Abstract Details
| Name: Naslim Neelamkodan Affiliation: School of Physics, University of Hyderabad Conference ID: ASI2018_1700 Title : ALMA reveals molecular cloud N55 in the Large Magellanic Cloud as a site of massive star formation Authors and Co-Authors : K. Tokuda (Osaka Prefecture University, Osaka, Japan) T. Onishi (Osaka Prefecture University, Osaka, Japan) F. Kemper (Academia Sinica Institute of Astronomy and Astrophysics, Taipei, Taiwan) T. Wong (University of Illinois, Urbana, USA) O. Morata(Academia Sinica Institute of Astronomy and Astrophysics, Taipei, Taiwan) S. Takada (Osaka Prefecture University, Osaka, Japan) R. Harada (Osaka Prefecture University, Osaka, Japan) A. Kawamura (National Astronomical Observatory of Japan, Tokyo, Japan) K. Saigo (National Astronomical Observatory of Japan, Tokyo, Japan) R. Indebetouw (National Radio Astronomical Observatory, Charlottesville, USA) S. C. Madden (CEA Saclay, Paris, France) S. Hony (Max Planck Institute for Astronomy, Heidelberg, Germany) M. Meixner (Space Telescope Science Institute, Baltimore, USA) Abstract Type : Contributed Talk Abstract Category : Extragalactic astronomy Abstract : Most stars form as clusters in Giant Molecular Clouds (GMCs) which encompass cold molecular gas and dust with masses 10^4 - 10^5. Therefore, understanding the evolution of dust and gas in GMCs is important to understand the formation of stars in galaxies. The GMCs are composed of sub-parsec-sized clumps, the size of which is determined by the forces of gravity and magneto-turbulent pressure. Stars form inside these clumps, hence a detailed understanding of the star formation process requires a sub-parsec scale resolution view of GMCs and accurate measurements of the physical parameters of these clumps. Spatially resolved CO observations in large-scale surveys have been carried out in the nearest low-metallicity galaxy, the Large Magellanic Cloud (LMC), with an aim to investigate whether the GMC characteristics and star formation conditions follow universal patterns. There has been high spatial resolution (sub-parsec) mapping of 12CO(2-1) and 13CO(2-1) observations with the Atacama Large Millimeter Array (ALMA) in the active star-forming regions, 30Doradus, N159 west, and N55 of the LMC. We here present the molecular cloud properties of N55 in the LMC using 12CO(1-0) and 13CO(1-0) observations obtained with ALMA. We have done a detailed study of molecular gas properties, to understand how the cloud properties of N55 differ from Galactic clouds. Most CO emission appears clumpy in N55, and molecular cores that have Young stellar objects (YSO) show larger linewidths and masses. We find that massive clumps are associated with high and intermediate mass YSOs. The size-linewidth coefficient shows a linear relation with mass surface density for N55 clumps as in many Milky Way quiescent clouds, indicating that clouds are virialized with negligible external pressure. In addition, the size-linewidth relation shows a power law relation with the index of 0.5+-/0.05. We found a CO-to-H2 conversion factor, Xco, 6.5X10^20 cm^-2 (K km s-1)^-1 at a spatial scale 0.8 pc which is about two times higher than Orion CO-to-H2 conversion factor measured for similar spatial scale. The power law relation of clump mass function in N55 shows similar behavior to the 12CO(2-1) clumps in star-forming region 30Doradus observed with ALMA, and the 13CO(1-0) clumps of Gemini-Augira in the Milky Way observed with 4m Nagoya Telescope. This power-law behavior of clump mass function in N55 is consistent with many Galactic clouds. |