SMA Observations of W3(OH) Complex: Physical and Chemical Differentiation between W3(H${}_2$O) and W3(OH)

Abstract

We report on the Submillimeter Array (SMA) observations of molecular lines at 270 GHz toward W3(OH) and W3(H${}_2$O) complex. Although previous observations already resolved the W3(H${}_2$O) into two or three sub-components, the physical and chemical properties of the two sources are not well constrained. Our SMA observations clearly resolved W3(OH) and W3(H${}_2$O) continuum cores. Taking the advantage of the line fitting tool XCLASS, we identified and modeled a rich molecular spectrum in this complex, including multiple CH${}_3$CN and CH${}_3$OH transitions in both cores. HDO, C${}_2$H${}_5$CN, O${}^{13}$CS, and vibrationally excited lines of HCN, CH${}_3$CN, and CH${}_3$OCHO were only detected in W3(H${}_2$O). We calculate gas temperatures and column densities for both cores. The results show that W3(H${}_2$O) has higher gas temperatures, and larger column densities than W3(OH) as previously observed, suggesting physical and chemical differences between the two cores. We compare the molecular abundances in W3(H${}_2$O) to those in the Sgr B2(N) hot core, the Orion KL hot core and the Orion Compact Ridge, and discuss the chemical origin of specific species. An east-west velocity gradient is seen in W3(H${}_2$O), and the extension is consistent with the bipolar outflow orientation traced by water masers and radio jets. A north-south velocity gradient across W3(OH) is also observed. However, with current observations we can not assure if the velocity gradients are caused by rotation, outflow or radial velocity differences of the sub-components in W3(OH).

Accepted by ApJ

References in corpus (6)

• Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores
• Water maser motions in W3(OH) and a determination of its distance
• Herschel observations of EXtra-Ordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey Toward Orion KL I. Methods
• Herschel observations of EXtraordinary Sources: Analysis of the full Herschel/HIFI molecular line survey of Sagittarius B2(N)
• Structure of W3(OH) from Very High Spectral Resolution Observations of 5 Centimeter OH Masers
• Early-stage star forming cloud cores in GLIMPSE Extended Green Objects (EGOs) as traced by organic species

Cited by in corpus (12)

• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- I. Survey description and a first look at G9.62+0.19
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- VIII. A search for hot cores by using C${}_2$H${}_5$CN, CH${}_3$OCHO and CH${}_3$OH lines
• Correlations of Methyl Formate (CH3OCHO), Dimethyl Ether (CH3OCH3) and Ketene (H2CCO) in High-mass Star-forming Regions
• Probing the kinematics and chemistry of the hot core Mon R 2 IRS 3 using ALMA observations
• The physical and chemical structure of high-mass star-forming regions. Unraveling chemical complexity with the NOEMA large program "CORE"
• APEX Millimeter Observations of Methanol Emission Toward High-Mass Star-Forming Cores
• Redshifted methanol absorption tracing infall motions of high-mass star formation regions
• Mapping Physical Conditions in Neighboring Hot Cores: NOEMA Studies of W3(H${}_2$O) and W3(OH)
• Comparing Complex Chemistry in Neighboring Hot Cores: NOEMA Studies of W3(H${}_2$O) and W3(OH)
• The LMT 2 millimeter receiver system (B4R). II. Science demonstration observations toward Orion-KL/OMC-1
• 3 mm Spectroscopic Observations of Massive Star-Forming Regions with IRAM 30-m
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- X. Chemical differentiation among the massive cores in G9.62+0.19