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Star Formation Activity in High MH /LB Galaxies

Published online by Cambridge University Press:  14 August 2015

L. Van Zee
L. Van Zee*
Affiliation:
National Radio Astronomy Observatory PO Box O, Socorro, NM 87801, USA

Abstract

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The results of an investigation of the evolutionary status of fifteen gas-rich, low surface brightness dwarf galaxies (LSBDGs) are presented. LSBDGs are defined by unusually high values of MH/LB and the presence of extended HI envelopes. At both the present epoch and the past, the star formation process appears to be inefficient: the LSBDGs are underluminous for their HI mass and very little active star formation is currently observed. Analysis of global optical colors and elemental enrichments indicate that these objects are not “young” systems; rather, star formation has been occurring for several Gyr. One clue to the star formation history of these objects is that the global gas density is significantly lower than the Toomre instability criterion throughout the gas disk. Local peaks in the HI surface density, however, approach the instability criterion and are correlated with sites of active star formation. Thus, while star formation appears to be inhibited globally, the local gas distribution plays a crucial role in regulating the star formation activity in these low mass galaxies.

Type
II. Joint Discussions
Information
Highlights of Astronomy , Volume 11 , Issue 1: Highlights of Astronomy. As presented at the XXIIIrd General Assembly of the IAU (Part A), 1997 , 1998 , pp. 130 - 131
Copyright
Copyright © Kluwer 1998

References

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