Saved in:
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2024
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2408.09252 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866913471040323584 |
|---|---|
| author | Takekawa, Shunya Oka, Tomoharu Tsujimoto, Shiho Yokozuka, Hiroki Harada, Nanase Kaneko, Miyuki Enokiya, Rei Iwata, Yuhei |
| author_facet | Takekawa, Shunya Oka, Tomoharu Tsujimoto, Shiho Yokozuka, Hiroki Harada, Nanase Kaneko, Miyuki Enokiya, Rei Iwata, Yuhei |
| contents | We report the discovery of a characteristic trend in the intensity ratios of SiO emissions across the Central Molecular Zone (CMZ) of our Galaxy. Using the Nobeyama Radio Observatory 45-m telescope, we conducted large-scale, high-sensitivity imaging observations in molecular lines including SiO $J$=2$-$1 and CS $J$=2$-$1. By identifying SiO-emitting clouds and examining their intensity ratios relative to the other molecular lines, we unveiled a parabolic-like trend showing lower ratios near the Galactic nucleus, Sgr A$^*$, with gradual increases toward the edges of the CMZ. This pattern suggests a possible outburst of the nucleus within the last $\sim 10^5$ yr, which may have propagated through the entire CMZ with strong shocks. Alternatively, the observed trend may also be attributed to the destruction of small dust grains by high-energy photons. Our results can potentially lead to a new perspective on the history of nuclear activity and its impact on the surrounding molecular environment. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2408_09252 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Parabolic-like Trend in SiO Ratios throughout the Central Molecular Zone: Possible Signature of a Past Nuclear Activity in the Galactic Center Takekawa, Shunya Oka, Tomoharu Tsujimoto, Shiho Yokozuka, Hiroki Harada, Nanase Kaneko, Miyuki Enokiya, Rei Iwata, Yuhei Astrophysics of Galaxies We report the discovery of a characteristic trend in the intensity ratios of SiO emissions across the Central Molecular Zone (CMZ) of our Galaxy. Using the Nobeyama Radio Observatory 45-m telescope, we conducted large-scale, high-sensitivity imaging observations in molecular lines including SiO $J$=2$-$1 and CS $J$=2$-$1. By identifying SiO-emitting clouds and examining their intensity ratios relative to the other molecular lines, we unveiled a parabolic-like trend showing lower ratios near the Galactic nucleus, Sgr A$^*$, with gradual increases toward the edges of the CMZ. This pattern suggests a possible outburst of the nucleus within the last $\sim 10^5$ yr, which may have propagated through the entire CMZ with strong shocks. Alternatively, the observed trend may also be attributed to the destruction of small dust grains by high-energy photons. Our results can potentially lead to a new perspective on the history of nuclear activity and its impact on the surrounding molecular environment. |
| title | Parabolic-like Trend in SiO Ratios throughout the Central Molecular Zone: Possible Signature of a Past Nuclear Activity in the Galactic Center |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2408.09252 |