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%.
Author
E. A. C. Mills
University of Kansas
Mark Gorski
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
K. L. Emig
Leiden University
National Radio Astronomy Observatory
A. D. Bolatto
Flatiron Institute
University of Maryland
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
New Mexico Institute of Mining and Technology
F. Walter
Max Planck Society
N. Krieger
Max Planck Society
J. Ott
National Radio Astronomy Observatory
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 919 2 105Subject Categories (SSIF 2011)
Meteorology and Atmospheric Sciences
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
DOI
10.3847/1538-4357/ac0fe8