Sanchez-Monge, A., Beltran, M. T., Cesaroni, R., Etoka, S., Galli, D., Kumar, M. S. N., Moscadelli, L., Stanke, T., van der Tak, F. F. S., Vig, S., Walmsley, C. M., Wang, K. -S., Zinnecker, H., Elia, D., Molinari, S. and Schisano, E. (2014). A necklace of dense cores in the high-mass star forming region G35.20-0.74 N: ALMA observations. Astron. Astrophys., 569. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Context. The formation process of high-mass stars (with masses >8 M-circle dot) is still poorly understood, and represents a challenge from both the theoretical and observational points of view. The advent of the Atacama Large Millimeter Array (ALMA) is expected to provide observational evidence to better constrain the theoretical scenarios. Aims. The present study aims at characterizing the high-mass star forming region G35.20-0.74 N, which is found associated with at least one massive outflow and contains multiple dense cores, one of them recently found associated with a Keplerian rotating disk. Methods. We used the radio-interferometer ALMA to observe the G35.20-0.74 N region in the submillimeter continuum and line emission at 350 GHz. The observed frequency range covers tracers of dense gas (e.g., (HCO+)-C-13, (CO)-O-17), molecular outflows (e.g., SiO), and hot cores (e.g., CH3CN, CH3OH). These observations were complemented with infrared and centimeter data. Results. The ALMA 870 mu m continuum emission map reveals an elongated dust structure (similar to 0.15 pc long and similar to 0.013 pc wide; full width at half maximum) perpendicular to the large-scale molecular outflow detected in the region, and fragmented into a number of cores with masses similar to 1-10 M-circle dot and sizes similar to 1600 AU (spatial resolution similar to 960 AU). The cores appear regularly spaced with a separation of similar to 0.023 pc. The emission of dense gas tracers such as (HCO+)-C-13 or (CO)-O-17 is extended and coincident with the dust elongated structure. The three strongest dust cores show emission of complex organic molecules characteristic of hot cores, with temperatures around 200 K, and relative abundances 0.2-2 x 10(-8) for CH3CN and 0.6-5 x 10(-6) for CH3OH. The two cores with highest mass (cores A and B) show coherent velocity fields, with gradients almost aligned with the dust elongated structure. Those velocity gradients are consistent with Keplerian disks rotating about central masses of 4-18 M-circle dot. Perpendicular to the velocity gradients we have identified a large-scale precessing jet/outflow associated with core B, and hints of an east-west jet/outflow associated with core A. Conclusions. The elongated dust structure in G35.20-0.74 N is fragmented into a number of dense cores that may form high-mass stars. Based on the velocity field of the dense gas, the orientation of the magnetic field, and the regularly spaced fragmentation, we interpret this elongated structure as the densest part of a 1D filament fragmenting and forming high-mass stars.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Sanchez-Monge, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Beltran, M. T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Cesaroni, R.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Etoka, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Galli, D.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Kumar, M. S. N.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Moscadelli, L.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Stanke, T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
van der Tak, F. F. S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Vig, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Walmsley, C. M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wang, K. -S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Zinnecker, H.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Elia, D.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Molinari, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Schisano, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-429579
DOI: 10.1051/0004-6361/201424032
Journal or Publication Title: Astron. Astrophys.
Volume: 569
Date: 2014
Publisher: EDP SCIENCES S A
Place of Publication: LES ULIS CEDEX A
ISSN: 1432-0746
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
YOUNG STELLAR OBJECTS; GRAIN-SURFACE-CHEMISTRY; MOLECULAR LINE SURVEY; GHZ METHANOL MASERS; HOT-CORE; MAGNETIC-FIELD; ORION-KL; MIDINFRARED INTERFEROMETRY; HIERARCHICAL FRAGMENTATION; INTERSTELLAR JETSMultiple languages
Astronomy & AstrophysicsMultiple languages
URI: http://kups.ub.uni-koeln.de/id/eprint/42957

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