2009/10/02 by Yoji Mizuno, Akiko Kawamura, Toshikazu Onishi +43
Chemistry · Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Extinction (optical mineralogy) #Large Magellanic Cloud #Line (geometry) #Molecular Spectroscopy and Structure #Molecular cloud #Physics #Star cluster #Star formation #Stars #Stellar, planetary, and galactic studies #astro-ph.CO
paper · pdf · doi:10.1093/pasj/62.1.51
arxiv created 2009/10/02 · openalex publication_date 2010/02/25 · arxiv updated 2015/05/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Abstract New 12CO J = 4–3 and 13CO J = 3–2 observations of the N 159 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, J = 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&x2013;80 K and ∼3 × 103cm-3 in N 159 W and N 159 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 HII regions as well as midinfrared emission obtained with the Spitzer MIPS. The N 159 E clump is associated with cluster(s) embedded, as observed at 24μm by the Spitzer MIPS, and the derived high temperature, 80 K, is interpreted as being heated by these sources. The N 159 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 N 159 W peak represents a pre-star-cluster core of ∼105 M\odot which deserves further detailed studies. The N 159 S clump shows little sign of star formation, as is consistent with the lower temperature, 30 K, and has a somewhat lower density than N 159 W and N 159 E. The N 159 S clump is also a candidate for future star formation.