1. Barred Magellanic Spirals in Ursa Major and Canes Venatici: Global Properties
Kwayera Davis
(College of Charleston)
Advisor: Eric Wilcots
(University of Wisconsin-Madison)
University of Wisconsin-Madison REU 2003

2. Motivation Some galaxy types are not well studied
We want to better understand their
formation
evolution
interaction with neighbours
structure
dark matter distribution

3. Barred Magellanic Spirals (SBms)
SBms are a transitional class
Some spiral structure
Some irregular structure
Barred
The LMC is a SBm

4. This is in the radio part of the e.m. Spectrum
H I emission
Neutral(atomic) hydrogen atom
1 proton and 1 electron
Electron changes spin
Light emitted
21 cm wavelength
1.4 GHz frequency
This is in the radio part of the e.m. Spectrum

5. Observing H I with the VLA
The Very Large Array is an interferometer
30'' resolution
Observations in C configuration
Compact array gives increased sensitivity
H I line allows velocity determination
We know the radial velocity of the hydrogen gas we are seeing

6. NGC 3264

7. NGC 4288

8. NGC 4861

9. Conclusions rotation curves are fairly typical
also have interesting differences
further analysis should be possible

10. Further Work Compare H I to optical image from WIYN
Calculate dark matter distribution
Compare with predictions of dark matter models

11. Acknowledgments I would like to thank
University of Wisconsin-Madison REU Program
My advisor Dr. Eric Wilcots
My research partner Stephanie Bush
The scientists working in the department
My fellow students

12. This Experience

13. Some Optical Images