SEARCHING FOR NEW HYPERCOMPACT H II REGIONS

Journal Article · Tue Sep 20 04:00:00 EDT 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/739/1/L9· OSTI ID:21565475

Sanchez-Monge, Alvaro ^[1]; Pandian, Jagadheep D ^[2]; Kurtz, Stan ^[3]

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1. Osservatorio Astrofisico di Arcetri, INAF, Largo E. Fermi 5, I-50125 Firenze (Italy)
2. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States)
3. Centro de RadioastronomIa y Astrofisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 3-72, 58090 Morelia, Michoacan (Mexico)

Hypercompact (HC) H II regions are, by nature, very young H II regions, associated with the earliest stages of massive star formation. They may represent the transition phase as an early B-type star grows into an O-type star. Unfortunately, so few HC H II regions are presently known that their general attributes and defining characteristics are based on small number statistics. A larger sample is needed for detailed studies and good statistics. Class II methanol masers are one of the best indicators of the early stages of massive star formation. Using the Arecibo Methanol Maser Galactic Plane Survey-the most sensitive blind survey for 6.7 GHz methanol masers to date-we selected 24 HC H II region candidates. We made Expanded Very Large Array continuum observations at 3.6 and 1.3 cm to search for HC H II regions associated with these masers. We identified six potential HC H II regions in our sample based on the presence of optically thick free-free emission. Overall, we find that 30% of the methanol masers have an associated centimeter radio continuum source (separation less than 0.1 pc), which is in general agreement with previous studies.

• OSTI ID: 21565475
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 739; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ALCOHOLS
AMPLIFIERS
ELECTRONIC EQUIPMENT
EQUIPMENT
EVOLUTION
HYDROXY COMPOUNDS
MASERS
METHANOL
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
ORGANIC COMPOUNDS
STAR EVOLUTION
STARS