Star Formation Occurs in Dense Gas, but What Does “Dense” Mean?
نویسندگان
چکیده
منابع مشابه
The Star Formation Rate and Dense Molecular Gas in Galaxies
HCN luminosity is a tracer of dense molecular gas, n(H2) > ∼3 × 10 cm, associated with star-forming giant molecular cloud (GMC) cores. We present the results and analysis of our survey of HCN emission from 65 infrared galaxies including 9 ultraluminous infrared galaxies (ULIGs, LIR > ∼10 L⊙), 22 luminous infrared galaxies (LIGs, 10 L⊙ < LIR < ∼10 L⊙) and 34 normal spiral galaxies with lower IR ...
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It has been known for more than 30 years that star formation in giant molecular clouds (GMCs) is slow, in the sense that only ∼ 1% of the gas forms stars every free-fall time. This result is entirely independent of any particular model of molecular cloud lifetime or evolution. Here we survey observational data on higher density objects in the interstellar medium, including infrared dark clouds ...
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Abstract. An imaging survey of CO(1−0), HCN(1−0), and HCO(1−0) lines in the centers of nearby Seyfert galaxies has been conducted using the Nobeyama Millimeter Array and the RAINBOW interferometer. Preliminary results reveal that 3 Seyferts out of 7 show abnormally high HCN/CO and HCN/HCO ratios, which cannot occur even in nuclear starburst galaxies. We suggest that the enhanced HCN emission or...
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The early stages of the star formation process are closely related to the condition of the parent interstellar medium, in particular to the heating/cooling balance, which itself is a function of ambient conditions. Important questions such as dust abundance, size distribution, temperature distribution, fraction of molecular gas, fraction of dense gas, gas surface density and total amount of gas...
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We investigate the relationship between the star formation rate (SFR) and dense molecular gas mass in the nuclei of galaxies. To do this, we utilize the observed 850 mm luminosity as a proxy for the infrared luminosity ( ) and SFR, and we correlate this with the observed CO( ) luminosity. We find tentative evidence that L J p 3–2 IR the -CO( ) index is similar to the Kennicutt-Schmidt (KS) inde...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2020
ISSN: 1538-4357
DOI: 10.3847/1538-4357/ab8938