Results 11 to 20 of about 23,810 (131)

Turbulent viscosity in clumpy accretion disks II supernova driven turbulence in the Galaxy [PDF]

Astronomy & Astrophysics, 2003
An analytical model for a turbulent clumpy gas disk is presented where turbulence is maintained by the energy input due to supernovae. Expressions for the disk parameters, global filling factors, molecular fractions, and star formation rates are given as
Allen, Avillez, B. Vollmer, Boulares, Elmegreen, Gazol-Patino, Hollenbach, Korpi, Paczynski, Prantzos, Rosen, Rownd, Spitzer, Strong, T. Beckert, Tammann, Thornton, Toomre, Vollmer, Wada, Wada, Wong, Wong   +22 more
core   +2 more sources

The Reliability of Accretion Disk Inclination Derived from X-Ray Spectroscopy of Active Galaxies

The Astrophysical Journal
The inclination angle of substructures in active galaxies gives insights into physical components from scales of the vicinity of the central black hole to the entire host galaxy. We use the self-consistent reflection spectral model RELXILL to measure the
Rong Du, Yuanze Ding, Luis C. Ho, Ruancun Li   +3 more
doaj   +4 more sources

Investigating the Impact of Metallicity on Star Formation in the Outer Galaxy. I. VLT/KMOS Survey of Young Stellar Objects in Canis Major

The Astrophysical Journal Supplement Series, 2023
The effects of metallicity on the evolution of protoplanetary disks may be studied in the outer Galaxy where the metallicity is lower than in the solar neighborhood.
Dominika Itrich, Agata Karska, Marta Sewiło, Lars E. Kristensen, Gregory J. Herczeg, Suzanne Ramsay, William J. Fischer, Benoît Tabone, Will R. M. Rocha, Maciej Koprowski, Ngân Lê, Beata Deka-Szymankiewicz   +11 more
doaj   +1 more source

The Space Density of Extended Ultraviolet (XUV) Disks in the Local Universe and Implications for Gas Accretion on to Galaxies [PDF]

, 2011
We present results of the first unbiased search for extended UV (XUV)-disk galaxies undertaken to determine the space density of such galaxies. Our sample contains 561 local (0.001 < z < 0.05) galaxies that lie in the intersection of available GALEX deep
Bianchi, Luciana, Heckman, Timothy M., Lemonias, Jenna J., Madore, Barry F., Martin, D. Christopher, Rich, R. Michael, Schiminovich, David, Seibert, Mark, Thilker, David, Treyer, Marie A., Wyder, Ted K.   +10 more
core   +9 more sources

Similar Signatures of Coplanar Gas Inflow and Disk Warps in Galactic Gas Kinematic Maps

The Astrophysical Journal, 2023
Hydrodynamic simulations suggest that galactic gas disks form when coplanar gas spirals into the inner regions of the disk. We recently presented a simple modified accretion disk model of viscous galactic disks in which star formation is fed by a radial ...
Enci Wang, Simon J. Lilly
doaj   +1 more source

SHRINKING GALAXY DISKS WITH FOUNTAIN-DRIVEN ACCRETION FROM THE HALO [PDF]

The Astrophysical Journal, 2014
Star formation in most galaxies requires cosmic gas accretion because the gas consumption time is short compared to the Hubble time. This accretion presumably comes from a combination of infalling satellite debris, cold flows, and condensation of hot halo gas at the cool disk interface, perhaps aided by a galactic fountain.
Elmegreen, Bruce G., Struck, Curtis, Hunter, Deidre A.   +2 more
openaire   +2 more sources

Turbulent viscosity in clumpy accretion disks [PDF]

Astronomy & Astrophysics, 2002
The equilibrium state of a turbulent clumpy gas disk is analytically investigated. The disk consists of distinct self-gravitating clouds. Gravitational cloud-cloud interactions transfer energy over spatial scales and produce a viscosity, which allows mass accretion in the gas disk.
Vollmer, B., Beckert, T.
openaire   +2 more sources

Radiation Transport Two-temperature GRMHD Simulations of Warped Accretion Disks

The Astrophysical Journal Letters, 2023
In many black hole (BH) systems, the accretion disk is expected to be misaligned with respect to the BH spin axis. If the scale height of the disk is much smaller than the misalignment angle, the spin of the BH can tear the disk into multiple ...
M. T. P. Liska, N. Kaaz, G. Musoke, A. Tchekhovskoy, O. Porth   +4 more
doaj   +1 more source

Accretion disk versus jet orientation in H₂O megamaser galaxies [PDF]

Astronomy & Astrophysics, 2019
Context. An essential part of the paradigm describing active galactic nuclei is the alignment between the radio jet and the associated rotation axis of the sub-pc accretion disks. Because of the small linear and angular scales involved, this alignment has not yet been checked in a sufficient number of low luminosity active galactic nuclei (LLAGNs ...
Kamali, F., Henkel, C., Koyama, S., Kuo, C., Condon, J., Brunthaler, A., Reid, M., Greene, J., Menten, K., Impellizzeri, C., Braatz, J., Litzinger, E., Kadler, M.   +12 more
openaire   +3 more sources

Gas Accretion Can Drive Turbulence in Galaxies

The Astrophysical Journal, 2023
The driving of turbulence in galaxies is deeply connected with the physics of feedback, star formation, outflows, accretion, and radial transport in disks.
John C. Forbes, Razieh Emami, Rachel S. Somerville, Shy Genel, Dylan Nelson, Annalisa Pillepich, Blakesley Burkhart, Greg L. Bryan, Mark R. Krumholz, Lars Hernquist, Stephanie Tonnesen, Paul Torrey, Viraj Pandya, Christopher C. Hayward   +13 more
doaj   +1 more source