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.

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Cited by in corpus (10)

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