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Proposal Identication No.: A1369 Date Received: 1999-Sep-28 19:32:35
Technical Page
Proposal Type: Regular
General Category: Astronomy
Sub-Category: Spectroscopy
Observation Category: Extragalactic
Total Time Requested: 40 Hours
Proposal Title: Gas Mass Fractions and the Evolution of LSB Dwarf Galaxies
ABSTRACT:
This project is to obtain H I measurements of a newly discovered sample of low surface brightness (LSB)
dwarf galaxies. These galaxies represent new extremes in M T =L, MHI =L and the ratio of stars to gas.
Comparisons of the H I and optical properties will yield information of their past star formation, but
more importantly the H I data is a crucial rst step in an radio and optical study of this class of objects.
Previous work on brighter LSB dwarfs has shown them to have low star formation rates and high gas
fractions. This, of course, is providing us with a clue to their history in that the stellar densities are low
and gas fractions high because they have failed to convert their gas supply into stars with the same
eфciency as the rest of the Hubble sequence. Questions on how LSB dwarfs arrived at their present state
of low density and extremely low current rates of star formation, yet very blue optical colors, are strongly
connected to the evolution of their gas supply. This evolution is parameterized by the ratio of optical to
gas parameters, which we wish to obtain with this proposal. We also anticipate that this sample of 40
galaxies will also represent a new range of dark matter dominance and provide some insight into the
distribution of light and matter on small galaxy scales.
Name Institution E-mail Phone Student
James Schombert University of Oregon js@abyss.uoregon.edu (541) 346-5214 no
Instrument Setup
L-narrow
Atmospheric Optical Instruments:
Special Equipment or setup: none
RFI Considerations
Frequency Ranges Planned
1350 - 1423
1