Class II 6.7 GHz Methanol Maser Association with Young Massive Cores Revealed by ALMA

Journal Article · Fri Feb 10 04:00:00 EST 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/836/1/59· OSTI ID:22869391

Chibueze, James O.; Alhassan, Jibrin A. ^[1]; Csengeri, Timea; Menten, Karl M. ^[2]; Tatematsu, Ken’ichi; Hasegawa, Tetsuo; Iguchi, Satoru ^[3]; Higuchi, Aya E. ^[4]; Bontemps, Sylvain ^[5]

---

1. Department of Physics and Astronomy, Faculty of Physical Sciences, University of Nigeria, Carver Building, 1 University Road, Nsukka (Nigeria)
2. Max Planck Institute for Radioastronomy, Auf dem Hügel 69, D-53121 Bonn (Germany)
3. National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
4. The Institute of Physical and Chemical Research (RIKEN), 2-1, Hirosawa, Wako-shi, Saitama 351-0198 (Japan)
5. OASU/LAB-UMR5804, CNRS, Université Bordeaux 1, F-33270 Floirac (France)

We explored the implication of the association (or lack of it) of 6.7 GHz class II methanol (CH{sub 3}OH) masers with massive dense cores (MDCs) detected (within a sample of ATLASGAL selected infrared quiet massive clumps) at 0.9 mm with Atacama Large Millimeter/submillimeter array. We found 42 out of the 112 cores (37.5%) detected with the Atacama Compact Array (ACA) to be associated with 6.7 GHz CH{sub 3}OH masers. The lowest mass core with CH{sub 3}OH maser association is ∼12 M{sub ⊙}. The angular offsets of the ACA cores from the 6.7 GHz CH{sub 3}OH maser peak positions range from 0.″17 to 4.″79, with a median value of 2.″19. We found a weak correlation between the 0.9 mm continuum (MDCs) peak fluxes and the peak fluxes of their associated methanol multibeam (MMB) 6.7 GHz CH{sub 3}OH masers. About 90% of the cores associated with 6.7 GHz CH{sub 3}OH masers have masses of >40 M {sub ⊙}. The CH{sub 3}OH maser containing cores are candidates for embedded high-mass protostellar objects in their earliest evolutionary stages. With our ACA 0.9 continuum data compared with the MMB 6.7 GHz CH{sub 3}OH maser survey, we have constrained the cores already housing massive protostars based on their association with the radiatively pumped 6.7 GHz CH{sub 3}OH masers.

• OSTI ID: 22869391
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 836; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPARATIVE EVALUATIONS
MASERS
MASS
METHANOL
PROTOSTARS
STAR EVOLUTION
STARS