Discovery of molecular loop 3 in the Galactic center: Evidence for a positive-velocity magnetically floated loop towards L = 355°-359°

Motosuji Fujishita, Kazufumi Torii, Natsuko Kudo, Tokuichi Kawase, Hiroaki Yamamoto, Akiko Kawamura, Norikazu Mizuno, Toshikazu Onishi, Akira Mizuno, Mami Machida, Kunio Takahashi, Satoshi Nozawa, Ryoji Matsumoto, Yasuo Fukui

研究成果: ジャーナルへの寄稿記事

10 引用 (Scopus)

抄録

We have discovered a molecular dome-like feature towards 355° ≤ l ≤ 359° and 0° ≤ b ≤ 2°. The large velocity dispersions of 50-100km s-1 of this feature are much larger than those in the Galactic disk, and indicate that the feature is located in the Galactic center, probably within ∼ 1 kpc of Sgr A*. The distribution has a projected length of ∼ 600 pc and a height of ∼ 300 pc from the Galactic disk, and shows a large-scale monotonic velocity gradient of ∼ 130 km s -1 per ∼ 600 pc. The feature is also associated with H I gas having a more continuous spatial and velocity distribution than that of 12CO. We interpret the feature as being a magnetically floated loop similar to loops 1 and 2, and name it "loop 3". Loop 3 is similar to loops 1 and 2 in its height and length, but is different from loops 1 and 2 in that the inner part of loop 3 is filled with molecular emission. We have identified two foot points at both ends of loop 3. H i, 12CO, and 13CO datasets were used to estimate the total mass and the kinetic energy of loop 3 to be ∼3.0 × 106 MOdot; and ∼ 1.7 × 1052 erg. The huge size, velocity dispersions, and energy are consistent with the magnetic origin of the Parker instability, as in the case of loops 1 and 2, but is difficult to be explained by multiple stellar explosions. We argue that loop 3 is in an earlier evolutionary phase than loops 1 and 2 based on the innerfilled morphology and the relative weakness of the foot points. This discovery indicates that the western part of the nuclear gas disk of ∼ 1 kpc radius is dominated by the three well-developed magnetically floated loops, and suggests that the dynamics of the nuclear gas disk is strongly affected by magnetic instabilities.

元の言語英語
ページ(範囲)1039-1053
ページ数15
ジャーナルPublications of the Astronomical Society of Japan
61
発行部数5
DOI
出版物ステータス出版済み - 2009

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gas
erg
kinetic energy
dome
explosion
gases
energy
domes
distribution
explosions
spatial distribution
velocity distribution
gradients
radii
estimates

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

これを引用

Discovery of molecular loop 3 in the Galactic center : Evidence for a positive-velocity magnetically floated loop towards L = 355°-359°. / Fujishita, Motosuji; Torii, Kazufumi; Kudo, Natsuko; Kawase, Tokuichi; Yamamoto, Hiroaki; Kawamura, Akiko; Mizuno, Norikazu; Onishi, Toshikazu; Mizuno, Akira; Machida, Mami; Takahashi, Kunio; Nozawa, Satoshi; Matsumoto, Ryoji; Fukui, Yasuo.

:: Publications of the Astronomical Society of Japan, 巻 61, 番号 5, 2009, p. 1039-1053.

研究成果: ジャーナルへの寄稿記事

Fujishita, M, Torii, K, Kudo, N, Kawase, T, Yamamoto, H, Kawamura, A, Mizuno, N, Onishi, T, Mizuno, A, Machida, M, Takahashi, K, Nozawa, S, Matsumoto, R & Fukui, Y 2009, 'Discovery of molecular loop 3 in the Galactic center: Evidence for a positive-velocity magnetically floated loop towards L = 355°-359°', Publications of the Astronomical Society of Japan, 巻. 61, 番号 5, pp. 1039-1053. https://doi.org/10.1093/pasj/61.5.1039
Fujishita, Motosuji ; Torii, Kazufumi ; Kudo, Natsuko ; Kawase, Tokuichi ; Yamamoto, Hiroaki ; Kawamura, Akiko ; Mizuno, Norikazu ; Onishi, Toshikazu ; Mizuno, Akira ; Machida, Mami ; Takahashi, Kunio ; Nozawa, Satoshi ; Matsumoto, Ryoji ; Fukui, Yasuo. / Discovery of molecular loop 3 in the Galactic center : Evidence for a positive-velocity magnetically floated loop towards L = 355°-359°. :: Publications of the Astronomical Society of Japan. 2009 ; 巻 61, 番号 5. pp. 1039-1053.
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title = "Discovery of molecular loop 3 in the Galactic center: Evidence for a positive-velocity magnetically floated loop towards L = 355°-359°",
abstract = "We have discovered a molecular dome-like feature towards 355° ≤ l ≤ 359° and 0° ≤ b ≤ 2°. The large velocity dispersions of 50-100km s-1 of this feature are much larger than those in the Galactic disk, and indicate that the feature is located in the Galactic center, probably within ∼ 1 kpc of Sgr A*. The distribution has a projected length of ∼ 600 pc and a height of ∼ 300 pc from the Galactic disk, and shows a large-scale monotonic velocity gradient of ∼ 130 km s -1 per ∼ 600 pc. The feature is also associated with H I gas having a more continuous spatial and velocity distribution than that of 12CO. We interpret the feature as being a magnetically floated loop similar to loops 1 and 2, and name it {"}loop 3{"}. Loop 3 is similar to loops 1 and 2 in its height and length, but is different from loops 1 and 2 in that the inner part of loop 3 is filled with molecular emission. We have identified two foot points at both ends of loop 3. H i, 12CO, and 13CO datasets were used to estimate the total mass and the kinetic energy of loop 3 to be ∼3.0 × 106 MOdot; and ∼ 1.7 × 1052 erg. The huge size, velocity dispersions, and energy are consistent with the magnetic origin of the Parker instability, as in the case of loops 1 and 2, but is difficult to be explained by multiple stellar explosions. We argue that loop 3 is in an earlier evolutionary phase than loops 1 and 2 based on the innerfilled morphology and the relative weakness of the foot points. This discovery indicates that the western part of the nuclear gas disk of ∼ 1 kpc radius is dominated by the three well-developed magnetically floated loops, and suggests that the dynamics of the nuclear gas disk is strongly affected by magnetic instabilities.",
author = "Motosuji Fujishita and Kazufumi Torii and Natsuko Kudo and Tokuichi Kawase and Hiroaki Yamamoto and Akiko Kawamura and Norikazu Mizuno and Toshikazu Onishi and Akira Mizuno and Mami Machida and Kunio Takahashi and Satoshi Nozawa and Ryoji Matsumoto and Yasuo Fukui",
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T1 - Discovery of molecular loop 3 in the Galactic center

T2 - Evidence for a positive-velocity magnetically floated loop towards L = 355°-359°

AU - Fujishita, Motosuji

AU - Torii, Kazufumi

AU - Kudo, Natsuko

AU - Kawase, Tokuichi

AU - Yamamoto, Hiroaki

AU - Kawamura, Akiko

AU - Mizuno, Norikazu

AU - Onishi, Toshikazu

AU - Mizuno, Akira

AU - Machida, Mami

AU - Takahashi, Kunio

AU - Nozawa, Satoshi

AU - Matsumoto, Ryoji

AU - Fukui, Yasuo

PY - 2009

Y1 - 2009

N2 - We have discovered a molecular dome-like feature towards 355° ≤ l ≤ 359° and 0° ≤ b ≤ 2°. The large velocity dispersions of 50-100km s-1 of this feature are much larger than those in the Galactic disk, and indicate that the feature is located in the Galactic center, probably within ∼ 1 kpc of Sgr A*. The distribution has a projected length of ∼ 600 pc and a height of ∼ 300 pc from the Galactic disk, and shows a large-scale monotonic velocity gradient of ∼ 130 km s -1 per ∼ 600 pc. The feature is also associated with H I gas having a more continuous spatial and velocity distribution than that of 12CO. We interpret the feature as being a magnetically floated loop similar to loops 1 and 2, and name it "loop 3". Loop 3 is similar to loops 1 and 2 in its height and length, but is different from loops 1 and 2 in that the inner part of loop 3 is filled with molecular emission. We have identified two foot points at both ends of loop 3. H i, 12CO, and 13CO datasets were used to estimate the total mass and the kinetic energy of loop 3 to be ∼3.0 × 106 MOdot; and ∼ 1.7 × 1052 erg. The huge size, velocity dispersions, and energy are consistent with the magnetic origin of the Parker instability, as in the case of loops 1 and 2, but is difficult to be explained by multiple stellar explosions. We argue that loop 3 is in an earlier evolutionary phase than loops 1 and 2 based on the innerfilled morphology and the relative weakness of the foot points. This discovery indicates that the western part of the nuclear gas disk of ∼ 1 kpc radius is dominated by the three well-developed magnetically floated loops, and suggests that the dynamics of the nuclear gas disk is strongly affected by magnetic instabilities.

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