HVC's Favouring Star Forming Processes in galaxy discs: a basic calculation and some recent HI observations

Buenrostro, V.; Brinks, E.; Casuso, E.; Beckman, J. E.
Bibliographical reference

EAS Publications Series, Volume 56, 2012, pp.323-326

Advertised on:
9
2012
Number of authors
4
IAC number of authors
3
Citations
0
Refereed citations
0
Description
Indirect evidence from detailed chemical evolution studies shows that infall of low metallicity gas appears to have proceeded at a rather constant rate during the lifetime of the Galactic disk. We explore two possible implications: (a) the effect of an infalling high velocity cloud (HVC) on interstellar cloud stability leading to enhanced star formation, and (b) the presence of these HVC's around neighbouring galaxies, which would generalize this aspect of the evolution of galaxies in groups. (a) Using a simple analytical model we show how the overpressure produced in the galactic plane by HVC infall reduces the effective Jeans mass of the existing clouds, thus tending to enhance the SFR. (b) Using HI data from the THINGS survey we detect HI "fluff" around 4 galaxies of a total sample of 32 observed. Projecting some of the largest Galactic HVC's to the distances of the THINGS galaxies we produce a useful estimate of the fraction of the HVC masses that we can detect at these distances, finding a value of order 10%, and go on to make tentative estimates about infall rates for nearby galaxies.
Related projects
Poster Almeria Astronomy week
Kinematic, Structural and Composition Studies of the Interstellar and Intergalactic Media
The basic objective of the broject is to investigate the evolution of galaxies by deepening our understanding of the interaction between the insterstellar medium and the stars.The main technique which we use is the two-dimensional kinematic study of whole galaxies observed using our instrument:GHaFaS, a Fabry-Perot interferometer on the William
Prof.
John E. Beckman