| Name: | DEBANGAN MAJI |
| Affiliation: | National Centre For Radio Astrophysics - Tata Institute Of Fundamental Research, Pune |
| Conference ID: | ASI2025_664 |
| Title: | Cool phase temperature of atomic hydrogen in the Galactic centre region |
| Authors: | Debangan Maji 1, Subhashis Roy 1 |
| Authors Affiliation: | 1 National Centre for Radio Astrophysics - TIFR, Pune-411007, India |
| Mode of Presentation: | Oral |
| Abstract Category: | Stars, Interstellar Medium, and Astrochemistry in Milky Way |
| Abstract: | The central one-kilo-parsec region of our Milky Way (MW) Galaxy is typically referred to as the Galactic Centre (GC) region. Most of the physical quantities like gas density, velocity dispersion, temperature, etc. in this region are significantly higher than those found in the disk of our galaxy. GC region cannot be seen in optical wavelengths due to large interstellar extinction by dust in the Galactic plane. It can, however, be studied in radio bands. Atomic hydrogen (HI) in the ISM is a two-phase medium (cool & warm phase), which can provide a wealth of information on the interstellar medium (ISM) in the GC region. Given the high temperature of the ISM in the region, we expect the cold HI to have a significantly higher spin temperature than the rest of the Galaxy. HI spin temperature can be measured using 21 cm emission and absorption spectrum. However, the measured spin temperature is the column density weighted harmonic mean of those two phases. Therefore, it is very challenging to separate the contribution of the cool phase, and it can only provide an upper limit. Following Dickey et. al. (2003) and Strasser et. al. (2007), we are separating the contribution of the warm phase, and finding the HI cool phase temperature. For this work, we are using existing archival HI data towards this region. Results from the work will be presented here. |
