Early-stage star forming cloud cores in GLIMPSE Extended Green Objects (EGOs) as traced by organic species

Abstract

In order to investigate the physical and chemical properties of massive star forming cores in early stages, we analyse the excitation and abundance of four organic species, CH3OH, CH3OCH3, HCOOCH3 and CH3CH2CN, toward 29 Extended Green Object (EGO) cloud cores that were observed by our previous single dish spectral line survey. The EGO cloud cores are found to have similar methanol J_3-J_2 rotation temperatures of ~44 K, a typical linear size of ~0.036 pc, and a typical beam averaged methanol abundance of several 10^(-9) (the beam corrected value could reach several 10^(-7)). The abundances of the latter three species, normalized by that of methanol, are found to be correlated also across a large variety of clouds such as EGO cloud cores, hot corinos, massive hot cores and Galactic Center clouds. The chemical properties of the EGO cloud cores lie between that of hot cores and hot corinos. However, the abundances and abundance ratios of the four species can not be satisfactorily explained by recent chemical models either among the EGO cloud cores or among the various types of cloud cores from literature.

References in corpus (41)

• Toward Understanding Massive Star Formation
• Cold Dark Clouds: The Initial Conditions for Star Formation
• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• A three-phase chemical model of hot cores: the formation of glycine
• Global collapse of molecular clouds as a formation mechanism for the most massive stars
• Testing grain-surface chemistry in massive hot-core regions
• How Many Infrared Dark Clouds can form Massive Stars and Clusters?
• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• Molecular Evolution in Collapsing Prestellar Cores
• On the Rapid Collapse and Evolution of Molecular Clouds
• Fragmentation at the Earliest Phase of Massive Star Formation
• The Simultaneous Formation of Massive Stars and Stellar Clusters
• Hot corinos in NGC1333-IRAS4B and IRAS2A
• The Lifetimes and Evolution of Molecular Cloud Cores
• The formation of molecular clouds in spiral galaxies
• Organic Molecules in the Galactic Center. Hot Core Chemistry without Hot Cores
• A 95 GHz Class I Methanol Maser Survey Toward GLIMPSE Extended Green Objects (EGOs)
• Distinct Chemical Regions in the "Prestellar" Infrared Dark Cloud (IRDC) G028.23-00.19
• Bipolar Molecular Outflows and Hot Cores in GLIMPSE Extended Green Objects (EGOs)
• A Molecular Line Observation toward Massive Clumps Associated with Infrared Dark Clouds
• Outflow and dense gas emission from massive Infrared Dark Clouds
• Kinematics and Chemistry of the Hot Molecular Core in G34.26+0.15 at High Resolution
• A Search for Infall Evidence in EGOs I: the Northern Sample
• A Water Maser and Ammonia Survey of GLIMPSE Extended Green Objects (EGOs)
• Deep Very Large Array Radio Continuum Surveys of GLIMPSE Extended Green Objects (EGOs)
• TMC-1C: an accreting starless core
• Line profiles of molecular ions toward the pre-stellar core LDN 1544
• Dynamical and chemical properties of the "starless" core L1014
• Early stage massive star formation near the Galactic Center: Sgr C
• Organic species in Infrared Dark Clouds
• ALMA Observations of the IRDC Clump G34.43+00.24 MM3: Hot Core and Molecular Outflows
• The Protocluster G18.67+0.03: A Test Case for Class I Methanol Masers as Evolutionary Indicators for Massive Star Formation
• A 1-mm spectral line survey toward GLIMPSE Extended Green Objects (EGOs)
• Initial conditions for star formation in clusters: physical and kinematical structure of the starless core Oph A-N6
• Kinematics and chemistry of the hot core in G20.08-0.14N
• Unbound Star-forming Molecular Clouds
• Study of the dense molecular gas surrounding the "Extended Green Object" G35.03+0.35
• A multi-transition molecular line study of infrared dark cloud G331.71+00.59

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• Chemical Diversity in Three Massive Young Stellar Objects associated with 6.7 GHz CH${}_3$OH Masers
• VLA Survey of Dense Gas in Extended Green Objects: Prevalence of 25 GHz Methanol Masers
• Young Stellar Populations in MYStIX Star Forming Regions: Candidate Protostars
• Multiwavelength investigation of extended green object G19.88-0.53: Revealing a protocluster