FASHI: A blind survey of 21cm HI absorption galaxies with FAST
| Autor: | Zhang, Chuan-Peng, Zhu, Ming, Jiang, Peng, Cheng, Cheng, Xu, Jin-Long, Yu, Nai-Ping, Liu, Xiao-Lan, Zhang, Bo |
|---|---|
| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | The FAST All Sky H I survey (FASHI) will cover the entire observable sky (about 22000 square degrees) with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). With the currently released data, we perform a blind survey of 21 cm H I absorption galaxies at redshift $z < 0.09$ over an area of about 10000 square degrees. We have detected 51 H I absorbers, including 21 previously known and 30 new ones. The probability of occurrence for the H I absorbers in all H I galaxies is 1/1078. The radio flux densities of the FASHI absorbers are mainly concentrated in the range of $S_{\rm 1.4GHz} = 10 \sim 100$ mJy, but also as low as 2.6 $\pm$ 0.4 mJy. We find that the H I column density and optical depth are negatively correlated across redshift. We also find that the host galaxies of the associated H I absorbers have relatively high star formation rates, and there is a negative correlation between the H I column density and the stellar mass in the host galaxy. Consequently, FAST has significantly improved the capabilities and performance for H I absorption observations and has provided a true blind survey of 21 cm H I absorption galaxies for such studies. Comment: 32 pages, 7 figures, 2 tables, submitted to ApJS in 05/24/2024, Comments are welcome |
| Databáze: | arXiv |
| Externí odkaz: |
|