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Proposal Identication No.: A1388 Date Received: 2000-Feb-01 14:56:33
Technical Page
Proposal Type: Regular
General Category: Astronomy
Sub-Category: Spectroscopy
Observation Category: Extragalactic
Total Time Requested: 6 Hours
Proposal Title: The Kinematics of Dwarf Irregular Galaxies
ABSTRACT:
Disentangling the contributions of ordered rotation and velocity dispersion to 21 cm prole widths is a necessary
prerequisite for using H I measurements of gas-rich dwarf galaxies as Tully-Fisher distance indicators and as
probes to their dark matter content. We propose high spectral resolution (0.65 km/s) 21 cm (L band) observations
of 15 dwarf irregular galaxies of optical diameters less than 1 arcminute. Previous Arecibo spectra of these
galaxies at a resolution of 8 km/s show single-peaked ( ~
Gaussian) proles. However, most spectra (212) of the
original survey dislayed the double-horned proles associated with a rotating gas disk. It is possible that the
rotation component of these 15 galaxies was masked by the binning. Successive smoothing of the high resolution
spectra will reveal any rotational component. For that portion of the sample (3 - 5) which are face-on, the high
resolution single-peaked proles will provide an estimate of the velocity dispersion of the gas. If scheduled, the
observations and analysis of the data will constitute a summer student project.
Name Institution E-mail Phone Student
Jo Ann Eder NAIC eder@naic.edu 787-878-2612
Instrument Setup
L-narrow
Atmospheric Optical Instruments:
Special Equipment or setup: none
RFI Considerations
Frequency Ranges Planned
1395 - 1420
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