Clustered Star Formation in the Center of NGC 253 Contributes to Driving the Ionized Nuclear Wind
Journal article, 2021

We present new 3 mm observations of the ionized gas toward the nuclear starburst in the nearby (D similar to 3.5 Mpc) galaxy NGC 253. With ALMA, we detect emission from the H40 alpha and He40 alpha lines in the central 200 pc of this galaxy on spatial scales of similar to 4 pc. The recombination line emission primarily originates from a population of approximately a dozen embedded super star clusters in the early stages of formation. We find that emission from these clusters is characterized by electron temperatures ranging from 7000 to 10,000 K and measures an average singly ionized helium abundance Y (+) = 0.25 +/- 0.06, both of which are consistent with values measured for H ii regions in the center of the Milky Way. We also report the discovery of unusually broad line width recombination line emission originating from seven of the embedded clusters. We suggest that these clusters contribute to the launching of the large-scale hot wind observed to emanate from the central starburst. Finally, we use the measured recombination line fluxes to improve the characterization of overall embedded cluster properties, including the distribution of cluster masses and the fractional contribution of the clustered star formation to the total starburst, which we estimate is at least 50%.


E. A. C. Mills

University of Kansas

Mark Gorski

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Extragalactic Astrophysics

K. L. Emig

Leiden University

National Radio Astronomy Observatory

A. D. Bolatto

University of Maryland

Flatiron Institute

R. C. Levy

University of Maryland

A. K. Leroy

Ohio State University

A. Ginsburg

University of Florida

J. D. Henshaw

Max Planck Society

L. K. Zschaechner

University of Helsinki

S. Veilleux

University of Maryland

K. Tanaka

Keio University

D. S. Meier

National Radio Astronomy Observatory Socorro

New Mexico Institute of Mining and Technology

F. Walter

Max Planck Society

N. Krieger

Max Planck Society

J. Ott

National Radio Astronomy Observatory Socorro

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 919 2 105

Subject Categories

Meteorology and Atmospheric Sciences

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics



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