| Summary: | 碩士 === 國立中央大學 === 天文研究所 === 95 === We have obtained Hαimages of three nearby face-on galaxies, M51, M83 and M101, by using the Lulin One-meter Telescope (LOT). We then compared these images to the near-infrared Ks band data which is obtained from the 2MASS catalog, in order to determine the Hα/K ratio of galaxies’ K-band arm regions and inter-arm regions. We have found that there is a significant enhancement of Hα/K ratio in K-band arm region, which refers to the location of the density wave. We have also found that the distribution of the HII regions locate on the leading edge of the K-band arms. Both evidences hint that the density wave is the dominant mechanism of star formation in these spiral galaxies, which is in agreement with the large-scale shock scenario, which predicts a high star formation efficiency in arm regions.
|
|---|
