A Catalog of 44GHz Methanol Masers in Massive Star-forming Regions. IV. The High-mass Protostellar Object Sample
Por:
Rodriguez-Garza, C. B., Kurtz, S. E., Gomez-Ruiz, A. I., Hofner, P., Araya, E. D., Kalenskii, S. V.
Publicada:
1 nov 2017
Resumen:
We present a survey of 56 massive star-forming regions in the 44 GHz
methanol maser transition made with the Karl G. Jansky Very Large Array
(VLA); 24 of the 56 fields showed maser emission. The data allow us to
demonstrate associations, at arcsecond precision, of the Class I maser
emission with outflows, H II regions, and shocks traced by 4.5 mu m
emission. We find a total of 83 maser components with line widths
ranging from 0.17 to 3.3 km s-(1), with a nearly flat distribution and a
median value of 1.1 km s(-1). The relative velocities of the masers with
respect to the systemic velocity of the host clouds range from -2.5 to
3.1 km s(-1), with a distribution peaking near zero. We also study the
correlation between the masers and the so-called extended green objects
(EGOs) from the GLIMPSE survey. Multiple sources in each field are
revealed from IR images as well as from centimeter continuum emission
from VLA archival data; in the majority of cases the 44 GHz masers are
positionally correlated with EGOs, which seem to trace the younger
sources in the fields. We report a possible instance of a 44 GHz maser
associated with a low-mass protostar. If confirmed, this region will be
the fifth known star-forming region that hosts Class I masers associated
with low-mass protostars. We discuss three plausible cases of maser
variability.
Filiaciones:
Rodriguez-Garza, C. B.:
Univ Nacl Autonoma Mexico, Inst Radioastron & Astrofis, Apartado Postal 3-72, Morelia 58089, Michoacan, Mexico
Kurtz, S. E.:
Univ Nacl Autonoma Mexico, Inst Radioastron & Astrofis, Apartado Postal 3-72, Morelia 58089, Michoacan, Mexico
Gomez-Ruiz, A. I.:
Inst Nacl Astrofis Opt & Electr, Luis E Erro 1, Puebla 72840, Mexico
Hofner, P.:
New Mexico Inst Min & Technol, Phys Dept, 801 Leroy Pl, Socorro, NM 87801 USA
Natl Radio Astron Observ, 1003 Lopezville Rd, Socorro, NM 87801 USA
Araya, E. D.:
Western Illinois Univ, Phys Dept, 1 Univ Circle, Macomb, IL 61455 USA
Kalenskii, S. V.:
Lebedev Phys Inst, Astro Space Ctr, Profsoyuznaya 84-32, Moscow 117997, Russia
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