Isaac Shlosman

University of Kentucky

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Clayton Heller

Georgia Southern University

J. H. Knapen

Instituto de Astrofísica de Canarias

Emilio Romano-Díaz

University of Bonn

Mitchell C. Begelman

University of Colorado Boulder

Yehuda Hoffman

Technion – Israel Institute of Technology

Seppo Laine

California Institute of Technology

R. F. Peletier

University of Groningen

Yang Luo

Yunnan University

Joel E. Tohline

Louisiana State University

Dimitris M. Christodoulou

University of Massachusetts Lowell

Cooperative Institutions

Max Planck Institute for Astronomy

University of Kentucky

Max Planck Society

Space Telescope Science Institute

Goddard Space Flight Center

California Institute of Technology

The University of Texas at Austin

Universidad Nacional Autónoma de México

Center for Astrophysics Harvard & Smithsonian

Centre National de la Recherche Scientifique

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Fueling nuclear activity in disk galaxies: Starbursts and monsters

The Astrophysical Journal (1994)

Clayton Heller Isaac Shlosman

view Abstract Citations (238) References (103) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Fueling Nuclear Activity in Disk Galaxies: Starbursts and Monsters Heller, Clayton H. ; Shlosman, Isaac Abstract We study the evolution of the gas distribution in a globally unstable galactic disk with a particular emphasis on the gasdynamics in the central kiloparsec and the fueling activity there. The two-component self-gravitating disk is embedded in a responsive halo of comparable mass. The gas and stars are evolved using a three-dimensional hybrid smoothed particle hydrodynamics/fit-body code and the gravitational interactions are calculated using a hierarchical TREE algorithm. A massive "star formation" is introduced when the gas becomes Jeans unstable and locally exceeds the critical density of ~100 M_sun_ pc^-3^. The newly formed OB stars deposit energy in the gas by means of radiation-driven winds and supernovae. This energy is partially thermalized (efficiency of a few percent); the rest is radiated away. Models without star formation are evolved for a comparison. The effect of a massive object at the disk center is studied by placing a "seed" black hole (BH) of 5 X 10^7^ M_sun_ with an accretion radius of 20 pc. The tendency of the system to form a massive object spontaneously is tested in models without the BH. We find that for models without star formation the bar- or dynamical friction-driven inflows lead to 1) domination of the central kpc by a few massive clouds that evolve into a single object probably via a cloud binary system, with and without a "seed" BH, 2) accretion onto the BH which has a sporadic character, and 3) formation of remnant disks around the BH with a radius of 60-80 pc which result from the capture and digestion of clouds. For models with star formation, we find that 1) the energy input into the gas induces angular momentum loss and inflow rates by a factor < 3,2) the star formation is concentrated mainly at the apocenters of the gaseous circulation in the stellar bar and in the nuclear region, 3) the nuclear starburst phase appears to be very luminous ~10^45^-10^46^ erg s^-1^ and episodic with a typical single burst duration of ~10^7^ yr, and 4) the starburst phase coincides with both the gas becoming dynamically important and the catastrophic growth of the BH. It ends with the formation of cold residual < 1 kpc radius gas disks. Models without the "seed" BH form < 1 kpc radius fat disks which dominate the dynamics. Gaseous bars follow, drive further inflow, and may fission into a massive cloud binary system at the center. Publication: The Astrophysical Journal Pub Date: March 1994 DOI: 10.1086/173874 Bibcode: 1994ApJ...424...84H Keywords: Disk Galaxies; Galactic Evolution; Gas Dynamics; Quasars; Seyfert Galaxies; Star Formation; Starburst Galaxies; Galactic Halos; Gravitational Effects; Hydrodynamics; Astrophysics; GALAXIES: EVOLUTION; GALAXIES: KINEMATICS AND DYNAMICS; GALAXIES: SEYFERT; GALAXIES: STARBURST; GALAXIES: STRUCTURE; HYDRODYNAMICS; GALAXIES: QUASARS: GENERAL; STARS: FORMATION full text sources ADS | data products SIMBAD (2)

Black hole (networking)

10.1086/173874

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Citations (199)

DARK MATTER HALOS AND EVOLUTION OF BARS IN DISK GALAXIES: COLLISIONLESS MODELS REVISITED

The Astrophysical Journal (2009)

Jorge Villa-Vargas Isaac Shlosman Clayton Heller

We construct and evolve families of steady-state models of stellar disks embedded in live DM halos, in order to study the dynamical and secular phases of bar evolution. These models are tested against those published in the literature in order to extend them and include the gaseous component in the follow up paper. We are interested in the angular momentum (J) redistribution in the disk-halo system. We confirm the previous results and quantify for the first time the dual role that the DM halos play in the bar evolution: more centrally concentrated halos dilute the dynamical processes, such as spontaneous bar instability and vertical buckling instability, and slowdown the J transfer, while facilitating it in the secular phase. Within the corotation radius (Rcr), the disk J remains nearly constant, as long as Rcr stays within the disk -- a sign that the lost J to the outer disk and the halo is being compensated by an influx of fresh J due to the outward motion of Rcr. This is feasible as long as the bar slowdown dominates the loss of J inside Rcr. We find that in some models the bar pattern speed stalls for prolonged time periods when Rcr is located outside the disk. This phenomenon appears concurrent with the near absence of J transfer between the disk and the halo. Furthermore, we confirm that stellar bars generally display the corotation to bar size ratios in the range of ~1-1.4, but only between the times of the first buckling and Rcr leaving the disk. The corotation-to-disk size ratio emerges as an important dynamic discriminator between various stages of barred disk evolution. Finally, we analyze a number of correlations between the basic parameters of a barred disk and a halo, some already reported in the literature and some new.

Dynamical friction

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10.1088/0004-637x/707/1/218

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Citations (44)

Induced Nested Galactic Bars inside Assembling Dark Matter Halos

The Astrophysical Journal (2007)

Clayton Heller Isaac Shlosman E. Athanassoula

We investigate the formation and evolution of nested bar systems in disk galaxies in a cosmological setting by following the development of an isolated dark matter (DM) and baryon density perturbation. The disks form within the assembling triaxial DM halos, and the feedback from the stellar evolution is accounted for in terms of supernovae and OB stellar winds. Focusing on a representative model, we show the formation of an oval disk and of a first generation of nested bars with characteristic subkiloparsec sizes and a few kiloparsec sizes. The system evolves through successive dynamical couplings and decouplings, forcing the gas inward, and settles in a state of resonant coupling. The inflow rate can support a broad range of activity within the central kiloparsec, from quasar to Seyfert types, supplemented by vigorous star formation as a by-product. The initial bar formation is triggered in response to the tidal torques from the triaxial DM halo, which acts as a finite perturbation. This first generation of bars does not survive for more than 4-5 Gyr; by that time, the secondary bar has totally dissolved, while the primary one has very substantially weakened, reduced to a fat oval. This evolution is largely due to chaos introduced by the interaction of the multiple nonaxisymmetric components.

10.1086/513104

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Citations (49)

THE DARK SIDE OF QSO FORMATION AT HIGH REDSHIFTS

The Astrophysical Journal (2011)

Emilio Romano-Díaz Isaac Shlosman Michele Trenti Yehuda Hoffman

Observed high-redshift QSOs, at z~6, may reside in massive dark matter (DM) halos of more than 10^{12} Msun and are thus expected to be surrounded by overdense regions. In a series of 10 constrained simulations, we have tested the environment of such QSOs. Comparing the computed overdensities with respect to the unconstrained simulations of regions empty of QSOs, assuming there is no bias between the DM and baryon distributions, and invoking an observationally-constrained duty-cycle for Lyman Break Galaxies, we have obtained the galaxy count number for the QSO environment. We find that a clear discrepancy exists between the computed and observed galaxy counts in the Kim et al. (2009) samples. Our simulations predict that on average eight z~6 galaxies per QSO field should have been observed, while Kim et al. detect on average four galaxies per QSO field compared to an average of three galaxies in a control sample (GOODS fields). While we cannot rule out a small number statistics for the observed fields to high confidence, the discrepancy suggests that galaxy formation in the QSO neighborhood proceeds differently than in the field. We also find that QSO halos are the most massive of the simulated volume at z~6 but this is no longer true at z~3. This implies that QSO halos, even in the case they are the most massive ones at high redshifts, do not evolve into most massive galaxy clusters at z=0.

QSOS

10.1088/0004-637x/736/1/66

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Dynamics of the Central kpc in Barred Galaxies: Theory and Modeling

arXiv (Cornell University) (2002)

Isaac Shlosman

The central kpc of barred galaxies exhibits a wealth of morphological information on different components with clear dynamical consequences. These include nuclear rings, spirals, bars, and more. We argue that this morphology is driven by large-scale stellar bars and analyze its consequences for gas dynamics and the distribution of star-forming regions. Specifically, we focus on gas flows in nested bar systems and study their origin, as well as the gravitational decoupling of gaseous nuclear bars with and without gas self-gravity. We find that the gas response in nested bars differs profoundly from that in single bars, and that no offset dust lanes form in the nuclear bars.

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A New Criterion for Bar-Forming Instability in Rapidly Rotating Gaseous and Stellar Systems. I. Axisymmetric Form

arXiv (Cornell University) (1994)

Dimitris M. Christodoulou Isaac Shlosman Joel E. Tohline

We analyze previous results on the stability of uniformly and differentially rotating, self-gravitating, gaseous and stellar, axisymmetric systems to derive a new stability criterion for the appearance of toroidal, m=2 Intermediate (I) and bar modes. In the process, we demonstrate that the bar modes in stellar systems and the m=2 I-modes in gaseous systems have many common physical characteristics and only one substantial difference: because of the anisotropy of the stress tensor, dynamical instability sets in at lower rotation in stellar systems. This difference is reflected also in the new stability criterion. The new stability parameter "alpha" is formulated first for uniformly rotating systems and is based on the angular momentum content rather than on the energy content of a system. For stability of stellar systems "alpha" = 0.254-0.258, while it is in the range of 0.341-0.354 for gaseous systems. For uniform rotation, one can write "alpha" as a function of the total (rotational) kinetic and gravitational energies, and of a parameter which is characteristic of the topology/connectedness and the geometric shape of a system. "Alpha" can be extended to and calculated for a variety of differentially rotating, gaseous and stellar, axisymmetric disk and spheroidal models whose equilibrium structures and stability characteristics are known. We also estimate "alpha" for gaseous toroidal models and for stellar disk systems embedded in an inert or responsive "halo". We find that the new stability criterion holds equally well for all these previously published axisymmetric models.

Stability criterion

10.48550/arxiv.astro-ph/9411031

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Bar-Driven Disk Evolution: Grand Design Nuclear Spirals

Shardha Jogee Isaac Shlosman Seppo Laine P. Englmaier J. H. Knapen

Original paper can be found at: http://www.astrosociety.org/pubs/cs/286.html--Copyright Astronomical Society of the Pacific

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Dynamics of Line‐driven Winds from Disks in Cataclysmic Variables. II. Mass‐Loss Rates and Velocity Laws

The Astrophysical Journal (1999)

Achim Feldmeier Isaac Shlosman P. Vitello

We analyze the dynamics of two-dimensional stationary, line-driven winds from accretion disks in cataclysmic variable (CV) stars by generalizing the formalism of Castor, Abbott, and Klein (CAK) for O stars. In Paper I, we solved the wind Euler equation, derived its two eigenvalues, and addressed the solution topology and wind geometry. Here, we focus on mass-loss rates and velocity laws of the wind. We find that disk winds, even in luminous nova-like variables, have low optical depth, even in the strongest driving lines. This suggests that thick-to-thin transitions in these lines occur in the wind. For disks with a realistic radial temperature law, the mass loss is dominated by gas emanating from the inner decade in radius. The total mass-loss rate associated with the wind from a disk of luminosity 10 L☉ is ~10-12 M☉ yr-1, or 10-4 of the mass accretion rate. This is 1 order of magnitude below the lower limit obtained from fitting P Cygni line profiles using kinematical wind models when the Lyman continuum is suppressed. The difficulties associated with such small mass-loss rates for line-driven winds from disks in CVs are principal and confirm our previous work on this subject. We conjecture that this issue may be resolved by detailed non-LTE calculations of the CAK line force within the context of CV disk winds and/or by better accounting for the disk energy distribution and wind ionization structure. We find that the wind velocity profile is well approximated by the empirical law used in kinematical modeling. The acceleration length scale is given by the footpoint radius of the wind streamline in the disk. This suggests an upper limit of ~10rwd to the acceleration scale, which is smaller by factor of a few as compared with values derived from line fitting.

Polar wind

10.1086/307977

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Citations (20)

Flat-cored Dark Matter in Cuspy Clusters of Galaxies

The Astrophysical Journal (2004)

Amr El‐Zant Yehuda Hoffman Joel R. Primack F. Combes Isaac Shlosman

Sand and coworkers have measured the central density profile of cluster MS 2137-23 with gravitational lensing and velocity dispersion and removed the stellar contribution with a reasonable M/L. The resulting dark matter (DM) distribution within r < 50 h-1 kpc was fitted by a density cusp of r-β with β = 0.35, in an apparent contradiction to the cold dark matter prediction of β ~ 1. The disagreement worsens if adiabatic compression of the DM by the infalling baryons is considered. Following El-Zant, Shlosman, & Hoffman, we argue that dynamical friction acting on galaxies moving within the DM background counters the effect of adiabatic compression by transfering their orbital energy to the DM, thus heating up and softening the cusp. Using N-body simulations we show that indeed the inner DM distribution flattens (with β ≈ 0.35 for a cluster like MS 2137-23) when the galaxies spiral inward. We find as a robust result that while the DM distribution becomes core-like, the overall mass distribution preserves its cuspy nature, in agreement with X-ray and lensing observations of clusters.

Velocity dispersion

Mass distribution

10.1086/421938

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Citations (186)

Ly α properties of simulated galaxies in overdense regions: effects of galactic winds at $z \gtrsim 6$

Monthly Notices of the Royal Astronomical Society (2019)

Raphael Sadoun Emilio Romano-Díaz Isaac Shlosman Zheng Zheng

We perform Monte-Carlo radiative transfer calculations to model the Lyman alpha properties of galaxies in high-resolution, zoom-in cosmological simulations at z ~ 6.6. The simulations include both constrained and unconstrained runs, representing respectively a highly overdense region and an average field. Different galactic wind models are used in the simulations in order to investigate the effects of these winds on the apparent Ly alpha properties of galaxies. We find that, for models including galactic winds, the Ly alpha properties of massive galaxies residing in the overdense region match well recent observations of luminous Ly alpha emitters (LAEs) at z ~ 6-7, in terms of apparent Ly alpha luminosity, Ly alpha line width and Ly alpha equivalent width distributions. Without winds, the same galaxies appear less Ly alpha bright as a result of both differences in the line profile emerging from galaxies themselves, and, in the distributions of neutral gas in the circumgalactic (CGM) and intergalactic medium (IGM). We also study the relations between apparent Ly alpha luminosity and various galaxy properties: stellar mass, star formation rate (SFR) and host halo mass. At fixed halo mass, the apparent Ly alpha luminosity of galaxies appears to depend on the large-scale environment while this is no longer true for galaxies at a given stellar mass or SFR. We provide simple linear fits to these relations that can be used for quickly constructing mock LAE samples from N-body simulations. Our results suggest that the observed luminous LAEs at z ~ 6.6 are hosted by ~10^{12} h^{-1} Mo, dark matter haloes, residing in large, overdense ionized regions.

Equivalent width

Stellar mass

10.1093/mnras/stz297

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Citations (7)