scholarly journals Radiation-driven outflows in AGNs: revisiting feedback effects of scattered and reprocessed photons

2019 ◽  
Vol 490 (2) ◽  
pp. 2567-2578 ◽  
Author(s):  
Amin Mosallanezhad ◽  
Feng Yuan ◽  
Jeremiah P Ostriker ◽  
Fatemeh Zahra Zeraatgari ◽  
De-Fu Bu

ABSTRACT We perform 2D hydrodynamical simulations of slowly rotating accretion flows in the region of $0.01\!-\!7\, \mathrm{pc}$ around a supermassive black holes with $M_\mathrm{BH} = 10^{8} \, \mathrm{M}_{\odot }$. The accretion flow is irradiated by the photons from the central active galactic nucleus (AGN). In addition to the direct radiation from the AGN, we have also included the ‘re-radiation’, i.e. the locally produced radiation by Thomson scattering, line, and bremsstrahlung radiation. Compare to our previous work, we have improved the calculation of radiation force due to the Thomson scattering of X-ray photons from the central AGN. We find that this improvement can significantly increase the mass flux and velocity of outflow. We have compared the properties of outflow – including mass outflow rate, velocity, and kinetic luminosity of outflow – in our simulation with the observed properties of outflow in AGNs and found that they are in good consistency. This implies that the combination of line and re-radiation forces is the possible origin of observed outflow in luminous AGNs.

2020 ◽  
Vol 15 (S359) ◽  
pp. 131-135
Author(s):  
S. B. Kraemer ◽  
T. J. Turner ◽  
D. M. Crenshaw ◽  
H. R. Schmitt ◽  
M. Revalski ◽  
...  

AbstractWe have analyzed Chandra/High Energy Transmission Grating spectra of the X-ray emission line gas in the Seyfert galaxy NGC 4151. The zeroth-order spectral images show extended H- and He-like O and Ne, up to a distance r ˜ 200 pc from the nucleus. Using the 1st-order spectra, we measure an average line velocity ˜230 km s–1, suggesting significant outflow of X-ray gas. We generated Cloudy photoionization models to fit the 1st-order spectra; the fit required three distinct emission-line components. To estimate the total mass of ionized gas (M) and the mass outflow rates, we applied the model parameters to fit the zeroth-order emission-line profiles of Ne IX and Ne X. We determined an M ≍ 5.4 × 105Mʘ. Assuming the same kinematic profile as that for the [O III] gas, derived from our analysis of Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra, the peak X-ray mass outflow rate is approximately 1.8 Mʘ yr–1, at r ˜ 150 pc. The total mass and mass outflow rates are similar to those determined using [O III], implying that the X-ray gas is a major outflow component. However, unlike the optical outflows, the X-ray emitting mass outflow rate does not drop off at r > 100pc, which suggests that it may have a greater impact on the host galaxy.


2019 ◽  
Vol 623 ◽  
pp. A82 ◽  
Author(s):  
G. A. Kriss ◽  
N. Arav ◽  
D. Edmonds ◽  
J. Ely ◽  
J. S. Kaastra ◽  
...  

Aims. To elucidate the location, physical conditions, mass outflow rate, and kinetic luminosity of the outflow from the active nucleus of the Seyfert 1 galaxy Mrk 509, we used coordinated UV and X-ray spectral observations in 2012 to follow up our lengthier campaign conducted in 2009. Methods. We observed Mrk 509 with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) on 2012-09-03 and 2012-10-11 coordinated with X-ray observations using the High Energy Transmission Grating on the Chandra X-ray Observatory. Our far-ultraviolet spectra used grating G140L on COS to cover wavelengths from 920–2000 Å at a resolving power of ∼2000, and gratings G130M and G160M to cover 1160–1750 Å at a resolving power of ∼15, 000. Results. We detect variability in the blueshifted UV absorption lines on timescales spanning 3–12 years. The inferred densities in the absorbing gas are greater than log n cm−3 ∼ 3. For ionization parameters ranging over log U = −1.5 to −0.2, we constrain the distances of the absorbers to be closer than 220 pc to the active nucleus. Conclusions. The impact on the host galaxy appears to be confined to the nuclear region.


2020 ◽  
Vol 492 (2) ◽  
pp. 2553-2571 ◽  
Author(s):  
Ivan Almeida ◽  
Rodrigo Nemmen

ABSTRACT Outflows produced by a supermassive black hole (SMBH) can have important feedback effects in its host galaxy. An unresolved question is the nature and properties of winds from SMBHs accreting at low rates in low-luminosity active galactic nuclei (LLAGNs). We performed two-dimensional numerical, hydrodynamical simulations of radiatively inefficient accretion flows on to non-spinning black holes. We explored a diversity of initial conditions in terms of rotation curves and viscous shear stress prescriptions, and evolved our models for very long durations of up to 8 × 105GM/c3. Our models resulted in powerful subrelativistic, thermally driven winds originated from the corona of the accretion flow at distances 10−100 GM/c2 from the SMBH. The winds reached velocities of up to 0.01c with kinetic powers corresponding to $0.1\!-\!1 {\,{\rm per\, cent}}$ of the rest-mass energy associated with inflowing gas at large distances, in good agreement with models of the ‘radio mode’ of AGN feedback. The properties of our simulated outflows are in broad agreement with observations of winds in quiescent galaxies that host LLAGNs, which are capable of heating ambient gas and suppressing star formation.


2019 ◽  
Vol 631 ◽  
pp. A13
Author(s):  
J. M. Ramírez-Velásquez ◽  
L. Di G. Sigalotti ◽  
R. Gabbasov ◽  
J. Klapp ◽  
E. Contreras

We present the classical Bondi accretion theory for the case of non-isothermal accretion processes onto a supermassive black hole (SMBH), including the effects of X-ray heating and the radiation force due to electron scattering and spectral lines. The radiation field is calculated by considering an optically thick, geometrically thin, standard accretion disc as the emitter of UV photons and a spherical central object as a source of X-ray emission. In our analysis, the UV emission from the accretion disc is assumed to have an angular dependence, and the X-ray radiation from the central object is assumed to be isotropic. This allows us to build streamlines in any angular direction. The influence of both types of radiation is evaluated for different flux fractions of the X-ray and UV emissions with and without the effects of spectral line driving. We find that the radiation emitted near the SMBH interacts with the infalling matter and modifies the accretion dynamics. In the presence of line driving, a transition takes place from pure type 1 and 2 to type 5 solutions, which takes place regardless of whether the UV emission dominates the X-ray emission. We computed the radiative factors at which this transition occurs, and discard type 5 solution from all our models. We also provide estimated values of the accretion radius and accretion rate in terms of the classical Bondi values. The results are useful for constructing proper initial conditions for time-dependent hydrodynamical simulations of accretion flows onto SMBHs at the centre of galaxies.


2020 ◽  
Vol 497 (4) ◽  
pp. 5103-5117
Author(s):  
Guilherme S Couto ◽  
Thaisa Storchi-Bergmann ◽  
Aneta Siemiginowska ◽  
Rogemar A Riffel ◽  
Raffaella Morganti

ABSTRACT We investigate the ionized gas excitation and kinematics in the inner $4.3\, \times \, 6.2$ kpc2 of the merger radio galaxy 4C+29.30. Using optical integral field spectroscopy with the Gemini North Telescope, we present flux distributions, line-ratio maps, peak velocities and velocity dispersion maps as well as channel maps with a spatial resolution of $\approx\! 955\,$ pc. We observe high blueshifts of up to $\sim\! -650\,$$\rm km\, s^{-1}$ in a region ∼1 arcsec south of the nucleus (the southern knot – SK), which also presents high velocity dispersions ($\sim\! 250\,$$\rm km\, s^{-1}$), which we attribute to an outflow. A possible redshifted counterpart is observed north from the nucleus (the northern knot – NK). We propose that these regions correspond to a bipolar outflow possibly due to the interaction of the radio jet with the ambient gas. We estimate a total ionized gas mass outflow rate of $\dot{M}_{\mathrm{ out}} = 25.4 ^{+11.5 }_{ -7.5}\,$ M⊙ yr−1with a kinetic power of $\dot{E} = 8.1 ^{+10.7 }_{ -4.0} \times 10^{42}\,$ erg s−1, which represents $5.8 ^{+7.6 }_{ -2.9} {{\ \rm per\ cent}}$ of the active galactic nucleus (AGN) bolometric luminosity. These values are higher than usually observed in nearby active galaxies with the same bolometric luminosities and could imply a significant impact of the outflows in the evolution of the host galaxy. The excitation is higher in the NK – that correlates with extended X-ray emission, indicating the presence of hotter gas – than in the SK, supporting a scenario in which an obscuring dust lane is blocking part of the AGN radiation to reach the southern region of the galaxy.


2013 ◽  
Vol 9 (S303) ◽  
pp. 307-311 ◽  
Author(s):  
A. Ballone ◽  
M. Schartmann ◽  
A. Burkert ◽  
S. Gillessen ◽  
R. Genzel ◽  
...  

AbstractThe origin of the dense gas cloud “G2” discovered in the Galactic center (Gillessen et al. 2012) is still a debated puzzle. G2 might be a diffuse cloud or the result of an outflow from an invisible star embedded in it. We present here detailed simulations of the evolution of winds on G2's orbit. We find that the hydrodynamic interaction with the hot atmosphere present in the Galactic center and the extreme gravitational field of the supermassive black hole must be taken into account when modeling such a source scenario. We also find that in this scenario most of the Brγ luminosity is expected to come from the highly filamentary densest shocked wind material. G2's observational properties can be used to constrain the properties of the outflow and our best model has a mass outflow rate of Ṁw=8.8 × 10−8 M⊙ yr−1 and a wind velocity of vw = 50 km s−1. These values are compatible with those of a young TTauri star wind, as already suggested by Scoville & Burkert (2013).


2007 ◽  
Vol 3 (S245) ◽  
pp. 263-268
Author(s):  
Tahir Yaqoob

AbstractAbsorption in the X-ray spectra of active galactic nuclei from outflowing gas can be modeled to yield critical physical information on the outflows. The outflow rate of mass ejected back into the ISM of the host galaxy and the resulting feedback could potentially have an impact on evolution. We give a brief overview of the current observational constraints on the outflows that should be taken into account by models of evolution and feedback.


2019 ◽  
Vol 491 (3) ◽  
pp. 3730-3750
Author(s):  
P Kosec ◽  
A C Fabian ◽  
C Pinto ◽  
D J Walton ◽  
S Dyda ◽  
...  

ABSTRACT Hercules X-1 is one of the best-studied highly magnetized neutron star X-ray binaries with a wealth of archival data. We present the discovery of an ionized wind in its X-ray spectrum when the source is in the high state. The wind detection is statistically significant in most of the XMM–Newton observations, with velocities ranging from 200 to 1000 km s−1. Observed features in the iron K band can be explained by both wind absorption and a forest of iron emission lines. However, we also detect nitrogen, oxygen, and neon absorption lines at the same systematic velocity in the high-resolution Reflection Grating Spectrometer grating spectra. The wind must be launched from the accretion disc, and could be the progenitor of the ultraviolet absorption features observed at comparable velocities, but the latter likely originate at significantly larger distances from the compact object. We find strong correlations between the ionization level of the outflowing material and the ionizing luminosity as well as the superorbital phase. If the luminosity is driving the correlation, the wind could be launched by a combination of Compton heating and radiation pressure. If instead the superorbital phase is the driver for the variations, the observations are likely scanning the wind at different heights above the warped accretion disc. If this is the case, we can estimate the wind mass outflow rate, corrected for the limited launching solid angle, to be roughly 70 per cent of the mass accretion rate.


2018 ◽  
Vol 619 ◽  
pp. A74 ◽  
Author(s):  
Giacomo Venturi ◽  
Emanuele Nardini ◽  
Alessandro Marconi ◽  
Stefano Carniani ◽  
Matilde Mingozzi ◽  
...  

Context. Ionized outflows, revealed by broad asymmetric wings of the [O III] λ5007 line, are commonly observed in active galactic nuclei (AGN) but the low intrinsic spatial resolution of the observations has generally prevented a detailed characterization of their properties. The MAGNUM survey aims at overcoming these limitations by focusing on the nearest AGN, including NGC 1365, a nearby Seyfert galaxy (D ∼ 17 Mpc), hosting a low-luminosity active nucleus (Lbol ∼ 2 × 1043 erg s−1). Aims. We want to obtain a detailed picture of the ionized gas in the central ∼5 kpc of NGC 1365 in terms of physical properties, kinematics, and ionization mechanisms. We also aim to characterize the warm ionized outflow as a function of distance from the nucleus and its relation with the nuclear X-ray wind. Methods. We employed optical integral-field spectroscopic observations from VLT/MUSE to investigate the warm ionized gas and Chandra ACIS-S X-ray data for the hot highly-ionized phase. We obtained flux, kinematic, and diagnostic maps of the optical emission lines, which we used to disentangle outflows from gravitational motions in the disk and measure the gas properties down to a spatial resolution of ∼70 pc. We then performed imaging spectroscopy on Chandra ACIS-S data guided by the matching with MUSE maps. Results. The [O III] emission mostly traces a kpc-scale biconical outflow ionized by the AGN having velocities up to ∼200 km s−1. Hα emission traces instead star formation in a circumnuclear ring and along the bar, where we detect non-circular streaming gas motions. Soft X-rays are predominantly due to thermal emission from the star-forming regions, but we manage to isolate the AGN photoionized component which nicely matches the [O III] emission. The mass outflow rate of the extended ionized outflow is similar to that of the nuclear X-ray wind and then decreases with radius, implying that the outflow either slows down or that the AGN activity has recently increased. However, the hard X-ray emission from the circumnuclear ring suggests that star formation might in principle contribute to the outflow. The integrated mass outflow rate, kinetic energy rate, and outflow velocity are broadly consistent with the typical relations observed in more luminous AGN.


2020 ◽  
Vol 493 (3) ◽  
pp. 3893-3910
Author(s):  
S B Kraemer ◽  
T J Turner ◽  
J D Couto ◽  
D M Crenshaw ◽  
H R Schmitt ◽  
...  

ABSTRACT We have analysed Chandra/High Energy Transmission Gratings spectra of the X-ray emission line gas in the Seyfert galaxy NGC 4151. The zeroth-order spectral images show extended H- and He-like O and Ne, up to a distance r ∼ 200 pc from the nucleus. Using the first-order spectra, we measure an average line velocity ∼−230 km s−1, suggesting significant outflow of X-ray gas. We generated cloudy photoionization models to fit the first-order spectra; the fit required three distinct emission line components. To estimate the total mass of ionized gas and the mass outflow rates, we applied the model parameters to fit the zeroth-order emission line profiles of Ne ix and Ne x. We determined the total mass of ≈5.4 × 105 M⊙. Assuming the same kinematic profile as that for the [O iii] gas, derived from our analysis of Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra, the peak X-ray mass outflow rate was ≈1.8 M⊙ yr−1, at r ∼ 150 pc. The total mass and mass outflow rates are similar to those determined using [O iii], implying that the X-ray gas is a major outflow component. However, unlike the optical outflows, the X-ray outflow rate does not drop off at r > 100 pc, which suggests that it may have a greater impact on the host galaxy.


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