Speaker
Description
We present the 21 cm neutral hydrogen (HI) observations of 439 nearby galaxies from the Green Bank Telescope, USA. Our targets are drawn from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) program, whose sample is uniformly selected from the SDSS Data Release 13 with the stellar mass greater than 10$^9$ $M_{sun}$ and no pre-selection on galaxy type. The average redshift of the sample is z $\simeq$ 0.03. The primary goal of the project is to study how the HI detectability and mass depend on host galaxy properties, specifically, the stellar mass and the presence of active galactic nuclei (AGN). In this presentation, we report the HI detection fraction and gas fraction as a function of galaxy's locus on the color-magnitude diagram (CMD), as well as the HI detection fraction as a function of the incidence of AGN, base on the Baldwin-Phillips-Terlevich (BPT) diagnostics using the SDSS optical spectroscopy. We found that both the HI detection fraction and the neutral gas fraction in the 'blue cloud' locus on the CMD is significantly higher than in the 'red sequence'. Our observations indicated that the incidence of AGN does not show significant preference in the HI gas properties.
