Deep CO Observations and the CO-to-H-2 Conversion Factor in DDO 154, a Low Metallicity Dwarf Irregular Galaxy

作者：Komugi Shinya^*; Yasui Chikako; Kobayashi Naoto; Hatsukade Bunyo; Kohno Kotaro; Sofue Yoshiaki; Kyu Shiori

来源：Publications of the Astronomical Society of Japan, 2011, 63(1): L1-L5.

• galaxies: individual (DDO 154)
• galaxies: ISM
• ISM: molecules
• stars: formation

We present a deep spectroscopic search for CO emission in the dwarf irregular galaxy DDO 154, which has an Oxygen abundance of only 1/20 of the solar value. The observations were conducted in order to constrain the CO-to-H-2 conversion factor at low metallicity. No CO was detected, however, despite being one of the sensitive observations done towards galaxies of this type. We succeed in putting a strong lower limit on the conversion factor, at least 10-times the Galactic value. Our result supports previous studies that argue for a high conversion factor at low metallicity.

• 出版日期2011
• 单位中国科学院国家天文台