A spectacular outflow in an obscured quasar
TL;DR: In this paper, the authors present two long-slit Magellan LDSS-3 spectra that reveal a pair of symmetric 10 kpc size outflows emerging from this nucleus, with observed expansion velocities of approximately 250 km s{sup -1} in projection.
Abstract: SDSS J1356+1026 is a pair of interacting galaxies at redshift z = 0.123 that hosts a luminous obscured quasar in its northern nucleus. Here we present two long-slit Magellan LDSS-3 spectra that reveal a pair of symmetric {approx}10 kpc size outflows emerging from this nucleus, with observed expansion velocities of {approx}250 km s{sup -1} in projection. We present a kinematic model of these outflows and argue that the deprojected physical velocities of expansion are likely {approx}1000 km s{sup -1} and that the kinetic energy of the expanding shells is likely 10{sup 44-45} erg s{sup -1}, with an absolute minimum of >10{sup 42} erg s{sup -1}. Although a radio counterpart is detected at 1.4 GHz, it is faint enough that the quasar is considered to be radio quiet by all standard criteria, and there is no evidence of extended emission due to radio lobes, whether aged or continuously powered by an ongoing jet. We argue that the likely level of star formation is insufficient to power the observed energetic outflow and that SDSS J1356+1026 is a good case for radio-quiet quasar feedback. In further support of this hypothesis, polarimetric observations show that the direction of quasar illumination is coincident with themore » direction of the outflow.« less
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TL;DR: In this article, it was shown that the radiative or quasar mode of feedback can account for the observed proportionality between the central black hole and the host galaxy mass, which can lead to ejection or heating of the gas.
Abstract: Radiation, winds, and jets from the active nucleus of a massive galaxy can interact with its interstellar medium, and this can lead to ejection or heating of the gas. This terminates star formation in the galaxy and stifles accretion onto the black hole. Such active galactic nuclei (AGN) feedback can account for the observed proportionality between the central black hole and the host galaxy mass. Direct observational evidence for the radiative or quasar mode of feedback, which occurs when AGN are very luminous, has been difficult to obtain but is accumulating from a few exceptional objects. Feedback from the kinetic or radio mode, which uses the mechanical energy of radio-emitting jets often seen when AGN are operating at a lower level, is common in massive elliptical galaxies. This mode is well observed directly through X-ray observations of the central galaxies of cool core clusters in the form of bubbles in the hot surrounding medium. The energy flow, which is roughly continuous, heats the hot intraclu...
2,299 citations
TL;DR: Simba as discussed by the authors is the next generation of the Mufasa cosmological galaxy formation simulations run with Gizmo's meshless finite mass hydrodynamics, which includes updates to Mufaa's sub-resolution star formation and feedback prescriptions, and introduces black hole growth via the torque-limited accretion model of Angles-Alcazar et al.
Abstract: We introduce the Simba simulations, the next generation of the Mufasa cosmological galaxy formation simulations run with Gizmo's meshless finite mass hydrodynamics. Simba includes updates to Mufasa's sub-resolution star formation and feedback prescriptions, and introduces black hole growth via the torque-limited accretion model of Angles-Alcazar et al. (2017) from cold gas and Bondi accretion from hot gas, along with black hole feedback via kinetic bipolar outflows and X-ray energy. Ejection velocities are taken to be ~10^3 km/s at high Eddington ratios, increasing to ~8000 km/s at Eddington ratios below 2%, with a constant momentum input of 20L/c. Simba further includes an on-the-fly dust production, growth, and destruction model. Our Simba run with (100 Mpc/h)^3 and 1024^3 gas elements reproduces numerous observables, including galaxy stellar mass functions at z=0-6, the stellar mass--star formation rate main sequence, HI and H2 fractions, the mass-metallicity relation at z=0 and z=2, star-forming galaxy sizes, hot gas fractions in massive halos, and z=0 galaxy dust properties. However, Simba also yields an insufficiently sharp truncation of the z=0 mass function, and too-large sizes for low-mass quenched galaxies. We show that Simba's jet feedback is primarily responsible for quenching massive galaxies.
518 citations
TL;DR: In this article, the authors focus on the question of how common are kilo-parsec scale ionised outflows in the host galaxies of powerful active galactic nuclei (AGN) and what are their properties (e.g., spatial extents, morphologies and energetics).
Abstract: In this chapter we aim to address the question: how common are kilo-parsec scale ionised outflows in the host galaxies of powerful active galactic nuclei (AGN; i.e., quasars) and what are their properties (e.g., spatial extents, morphologies and energetics)? We select 16 targets for spatially-resolved spectroscopy (i.e., integral field unit [IFU] observations) from a well-constrained parent sample of \(\approx \)24,000 AGN. This means that we can place our observations into the context of the overall AGN population and therefore learn about the population as a whole. Our targets are \(z<0.2\) type 2 quasars that are radio-quiet, with star formation rates (\(\lesssim \)[10–100]\(\mathrm{M}_{\odot }\,\mathrm{yr}^{-1}\)) that are consistent with normal star-forming galaxies. We present Gemini-GMOS IFU observations covering the [O iii]\(\lambda \lambda 4959,5007\) and H\(\beta \) emission lines. We find high-velocity ionised gas (velocity widths \({\approx }600\)–1500 km s\(^{-1}\); maximum velocities \({\le }1700\) km s\(^{-1}\)) with observed spatial extents of \(\gtrsim \)(6–16) kpc in all targets. We show that our targets are representative of \(z<0.2\), type 2 quasars and that ionised outflows are not only common but also in \(\ge \)70 % (3\(\sigma \) confidence) of cases, they are extended over kiloparsec scales. Both star formation and AGN activity appear to be energetically viable to drive the outflows and we find no definitive evidence that favours one process over the other. Although uncertain, we derive mass outflow rates (typically \({\approx }10 \times \) the SFRs), kinetic energies (\({\approx }0.5\)–10 % of \(L_{\mathrm{AGN}}\)) and momentum rates (typically \({\gtrsim }[10\)–\(20]\times L_{\mathrm{AGN}}/c\)) consistent with theoretical models that predict that AGN-driven outflows play a significant role in shaping the evolution of galaxies.
474 citations
TL;DR: In this paper, the authors acknowledge support from the FP7 Career Integration Grant “eEASy” (CIG 321913), LZ acknowledges support from ASI/INAF grant I/037/12/0 and CF acknowledges funding from the European Union Horizon 2020 research and innovation programme under the Marie SklodowskaCurie grant agreement No 664931.
Abstract: This work was supported by ASI/INAF contract I/009/10/0 and INAF PRIN 2011, 2012 and 2014. MB acknowledges support from the FP7 Career Integration Grant “eEASy” (CIG 321913). LZ acknowledges support from ASI/INAF grant I/037/12/0. CF acknowledges funding from the European Union Horizon 2020 research and innovation programme under the Marie SklodowskaCurie grant agreement No 664931. CC acknowledges funding from the European Union Horizon 2020 research and innovation programme under the Marie SklodowskaCurie grant agreement No 664931 and support from Swiss National Science Foundation Grants PP00P2 138979 and PP00P2 166159. RM acknowledges the ERC Advanced Grant 695671 QUENCH and support from the Science and Technology Facilities Council (STFC).
427 citations
TL;DR: In this paper, it is shown that cooling of high-velocity shocked winds in AGN is in fact inefficient in a wide range of circumstances, including conditions relevant to ultraluminous infrared galaxies (ULIRGs), resulting in energy-conserving outflows.
Abstract: Active galactic nuclei (AGN) drive fast winds in the interstellar medium of their host galaxies. It is commonly assumed that the high ambient densities and intense radiation fields in galactic nuclei imply short cooling times, thus making the outflows momentum conserving. We show that cooling of high-velocity shocked winds in AGN is in fact inefficient in a wide range of circumstances, including conditions relevant to ultraluminous infrared galaxies (ULIRGs), resulting in energy-conserving outflows. We further show that fast energy-conserving outflows can tolerate a large amount of mixing with cooler gas before radiative losses become important. For winds with initial velocity vin ≳ 10 000 km s−1, as observed in ultraviolet and X-ray absorption, the shocked wind develops a two-temperature structure. While most of the thermal pressure support is provided by the protons, the cooling processes operate directly only on the electrons. This significantly slows down inverse Compton cooling, while free–free cooling is negligible. Slower winds with vin ∼ 1000 km s−1, such as may be driven by radiation pressure on dust, can also experience energy-conserving phases but under more restrictive conditions. During the energy-conserving phase, the momentum flux of an outflow is boosted by a factor ∼vin/2vs by work done by the hot post-shock gas, where vs is the velocity of the swept-up material. Energy-conserving outflows driven by fast AGN winds (vin ∼ 0.1c) may therefore explain the momentum fluxes of galaxy-scale outflows recently measured in luminous quasars and ULIRGs. Shocked wind bubbles expanding normal to galactic discs may also explain the large-scale bipolar structures observed in some systems, including around the Galactic Centre, and can produce significant radio, X-ray and γ-ray emission. The analytic solutions presented here will inform implementations of AGN feedback in numerical simulations, which typically do not include all the important physics.
421 citations
References
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TL;DR: In this article, the average extinction law over the 3.5 micron to 0.125 wavelength range was derived for both diffuse and dense regions of the interstellar medium. And the validity of the law over a large wavelength interval suggests that the processes which modify the sizes and compositions of grains are stochastic in nature.
Abstract: The parameterized extinction data of Fitzpatrick and Massa (1986, 1988) for the ultraviolet and various sources for the optical and near-infrared are used to derive a meaningful average extinction law over the 3.5 micron to 0.125 wavelength range which is applicable to both diffuse and dense regions of the interstellar medium. The law depends on only one parameter R(V) = A(V)/E(B-V). An analytic formula is given for the mean extinction law which can be used to calculate color excesses or to deredden observations. The validity of the law over a large wavelength interval suggests that the processes which modify the sizes and compositions of grains are stochastic in nature and very efficient.
11,704 citations
TL;DR: The Sloan Digital Sky Survey (SDSS) as mentioned in this paper provides the data to support detailed investigations of the distribution of luminous and non-luminous matter in the Universe: a photometrically and astrometrically calibrated digital imaging survey of pi steradians above about Galactic latitude 30 degrees in five broad optical bands.
Abstract: The Sloan Digital Sky Survey (SDSS) will provide the data to support detailed investigations of the distribution of luminous and non- luminous matter in the Universe: a photometrically and astrometrically calibrated digital imaging survey of pi steradians above about Galactic latitude 30 degrees in five broad optical bands to a depth of g' about 23 magnitudes, and a spectroscopic survey of the approximately one million brightest galaxies and 10^5 brightest quasars found in the photometric object catalog produced by the imaging survey. This paper summarizes the observational parameters and data products of the SDSS, and serves as an introduction to extensive technical on-line documentation.
10,039 citations
Donald G. York1, Jennifer Adelman2, John E. Anderson2, Scott F. Anderson3 +148 more•Institutions (29)
TL;DR: The Sloan Digital Sky Survey (SDSS) as discussed by the authors provides the data to support detailed investigations of the distribution of luminous and non-luminous matter in the universe: a photometrically and astrometrically calibrated digital imaging survey of π sr above about Galactic latitude 30° in five broad optical bands to a depth of g' ~ 23 mag.
Abstract: The Sloan Digital Sky Survey (SDSS) will provide the data to support detailed investigations of the distribution of luminous and nonluminous matter in the universe: a photometrically and astrometrically calibrated digital imaging survey of π sr above about Galactic latitude 30° in five broad optical bands to a depth of g' ~ 23 mag, and a spectroscopic survey of the approximately 106 brightest galaxies and 105 brightest quasars found in the photometric object catalog produced by the imaging survey. This paper summarizes the observational parameters and data products of the SDSS and serves as an introduction to extensive technical on-line documentation.
9,835 citations
Book•
01 Jan 1989
TL;DR: In this paper, a comparison of theory with observations internal dynamics of gaseous nebulae interstellar dust H II regions in the galactic context is presented. But the results are limited to the case of active galactic nuclei.
Abstract: Photoionization equilibrium thermal equilibrium calculation of emitted spectrum comparison of theory with observations internal dynamics of gaseous nebulae interstellar dust H II regions in the galactic context planetary nebulae nova and supernova remnants active galactic nuclei - diagnostic and physics active galactic nuclei - results.
6,090 citations
TL;DR: The NRAO VLA Sky Survey (NVSS) covers the sky north of J2000 at 1.4 GHz as discussed by the authors, including a set of 2326 4?? 4? continuum cubes with three planes containing Stokes I, Q, and U images plus a catalog of almost 2? 106 discrete sources stronger than S 2.5 mJy.
Abstract: ?????The NRAO VLA Sky Survey (NVSS) covers the sky north of J2000.0 ? = -40? (82% of the celestial sphere) at 1.4 GHz. The principal data products are (1) a set of 2326 4? ? 4? continuum cubes with three planes containing Stokes I, Q, and U images plus (2) a catalog of almost 2 ? 106 discrete sources stronger than S ? 2.5 mJy. The images all have ? = 45'' FWHM resolution and nearly uniform sensitivity. Their rms brightness fluctuations are ? ? 0.45 mJy beam-1 ? 0.14 K (Stokes I) and ? ? 0.29 mJy beam-1 ? 0.09 K (Stokes Q and U). The rms uncertainties in right ascension and declination vary from 1'' for the N ? 4 ? 105 sources stronger than 15 mJy to 7'' at the survey limit. The NVSS was made as a service to the astronomical community. All data products, user software, and updates are being released via the World Wide Web as soon as they are produced and verified.
5,441 citations