Mechanism of star-formation in spiral galaxies M51, M83 and M101

• Main Authors: I-Chenn Chen, 陳以忱
• Other Authors: 葉永烜
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/87418018919547187292

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.