Ammonia observations of Planck cold cores
Berdikhan D. Esimbek J. Henkel C. Zhou J. Tang X. Liu T. Wu G. Li D. He Y. Komesh T. Tursun K. Zhou D. Imanaly E. Jandaolet Q.
1 April 2024EDP Sciences
Astronomy and Astrophysics
2024#684
Single-pointing observations of NH3 (1,1) and (2,2) were conducted toward 672 Planck Early Cold Cores (ECCs) using the Nanshan 26-m radio telescope. Out of these sources, a detection rate of 37% (249 cores) was achieved, with a NH3 (1,1) hyperfine structure detected in 187 cores and NH3 (2,2) emission lines detected in 76 of them. The detection rate of NH3 is positively correlated with the continuum emission fluxes at a frequency of 857 GHz. Among the observed 672 cores, ~22% have associated stellar and infrared objects within the beam size (~2′). This suggests that most of the cores in our sample may be starless. The kinetic temperatures of the cores range from 8.9 to 20.7 K, with an average of 12.3 K, indicating a coupling between gas and dust temperatures. The ammonia column densities range from 3.6 × 1014 to 6.07 × 1015 cm-2, with a median value of 2.04 × 1015 cm-2. The fractional abundances of ammonia range from 0.3 to 9.7 × 10-7, with an average of 2.7 × 10-7, which is one order of magnitude larger than that of massive star-forming (MSF) regions and infrared dark clouds (IRDCs). The correlation between thermal and nonthermal velocity dispersion of the NH3 (1,1) inversion transition indicates the dominance of supersonic nonthermal motions in the dense gas traced by NH3, and the relationship between these two parameters in Planck cold cores is weaker, with lower values observed for both parameters relative to other samples under our examination. The cumulative distribution shapes of line widths in the Planck cold cores closely resemble those of the dense cores found in regions of Cepheus, in addition to Orion L1630 and L1641, with higher values compared to Ophiuchus.
ISM: clouds , ISM: kinematics and dynamics , ISM: molecules , Stars: formation , Surveys
Text of the article Перейти на текст статьи
Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, 830011, China
University of Chinese Academy of Sciences, Beijing, 100080, China
Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, JiangSu, Nanjing, 210008, China
Xinjiang Key Laboratory of Radio Astrophysics, Urumqi, 830011, China
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, Bonn, 53121, Germany
Astronomy Department, King Abdulaziz University, PO Box 80203, Jeddah, 21589, Saudi Arabia
Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai, 200030, China
Energetic Cosmos Laboratory, Nazarbayev University, Astana, 010000, Kazakhstan
Institute of Experimental and Theoretical Physics, Al-Farabi Kazakh National University, Almaty, 050040, Kazakhstan
Xinjiang Astronomical Observatory
University of Chinese Academy of Sciences
Key Laboratory of Radio Astronomy
Xinjiang Key Laboratory of Radio Astrophysics
Max-Planck-Institut für Radioastronomie
Astronomy Department
Shanghai Astronomical Observatory
Energetic Cosmos Laboratory
Institute of Experimental and Theoretical Physics
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026