Statistical properties of molecular clouds in the galactic center

Tomoharu Oka, Tetsuo Hasegawa, Fumio Sato, Masato Tsuboi, Atsushi Miyazaki, Masahiro Sugimoto

Research output: Contribution to journalArticle

92 Citations (Scopus)

Abstract

The data from the Nobeyama Radio Observatory 45 m telescope Galactic Center CO survey have been analyzed to generate a compilation of molecular clouds with intense CO emission in this region. Clouds are identified in an automated manner through the main part of the survey data for all CO emission peaks exceeding 10 K (TR*). The measured parameters of identified clouds are analyzed and cross-correlated to compare with those of clouds in the Galactic disk. For the clouds in the Galactic center (GC), we find the scaling laws of the type σV ∝ S0.40 and MVT ∝ (LCO)0.88, which are similar to those of clouds in the Galactic disk. All the GC clouds identified have larger velocity widths and virial theorem masses each above the σV-S and LCO-MVT lines of the disk clouds. We diagnosed gravitational stabilities of identified clouds assuming that the disk clouds are nearly at the onset of gravitational instability. All the clouds and cloud complexes in the GC are gravitationally stable, indicating they are in equilibrium with high pressure in the GC environment. Gravitationally less stable clouds follow the main ridge of intense CO emission, part of which define two rigidly rotating molecular arms. The velocity dispersion of a cloud correlates inversely with the degree of gravitational instability. It is concluded that mechanisms such as orbit crowding at the inner Lindblad resonance may promote gravitational instability and subsequent star formation.

Original languageEnglish
Pages (from-to)348-362
Number of pages15
JournalAstrophysical Journal
Volume562
Issue number1 PART I
DOIs
Publication statusPublished - 2001
Externally publishedYes

Fingerprint

molecular clouds
gravitational instability
virial theorem
crowding
scaling laws
star formation
ridges
observatories
observatory
theorems
telescopes
radio
orbits

Keywords

  • Galaxies: ISM
  • Galaxies: nuclei
  • Galaxy: center
  • ISM: clouds
  • Radio lines: ISM

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Oka, T., Hasegawa, T., Sato, F., Tsuboi, M., Miyazaki, A., & Sugimoto, M. (2001). Statistical properties of molecular clouds in the galactic center. Astrophysical Journal, 562(1 PART I), 348-362. https://doi.org/10.1086/322976

Statistical properties of molecular clouds in the galactic center. / Oka, Tomoharu; Hasegawa, Tetsuo; Sato, Fumio; Tsuboi, Masato; Miyazaki, Atsushi; Sugimoto, Masahiro.

In: Astrophysical Journal, Vol. 562, No. 1 PART I, 2001, p. 348-362.

Research output: Contribution to journalArticle

Oka, T, Hasegawa, T, Sato, F, Tsuboi, M, Miyazaki, A & Sugimoto, M 2001, 'Statistical properties of molecular clouds in the galactic center', Astrophysical Journal, vol. 562, no. 1 PART I, pp. 348-362. https://doi.org/10.1086/322976
Oka T, Hasegawa T, Sato F, Tsuboi M, Miyazaki A, Sugimoto M. Statistical properties of molecular clouds in the galactic center. Astrophysical Journal. 2001;562(1 PART I):348-362. https://doi.org/10.1086/322976
Oka, Tomoharu ; Hasegawa, Tetsuo ; Sato, Fumio ; Tsuboi, Masato ; Miyazaki, Atsushi ; Sugimoto, Masahiro. / Statistical properties of molecular clouds in the galactic center. In: Astrophysical Journal. 2001 ; Vol. 562, No. 1 PART I. pp. 348-362.
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