New Look at the Molecular Superbubble Candidate in the Galactic Center

Abstract

The $l=+1.{}^{\circ }3$ region in the Galactic center is characterized by multiple shell-like structures and their extremely broad velocity widths. We revisit the molecular superbubble hypothesis for this region, based on high resolution maps of CO {\it J}=1--0, ${}^{13}$CO {\it J}=1--0, H${}^{13}$CN {\it J}=1--0, H${}^{13}$CO${}^{+}$ {\it J}=1--0, SiO {\it J}=2--1, and CS {\it J}=2--1 lines obtained from the Nobeyama radio observatory 45-m telescope, as well as CO {\it J}=3--2 maps obtained from the James Clerk Maxwell telescope. We identified eleven expanding shells with total kinetic energy and typical expansion time $E_{\mathrm{kin}}\sim 10^{51.9}$ erg and $t_{\exp }\sim 10^{4.9}$ yr, respectively. In addition, the $l=+1.{}^{\circ }3$ region exhibited high SiO {\it J}=2--1/H${}^{13}$CN {\it J}=1--0 and SiO {\it J}=2--1/H${}^{13}$CO${}^{+}$ {\it J}=1--0 intensity ratios, indicating that the region has experienced dissociative shocks in the past. These new findings confirm the molecular superbubble hypothesis for the $l=+1.{}^{\circ }3$ region. The nature of the embedded star cluster, which may have supplied 20--70 supernova explosions within 10${}^5$ yr, is discussed. This work also show the importance of compact broad-velocity-width features in searching for localized energy sources hidden behind severe interstellar extinction and stellar contamination.

References in corpus (3)

• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• Star Formation in the Central 400 pc of the Milky Way: Evidence for a Population of Massive YSOs
• Discovery of Two Small High-Velocity Compact Clouds in the Central 10 Parsecs of Our Galaxy

Cited by in corpus (1)

• Catalog of High Velocity Dispersion Compact Clouds in the Central Molecular Zone of Our Galaxy