Dense core properties in the infrared dark cloud G14.225-0.506 revealed by ALMA

Journal Article · Tue Dec 20 04:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/833/2/209· OSTI ID:22869646

Ohashi, Satoshi ^[1]; Sanhueza, Patricio; Nakamura, Fumitaka; Tatematsu, Ken’ichi ^[2]; Chen, Huei-Ru Vivien ^[3]; Zhang, Qizhou ^[4]; Busquet, Gemma ^[5]; Palau, Aina ^[6]

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1. Department of Astronomy, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)
2. National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
3. Institute of Astronomy and Department of Physics, National Tsing Hua University, 101, Sec. 2, Kuang Fu Road, Hsinchu 30013, Taiwan (China)
4. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02318 (United States)
5. Institut de Ciències de l’Espai (IEEC-CSIC), Campus UAB, Carrer de Can Magrans, S/N. E-08193, Barcelona, Catalunya (Spain)
6. Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, P.O. Box 3-72, 58090 Morelia, Michoacán, México (Mexico)

We have performed a dense core survey toward the Infrared Dark Cloud G14.225-0.506 at 3 mm continuum emission with the Atacama Large Millimeter/Submillimeter Array (ALMA). This survey covers the two hub-filament systems with an angular resolution of ∼3{sup ′′} (∼0.03 pc). We identified 48 dense cores. 20 out of the 48 cores are protostellar due to their association with young stellar objects (YSOs) and/or X-ray point-sources, while the other 28 cores are likely prestellar and unrelated with known IR or X-ray emission. Using APEX 870 μm continuum emission, we also identified the 18 clumps hosting these cores. Through virial analysis using the ALMA N{sub 2}H{sup +} and VLA/Effelsberg NH{sub 3} molecular line data, we found a decreasing trend in the virial parameter with decreasing scales from filaments to clumps, and then to cores. The virial parameters of 0.1–1.3 in cores indicate that cores are likely undergoing dynamical collapse. The cumulative core mass function for the prestellar core candidates has a power law index of α=1.6, with masses ranging from 1.5 to 22 M{sub ⊙}. We find no massive prestellar or protostellar cores. Previous studies suggest that massive O-type stars have not been produced yet in this region. Therefore, high-mass stars should be formed in the prestellar cores by accreting a significant amount of gas from the surrounding medium. Another possibility is that low-mass YSOs become massive by accreting from their parent cores that are fed by filaments. These two possibilities might be consistent with the scenario of global hierarchical collapse.

• OSTI ID: 22869646
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 833; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
EMISSION
MASS
POINT SOURCES
RESOLUTION
STAR EVOLUTION
STARS
X RADIATION