Astronomy and Astrophysics – Astrophysics
Scientific paper
Mar 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...424...84h&link_type=abstract
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 424, no. 1, p. 84-105
Astronomy and Astrophysics
Astrophysics
178
Disk Galaxies, Galactic Evolution, Gas Dynamics, Quasars, Seyfert Galaxies, Star Formation, Starburst Galaxies, Galactic Halos, Gravitational Effects, Hydrodynamics
Scientific paper
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/N-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 approximately 100 solar mass 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 107 solar mass 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 enrgy input into the gas induces angular momentum loss and inflow rates by a factor less than 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 approximately 1045-1046 erg/s and episodic with a typical single burst duration of aproximately 107 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 less than 1 kpc radius gas disks. Models without the 'seed' BH form less than 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.
Heller Clayton H.
Shlosman Isaac
No associations
LandOfFree
Fueling nuclear activity in disk galaxies: Starbursts and monsters does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Fueling nuclear activity in disk galaxies: Starbursts and monsters, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fueling nuclear activity in disk galaxies: Starbursts and monsters will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1870916