Warm and dense molecular gas in the N 159 region:12CO J =4-3 and13CO J = 3-2 observations with NANTEN2 and ASTE

Yoji Mizuno, Akiko Kawamura, Toshikazu Onishi, Tetsuhiro Minamidani, Erik Muller, Hiroaki Yamamoto, Takahiro Hayakawa, Norikazu Mizuno, Akira Mizuno, Jürgen Stutzki, Jorge L. Pineda, Uli Klein, Frank Bertoldi, Bon Chul Koo, Monica Rubio, Michael Burton, Arnold Benz, Hajime Ezawa, Nobuyuki Yamaguchi, Kotaro KohnoTetsuo Hasegawa, Ke N.Ichi Tatematsu, Masafumi Ikeda, Jürgen Ott, Tony Wong, Annie Hughes, Margaret Meixner, Remy Indebetouw, Karl D. Gordon, Barbara Whitney, Jean Philippe Bernard, Yasuo Fukui

Research output: Contribution to journalArticlepeer-review

Abstract

New 12CO J = 4-3 and 13CO J = 3-2 observations of the N159 region, an active site of massive star formation in the Large Magellanic Cloud, have been made with the NANTEN2 and ASTE submillimeter telescopes, respectively. The 12CO J = 4-3 distribution is separated into three clumps, each associated with N 159 W, N 159 E, and N 159 S. These new measurements toward the three clumps are used in coupled calculations of molecular rotational excitation and line radiation transfer, along with other transitions of the 12CO J = 1-0, J = 2-1, J = 3-2, and J = 7-6 as well as the isotope transitions of 13CO J = 1-0, J = 2-1, / = 3-2, and J = 4-3. The 13CO J = 3-2 data were newly taken for the present work. The temperatures and densities were found to be ∼ 70-80 K and ∼3 × 103cm-3 in N159 W and N159 E, and ∼30 K and ∼ 1.6 × 103cm-3 in N 159 S. These results were compared with the star-formation activity based on data of young stellar clusters and H II regions as well as midinfrared emission obtained with the Spitzer MIPS. The N159 E clump is associated with cluster(s) embedded, as observed at 24 μm by the Spitzer MIPS, and the derived high temperature, 80 K, is interpreted as being heated by these sources. The N159 E clump is likely to be responsible for a dark lane in a large H II region by dust extinction. On the other hand, the N 159 W clump is associated with clusters embedded mainly toward the eastern edge of the clump only. These clusters show offsets of 20"-40" from the 12CO J = 4-3 peak, and are probably responsible for heating indicated by the derived high temperature, 70 K. The N 159 W clump exhibits no sign of star formation toward the 12CO J = 4-3 peak position and its western region that shows enhanced R4-3/1-0 and R3-2/1-0 ratios. We therefore suggest that the N159 W peak represents a pre-star-cluster core of ∼ 105 M⊙ which deserves further detailed studies. The N159 S clump shows little sign of star formation, as is consistent with the lower temperature, 30 K, and has a somewhat lower density than N159 W and N 159 E. The N159 S clump is also a candidate for future star formation.

Original languageEnglish (US)
Pages (from-to)51-67
Number of pages17
JournalPublications of the Astronomical Society of Japan
Volume62
Issue number1
DOIs
StatePublished - 2010

Keywords

  • Galaxies: Magellanic clouds
  • ISM: Clouds
  • ISm: Molecules
  • Stars: Formation
  • Submillimeter

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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