RADIO CONTINUUM OBSERVATIONS OF THE GALACTIC CENTER: PHOTOEVAPORATIVE PROPLYD-LIKE OBJECTS NEAR SGR A*
We present radio images within 30″ of Sgr A∗ based on recent VLA observations at 34 GHz with 7.8 μJy sensitivity and resolution of mas. We report 44 partially resolved compact sources clustered in two regions in the E arm of ionized gas that orbits Sgr A∗. These sources have size scales ranging betw...
| Autores: | , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/398042 |
| Acceso en línea: | http://hdl.handle.net/10261/398042 |
| Access Level: | acceso abierto |
| Palabra clave: | Galaxy: center H ii regions ISM: general Radio continuum: ISM Stars: protostars |
| Sumario: | We present radio images within 30″ of Sgr A∗ based on recent VLA observations at 34 GHz with 7.8 μJy sensitivity and resolution of mas. We report 44 partially resolved compact sources clustered in two regions in the E arm of ionized gas that orbits Sgr A∗. These sources have size scales ranging between ∼50 and 200 mas (400-1600 AUs), and a bow- shock appearance facing the direction of Sgr A∗. Unlike the bow-shock sources previously identified in the near-IR but associated with massive stars, these 34 GHz sources do not appear to have near-IR counterparts at 3.8 μm. We interpret these sources as a candidate population of photoevaporative protoplanetary disks (proplyds) that are associated with newly formed low mass stars with mass loss rates ∼10-7-10-6 M⊙yr-1 and are located at the edge of a molecular cloud outlined by ionized gas. The disks are externally illuminated by strong Lyman continuum radiation from the ∼100 OB and WR massive stars distributed within 10″ of Sgr A∗. The presence of proplyds implies current in situ star formation activity near Sgr A∗ and opens a window for the first time to study low mass star, planetary, and brown dwarf formations near a supermassive black hole. © 2015. The American Astronomical Society. All rights reserved. |
|---|