the effect of supermassive black holes feedback on quasar host galaxies

In order to gauge the role that active galactic nuclei play in the evolution of galaxies via the effect of kinetic feedback in nearby QSO 2’s (z ∼ 0.3), we observed eight such objects with bolometric luminosities Lbol∼1046ergs−1 using Gemini Multi-Object Spectrograph-integral field units. The emission lines were fitted with at least two Gaussian curves, the broadest of which we attributed to gas kinetically disturbed by an outflow. We found that the maximum extent of the outflow ranges from ∼1 to 8 kpc, being ∼0.5±0.3 times the extent of the [OIII] ionized gas region. Our ‘default’ assumptions for the gas density (obtained from the [SII] doublet) and outflow velocities resulted in peak mass outflow rates of M˙defout∼ 3–30 M⊙yr−1 and outflow power of E˙defout∼1041–1043ergs−1⁠. The corresponding kinetic coupling efficiencies are εdeff=E˙defout/Lbol∼7×10−4–0.5 per cent, with the average efficiency being only 0.06 per cent (0.01 per cent median), implying little feedback powers from ionized gas outflows in the host galaxies. We investigated the effects of varying assumptions and calculations on M˙out and E˙out regarding the ionized gas densities, velocities, masses, and inclinations of the outflow relative to the plane of the sky, resulting in average uncertainties of 1 dex. In particular, we found that better indicators of the [OIII] emitting gas density than the default [SII] line ratio, such as the [ArIV] λλ4711,40 line ratio, result in almost an order of magnitude decrease in the εf

Bipolar ionization cones in the extended narrow-line region of nearby QSO2s

We have used narrowband [O III] λλ4959, 5007 and Hα+[N II] λλ6548, 84 Hubble Space Telescope (HST) images of nine luminous (L[O III]>1042 erg s−1) type 2 QSOs with redshifts 0.1<z<0.5 in order to constrain the geometry of their extended narrow-line regions (ENLRs), as recent ground-based studies suggest that these regions become more spherical at high luminosities due to destruction of the torus. We instead find elongated ENLRs reaching 4–19 kpc from the nucleus and bipolar ionization cones in [O III]/(Hα+[N II]) excitation maps indicating that the torus survives these luminosities, allowing the escape of ≈10 times higher ionizing photon rates along the ionization axis than perpendicular to it. The exceptional HST angular resolution was key to our success in arriving at these conclusions. Combining our measurements with previous ones based on similar HST data, we have revisited the relation between the ENLR radius Rmaj and L[O III] over the range 39<log(L[O III])<43.5 (L in erg s−1): log(Rmaj)=(0.51±0.03) log(L[O III]) −18.12±0.98. The radius of the ENLR keeps increasing with L[O III] in our data, implying that the ENLR can extend to distances beyond the limit of the galaxy if gas is present there—e.g., from active galactic nucleus (AGN) outflows or interactions, seen in six objects of our sample. We attribute the flattening previously seen in this relation to the fact that the ENLR is matter-bounded, meaning that ionizing photons usually escape to the intergalactic medium in luminous AGNs. Estimated ionized gas masses of the ENLRs range from 0.3 to 2×108Me, and estimated powers for associated outflows range from <0.1% to a few percent of the QSO luminosity