Multi-epoch VLBA H2O maser observations towards the massive YSOs AFGL 2591 VLA 2 and VLA 3
We present multi-epoch Very Long Baseline Array (VLBA) H2O maser observations towards the massive young stellar objects (YSOs) VLA 2 and VLA 3 in the star-forming region AFGL 2591. Through these observations, we have extended the study of the evolution of the masers towards these objects up to a tim...
| Autores: | , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/392492 |
| Acceso en línea: | http://hdl.handle.net/10261/392492 |
| Access Level: | acceso abierto |
| Palabra clave: | Masers Stars: formation ISM: individual objects: AFGL 2591 ISM: jets and outflows |
| Sumario: | We present multi-epoch Very Long Baseline Array (VLBA) H2O maser observations towards the massive young stellar objects (YSOs) VLA 2 and VLA 3 in the star-forming region AFGL 2591. Through these observations, we have extended the study of the evolution of the masers towards these objects up to a time-span of ∼10 yr, measuring their radial velocities and proper motions. The H2O masers in VLA 3, the most massive YSO in AFGL 2591 (∼30-40 M⊙), are grouped within projected distances of ≲40 mas (≲130 au) from VLA 3. In contrast to other H2O masers in AFGL 2591, the masers associated with VLA 3 are significantly blueshifted (up to ∼30 km s-1) with respect to the velocity of the ambient molecular cloud. We find that the H2O maser cluster as a whole has moved westwards of VLA 3 between the 2001 and 2009 observations, with a proper motion of ∼1.2 mas yr-1 (∼20 km s-1). We conclude that these masers are tracing blueshifted outflowing material, shock excited at the inner parts of a cavity seen previously in ammonia molecular lines and infrared images, and proposed to be evacuated by the outflow associated with the massive VLA 3 source. The masers in the region of VLA 2 are located at projected distances of ∼0.7 arcsec (∼2300 au) north from this source, with their kinematics suggesting that they are excited by a YSO other than VLA 2. This driving source has not yet been identified. © 2013 The Authors |
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