| Name: | Sameer Patidar |
| Affiliation: | Indian Institute of Space Science and Technology, Thiruvananthapuram |
| Conference ID : | ASI2024_914 |
| Title : | Tracing Baryons in the Warm Hot Intergalactic Medium using Broad Lyman-α Absorbers |
| Authors : | Sameer Patidar1, Vikram Khaire1,2, Anand Narayanan1 |
| Authors Affiliation: | 1 Indian Institute of Space Science & Technology, Thiruvananthapuram, Kerala-695547, India
2 University of California Santa Barbara, Santa Barbara, CA-93106, USA |
| Mode of Presentation: | Poster |
| Abstract Category : | Galaxies and Cosmology |
| Abstract : | Baryons have a very intricate distribution in the present universe (z~0). Around 90% of them reside outside the galaxies in the intergalactic medium (IGM) and circumgalactic medium. Even in IGM, they show multiphase structure, viz. cool (~10^4 K) photoionized phase and shock heated warm-hot (~10^5 - 10^7 K) phase. The warm-hot (WHIM) phase has been challenging to observe, leading to uncertainties in the baryon inventory in this phase.
In the present work, we attempt to address these uncertainties. We use high-quality HST/COS data to probe the WHIM using Broad Lyman-α Absorbers (BLAs). We do a comprehensive survey of BLAs over a large dataset consisting of 82 quasar lines of sight (LOS). We first identify the candidate BLA systems along each of these 82 LOS by selecting absorbers having Lyman-alpha absorption lines with Doppler parameters above 45 km/s. We get a total of 568 such systems and then choose a subset of these systems having absorption from 3 or more distinct metal ions, which are needed to model the ionization conditions. Finally, we get a set of 28 such absorber systems. Then, by suitably modeling the ionization conditions prevalent in these 28 absorbers along with analyzing their galaxy environment, we deduce the origins of these absorber systems. We present the results from an in-depth analysis of these systems, tracing multiple phases in WHIM. Furthermore, we use results from these 28 absorber systems to the complete set of 568 identified BLA candidates to estimate the contribution of BLAs to the total cosmic baryon inventory. |
