A wind-blown bubble in the Central Molecular Zone cloud G0.253+0.016. Issue 4 (17th December 2021)

• Record Type: Journal Article
• Authors: Henshaw, Jonathan D; Krumholz, Mark R; Butterfield, Natalie O; Mackey, Jonathan; Ginsburg, Adam; Haworth, Thomas J; Nogueras-Lara, Francisco; Barnes, Ashley T; Longmore, Steven N; Bally, John; Kruijssen, J M Diederik; Mills, Elisabeth A C; Beuther, Henrik; Walker, Daniel L; Battersby, Cara; Bulatek, Alyssa; Henning, Thomas; Ott, Juergen; Soler, Juan D
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 509:Issue 4(2022)
• Page Start: 4758
• Page End: 4774
• Publication Date: 2021-12-17
• Subjects: ISM: bubbles -- ISM: clouds -- H ii regions -- ISM: kinematics and dynamics -- ISM: structure -- Galaxy: centre; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab3039
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: G0.253+0.016, commonly referred to as 'the Brick' and located within the Central Molecular Zone, is one of the densest (≈10 3–4 cm −3 ) molecular clouds in the Galaxy to lack signatures of widespread star formation. We set out to constrain the origins of an arc-shaped molecular line emission feature located within the cloud. We determine that the arc, centred on $\lbrace l_{0}, b_{0}\rbrace =\lbrace 0{_{.}^{\circ}} 248, \, 0{_{.}^{\circ}} 018\rbrace$, has a radius of 1.3 pc and kinematics indicative of the presence of a shell expanding at $5.2^{+2.7}_{-1.9}$ $\mathrm{\, km\, s}^{-1}$ . Extended radio continuum emission fills the arc cavity and recombination line emission peaks at a similar velocity to the arc, implying that the molecular gas and ionized gas are physically related. The inferred Lyman continuum photon rate is N LyC = 10 46.0 –10 47.9 photons s −1, consistent with a star of spectral type B1-O8.5, corresponding to a mass of ≈12–20 M⊙ . We explore two scenarios for the origin of the arc: (i) a partial shell swept up by the wind of an interloper high-mass star and (ii) a partial shell swept up by stellar feedback resulting from in situ star formation. We favour the latter scenario, finding reasonable (factor of a few) agreement between its morphology, dynamics, and energetics and those predicted for an expanding bubble driven by the wind from a high-mass star. The immediate implication is that G0.253+0.016 may not be as quiescent as is commonly accepted. We speculate that the cloud may have produced a ≲10 3 M⊙ star cluster ≳0.4 Myr ago, and demonstrate that the high-extinction and stellar crowding observed towards G0.253+0.016 may help to obscure such a star cluster from detection.