Hostname: page-component-7c8c6479df-r7xzm Total loading time: 0 Render date: 2024-03-28T09:11:17.989Z Has data issue: false hasContentIssue false

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

Published online by Cambridge University Press:  17 September 2012

V. Buenrostro
Affiliation:
Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain. e-mail: valeria@iac.es, eca@iac.es, jeb@iac.es;
E. Brinks
Affiliation:
University of Hertfordshire, Hatfield, UK; e-mail: E.Brinks@herts.ac.uk;
E. Casuso
Affiliation:
Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain. e-mail: valeria@iac.es, eca@iac.es, jeb@iac.es;
J.E. Beckman
Affiliation:
Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain. e-mail: valeria@iac.es, eca@iac.es, jeb@iac.es; Consejo Superior de Investigaciones Científicas, Spain
Get access

Abstract

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.

Type
Research Article
Copyright
© EAS, EDP Sciences, 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

de Avillez, M.A., 2000, MNRAS, 315, 479CrossRef
Blitz, L., Spergel, D.N., Teuben, P.J., Hartmann, D., & Burton, W.B., 1999, ApJ, 514, 818CrossRef
Bregman, J.N., 1980, ApJ, 236, 577CrossRef
Casuso, E., Beckman, J.E., & Buenrostro, V., 2006, PASP, 118, 833CrossRef
Comeron, F., & Torra, J., 1992, A&A, 261, 94
Goldreich, P., & Lynden-Bell, D., 1965, MNRAS, 130, 125CrossRef
Peek, J.E.G., Putman, M.E., McKee, C.F., Heiles, C., & Stanimirović, S., 2007, ApJ, 656, 907CrossRef
Quilis, V., Ibanez, J.M.A., & Saez, D., 1996, ApJ, 469, 11CrossRef
Santillán, A., Sánchez-Salcedo, F.J., & Franco, J., 2007, ApJ, 662, L19CrossRef
Thilker, D.A., Braun, R., Walterbos, R.A.M., et al., 2004, ApJ, 601, L39CrossRef
Wakker, B.P., & van Woerden, H., 1991, A&A, 250, 509
Walter, F., Brinks, E., de Blok, W.J.G., et al., 2008, AJ, 136, 2563CrossRef
Westmeier, T., Braun, R., & Thilker, D., 2005, A&A, 436, 101