Lunch talk on Oct. 16, 2023

Cosmological-Scale HI Distribution Around Galaxies and AGN Probed with Massive Spectroscopic Data

Speaker: Dongsheng Sun (University of Tokyo)

Venue: Video Conference

Time: 12:30 PM, Monday, Oct. 16, 2023

Abstract: 

We present two 3-dimensional (3D) Hi tomographic maps of cosmological-scale neutral hydrogen (HI) distributions at z = 2 − 3 over areas of 99 deg2 and 738. 79 deg2 within the Fall and the Spring fields, respectively, traced by the foreground Lyα forest absorptions of over 12,000 quasars from the Sloan Digital Sky Survey (SDSS) in the redshift range z = 2.08 − 3.68. We investigate the average cosmological-scale (> 10 cMpc) 2-dimensional (2D), which corresponds to the line-of-sight (LoS) and transverse to line-of-sight (Trans) directions, and radial HI distributions around the galaxies and AGN at z = 2 − 3 with the reconstructed 3D HI tomographic maps and the sources obtained by the Hobby Eberly Telescope Dark Energy eXperiment (HETDEX) and SDSS surveys. We find that the average cosmological-scale HI absorption around galaxies is smaller than the one of AGN. In addition, we see the LoS HI distribution of our AGN sample is consistent with the model of the previous study and find a weak HI absorption region in the LoS HI distribution at the large scale, ≳ 20 h−1cMpc, may be explained by the combination of the radiation effect and the velocity gradient due to the infall of matter. We also investigate the average cosmological-scale Hi distributions for type-1 and type-2 AGN. We find the HI absorption around the type-2 AGN is similar to that of the type-1 AGN on average. Moreover, our results show an anti-correlation between the rest-frame 1350 ̊A luminosity and the HI absorption of the type-1 AGN.

Report PPT:  SWIFAR_Dongsheng Sun.pptx