A dynamical model for the extraplanar gas in spiral galaxies

By Filippo Fraternali, J. Binney. 2005

143 citations recorded by the source corpus.

Recent H I observations reveal that the discs of spiral galaxies are surrounded by extended gaseous haloes. This extra-planar gas reaches large distances (several kpc) from the disc and shows peculiar kinematics (low rotation and inflow). We have modelled the extra-planar gas as a continuous flow of material from the disc of a spiral galaxy into its halo region. The output of our models are pseudo-data cubes that can be directly compared to the H I data. We have applied these models to two spiral galaxies (NGC891 and NGC2403) known to have a substantial amount of extraplanar gas. Our models are able to reproduce accurately the vertical distribution of extra-planar gas for an energy input corresponding to a small fraction (<4 %) of the energy released by supernovae. However they fail in two important aspects: 1) they do not reproduce the right gradient in rotation velocity; 2) they predict a general outflow of the extra-planar gas, contrary to what is observed. We show that neither of these difficulties can be removed if clouds are ionized and invisible at 21cm as they leave the disc but become visible at some point on their orbits. We speculate that these failures indicate the need for accreted material from the IGM that could provide the low angular momentum and inflow required.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering, Instrumentation

View Paper: https://www.semanticscholar.org/paper/7869eb1e448e5603895b9bcbe5d3891aae2a3807

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. J. Binney
2. Filippo Fraternali
3. T. Oosterloo
4. R. Sancisi
5. J. Hulst
6. R. Boomsma
7. Jo Bovy
8. Justin I. Read

In Electrical and Electronic Engineering

1. Filippo Fraternali
2. T. Oosterloo
3. R. Sancisi
4. J. Binney

In Instrumentation

1. Filippo Fraternali
2. T. Oosterloo
3. R. Sancisi
4. J. Binney
5. Jo Bovy
6. P. McMillan
7. Justin I. Read
8. Hans-Walter Rix

Citations in the corpus

• Accretion of gas on to nearby spiral galaxies (2008, methodology): “Our pure fountain model is described in Fraternali & Binney (2006).”
• HI holes and high-velocity clouds in the spiral galaxy NGC 6946 (2008, methodology): “It seems unlikely that galactic fountain models, by themselves, can explain it (Fraternali & Binney 2006; Heald et al. 2006).”