Radio continuum observations of the galactic center: Photoevaporative proplyd-like objects near Sgr A∗

DOI: 
10.1088/2041-8205/801/2/L26
Publication date: 
01/01/2015
Main author: 
Yusef-Zadeh F.
IAA authors: 
Schödel, R.
Authors: 
Yusef-Zadeh F., Roberts D.A., Wardle M., Cotton W., Schödel R., Royster M.J.
Journal: 
Astrophysical Journal Letters
Publication type: 
Article
Volume: 
801
Pages: 
Number: 
L26
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 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.
Database: 
SCOPUS
Keywords: 
Galaxy: center; H II regions; ISM: general; radio continuum: ISM; stars: protostars