| Name: | NISHIKANTA KHANDAI |
| Affiliation: | NISER |
| Conference ID : | ASI2022_608 |
| Title : | The Distribution of Neutral Hydrogen in the Local Universe |
| Authors : | Nishikanta Khandai, Saili Dutta, Sandeep Rana, Biprateep Dey |
| Abstract Type: | Invited |
| Abstract Category : | Plenary |
| Abstract : | We use a survey volume common to the SDSS and ALFALFA surveys to constrain the conditional neutral hydrogen (HI) mass and velocity-width functions, conditioned on optical color and/or magnitude. This allows us to further constrain the distribution function of the cosmic HI density in the color-magnitude plane of galaxies. We find that the distribution has a long tail towards faint blue galaxies and luminous red galaxies. About 10% of the HI budget is associated with low surface brightness galaxies whereas 18% is locked up in the red population of galaxies. We use these abundances and recent stacking results from the ALFALFA survey to constrain the halo mass function of HI-selected galaxies. The transition halo mass scale in the halo mass - HI mass relation is smaller by ~ 1.4 dex to that of the halo mass - stellar mass relation, suggesting that baryonic processes like heating and feedback in larger mass halos suppress HI gas on a shorter time scale compared to star formation. We show that our observationally calibrated HI halo model reproduces the clustering of HI selected galaxies. |