A molecular cloud and an expanding cavity adjacent to the nonthermal filaments of the Galactic center radio arc

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

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Large-scale CO images taken with the 2 × 2 focal-plane array receiver on the 45 m telescope of Nobeyama Radio Observatory reveal parsec-scale structure of molecular gas around the Galactic center radio arc. The LVG analysis shows that the gas kinetic temperature is considerably enhanced (Tk ≥ 70K) in CO 0.13-0.13, a cloud which seems to be in contact with the nonthermal filaments of the Galactic center radio arc. This lends support for an interaction between CO 0.13-0.13 and the nonthermal filaments. The interaction with the strong magnetic field in and around the nonthermal filaments may heat up the molecular gas in CO 0.13-0.13 through shock dissipation and/or magnetic viscosity. We also find an expanding cavity adjacent to the nonthermal filaments. The shell has a radius of ∼ 5 pc and an expansion velocity of 25kms-1. This expanding cavity might have been formed by several hundred supernovae or a single hypernova within 3 × 105 yr. Magnetic tubes in this region could have been swept up by the expanding cavity, and compressed by interactions with CO 0.13-0.13. An interaction between the cloud and magnetic field may accelerate electrons to relativistic energies through shock acceleration or magnetic field reconnection.

Original languageEnglish
Pages (from-to)779-786
Number of pages8
JournalPublications of the Astronomical Society of Japan
Volume53
Issue number5
Publication statusPublished - 2001 Oct 25
Externally publishedYes

Fingerprint

molecular clouds
filaments
cavity
arcs
radio
magnetic field
cavities
molecular gases
gas
magnetic field reconnection
shock
interactions
dissipation
focal plane devices
viscosity
observatory
magnetic fields
shell
supernovae
electron

Keywords

  • Galaxies: nuclei
  • Galaxy: center
  • ISM: clouds
  • ISM: molecules

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

A molecular cloud and an expanding cavity adjacent to the nonthermal filaments of the Galactic center radio arc. / Oka, Tomoharu; Hasegawa, Tetsuo; Sato, Fumio; Tsuboi, Masato; Miyazaki, Atsushi.

In: Publications of the Astronomical Society of Japan, Vol. 53, No. 5, 25.10.2001, p. 779-786.

Research output: Contribution to journalArticle

Oka, Tomoharu ; Hasegawa, Tetsuo ; Sato, Fumio ; Tsuboi, Masato ; Miyazaki, Atsushi. / A molecular cloud and an expanding cavity adjacent to the nonthermal filaments of the Galactic center radio arc. In: Publications of the Astronomical Society of Japan. 2001 ; Vol. 53, No. 5. pp. 779-786.
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