Molecular Cloud Cores in the Galactic Center 50 $\mathrm{km}{\mathrm{s}}^{-1}$ Molecular Cloud

Abstract

The Galactic Center 50 km s${}^{-1}$ Molecular Cloud (50MC) is the most remarkable molecular cloud in the Sagittarius A region. This cloud is a candidate for the massive star formation induced by cloud-cloud collision (CCC) with a collision velocity of $\sim 30\mathrm{km}{\mathrm{s}}^{-1}$ that is estimated from the velocity dispersion. We observed the whole of the 50MC with a high angular resolution ($\sim 2.0^{\prime \prime }\times 1.4^{\prime \prime }$) in ALMA cycle 1 in the H${}^{13}$CO${}^{+}J=1-0$ and ${\mathrm{C}}^{34}\mathrm{S}J=2-1$ emission lines. We identified 241 and 129 bound cores with a virial parameter of less than 2, which are thought to be gravitationally bound, in the H${}^{13}$CO${}^{+}$ and ${\mathrm{C}}^{34}\mathrm{S}$ maps using the clumpfind algorithm, respectively. In the CCC region, the bound ${\mathrm{H}}^{13}\mathrm{C}{\mathrm{O}}^{+}$ and ${\mathrm{C}}^{34}\mathrm{S}$ cores are 119 and 82, whose masses are $68\%$ and $76\%$ of those in the whole 50MC, respectively. The distribution of the core number and column densities in the CCC are biased to larger densities than those in the non-CCC region. The distributions indicate that the CCC compresses the molecular gas and increases the number of the dense bound cores. Additionally, the massive bound cores with masses of $>3000M_{\odot }$ exist only in the CCC region, although the slope of the core mass function (CMF) in the CCC region is not different from that in the non-CCC region. We conclude that the compression by the CCC efficiently formed massive bound cores even if the slope of the CMF is not changed so much by the CCC.

References in corpus (4)

• Star Formation in the Central 400 pc of the Milky Way: Evidence for a Population of Massive YSOs
• Molecular clouds towards RCW 49 and Westerlund 2; Evidence for cluster formation triggered by cloud-cloud collision
• Isolating signatures of major cloud-cloud collisions using position-velocity diagrams
• A cluster in the making: ALMA reveals the initial conditions for high-mass cluster formation

Cited by in corpus (3)

• Virial Clumps in Central Molecular Zone Clouds
• G-0.02-0.07, the Compact HII Region Complex nearest to the Galactic Center with ALMA
• Hot Molecular Core Candidates in the Galactic Center 50 km/s Molecular Cloud