Mario Livio
Publications

Accretion disks in the publication record

73 entries1977 – 2007 58 refereed

Accretion is the spine of the entire record. Matter falling toward a compact object cannot fall straight in: it arrives carrying angular momentum, so it settles into a rotating disk and works inward only as fast as that angular momentum can be carried outward. Everything else follows from that constraint. The disk heats because gravitational energy is released on the way down, and the light we observe is that release, not the object at the centre.

The awkward part is the transport. Ordinary molecular viscosity in a disk of this size is far too weak to move angular momentum at anything like the observed rate, so some other mechanism has to be doing it — turbulence, magnetic stress, waves. The standard workaround is to bundle the whole unknown into a single dimensionless parameter, alpha, and fit it. A 2007 entry asks the question in the title directly: accretion disc viscosity — how big is alpha?

What the papers address

Stability comes first, both chronologically and logically. Two of the earliest entries in the whole index, from 1977 and 1981, are on the stability of accretion disks and on their stability to short-wavelength perturbations. The question is whether a smooth disk stays smooth: if small ripples grow instead of damping, the disk is not a steady structure but an intermittent one, and the light curve should show it.

Geometry is the second theme. A thin disk and a thick one behave differently enough to need separate treatment, and papers through the 1980s work on thick-disk equations and on what happens where the incoming stream meets the disk edge without joining it smoothly. A 1986 paper on stream–disk interaction in accreting compact objects is about precisely that collision, which turns out to be where a good deal of the observable variability originates.

Then there is what a disk does other than accrete. Warping and precession appear in a 2006 paper spanning galactic and extragalactic disks, on the theme that a disk need not stay in one plane. Outflow is the larger case: several papers ask how a disk launches material along its rotation axis, which is the point at which this subject and the jet papers become the same subject.

Wind accretion is the odd case out and worth noting because it inverts the usual picture. In a 1984 paper on wind accretion onto white dwarfs the mass does not arrive by overflow from a companion at all but is captured from that companion’s stellar wind, which produces a different disk and a different eruption history.

How the group changes over time

The early papers treat the disk as the object of study; the later ones treat it as an instrument. By 2004, variability in black hole accretion disks is a paper about using the disk to infer something about the hole. By 2005, disks and planets around massive white dwarfs uses disks to ask where planets can form. The physics being applied is largely the physics worked out in the first decade of the record.

One thing does not change: alpha is still a parameter and not a derivation. The 2007 entry asking how big it is arrives thirty years after the first stability paper in this index, which is a reasonable measure of how hard the transport problem turned out to be.

The 73 entries listed below are the subset of the 325-entry index that this site classifies under accretion disks, dated 1977 to 2007. Because accretion underlies most of the record, this facet is the widest of the four: a title naming a disk, a viscosity or an inflow is counted here even when the object it orbits gives the paper its other label. Read the count as a lower bound on how much of the record is about accretion.

Concentric paper rings tilted at a steep angle, narrowing and warming toward a dark centre, with two pale streamers curving inward

The 73 entries

  1. King, A. R., Pringle, J. E., & Livio, M., “Accretion disc viscosity: how big is alpha?” MNRAS, 376, 1740, (2007).
  2. Caproni, A., Livio, M., Abraham, Z., & Mosquera Cuesta, H. J., “Warping and Precession in Galactic and Extragalactic Accretion Disks,” ApJ, 653, 112, (2006).
  3. Livio, M., Pringle, J. E., & Wood, K., “Disks and Planets around Massive White Dwarfs,” ApJ, 632, L37, (2005).
  4. King, A. R., Pringle, J. E., West, R. G., & Livio, M., “Variability in Black Hole Accretion Disks,” MNRAS, 348, 111 (2004).
  5. Hujeirat, A., Livio, M., Camenzind, M., & Burkert, A., “A Model for the Disk-Jet Connection in Black Hole Accreting Systems,” A&A, 408, 415 (2003).
  6. Livio, M., Pringle, J. E., & King, A. R., “The Disk-Jet Connection in Microquasars and AGN,” ApJ, 593, 184 (2003).
  7. Biretta, J. A., Junor, W., & Livio, M., “Evidence for Initial Jet Formation by an Accretion Disk in the Radio Galaxy M87,” New Astron. Rev., 46, 239 (2002).
  8. Armitage, P. J., Livio, M., & Pringle, J. E., “Episodic Accretion in Magnetically Layered Protoplanetary Discs,” MNRAS, 324, 705 (2001).
  9. Ogilvie, G. I. & Livio, M., “Launching of Jets and the Vertical Structure of Accretion Disks,” ApJ, 553, 158 (2001).
  10. Armitage, P. & Livio, M., “Black Hole Formation Via Hypercritical Accretion,” ApJ, 532, 540 (2000).
  11. Godon, P. & Livio, M., “The Formation and Role of Vortices in Protoplanetary Disks,” ApJ, 537, 396 (2000).
  12. Livio, M., “Accretion Disks: Limit Cycles and Instabilities,” in Astrophysical Disks, (Cambridge, CUP), p. 33 (1999).
  13. Godon, P. & Livio, M., “On the Non-Linear Hydrodynamic Stability of Thin Keplerian Disks,” ApJ, 521, 319 (1999).
  14. Siess, L. & Livio, M., “The Accretion of Brown Dwarfs and Planets by Giant Stars I,” MNRAS, 304, 925 (1999).
  15. Siess, L. & Livio, M., “The Accretion of Brown Dwarfs and Planets by Giant Stars II,” MNRAS, 308, 1133 (1999).
  16. Godon, P. & Livio, M., “Vortices in Protoplanetary Disks,” ApJ, 523, 350 (1999).
  17. Armitage, P. & Livio, M., “Hydrodynamics of the Stream-Disk Impact in Interacting Binaries,” ApJ, 493, 898 (1998).
  18. Ogilvie, G. I. & Livio, M., “On the Diffculty of Launching an Outflow from an Accretion Disk,” ApJ, 499, 329 (1998).
  19. Godon, P., Livio, M., & Lubow, S., “Spiral Shocks in Accretion Disks,” MNRAS, 295, L11 (1998).
  20. DellaValle, M. & Livio, M., “The Spectroscopic Differences between Disk and Thick Disk Novae,” ApJ, 506, 818 (1998).
  21. Storchi-Bergmann, T., Eracleous, M., Ruiz, M. T., Livio, M., Wilson, A. S., & Filippenko, A. V., “A Precessing Accretion Disk in the Nucleus of NGC 1097,” ApJ, 489, 87 (1997).
  22. Livio, M. & Xu, C. “On the Evidence for Accretion Disks in Active Galactic Nuclei,” ApJ, 478, L63 (1997).
  23. Livio, M. & Pringle, J. E., “Wobbling Accretion Disks, Jets, and Point-Symmetric Nebulae,” ApJ, 486, 835 (1997).
  24. Armitage, P. J. & Livio, M., “Accretion Disks in Interacting Binaries: Simulations of the Stream-Disk Impact,” ApJ, 470, 1024 (1996).
  25. Warner, B., Livio, M., & Tout, C., “Dwarf Nova Outbursts in Truncated Accretion Disks, Down with Low Alphas,” MNRAS, 282, 735, (1996).
  26. Armitage, P. J., Livio, M., & Pringle, J. E., “Dynamo Driven Accretion Discs and Dwarf Nova Eruptions,” ApJ, 457, 332 (1996).
  27. Cannizzo, J. K., Chen, W., & Livio, M., “The Accretion Disk Limit Cycle Instability in Black Hole X-Ray Binaries,” ApJ, 454, 880 (1996).
  28. Livio, M., “Angular Momentum Transport in Accretion Disks,” in Cataclysmic Variables, eds. A. Bianchini, et al., p. 349 (1995).
  29. Eracleous, M., Livio, M., Halpern, J. P., & Storchi-Bergmann, T., “Elliptical Accretion Disks in Active Galactic Nuclei,” ApJ, 438, 610 (1995).
  30. Hellier, C. & Livio, M., “Disk-Overflow Accretion in GK Persei?” ApJ, 424, L57 (1994).
  31. Soker, N. & Livio, M., “Disks and Jets in Planetary Nebulae,” ApJ, 421, 219 (1994).
  32. Balsara, D., Livio, M., & O’Dea, C. P., “Galaxies in Clusters: Gas Stripping and Accretion,” ApJ, 437, 83 (1994).
  33. Dgani, R., Livio, M., & Regev, O., “On the Effects of Tidal Interaction on Thin Accretion Disks,” ApJ, 436, 270 (1994).
  34. Livio, M., “Intriguing Morphologies, Jets and Disks in Planetary Nebulae,” in Theory of Accretion Disks II, eds. W. Duschl, et al., p. 411 (1993).
  35. Livio, M., “On the Possibility of Obtaining Type Ia Supernovae and Accretion Induced Collapses from Cataclysmic Variables and Related Objects,” in Cataclysmic Variables and Related Physics, eds. O. Regev and G. Shaviv, Ann. Isr. Acad. Sci., p. 57 (1993).
  36. Livio, M., “The Interaction between the Stream and the Accretion Disk,” in Accretion Disks in Compact Stellar Systems, ed. J. C. Wheeler, (Singapore: World Scientific), p. 243 (1993).
  37. Gat, O. & Livio, M., “Dynamical Stability of Two-Dimensional Accretion Flows,” ApJ, 396, 542 (1992).
  38. Matsuda, T., Ishii, T., Sekino, N., Sawada, K., Shima, E., Livio, M., & Anzer, U., “Numerical Simulations of 2D and 3D Accretion Flows,” MNRAS, 255, 183 (1992).
  39. Livio, M. & Truran, J. W., “Type I Supernovae and Accretion Induced Collapses from Cataclysmic Variables,” ApJ, 389, 695 (1992).
  40. Livio, M., “Wind Accretion by Compact Objects: The Flip-Flop In-stability,” in Evolutionary Processes in Interacting Binary Stars, ed. Y. Kondo, R. F. Sistero and R. S. Polidan, (Dordrecht: Kluwer), p. 185 (1992).
  41. Livio, M., “Accretion by Compact Objects from Stellar Winds,” Structure and Emission Properties of Accretion Disks, IAU Colloquium 129, eds. C. Bertout, et al., p. 263 (1991).
  42. Matsuda, T., Ishii, T., Livio, M., Anzer, V., & Börner, G., “Flip-Flop Instability of Wind-Fed Accretion Flow 2D and 3D Calculations,” the 28th Yamada Conference on Frontiers of X-Ray Astronomy, eds. Y. Tanaka and K. Koyama (Tokyo: University Academy Press) (1991).
  43. Livio, M., “On Accretion by Compact Objects from a Stellar Wind,” in Frontier Objects in Astrophysics and Particle Physics, Vulcano Workshop 1990, ed. F. Giovannelli, p. 67 (1991).
  44. Livio, M. & Spruit, H. C., “On the Mechanism of Angular Momentum Transport in Accretion Disks,” A&A, 252, 189 (1991).
  45. Matsuda, T., Sekino, N., Sawada, K., Shima, E., Livio, M., Anzer, U., & Börner, G., “On the Stability of Wind Accretion,” A&A, 248, 301 (1991).
  46. Livio, M., Soker, N., Matsuda, T., & Anzer, U., “The Nature of the ‘Flip-Flop’ Instability in Accretion Flows,” MNRAS, 253, 633 (1991).
  47. Abramowicz, M., Livio, M., Soker, N., & Szuszkiewicz, E., “Local Stability of Thick Accretion Disks,” A&A, 239, 399 (1990).
  48. Bunk, W., Livio, M., & Verbunt, F., “The Possibility of Observing Spiral Shocks in Accretion Disks,” A&A, 232, 371 (1990).
  49. Duschl, W. & Livio, M., “The Reaction of Accretion to Strong Input Mass Pulses,” in Active Galactic Nuclei, ed. P. Wiita (1990).
  50. Livio, M., Prialnik, D., & Regev, O., “Accretion onto Hot White Dwarfs,” ApJ, 341, 299 (1989).
  51. Sawada, K., Matsuda, T., Anzer, U., Borner, G., & Livio, M., “Inhomogeneous Wind Accretion,” A&A, 221, 263 (1989).
  52. Livio, M., “Merging White Dwarfs, Disk Formation and Type I Supernovae,” in NATO Advance Research Workshop on Theory of Accretion Disks, eds. F. Meyer, et al., p. 135 (1989).
  53. Duschl, W.& Livio, M., “On Mixed Mass Transfer and Disk Instability Models,” A&A, 209, 183 (1989).
  54. Dgani, R., Livio, M., & Soker, N., “On the Stream-Accretion Disk Interaction,” ApJ, 336, 350 (1989).
  55. Livio, M., “Accretion from Stellar Winds,” in IAU Colloquium 103, The Symbiotic Phenomenon, pp. 149–160 (1988).
  56. Livio, M. & Verbunt, F., “The Response of an Accretion Disk Radius to a Temporary Enhancement of Mass Transfer,” MNRAS, 232, 1 (1988).
  57. Soker, N., Regev, O., Livio, M., & Shara, M. M., “Massive Disk Formation Resulting from the Collision of a MS Star with a White Dwarf,” ApJ, 318, 760 (1987).
  58. Livio, M., Soker, N., de Kool, M., & Savonije, G. J., “Accretion from an Inhomogeneous Medium III: General Case and Observational Consequences,” MNRAS, 222, 235 (1986).
  59. Soker, N., Livio, M., de Kool, M., & Savonije, G. J., “Accretion of Angular Momentum from an Inhomogeneous Medium II: Isothermal Flow,” MNRAS, 221, 445 (1986).
  60. Abramowicz, M. A., Livio, M., & Lu, J., “Adiabatic Accretion of Rotating Matter onto a Black Hole,” in Proc. of Grossman Colloquium on General Relativity (1986).
  61. Livio, M., Soker, N., de Kool, M., & Savonije, G. J., “On Accretion of Angular Momentum from an Inhomogeneous Medium,” MNRAS, 218, 593 (1986).
  62. Livio, M., Soker, N., & Dgani, R., “On the Stream-Disk Interaction in Accreting Compact Objects,” ApJ, 305, 267 (1986).
  63. Livio, M., “The Problem of Accretion of Angular Momentum from an Inhomogeneous Medium,” Comments on Astrophysics, 11, 111 (1986).
  64. Prialnik, D. & Livio, M., “Episodic Accretion Events onto a White Dwarf,” MNRAS, 213, 407 (1985).
  65. Livio, M., Soker, N., de Kool, M., & Savonije, G. J., “On Accretion of Angular Momentum from an Inhomogeneous Medium,” in Recent Results on Cataclysmic Variables, ESA SP-236 (1985).
  66. Prialnik, D. & Livio, M., “The Outcome of Accretion onto Fully Convective Stars,” MNRAS, 216, 37 (1985).
  67. Abramowicz, M. A., Livio, M., Piran, T., & Wiita, P. J., “Local Stability of Thick Accretion Basic Equations and Parallel Perturbations in the Negligible Viscosity Case,” ApJ, 279, 367 (1984).
  68. Soker, N. & Livio, M., “On Accretion from a Medium Containing a Density Gradient,” MNRAS, 211, 927 (1984).
  69. Dgani, R. & Livio, M., “On the Analytical Properties of Alpha-Beta Disks,” MNRAS, 210, 393 (1984).
  70. Livio, M. & Warner, B., “Wind Accretion onto White Dwarfs,” Observatory, 104, 152 (1984).
  71. Prialnik, D., Livio, M., Shaviv, G., & Kovetz, A., “On the Role of the Accretion Rate in Nova Outbursts,” ApJ, 257, 312 (1982).
  72. Livio, M. & Shaviv, G., “The Stability of Accretion Disks to Short Wavelength Perturbations,” ApJ, 244, 290 (1981).
  73. Livio, M. & Shaviv, G., “On the Stability of Accretion Disks,” A&A, 55, 95 (1977).

Questions

Why does matter form a disk instead of falling straight in?

Because it has angular momentum. Infalling material can only lose energy quickly, by radiating; it cannot lose angular momentum quickly, so it settles into the lowest-energy configuration that conserves it, which is a rotating disk. The rate of accretion is then set by how fast angular momentum can be transported outward.

What is the alpha parameter?

A dimensionless stand-in for whatever provides the disk’s effective viscosity. Molecular viscosity is far too small to explain observed accretion rates, so the unknown transport mechanism is parametrised as alpha and constrained by fitting observations, because no derivation from first principles is available.

Are these papers about black holes specifically?

No. The same disk physics applies to white dwarfs, neutron stars, black holes and young stars, and a recurring argument in the record is that treating them as one problem is more productive than treating them as four.

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