Radio Continuum Observations of the Galactic Center: Photoevaporative Proplyd-like Objects near Sgr A*

Abstract

We present radio images within 30${}^{\prime \prime }$ of Sgr A* based on recent VLA observations at 34 GHz with 7.8 microJy sensitivity and resolution $\sim 88\times 46$ milliarcseconds (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 to 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 $\mu$m. 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} solar mass per year 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.

13 pages, 4 figures, ApJL (in press)

References in corpus (7)

• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• ALMA Observations of the Orion Proplyds
• Dusty Sources at the Galactic Center: The N- and Q-band view with VISIR
• IRS 13N: a new comoving group of sources at the Galactic Center
• Properties of bow-shock sources at the Galactic center
• The Discovery of Radio Stars within 10 arcseconds of Sgr A* at 7mm
• VLTI observations of IRS~3: The brightest compact MIR source at the Galactic Centre

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• ALMA Detection of Bipolar Outflows: Evidence for Low Mass Star Formation within 1pc of Sgr A*
• Polarized near-infrared light of the Dusty S-cluster Object (DSO/G2) at the Galactic Center
• A new bow-shock source with bipolar morphology in the vicinity of Sgr A*
• Radio observations of evaporating objects in the Cygnus OB2 region
• Tidally-disrupted Molecular Clouds falling to the Galactic Center