CMZoom. IV. Incipient High-mass Star Formation throughout the Central Molecular Zone

Abstract

In this work, we constrain the star-forming properties of all possible sites of incipient high-mass star formation in the Milky Way’s Galactic Center. We identify dense structures using the CMZoom 1.3 mm dust continuum catalog of objects with typical radii of ∼0.1 pc, and measure their association with tracers of high-mass star formation. We incorporate compact emission at 8, 21, 24, 25, and 70 μ m from the Midcourse Space Experiment, Spitzer, Herschel, and SOFIA, cataloged young stellar objects, and water and methanol masers to characterize each source. We find an incipient star formation rate (SFR) for the Central Molecular Zone (CMZ) of ∼0.08 M _⊙ yr ^−1 over the next few 10 ^5 yr. We calculate upper and lower limits on the CMZ’s incipient SFR of ∼0.45 and ∼0.05 M _⊙ yr ^−1 ,respectively, spanning roughly equal to and several times greater than other estimates of CMZ’s recent SFR. Despite substantial uncertainties, our results suggest the incipient SFR in the CMZ may be higher than previously estimated. We find that the prevalence of star formation tracers does not correlate with source volume density, but instead ≳75% of high-mass star formation is found in regions above a column density ratio ( N _SMA / N _Herschel ) of ∼1.5. Finally, we highlight the detection of atoll sources , a reoccurring morphology of cold dust encircling evolved infrared sources, possibly representing H ii regions in the process of destroying their envelopes.

Keywords

• Star formation
• Galactic center
• Milky Way Galaxy
• Young stellar objects
• Protostars