Radio Continuum Observations of the Galactic Center: Photoevaporative Proplyd-like Objects Near Sgr A*
Abstract
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 ∼ 88× 46 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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2015
- DOI:
- arXiv:
- arXiv:1502.03109
- Bibcode:
- 2015ApJ...801L..26Y
- Keywords:
-
- Galaxy: center;
- H ii regions;
- ISM: general;
- radio continuum: ISM;
- stars: protostars;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 13 pages, 4 figures, ApJL (in press)