Work

Galactic center mini-spiral by ALMA: Possible origin of the central cluster

Year: 2016

Type: article

Abstract: We present continuum images of the “Galactic center mini-spiral” in the 100, 250, and 340 GHz bands with analysis of the Cy.0 data acquired from the Atacama Large Millimeter/submillimeter Array (ALMA) archive. Good u-v coverage of the data and the “self-calibration” method give us the opportunity to obtain dynamic ranges of over 2 × 104 in the resultant maps of the 250 and 340 GHz bands. In particular, the image of the 340 GHz band has high dynamic ranges unprecedented in sub-millimeter waves. The angular resolutions attained are 1${^{\prime\prime}_{.}}$57 × 1${^{\prime\prime}_{.}}$33 in the 100 GHz band, 0${^{\prime\prime}_{.}}$63 × 0${^{\prime\prime}_{.}}$53 in the 250 GHz band, and 0${^{\prime\prime}_{.}}$44 × 0${^{\prime\prime}_{.}}$38 in the 340 GHz band, respectively. The continuum images clearly depict the “mini-spiral,” which is an ionized gas stream in the vicinity of Sgr A*. We found a tight correlation between the dust emission peaks and the OB/WR stars in the northern arm of the “mini-spiral.” The core mass function of the dust cores identified by the clumpfind algorithm would obey the flat power-law dN/dM ∝ M−1.5±0.4 on the high-mass side. These support the scenario that the star-forming cloud has fallen into the immediate vicinity of Sgr A* for the origin of the central cluster.

Source: Publications of the Astronomical Society of Japan

DOI: 10.1093/pasj/psw031

Authors: Masato Tsuboi, Yoshimi Kitamura, Makoto Miyoshi, Kenta Uehara, Takahiro Tsutsumi, Atsushi Miyazaki